Nutritional advice

Objectives:
The influence of dietary fat upon breast cancer mortality remains largely understudied despite extensive investigation into its influence upon breast cancer risk. Therefore, this review article has been conducted.

Does higher total fat or saturated fat dietary intake increase risk of breast-cancer-specific death (breast cancer mortality) among women?

Study design:
This review article included 15 prospective cohort studies investigating total fat and/or saturated fat intake (g/day) and breast cancer mortality.

Results and conclusions:
The investigators found there was no difference in risk of breast-cancer-specific death [HR = 1.14, 95% CI = 0.86 to 1.52, p = 0.34, n = 6] or all-cause death [HR = 1.73, 95% CI = 0.82 to 3.66, p = 0.15, n = 4] for women in the highest versus lowest category of total fat dietary intake.
No difference because HR of 1 was found in the 95% CI of 0.82 to 3.66. HR of 1 means no risk/association.

The investigators found for the highest versus lowest category of saturated fat dietary intake, a significantly increased risk of 51% for breast-cancer-specific death among women [HR = 1.51, 95% CI = 1.09 to 2.09, p 0.01 n = 4].
Significant because HR of 1 was not found in the 95% CI of 1.09 to 2.09. HR of 1 means no risk/association.

The investigators concluded that higher saturated fat dietary intake increases risk of breast-cancer-specific death among women.

Original title:
Dietary fat and breast cancer mortality: A systematic review and meta-analysis by Brennan SF, Woodside JV, […], Cantwell MM.

Link:
https://pubmed.ncbi.nlm.nih.gov/25692500/

Additional information of El Mondo:
Find more information/studies on fat consumption and breast cancer right here.

A diet high in saturated fat is a diet with more than 10 En% saturated fat.
The most easy way to follow a diet with more than 10 En% saturated fat is to choose only meals/products with more than 10 En% saturated fat. Check here which products contain more than 10 En% saturated fat.

However, the most practical way to follow a diet with more than 10 En% saturated fat is, all meals/products that you eat on a daily basis should contain on average more than 10 En% saturated fat.

To do this, use the 7-points nutritional profile app to see whether your daily diet contains more than 10 En% saturated fat.

However, a diet with more than 10 En% saturated fat is an unhealthy diet.

A diet low in saturated fat is a diet with maximum 7 En% saturated fat.
 

Objectives:
Fish oil supplementation has been shown to be associated with a lower risk of metabolic syndrome and benefit a wide range of chronic diseases, such as cardiovascular disease, type 2 diabetes and several types of cancers. However, the evidence of fish oil supplementation on glucose metabolism and insulin sensitivity is still controversial. Therefore, this review article (meta-analysis) has been conducted.

Does fish oil supplementation improve insulin sensitivity in humans?

Study design:
This review article included a total of 17 RCTs with 672 participants. One of the 17 studies was crossover design and others were parallel design.
The doses of active ingredients of fish oil (n-3 fatty acids) ranged from 1 g/d to 4 g/d. Duration of the interventions was ranged from 4 weeks to 24 weeks.
There was no suggestion of small study effect based on visual inspection of the funnel plot. Results of the Egger’s (p = 0.78) and Begg’s (p = 0.43) tests showed that there was no potential publication bias.

Results and conclusions:
The investigators found pooled analysis showed that fish oil supplementation had no effects on insulin sensitivity overall [SMD = 0.17, 95% CI = -0.15 to 0.48, p = 0.292, I2 = 58.1%, p = 0.001].

The investigators found subgroup analysis showed that fish oil supplementation significantly improved insulin sensitivity among people who were experiencing at least one symptom of metabolic disorders [SMD = 0.53, 95% CI = 0.17 to 0.88, p 0.001].

The investigators found subgroup analysis showed a positive effect of fish oil on insulin sensitivity among the short-term intervention group (12 weeks) rather than the long-term intervention group [SMD = 0.31, 95% CI = 0.01-0.61, p = 0.04].

The investigators found subgroup analysis showed that fish oil had no effects on insulin sensitivity among the healthy people or people with T2DM.

The investigators found there were no significant differences between subgroups of methods of insulin sensitivity and doses of omega-3 polyunsaturated fatty acids (n-3 PUFA) of fish oil supplementation.

The investigators found in sensitivity analysis that summary results did not differ significantly when omitting studies one at a time.

The investigators concluded that fish oil supplementation during 12 weeks improves insulin sensitivity among people who were experiencing at least one symptom of metabolic disorders.

Original title:
Fish oil supplementation and insulin sensitivity: a systematic review and meta-analysis by Gao H, Geng T, [...], Zhao Q.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5496233/

Additional information of El Mondo:
Find more information/studies on fish oil supplements and diabetes right here.

 

Objectives:
What is the relationship between dietary intake of 12 major food groups, including whole grains, refined grains, vegetables, fruit, nuts, legumes, eggs, dairy, fish, red meat, processed meat and sugar-sweetened beverages and colorectal cancer (CRC) risk?

Study design:
This review article included cohort studies.

Results and conclusions:
The investigators found in the linear dose-response meta-analysis, that every 30 g/d whole grains significantly reduced risk of colorectal cancer with 5% [RR = 0.95, 95% CI = 0.93 to 0.97, n = 9 cohort studies].

The investigators found in the linear dose-response meta-analysis, that every 100 g/d vegetables significantly reduced risk of colorectal cancer with 3% [RR = 0.97, 95% CI = 0.96 to 0.98, n = 15 cohort studies].

The investigators found in the linear dose-response meta-analysis, that every 100 g/d fruit significantly reduced risk of colorectal cancer with 3% [RR = 0.97, 95% CI = 0.95 to 0.99, n = 16 cohort studies]. 

The investigators found in the linear dose-response meta-analysis, that every 200 g/d dairy products significantly reduced risk of colorectal cancer with 7% [RR = 0.93, 95% CI = 0.91 to 0.94, n = 15 cohort studies]. 

The investigators found in the linear dose-response meta-analysis, that every 100 g/d red meat significantly increased risk of colorectal cancer with 12% [RR = 1.12, 95% CI = 1.06 to 1.19, n = 21 cohort studies].

The investigators found in the linear dose-response meta-analysis, that every 50 g/d processed meat significantly increased risk of colorectal cancer with 17% [RR = 1.17, 95% CI = 1.10 to 1.23, n = 16 cohort studies].

The investigators found some evidence for a nonlinear relationship between dietary intake of vegetables, fruit and dairy products and risk of colorectal cancer.

The investigators concluded that daily dietary intake of 30g whole grains, 100g vegetables,100g fruit and 200g dairy products reduce risk of colorectal cancer, while daily dietary intake of 100g red meat and 50g processed meat increase risk of colorectal cancer.

Original title:
Food groups and risk of colorectal cancer by Schwingshackl L, Schwedhelm C, [...], Schlesinger S.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29210053

Additional information of El Mondo:
Find more information/studies on different food groups and colorectal cancer right here.

Objectives:
Carnitine deficiency has been implicated as a potential pathway for cancer-related fatigue that could be treated with carnitine supplementation. Therefore, this review article (meta-analysis) has been conducted.

Does carnitine supplementation reduce cancer-related fatigue?

Study design:
This review article included 3 RCTs involving a total of 659 participants.

There were not enough studies to conduct sensitivity analyses to isolate potential sources of heterogeneity and test the robustness of findings.

Results and conclusions:
The investigators found in 3 RCTs involving a total of 659 participants that carnitine supplementation did not significantly reduce cancer-related fatigue [SMD = 0.06 points, 95% CI = -0.09 to 0.21, p = 0.45, I2 = 0%].
Clinical heterogeneity was evident from these studies in regards to the dose (2-4 g of carnitine per day), patient demographics (40-100% females included) and carnitine status.

The investigators concluded there is no evidence to support the use of carnitine supplementation (2-4 g of carnitine per day) for cancer-related fatigue.

Original title:
Efficacy and Effectiveness of Carnitine Supplementation for Cancer-Related Fatigue: A Systematic Literature Review and Meta-Analysis by Marx W, Teleni L, [...], Isenring E.

Link:
http://www.mdpi.com/2072-6643/9/11/1224/htm

Additional information of El Mondo:
Find more information/studies on carnitine, randomized controlled trials/cohort studies/subgroup analysis and cancer right here.

Objectives:
Previous studies regarding the relationship between carrot intake and risk of urothelial cancer have reported conflicting results. Therefore, this review article (meta-analysis) has been conducted.

Does a high consumption of carrot reduce urothelial cancer risk?

Study design:
This review article included a total of 6 epidemiological studies (4 case-control and 2 cohort studies) with 1,523 urothelial cancer cases.

There was no significant publication bias by Begg's test (p = 0.348) or Egger's test (p = 0.130).

Results and conclusions:
The investigators found overall analysis indicated a significantly reduced risk of 37% for urothelial cancer for high intake of carrot [OR = 0.63, 95% CI = 0.44-0.90, I2 = 79.6%, p 0.001].

The investigators found in the subgroup analysis by study design, a significantly reduced risk of 55% for urothelial cancer in case-control studies [OR = 0.45, 95% CI = 0.25-0.81]. However, this reduced risk was not significant in cohort studies [OR = 0.91, 95% CI = 0.67-1.24].
Not significant because OR of 1 was found in the 95% CI of 0.67 to 1.24. OR of 1 means no risk/association.

The investigators found, when separately analyzed by carrot type, a significantly reduced risk of 31% for cooked carrot [OR = 0.69, 95% CI 0.51-0.94], but the reduced risk was not significant for raw carrot [OR = 0.84, 95% CI = 0.37-1.93].

The investigators found in the stratified analysis by geographical region, a non-significantly reduced risk of 38% [OR = 0.62, 95% CI = 0.37-1.06], a non-significantly reduced risk of 30% [OR = 0.70, 95% CI = 0.29-1.67] and a non-significantly reduced risk of 47% [OR = 0.53, 95% CI = 0.22-1.26] for Europe, Asia and USA, respectively.

The investigators also found a non-significantly reduced risk of 44% [OR = 0.56, 95% CI = 0.27-1.17] and a non-significantly reduced risk of 27% [OR = 0.73, 95% CI = 0.12-4.60] for male and female, respectively.

The investigators concluded that a high intake of carrot might be associated with a low incidence of urothelial cancer. Might be associated because the reduced risk was not significant in cohort studies. Considering the limited included studies and huge heterogeneity, further large well-designed prospective cohort studies are warranted to confirm these findings.

Original title:
Carrot intake and incidence of urothelial cancer: a systematic review and meta-analysis by Luo X, Lu H, [...], Wang S.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5652827/

Additional information of El Mondo:
Find more information/studies on carrot consumption, randomized controlled trials/cohort studies/subgroup analysis and cancer right here.

Objectives:
Surgical resection remains the primary treatment for gastrointestinal (GI) malignancy including early-stage cancer. Omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been reported to have beneficial clinical and immune-modulating effects in the prognosis of gastrointestinal cancer patients undergoing surgery. Therefore, this review article (meta-analysis) has been conducted.

What is the impact of n-3 PUFA supplementation on postoperative inflammation status and immune function of gastrointestinal cancer patients?

Study design:
This review article included a total of 9 RCTs with 623 participants.

The homogeneous test detected no statistical heterogeneity between studies.

There was no evidence of publication bias following assessment by funnel plot, Egger’s test [p > 0.05] and Begg’s test [p > 0.05].

Results and conclusions:
The investigators found the n-3 PUFAs regime significantly resulted in lower levels of C-reactive protein [p 0.05], interleukin-6 [p 0.01] and higher levels of albumin, CD3+ T cells, CD4+ T cells and CD4+/CD8+ ratio [p 0.05] compared with the isocaloric nutrition regime.

The investigators found, however, no significant difference in the level of tumor necrosis factor-α between the n-3 PUFAs regime and the isocaloric nutrition regime [p = 0.17].

The investigators found that the level of CD8 + T cells significantly decreased compared with the isocaloric nutrition regime [p 0.0001].

The investigators concluded that n-3 PUFAs are effective in improving the nutritional status and immune function of gastrointestinal cancer patients undergoing surgery as they effectively enhance immunity and attenuate the inflammatory response. Although further larger trials are needed, these fatty acids should be widely used in the clinic.

Original title:
Effects of omega-3 fatty acids on patients undergoing surgery for gastrointestinal malignancy: a systematic review and meta-analysis by Yu J, Liu L, [...], Yang F.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5391568/

Additional information of El Mondo:
Find more information/studies on n-3 PUFA consumption and cancer right here.
 

Objectives:
The aim of this review article (meta-analysis) is to compare empirically derived dietary patterns in relation to cancer risk.

Study design:
This review article included observational studies, which evaluated the association with cancer risk between a posteriori derived dietary patterns.

Results and conclusions:
The investigators found a significantly 64% increased risk of cancer for the adoption of high-meat compared to plant-based dietary patterns [RR = 1.64, 95% CI = 1.02-2.63].

The investigators found a significantly 12% lower risk of cancer for individuals adopting a plant-based dietary pattern over a mixed one [RR = 0.88, 95% BI = 0.82-0.95].

The investigators concluded that plant-based dietary patterns decrease cancer risk; meanwhile meat-based dietary patterns increase cancer risk.

Original title:
Differences in the association between empirically derived dietary patterns and cancer: a meta-analysis by Bella F, Godos J, […], Sciacca S.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/27894200

Additional information of El Mondo:
Find more information/studies on veganism and cancer right here.
 

Objectives:
The potential glucose-lowering effects of pomegranate have been reported in animal and observational studies, but intervention studies in humans have generated mixed results. Therefore, this review article (meta-analysis) has been conducted.

What are the effects of pomegranate supplementation on measures of glucose control, insulin levels and insulin sensitivity in humans?

Study design:
This review article included 16 RCTs with 538 subjects. 14 trials adopted parallel study designs and the 2 remaining trials used crossover designs.
The total number of subjects included in each study ranged from 14 to 74 subjects.
The mean age of participants in each trial ranged from 30 to 70 years, with differing age ranges in most studies.
11 studies used pomegranate juice as a supplement (the dosage ranged from 120 to 500 ml/day).
2 studies used pomegranate seed oil as treatments (the dosage ranged from 400 to 2000 mg/day).
3 studies utilized pomegranate extract as the intervention (the dosage ranged from 710 to 1420 mg/day).  
The duration of the pomegranate intervention varied from 1 to 12 weeks (median: 5.5 weeks).

Overall, significant heterogeneity was detected for FBI and HOMA-IR, but subgroup analysis could not identify factors significantly influencing these parameters.
No significant publication bias was found.

Results and conclusions:
The investigators found that pomegranate did not significantly affect the measures of:
-FBG (fasting blood glucose) [WMD = -0.6 mg/dL, 95% CI = -2.79 to 1.58, p = 0.59, I2 = 0%];
-FBI (fasting blood insulin) [WMD = 0.29 μIU/mL, 95% CI = -1.16 to 1.75, p = 0.70, I2 = 60.4%];
-HOMA-IR (homeostatic model assessment of insulin resistance) [WMD = -0.04, 95% CI = -0.53 to 0.46, p = 0.88, I2 = 59.8%] or;
-HbA1c (glycated haemoglobin) [WMD = -0.11%, 95% CI = -0.39 to 0.18, p = 0.46, I2 = 0%].
These results were robust in sensitivity analysis.

The investigators found meta-regression analysis showed that the factor (dose of pomegranate juice supplementation) was not associated with the treatment effects on FBG level [coefficient = -0.006, 95% CI = -0.023 to 0.011, p = 0.46].

The investigators found no significant difference in the FBG-lowering effect between trials that were conducted in subjects with cardiovascular disease risk [WMD = 0.30 mg/dL, 95% CI = -2.36 to 2.97, p = 0.82] and those that were conducted in healthy individuals [WMD = -2.53 mg/dL, 95% CI = -6.36 to 1.30, p = 0.19].

The investigators found no statistically significant differences in the pooled effects of pomegranate on FBG in the subgroups stratified by study designs, intervention durations, types of intervention, baseline BMI and baseline FBG levels (FBG levels at the beginning of the studie).

The investigators concluded pomegranate supplements have no favourable effect on improvements in glucose and insulin metabolism. The current evidence suggests that daily pomegranate supplementation is not recommended as a potential therapeutic strategy in glycemic management. Further large-scale RCTs with longer duration are required to confirm these results.

Original title:
Lack of efficacy of pomegranate supplementation for glucose management, insulin levels and sensitivity: evidence from a systematic review and meta-analysis by Huang H, Liao D, […], Zhu Y.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5629805/

Additional information of El Mondo:
Find more information/studies on fruit consumption and diabetes right here.
 

Objectives:
Increasing evidence suggests that high consumption of meat is linked to lung cancer but the previous meta-analyses did not properly address the role of tobacco smoking as a potential confounder. Therefore, this review article (meta-analysis) has been conducted.

Does high consumption of meat increase lung cancer risk among never and non-smokers?

Study design:
This review article included 14 independent observational studies and a total of 5,368 subjects with lung cancer.
There was no indication of publication bias.

Results and conclusions:
The investigators found in 11 studies, a statistically significant 24% increased risk of lung cancer for high consumption of red meat [Summary Relative Risk = 1.24, 95% CI = 1.01-1.51, I2 = 31%].

The investigators found no significant associations between high consumption of other types of meat, fish or for heterocyclic amines and lung cancer risk.

The investigators found no significant risk estimates for the increase of one serving per week of any type of meat or fish.

The investigators concluded a high intake of red meat increases the risk of lung cancer among never and non-smokers.

Original title:
Carcinogenicity of High Consumption of Meat and Lung Cancer Risk Among Non-Smokers: A Comprehensive Meta-Analysis by Gnagnarella P, Caini S, […], Gandini S.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29016198

Additional information of El Mondo:
Find more information/studies on meat consumption, randomized controlled trials/cohort studies/subgroup analysis and cancer right here.

According to international recommendations, adults should aim to have a maximum of 70g red meat per day or 500g per week (cooked weight).
 

Objectives:
Several studies have investigated the relationship between serum selenium concentration and cervical cancer, but the results were inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Do high serum selenium levels reduce risk of cervical cancer among women?

Study design:
This review article included 12 studies investigating the association by univariate analysis and 5 studies by multivariate analysis.

Results and conclusions:
The investigators found in univariate analysis, that serum selenium levels in women with cervical cancer were significantly lower than in women without cervical cancer [SMD = -4.86, 95% CI = -6.03 to -3.69]. Subgroup analysis showed consistent results.

The investigators found in multivariate analysis, that serum selenium levels in women with cervical cancer were significantly lower than in women without cervical cancer [OR = 0.55, 95% CI = 0.42-0.73].

The investigators found after treatment, the serum selenium levels increased significantly [SMD = 2.59, 95% CI = 0.50-4.69].

The investigators concluded high serum selenium levels reduce risk of cervical cancer among women.

Original title:
Serum Selenium Levels and Cervical Cancer: Systematic Review and Meta-Analysis by He D, Wang Z, […], Chen D.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28255860

Additional information of El Mondo:
Find more information/studies on selenium, randomized controlled trials/cohort studies/subgroup analysis and cancer right here.

Univariate analysis is the simplest form of analyzing data. "Uni" means "one", thus in other words your data has only one variable.

High serum selenium levels can be obtained by consuming selenium-rich food items and/or taking selenium supplements.
 

Objectives:
Do patients with type 2 diabetes benefit from a low carbohydrate diet?

Study design:
This review article included a total of 9 RCTs with 734 patients with type 2 diabetes.

Results and conclusions:
The investigators found that low carbohydrate diet significantly reduced HbA1c level [WMD = -0.44, 95% CI = -0.61 to -0.26, p= 0.00] of patients with type 2 diabetes.

The investigators found that low carbohydrate diet significantly reduced triglycerides concentration [WMD = -0.33, 95% CI = -0.45 to -0.21, p = 0.00] of patients with type 2 diabetes.

The investigators found that low carbohydrate diet significantly increased HDL cholesterol concentration (WMD = 0.07, 95% CI = 0.03 to 0.11, p = 0.00] of patients with type 2 diabetes.

The investigators found that low carbohydrate diet was not associated with decreased level of total cholesterol and LDL cholesterol.

The investigators found subgroup analyses showed that short term intervention of low carbohydrate diet was effective for weight loss [WMD = -1.18, 95% CI = -2.32 to -0.04, p = 0.04] in patients with type 2 diabetes.

The investigators concluded there is a beneficial effect of low carbohydrate diet intervention on glucose control in patients with type 2 diabetes. The low carbohydrate diet intervention also has a positive effect on triglycerides and HDL cholesterol concentrations, but without significant effect on long term weight loss.

Original title:
Efficacy of low carbohydrate diet for type 2 diabetes mellitus management: A systematic review and meta-analysis of randomized controlled trials by Meng Y, Bai H, […], Chen L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28750216

Additional information of El Mondo:
Find more information/studies on carbohydrates and diabetes right here.

A low carbohydrate diet is a diet that is largely made up of meals/products with 20-40 En% carbohydrate. Practically, this means that all meals/products that you eat on a daily basis should on average contain 20-40 En% carbohydrate.
20-40 En% carbohydrate means that the total amounts of carbohydrate make up for a 20-40% of the total kcal of the diet. Check here which products contain 20-40 En% carbohydrate.

Objectives:
Several epidemiological studies have suggested that vitamin E could reduce the risk of uterine cervical neoplasm. However, controversial data were presented by different reports. Therefore, this review article (meta-analysis) has been conducted.

Do both high vitamin E intake and circulating vitamin E levels reduce risk of uterine cervical neoplasm?

Study design:
This review article included 15 case-control studies, involving 3,741 cases (those with uterine cervical neoplasm) and 6,328 controls (those without uterine cervical neoplasm).

There was no obvious publication bias.

Results and conclusions:
The investigators found in pooled analysis that the highest intake of vitamin E significantly reduced risk of cervical neoplasia with 42% [OR = 0.58, 95% CI = 0.47-0.72, I2 = 83%]. In addition, both vitamin E intake and blood levels of vitamin E were negatively correlated with cervical neoplasia risk.

The investigators found in subgroup analysis that the highest intake of dietary vitamin E significantly reduced risk of cervical neoplasia with 32% [OR = 0.68, 95% CI = 0.49-0.94, I2 = 70%].

The investigators found in subgroup analysis that the highest vitamin E blood levels significantly reduced risk of cervical neoplasia with 48% [OR = 0.52, 95% CI = 0.40-0.69, I2 = 86%].

The investigators found in subgroup analysis that vitamin E significantly reduced risk of cervical neoplasia with 40% [OR = 0.60, 95% CI = 0.45-0.78, I2 = 84%] in studies conducted in America and Europe.

The investigators found in subgroup analysis that the highest intake of vitamin E significantly reduced risk of cervical neoplasia with 46% [OR = 0.54, 95% CI = 0.39-0.76, I2 = 75%] in studies conducted in Asia.

The investigators found subgroup analysis stratified by different types of cervical neoplasm indicated that the highest intake (or serum level) of vitamin E significantly decreased risk of cervical cancer with 47% [OR = 0.53, 95% CI = 0.390.73, I2 = 77%] and cervical intraepithelial neoplasia (CIN) with 46% [OR = 0.54, 95% CI = 0.43-0.70, I2 = 79%]. Meanwhile, sensitivity analysis to assess the influence of each single study on the pooled ORs by omitting a research in each turn, showed combined ORs were not substantially different, indicating that the results of this meta-analysis were stable and reliable.

The investigators concluded that both vitamin E intake and circulating vitamin E levels could reduce cervical neoplasia risk, including cervical cancer and cervical intraepithelial neoplasia. In other words, sufficient supplementation of vitamin E might reduce the risk of cervical neoplasia. However, more randomized controlled trials and cohort studies with high quality are required to further validate this inverse relationship.

Original title:
Effect of vitamin E supplementation on uterine cervical neoplasm: A meta-analysis of case-control studies by Hu X, Li S, [...], Zhu X.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5567498/

Additional information of El Mondo:
Find more information/studies on vitamin E, randomized controlled trials/cohort studies/subgroup analysis and cancer right here.

Higher intake of vitamin E is an intake which covers the recommended daily allowance of vitamin E of at least 1 day.

Objectives:
Dietary fat may play a role in lung carcinogenesis. Findings from epidemiologic studies, however, remain inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Is there an association between dietary fat intake and the risk of lung cancer?

Study design:
This review article included 10 prospective cohort studies with a total of 1,445,850 participants, of which 18,822 incident cases (subjects with lung cancer).

The mean follow-up was 9.4 years. 

Results and conclusions:
The investigators found high intakes of total fat were associated with a 7% significant increased risk of lung cancer [for highest v lowest quintile: HR = 1.07, 95% CI = 1.00 to 1.15].

The investigators found high intakes of saturated fat were associated with a 14% significant increased risk of lung cancer [for highest v lowest quintile: HR = 1.14, 95% CI = 1.07 to 1.22].

The investigators found high intakes of saturated fat were associated with a 23% significant increased risk of lung cancer among current smokers [for highest v lowest quintile: HR = 1.23, 95% CI = 1.13 to 1.35, p for trend 0.001].

The investigators found high intakes of saturated fat were associated with a 61% significant increased risk of squamous cell lung cancer [for highest v lowest quintile: HR = 1.61, 95% CI = 1.38 to 1.88].

The investigators found high intakes of saturated fat were associated with a 40% significant increased risk of small cell carcinoma lung cancer [for highest v lowest quintile: HR = 1.40, 95% CI = 1.17 to 1.67].

The investigators found a high intake of polyunsaturated fat was associated with a 8% significant decreased risk of lung cancer [for highest v lowest quintile: HR = 0.92, 95% CI = 0.87 to 0.98, p for trend = 0.02].

The investigators found a 5% energy substitution of saturated fat with polyunsaturated fat was associated with a 16% and 17% lower risk of small cell and squamous cell carcinoma, respectively.

The investigators found no associations for monounsaturated fat.

The investigators concluded that high intakes of polyunsaturated fat decrease risk of lung cancer, while high intakes of saturated fat increase risk of lung cancer, particularly among smokers and for squamous cell and small cell carcinoma.

Original title:
Dietary Fat Intake and Lung Cancer Risk: A Pooled Analysis by Yang JJ, Yu D1, […], Shu XO.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28742456

Additional information of El Mondo:
Find more information/studies on fat and cancer right here.

A daily diet with high intakes of saturated fat is a diet that is largely made up of meals/products with more than 10 En% saturated fat, with a small part of meals/products with less than 10 En% saturated fat. Practically, this means that all meals/products that you eat on a daily basis should contain on average more than 10 En% saturated fat.
Check here which products contain more than 10% En% saturated fat.

A daily diet with low intakes of saturated fat is a diet that is largely made up of meals/products with less than 7 En% saturated fat, with a small part of meals/products with more than 7 En% saturated fat. Practically, this means that all meals/products that you eat on a daily basis should contain on average less than 7 En% saturated fat.
Check here which products contain less than 7% En% saturated fat.

Objectives:
Polyunsaturated fats (PUFAs) have been shown to reduce type 2 diabetes (T2DM) risk and improve insulin responsiveness in T2DM subjects, but whether the plant sources of omega-3 PUFA (alpha-linolenic acid [ALA]) have an effect on glycemic control requires further investigation. Therefore, this review article (meta-analysis) has been conducted.

Does alpha-linolenic acid dietary intake reduce diabetes risk?

Study design:
This review article included a total of 8 RCTs involving 212 participants with type 2 diabetes.
5 trials (62.5%) were parallel designs and 3 (37.5%) were crossover designs.
Participants were generally middle-aged (median age  =  54 years, range  =  47-64 years) and overweight or obese (median BMI  =  30.7, range  =  28.0-33.2).
Overall, participants had controlled diabetes (median HbA1c = 6.8%, median FBG = 7.95 mmol/L) and the majority of studies indicated the use of hypoglycemic drugs or other medications, although all studies excluded the use of insulin therapy.
The dose of ALA ranged from 1.5 to 7.4 g/day with a median assigned dose of 4.4, 5.4 and 5.4 g/day of ALA for trials that reported HbA1c, FBG and FBI, respectively.
The median duration of the treatment was 3 months, ranging from 2 to 12 months.
7 studies (87.5%) were considered high quality (MQS ≥8).

Results and conclusions:
The investigators found compared to a control diet, a median dose of 4.4 g/day of alpha-linolenic acid intake for a median duration of 3 months did not affect HbA1c (%) of patients with type 2 diabetes [MD =  -0.01, 95% = -0.32 to 0.31, p  =  0.96].

The investigators found compared to a control diet, a median alpha-linolenic acid dose of 5.4 g/day did not lower fasting blood glucose (FBG) of patients with type 2 diabetes [MD  = 0 .07, 95% CI = -0.61 to 0.76, p  = 0 .84] or fasting blood insulin (FBI) of patients with type 2 diabetes [MD  =  7.03, 95% CI = -5.84 to 19.89, p  = 0 .28].

The investigators found summary effect estimates were generally compromised by considerable and unexplained heterogeneity [I2 ≥ 75%].

The investigators found in the subgroup analysis of continuous predictors, a reduction in HbA1c (%) and FBG (mmol/L) was significantly associated with an increased intake of ALA.

The investigators found further adjustment for publication bias using Duval and Tweedie's trim-and-fill analysis provided an adjusted, significant MD of 0.25 [95% CI = -0.38 to -0.12, 0.001) for HbA1c (%).

The investigators concluded alpha-linolenic acid-enriched diet with a median alpha-linolenic acid dose of 4.4 g/day during 3 months has no effects on HbA1c, FBG or FBI in patients with type 2 diabetes. The scarce number of existing RCTs and the presence of heterogeneity in the meta-analysis limit the ability to make firm conclusions about alpha-linolenic acid in type 2 diabetes management. The potential for alpha-linolenic acid to have dose-dependent effects warrants further research in this area.

Original title:
The effect of alpha-linolenic acid on glycemic control in individuals with type 2 diabetes: A systematic review and meta-analysis of randomized controlled clinical trials by Jovanovski E1, Li D, […], Vuksan V.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5457843/

Additional information of El Mondo:
Find more information/studies on PUFA and diabetes right here.

4.4 g/day alpha-linolenic acid can be achieved by taking 1 to 2 tablespoons of flax or salba-chia seeds or about 12 whole walnuts per day.

 

Objectives:
Recently, several randomized controlled trials (RCTs) reported the association between the use of vitamin or antioxidant supplements and the risk of bladder cancer. However, those findings remain inconsistent and some studies even reported that vitamin and antioxidant supplements increased the risk of bladder cancer. Therefore, this review article (meta-analysis) has been conducted.

Is there an association between the use of vitamin or antioxidant supplements and the risk of bladder cancer?

Study design:
This review article included 14 RCTs with a total of 147,383 participants, which involved 89,972 in the supplement group and 57,411 in the control group.

The supplementation and follow-up periods ranged between 1 and 13 years.

The types of vitamin and antioxidant supplements were as follows: vitamin A, vitamin B6, vitamin C, vitamin D, vitamin E, beta-carotene, folic acid and selenium.
The dosage regimens in individual trials were as follows: vitamin A (200 mg or 25,000, 36,000 or 40,000 IU daily), vitamin B6 (25 or 100 mg daily), vitamin C (2,000 mg daily), vitamin D (1,600 IU daily), vitamin E (50 mg or 400 IU daily), beta-carotene (20 or 30 mg daily; 50 mg alternate day; 75 mg daily for 3-month cycles), folic acid (1.6 mg daily) and selenium (200 μg daily).

Publication bias was not observed [Begg's funnel plot, symmetrical and Egger's test, p for bias = 0.378].

Results and conclusions:
The investigators found in fixed-effect meta-analysis of all 14 trials that vitamin or antioxidant supplementation was not associated with the risk of bladder cancer [RR = 1.04, 95% CI = 0.92-1.17, I2 = 39.7%].

The investigators found regarding types of supplements, any type of vitamin and antioxidant supplements had no beneficial effect on the risk of bladder cancer:
-vitamin A [RR = 0.86, 95% CI = 0.65-1.13, I2 = 61.7%, n = 5];
-vitamin B6 [RR = 0.77, 95% CI = 0.49-1.20, I2 = 78.8%, n = 3];
-vitamin C [RR = 0.74, 95% CI = 0.36-1.54, I2 = 88.8%, n = 2];
-vitamin D [RR = 1.05, 95% CI = 0.85-1.29, n = 1];
-vitamin E [RR = 0.91, 95% CI = 0.69-1.19, I2 = 60.9%, n = 6];
-beta-carotene [RR = 1.19, 95% CI = 0.96-1.46, I2 = 0.0%, n = 6];
-folate [RR = 1.05, 95% CI = 0.85-1.29, n = 1] and
-selenium [RR = 1.09, 95% CI = 0.81-1.46, I2 = 0.0%, n = 2].

The investigators found overall, there was no significant effect of vitamin and antioxidant supplements in the subgroup meta-analyses by various factors such as dose of supplements, type of cancer prevention, methodological quality, duration of treatment, provider of supplements, type of control and number of participants.
However, the risk of bladder cancer was marginally increased in trials with the use of beta-carotene alone [RR = 1.44, 95% CI = 1.00-2.09, I2 = 0.0%, n = 3].

The investigators concluded that vitamin and antioxidant supplements have no overall preventive effect against bladder cancer. Instead, subgroup meta-analyses showed that beta-carotene supplementation marginally increased the risk of bladder cancer. Even though further large, high-quality trials are required to confirm these associations, the effects (either beneficial or harmful) of vitamin or antioxidant supplements on bladder cancer should not be overemphasized.

Original title:
Effects of Vitamin and Antioxidant Supplements in Prevention of Bladder Cancer: a Meta-Analysis of Randomized Controlled Trials by Park SJ, Myung SK, […], Lee YJ.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5334161/

Additional information of El Mondo:
Find more information/studies on vitamins, selenium, beta-carotene, antioxidants and cancer right here.

Objectives:
Protective effects of calcium supplementation against colorectal adenomas have been documented in systematic reviews; however, the results have not been conclusive. Therefore, this review article (meta-analysis) has been conducted.

Does calcium supplementation reduce colorectal adenomas?

Study design:
This review article included 5 RCTs involving 2,234 patients with a history of adenomas.
Based on visual inspection of the funnel plots as well as on quantitative measurement that used the Egger regression test, there was weak evidence of publication bias.
No major serious adverse events were associated with the use of calcium, but there was an increase in the incidence of hypercalcemia [p  = 0 .0095].
Random errors were evaluated with trial sequential analyses (TSAs). However, TSA indicated a lack of firm evidence for a beneficial effect of calcium supplementation.

Results and conclusions:
The investigators found quantitative pooling of results from all 5 RCTs indicated that the use of supplemental calcium lasting 3 to 5 years showed a statistically significant 17% reduction in risk of any recurrent colorectal adenomas [RR = 0.83, 95% CI = 0.75-0.93, I2  =  8.5%, p  =  0.36].

The investigators found in the sensitivity analysis of 3 trials with low bias risk a statistically significant 12% reduction in the recurrence of any colorectal adenomas [RR = 0.88, 95% CI = 0.79-0.99, I2  =  0%, p  =  0.54] in patients who were administered supplemental calcium versus placebo.

The investigators found no association between supplemental calcium and recurrence of advanced colorectal adenomas in trials with low risk of bias [RR = 1.02, 95% CI = 0.67-1.55, I2 =  17.5%].

The investigators found in the subgroup analysis of 3 trials with elemental calcium dose ≤ 1200 mg/day, a statistically significant 16% reduction in the recurrent of any colorectal adenomas [RR = 0.84, 95% CI = 0.73-0.97, I2  =  38.5%, p  = 0 .19].

However, a greater reduction of 26% [RR = 0.74, 95% CI = 0.56-0.97, I2  =  0%, p  = 0 .70] was observed in the subgroup analysis of 2 trials with elemental calcium dose ≥ 1600 mg/day.
Subgroup analyses demonstrated no statistically significant association with the reduction of advanced colorectal adenomas in any doses.

The investigators concluded the available good quality RCTs suggests a possible beneficial effect of calcium supplementation – preferably at least 1600 mg/day elemental calcium – on the recurrence of colorectal adenomas. However, TSA indicated that the accumulated evidence is still inconclusive. Therefore, large well-designed randomized trials with low risk of bias are needed.

Original title:
Effects of calcium on the incidence of recurrent colorectal adenomas: A systematic review with meta-analysis and trial sequential analysis of randomized controlled trials by Veettil SK, Ching SM, […], Chaiyakunapruk N.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5556213/

Additional information of El Mondo:
Find more information/studies on calcium and colorectal cancer right here.

Colorectal adenomas can lead to colorectal cancer.

Objectives:
With only 5-10% of breast cancer cases attributed to genetic inheritance, prevention efforts have focused on modifiable risk factors. Physical activity plays a role in reducing breast cancer risk; however, the interaction between physical activity and other modifiable risk factors, such as obesity, has received little attention. Therefore, this review article (meta-analysis) has been conducted.

What is the relationship between physical activity and breast cancer and how it may be modified by body mass index (BMI)?

Study design:
This review article included 18 cohort and 11 case-control studies.

Results and conclusions:
The investigators found overall, a significant reduction of 15% for breast cancer risk in postmenopausal women with a BMI 25 kg/m² for high versus low levels of physical activity [RR = 0.85, 95% CI = 0.79-0.92]. 

The investigators found overall, a significant reduction of 13% for breast cancer risk in postmenopausal women with a BMI ≥25 kg/m² for high versus low levels of physical activity for women [RR = 0.87, 95% CI = 0.81-0.93]. 

The investigators found overall, a non-significant reduction of 7% for breast cancer risk in postmenopausal women with a BMI ≥30 kg/m² for high versus low levels of physical activity for women [RR = 0.93, 95% CI = 0.76-1.13]. 

The investigators found, however, physical activity was not associated with a significant reduction in risk of breast cancer in premenopausal women in any BMI group.

The investigators concluded high levels of physical activity reduce risk of breast cancer in postmenopausal women with a BMI until 30. Since the included studies used diverse methods for assessment of physical activity and categories of BMI, results should be interpreted with caution and additional work is needed.

Original title:
Does obesity modify the relationship between physical activity and breast cancer risk? by Neil-Sztramko SE, Boyle T, […], Campbell KL.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28803384

Additional information of El Mondo:
Find more information/studies on breast cancer, BMI and physical activity right here.

Objectives:
In the 2007 World Cancer Research Fund/American Institute for Cancer Research Second Expert Report, the expert panel judged that there was strong evidence that alcoholic drinks and body fatness increased esophageal cancer risk, whereas fruits and vegetables probably decreased its risk. The judgments were mainly based on case-control studies. As part of the Continuous Update Project (CUP), this review article (meta-analysis) has been conducted.

What is the relationship between nutrition and esophageal cancer risk?

Study design:
This review article included a total of 57 cohort studies, used in previous 13 meta-analyses.

Results and conclusions:
The investigators found a significant reduced risk of 11% for esophageal adenocarcinoma for every increment of 100g/day vegetable intake [RR = 0.89, 95% CI = 0.80-0.99, n = 3].

The investigators found a significant increased risk of 47% for esophageal adenocarcinoma for every 5 unit increment in BMI [RR = 1.47, 95% CI = 1.34-1.61, n = 9].

The investigators found a significant reduced risk of 16% for esophageal squamous cell carcinoma for every increment of 100g/day fruit intake [RR = 0.84, 95% CI = 0.75-0.94, n = 3].

The investigators found a significant reduced risk of 36% for esophageal squamous cell carcinoma for every 5 unit increment in BMI [RR = 0.64, 95% CI = 0.56-0.73, n = 8].

The investigators found a significant increased risk of 59% for esophageal squamous cell carcinoma for every increment of 50g/day processed meat intake [RR = 1.59, 95% CI = 1.11-2.28, n = 3].

The investigators found a significant increased risk of 37% for esophageal squamous cell carcinoma for every increment of 100g/day processed and red meat intake [RR = 1.37, 95% CI = 1.04-1.82, n = 3].

The investigators found a significant increased risk of 25% for esophageal squamous cell carcinoma for every increment of 10g/day alcohol intake [RR = 1.25, 95% CI = 1.12-1.41, n = 6].

The investigators concluded evidence from cohort studies shows a protective role of vegetables and body weight control in esophageal adenocarcinomas development. For squamous cell carcinomas, higher intakes of red and processed meats and alcohol increase the risk, whereas fruits intake has a protective role.

Original title:
An update of the WCRF/AICR systematic literature review and meta-analysis on dietary and anthropometric factors and esophageal cancer risk by Vingeliene S, Chan DSM, […], Norat T.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28666313

Additional information of El Mondo:
Find more information/studies on vegetable, fruit, alcohol and meat consumption, significant/cohort/95% CI and cancer right here.
 

Objectives:
The relationship between intake of fish and n-3 fatty acids and endometrial cancer risk has not been consistent across epidemiological studies. Therefore, this review article (meta-analysis) has been conducted.

Do fish consumption and dietary EPA and DHA intake reduce endometrial cancer risk?

Study design:
This review article included 4 prospective cohort studies, 1 case-cohort study and 11 case-control studies (including 8 population-based case-control studies and 3 hospital-based case-control studies).
The prospective cohort studies had a mean follow-up of 6.5 to 9.1 years.
The highest category of fish ranged from >1-2 servings/week to >15.4 servings/week,
The highest category of DHA ranged from 143 to 227 mg/d.
The highest category of EPA ranged from 74.7 to 127 mg/d.

When fish intake was reported in unit of g/d, it was converted to serving/week by assuming 1 serving = 100g.
Overall, all 16 studies were classified as high-quality studies.
There was no publication bias.

Results and conclusions:
The investigators found a non-significant association between the highest vs. lowest category of fish consumption and endometrial cancer risk [RR = 1.04, 95% CI = 0.84-1.30, I2 = 80.4%].
According to the subgroup analyses, the null association persisted in strata according to study design, location, type of controls, number of cases, publication year and adjustments of energy intake, reproductive factors and smoking.

The investigators found in subgroup analyses for every one additional serving/week of fish intake, a significant reduced risk of 10% for endometrial cancer in studies conducted in Europe [RR = 0.90, 95% CI = 0.84-0.97]. Significant means that there is an association with a 95% confidence.

The investigators found in subgroup analyses for every one additional serving/week of fish intake, a significant increased risk of 15% for endometrial cancer in studies conducted in Asia [RR = 1.15, 95% CI = 1.10-1.21]. Significant because RR of 1 was not found in the 95% CI of 1.10 to 1.21. RR of 1 means no risk/association.

The investigators found in studies adjusting for smoking for every one additional serving/week of fish intake, a significant reduced risk of 5% for endometrial cancer [RR = 0.95, 95% CI = 0.91-1.00].

The investigators found in studies without an adjustment of smoking for every one additional serving/week of fish intake, a significant increased risk of 14% for endometrial cancer [RR = 1.14, 95% CI = 1.09-1.19].

The investigators found a non-significant inverse association between the highest category of DHA intake and endometrial cancer risk [RR = 0.85, 95% CI = 0.64-1.11, I2 = 59.6%]. However, the dose-response analysis suggested a significant non-linear relationship between DHA intake and endometrial cancer risk [p = 0.04 and p for heterogeneity = 0.39], with a decreased risk being detected for an intake of DHA no more than 175 mg/d.

The investigators concluded that there is a significant inverse association between every one additional serving/week of fish intake and endometrial cancer risk in studies conducted in Europe and studies adjusted for smoking. Furthermore, there is a significant non-linear relationship between DHA intake and risk of endometrial cancer, with a decreased risk being detected for an intake of DHA no more than 175 mg/d. Further well-designed studies are warranted to better characterize the relationship between fish, n-3 PUFA and endometrial cancer development.

Original title:
Dietary n-3 polyunsaturated fatty acids, fish consumption, and endometrial cancer risk: a meta-analysis of epidemiological studies by Hou R, Yao SS, […], Jiang L.

Link:
http://www.impactjournals.com/oncotarget/index.php?journal=oncotarget&page=article&op=view&path[]=18295&path[]=58664

Additional information of El Mondo:
Find more information/studies on fish consumption, significant/cohort/95% CI and cancer right here.
These fish contain 175 mg DHA.
 

Objectives:
Although several epidemiological studies have investigated the association between dietary calcium intake and the risk of esophageal cancer, the results are inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Does dietary calcium intake reduce risk of esophageal cancer?

Study design:
This review article included 3 cohort studies and 14 case-control studies, including 3,396 cases (subjects with esophageal cancer) and 346,815 controls (subjects without esophageal cancer).

Egger’s test showed no evidence of significant publication bias.

The sample size was large enough to evaluate the effect of calcium intake on esophageal cancer.

A dose-response effect analysis could not be performed due to the incomplete data of dietary calcium intake.

The average of highest dietary calcium intake in Asian populations was 621 mg/day.

Results and conclusions:
The investigators found for highest vs. lowest dietary calcium intake a significant reduced risk of 20% for esophageal cancer [pooled OR = 0.80, 95% CI = 0.71-0.91, I2 = 33.6%].
This significant reduced risk was also found in studies conducted in Asia [OR = 0.67, 95% CI = 0.52-0.86, I2 = 0.0%], studies published after 2000 [OR = 0.64, 95% CI = 0.53-0.77, I2 = 0.0%), studies adjusted for dietary energy intake [OR = 0.83, 95% CI = 0.70-0.98, I2 = 3.6%], studies of esophageal squamous cell carcinoma [OR = 0.76, 95% CI = 0.60-0.96, I2 = 28.3%], cohort studies [OR = 0.67, 95% CI = 0.54-0.84, I2 = 23.6%] and studies with high quality score [OR = 0.76, 95% CI = 0.66-0.87, I2 = 12.7%].

The investigators found in sensitivity analysis (conducted by leaving one study out in turn and pooling the ORs of the remaining studies) the summary ORs did not substantially change, which indicated that the results were statistically robust.

The investigators concluded that a higher intake (621 mg/day) of dietary calcium has protective effect against esophageal cancer - especially esophageal squamous cell cancer - in Asian populations. To further solidify the association of dietary calcium intake with the risk of esophageal cancer, well-designed studies - especially prospective cohort studies with validated FFQ and adjusted for dietary energy intake - should be conducted.

Original title:
Protective Effect of Dietary Calcium Intake on Esophageal Cancer Risk: A Meta-Analysis of Observational Studies by Li Q, Cui, L, […], Wang L.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5452240/

Additional information of El Mondo:
Find more information/studies on calcium, significant/cohort/95% CI and cancer right here.
 

Objectives:
It has been unclear whether supplemental probiotics therapy improves clinical outcomes in type 2 diabetic patients. Therefore, this meta-analysis (systematic review) has been conducted.

Do probiotics supplements improve clinical outcomes in type 2 diabetic patients?

Study design:
This review article included 12 RCTs involving 684 type 2 diabetic patients.

Results and conclusions:
The investigators found a significant decreased glucose level in the probiotics group [pooled standardized mean difference = -0.18 mg/dL, 95% CI = -0.35 to -0.01, p = 0.04, I2 = 64%, p = 0.004] compared to the control group.

The investigators found a significant reduction in HbA1c in the probiotics group [pooled standardized mean difference = -0.38%, 95% CI = -0.62 to -0.14, p = 0.002, I2 = 0%, p = 0.72] compared to the control group.

The investigators found a significant reduction in fasting insulin level in the probiotics group [pooled standardized mean difference = -0.38, 95% CI = -0.59 to -0.18, p = 0.003, I2 = 0%, p = 0.81] compared to the control group.

The investigators found a significant reduced HOMA-IR level in the probiotics group [pooled standardized mean difference = -0.99, 95% CI = -1.52 to -0.4, p = 0.0002, I2 = 86%, p 0.00001] compared to the control group.

The investigators found a significant reduced CRP level in the probiotics group [pooled standardized mean difference = -1.34 mg/L, 95% CI = -1.76 to -0.92, p 0.00001, I2 = 90%, p 0.00001] compared to the control group.

The investigators found a non-significant reduction in both triglyceride levels [SMD = -0.23, 95% CI = -0.48 to 0.02, p = 0.07, I2 = 52%, p = 0.03] and cholesterol levels [total cholesterol: SMD = -0.18, 95% CI = -0.42 to 0.06, p = 0.14, I2 = 47%, p = 0.05 and LDL-cholesterol: SMD = -0.03, 95% CI = -0.20 to 0.14, p = 0.73, I2 = 3%, p = 0.41] in the probiotics group compared to the control group.

The investigators concluded that probiotics supplementation is associated with significant improvement in HbA1c and fasting insulin in type 2 diabetes patients. These results may provide evidence for encouraging use of probiotics in patients with type 2 diabetes mellitus. However, more randomized placebo-controlled trials with larger sample sizes are warranted to confirm these findings.

Original title:
Effect of Probiotics on Glucose and Lipid Metabolism in Type 2 Diabetes Mellitus: A Meta-Analysis of 12 Randomized Controlled Trials by Yao K, Zeng L, [...], Zou X.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5491138/

Additional information of El Mondo:
Find more information/studies on probiotics and diabetes right here.

Objectives:
There have been inconsistent results about the association between consumption of fruits and vegetables and renal cell carcinoma (RCC) risk. Therefore, this review article (meta-analysis) has been conducted.

Does consumption of fruits and vegetables reduce renal cell carcinoma risk?

Study design:
This review article included 19 observational studies (4 cohort, 1 pooled and 14 case-control studies), involving 10,215 subjects with renal cell carcinoma.

Only 4 studies adjusted for all the 3 main risk factors for renal cell carcinoma (16 studies adjusted for tobacco smoking, 15 for BMI and 4 for hypertension).
The majority of included studies (16/19) were of high quality (NOS score ≥ 7).

Results and conclusions:
The investigators found for highest vs. lowest vegetables intake a significant reduced risk of 27% for renal cell carcinoma [SRR = 0.73, 95% CI = 0.63-0.85, I2 = 53.5%, p = 0.004]. Significant means that there is an association with a 95% confidence.

The investigators found for highest vs. lowest vegetables intake a non-significant reduced risk of 13% for renal cell carcinoma in cohort studies [SRR = 0.87, 95% CI = 0.72-1.06].

The investigators found in dose-response analysis a significant reduced risk of 10% for renal cell carcinoma per 1 serving/day vegetables intake [SRR = 0.90, 95% CI = 0.84-0.96, I2 = 69.0%, p 0.001].

The investigators found a non-linear association between vegetable intake and renal cell carcinoma risk [p = 0.001 for non-linearity] with a significant reduction in renal cell carcinoma risk when increasing the intake up to about 3 servings/d intake of vegetables. Higher intake was associated with a further, but more modest decrease in risk.

The investigators found for highest vs. lowest fruits intake a significant reduced risk of 14% for renal cell carcinoma [SRR = 0.86, 95% CI = 0.75-0.98, I2 = 47.4%, p = 0.012].

The investigators found for highest vs. lowest fruits intake a significant reduced risk of 28% for renal cell carcinoma among European [SRR = 0.72, 95% CI = 0.56-0.93]. However, this reduced risk was not significant among North Americans [SRR = 0.97, 95% CI = 0.81-1.16].

The investigators found for highest vs. lowest fruits intake a significant reduced risk of 22% for renal cell carcinoma in population-based case-control studies [SRR = 0.78, 95% CI = 0.63-0.97]. However, this reduced risk was not significant in cohort studies [SRR = 0.90, 95% CI = 0.73-1.10] and in hospital-based case-control studies [SRR = 0.96, 95% CI = 0.69-1.33].

The investigators found in dose-response analysis no associaition between 1 serving/day increment of fruits and renal cell carcinoma risk [SRR = 0.97, 95% CI = 0.93-1.01, I2 = 57.8%, p = 0.011].

The investigators found a linear association between fruits intake and renal cell carcinoma risk [p = 0.221 for non-linearity].

The investigators concluded that consumption of 1-3 servings/d vegetables and high fruits may lower the risk of renal cell carcinoma development. May lower, because significant associations for vegetables and fruits were only observed in case-control, but not in cohort studies. Because of the measurement errors of exposure assessment, the high heterogeneity across studies and unmeasured confounding factors, further investigation with good designs are needed.

Original title:
Consumption of fruits and vegetables and risk of renal cell carcinoma: a meta-analysis of observational studies by Zhang S, Jia Z, [...], Yang J.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5438616/

Additional information of El Mondo:
Find more information/studies on vegetables and fruits consumption, significant/cohort/95% CI and cancer right here.

Objectives:
Previous studies regarding the relationship between legume intake and risk of prostate cancer have reported inconsistent results. Therefore, this review article (meta-analysis) has been conducted.

Does legume intake reduce prostate cancer risk?

Study design:
This review article included 8 prospective cohort studies reporting 281,034 individuals and 10,234 incident prostate cancer cases.

Results and conclusions:
The investigators found when comparing high consumption of legumes with low consumption a significant reduced risk of 15% [RR = 0.85, 95% CI = 0.75-0.96, p = 0.010, I2 = 45.8%] for prostate cancer.

The investigators found dose-response meta-analysis indicated that the risk of prostate cancer reduced by 3.7% [95% CI = 1.5%-5.8%] for each 20 grams per day increment of legume intake.

The investigators concluded that a high dietary intake of legumes, at least 20 grams per day is associated with a low incidence of prostate cancer.

Original title:
Legume intake and risk of prostate cancer: a meta-analysis of prospective cohort studies by Li J and Mao QQ.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28423366

Additional information of El Mondo:
Find more information/studies on vegetables consumption and cancer right here.

Objectives:
Thyroid cancer (TC) is the most common malignancy of the endocrine system. The relationship between iodine intake and thyroid cancer risk is controversial always. Therefore, this review article (meta-analysis) has been conducted.

Does dietary intake of iodine reduce thyroid cancer risk?

Study design:
This review article included 8 case-control studies with in total 2213 subjects with thyroid cancer and 2761 subjects without thyroid cancer.

With regard to publication bias, owing to the limited number (below 10) of studies included in the saltwater fish, shellfish and iodine intake analyses, publication bias was not assessed.

Results and conclusions:
The investigators found adequate or excess iodine dietary intake (>300 μg/d) significantly decreased the risk of thyroid cancer with 26% [OR = 0.74, 95% CI = 0.60-0.92].

The investigators found high consumption of saltwater fish (≥3 times/wk or ≥12 times/mo) significantly decreased the risk of thyroid cancer with 28% [OR = 0.72, 95% CI = 0.55-0.95, p = 0.02].

The investigators found high consumption of shellfish (≥3 times/wk or ≥12 times/mo) significantly decreased the risk of thyroid cancer with 30% [OR = 0.70, 95% CI = 0.52-0.96, p = 0.03].

The investigators concluded a higher intake of dietary iodine (>300 μg/d) may decrease the risk of thyroid cancer in populations mainly based in coastal cities or on islands. May decrease, because this review article did not include cohort  studies.

Original title:
The relationship between iodine intake and the risk of thyroid cancer: A meta-analysis by Cao LZ, Peng XD, [...], Li S.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5440127/

Additional information of El Mondo:
Find more information/studies on iodine and fish consumption, meta-analysis/cohort studies and cancer right here.

Objectives:
Prostate cancer (PCa) is the fifth leading cause of cancer-related deaths worldwide. Many epidemiological studies have investigated the association between prostate cancer and lycopene, however, results have been inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Does lycopene reduce prostate cancer risk?

Study design:
This review article included 42 studies including 43,851 cases of prostate cancer reported from 692,012 participants.

Results and conclusions:
The investigators found dietary intake of lycopene was significantly associated with a reduced prostate cancer risk of 12% [RR = 0.88, 95% CI = 0.78-0.98, p = 0.017].

The investigators found circulating concentrations of lycopene were significantly associated with a reduced prostate cancer risk of 12% [RR = 0.88, 95% CI = 0.79-0.98, p = 0.019].

The investigators found sensitivity analyses within the dose-response analysis further revealed a significant linear dose-response for dietary lycopene and prostate cancer risk such that prostate cancer decreased by 1% for every additional 2 mg of lycopene consumed [p = 0.026].

The investigators found prostate cancer risk decreased by 3.5 to 3.6% for each additional 10 μg/dL of circulating lycopene in the linear and nonlinear models, respectively [p-linear = 0.004, p-non linear = 0.006].

The investigators found no association between lycopene and advanced prostate cancer. However, there was a trend for protection against prostate cancer aggressiveness [RR = 0.74, 95% CI = 0.55-1.00, p = 0.052].

The investigators concluded that higher dietary and circulating lycopene concentrations reduce prostate cancer risk. This was accompanied by dose-response relationships for dietary and circulating lycopene. Further studies are required to determine the mechanisms underlying these associations.

Original title:
Increased dietary and circulating lycopene are associated with reduced prostate cancer risk: a systematic review and meta-analysis by Rowles JL, Ranard KM, […], Erdman JW Jr.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28440323

Additional information of El Mondo:
Find more information/studies on lycopene consumption and cancer right here.