Nutritional advice

Objectives:
The prevalence of obesity and diabetes is increasing among children, adolescents and adults. Although estimates of the efficacy of exercise training on fasting insulin and insulin resistance have been provided for adults, similar estimates have not been provided for youth. Therefore, this review article has been conducted.

Study design:
This review article included 24 trials.

Results and conclusions:
The investigators found a small to moderate effect for exercise training on fasting insulin and improving insulin resistance in youth [Hedges’ d effect size = 0.48, 95% CI = 0.22-0.74, p 0.001 and 0.31, 95% CI = 0.06-0.56, p 0.05, respectively].

The investigators concluded there is evidence to support the use of exercise training in the prevention and treatment of type 2 diabetes in youth.

Original title:
Exercise and Insulin Resistance in Youth: A Meta-Analysis by Fedewa MV, Gist NH, […], Dishman RK.

Link:
http://www.pediatricsdigest.mobi/content/133/1/e163.abstract

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

Objectives:
The association of red meat consumption with the risk of stomach cancer has been reported by many studies, with inconclusive results. Therefore, this review article has been conducted.

Does a high red meat consumption increase stomach cancer risk?

Study design:
This review article included a total of 18 studies (cohort and case-control studies) involving 1,228,327 subjects.

Results and conclusions:
The investigators found for the highest versus lowest categories of red meat intake a significant increased risk of 37% for gastric cancer [pooled RR = 1.37, 95% CI = 1.18-1.59, I2 = 67.6%, p 0.001].

The investigators found in population-based case-control studies, a significant increased risk of 58% for gastric cancer [pooled RR = 1.58, 95% CI = 1.22-2.06, I2 = 73.0%, p 0.001].

The investigators found in hospital-based case-control studies, a significant increased risk of 63% for gastric cancer [pooled RR = 1.63, 95% CI = 1.38-1.92, I2 = 19.1%, p = 0.284].

The investigators found, however, no association among cohort studies [RR = 1.00, 95% CI = 0.83-1.20, I2 = 33.9%, p = 0.158].

The investigators found the significant association was also presented in the subgroup analysis by geographic area (Asia, Europe), publication year (≥2000), sample size (1,000, ≥1,000) and quality score (7 stars, ≥7 stars).

The investigators found in dose-response analysis that every 100 g/day increment in red meat intake significant increased gastric cancer risk with 17% [RR = 1.17, 95% CI = 1.05-1.32].

The investigators found in linear regression model that the risk of gastric cancer increased with increasing level of red meat consumption.

The investigators concluded that a increased intake of red meat might be a risk factor for stomach cancer. Might be because the risk was not significant among cohort studies. Therefore, further larger prospective cohort studies are warranted to verify this association.

Original title:
Red meat consumption and stomach cancer risk: a meta-analysis by Song P, Lu M, […], Zhao Q.

Link:
https://link.springer.com/article/10.1007/s00432-014-1637-z

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

Objectives:
The association between meat consumption and the risk of hepatocellular carcinoma (HCC) is still inconclusive. Therefore, this review article has been conducted.

Does meat consumption increase risk of hepatocellular carcinoma?

Study design:
This review article included 7 cohort studies and 10 case-control studies.

Results and conclusions:
The investigators found for the highest vs. lowest consumption levels a non-significant increased risk for hepatocellular carcinoma of 10% [RR = 1.10, 95% CI = 0.85-1.42] for red meat, a non-significant increased risk of 1% [RR = 1.01, 95% CI = 0.79-1.28] for processed meat and a non-significant decreased risk of 3% [RR = 0.97, 95% CI = 0.85-1.11] for total meat. Non-significant means, there is no association with a 95% confidence.

The investigators found for the highest vs. lowest consumption levels a significant decreased risk for hepatocellular carcinoma of 31% [RR = 0.69, 95% CI = 0.58-0.81] for white meat and a significant decreased risk of 22% [RR = 0.78, 95% CI = 0.67-0.90] for fish. The results remained quite stable after stratification by the confounding factors.
Significant means, there is an association with a 95% confidence.

The investigators concluded a high level of white meat or fish consumption reduces the risk of hepatocellular carcinoma, while intake of red meat, processed meat or total meat is not associated with hepatocellular carcinoma risk. These results suggest that dietary intervention may be a promising approach for prevention of hepatocellular carcinoma, which still need to be confirmed by further well-designed prospective studies and experimental research.

Original title:
Systematic review with meta-analysis: meat consumption and the risk of hepatocellular carcinoma by Luo J, Yang Y, [...], Zhu Y.

Link:
http://www.ncbi.nlm.nih.gov/pubmed/24588342

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

A review article of cohort studies or case-control studies will answer the following question:
"Should I change my diet?".

Objectives:
Is there an association between meat intake and risk of esophageal cancer?

Study design:
This review article included 7 cohort studies and 28 case-control studies.

Results and conclusions:
The investigators found for the highest versus lowest total meat consumption categories a non-significant increased risk of 19% [95% CI = 0.98-1.46] for esophageal cancer.

The investigators found for the highest versus lowest red meat consumption categories a significant increased risk of 55% [95% CI = 1.22-1.96] for esophageal cancer.

The investigators found for the highest versus lowest processed meat consumption categories a significant increased risk of 33% [95% CI = 1.04-1.69] for esophageal cancer.

The investigators found for the highest versus lowest white meat consumption categories a significant decreased risk of 28% [95% CI = 0.60-0.86] for esophageal cancer.

The investigators found for the highest versus lowest poultry consumption categories a significant decreased risk of 17% [95% CI = 0.72-0.96] for esophageal cancer.

The investigators found for the highest versus lowest fish consumption categories a non-significant decreased risk of 5% [95% CI = 0.76-1.19] for esophageal cancer.

The investigators found when stratified by histological subtype, positive associations among esophageal squamous cell carcinoma and red meat, white meat and poultry and esophageal adenocarcinoma with total meat and processed meat.

The investigators concluded red meat and processed meat consumption increase risk of esophageal cancer, while white meat and poultry decrease risk of esophageal cancer. Fish consumption is not associated with incidence of esophageal cancer.

Original title:
Meat consumption is associated with esophageal cancer risk in a meat- and cancer-histological-type dependent manner by Zhu HC, Yang X, […], Sun XC.

Link:
http://www.ncbi.nlm.nih.gov/pubmed/24395380

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

Objectives:
Previous observational studies regarding the existence of an association between folate intake and the risk of breast cancer have been inconsistent. Therefore, this review article has been conducted.

Does a higher dietary folate intake reduce breast cancer risk?

Study design:
This review article included 14 prospective cohort studies that reported data on 677,858 individuals.
The participant follow-up period ranged 4.7-17.4 years and the number of individuals per study ranged 11,699-88,818.
There was no publication bias.

Results and conclusions:
The investigators found no association between dietary folate intake and breast cancer risk for highest versus lowest category  [RR =  0.97, 95% CI = 0.90-1.05, p  = 0.451, I2 =  57.5%, p = 0.004].

The investigators found dose-response meta-analysis findings showed no association between the risk of breast cancer and a 100 µg/day increase in dietary folate intake [RR = 0.99, 95% CI = 0.98-1.01, p = 0.361, I2 = 66.2%, p 0.001].

The investigators found evidence of a nonlinear relationship between dietary folate intake and the risk of breast cancer.

A daily dietary folate intake of 200-320 µg was associated with a reduced risk of breast cancer. However, daily folate intake levels >400 µg was associated with a increased risk of breast cancer.

The investigators found overall folate intake level was associated with a reduced breast cancer risk of 36% if the patients had a daily alcohol intake >10 g [RR for highest versus lowest category = 0.64, 95% CI = 0.43-0.97].

The investigators concluded there are no effects of increased dietary folate intake on the incidence of breast cancer. But, a daily dietary folate intake of 200-320 µg was associated with a reduced risk of breast cancer. However, daily folate intake levels >400 µg was associated with a increased risk of breast cancer. Future studies should focus on specific populations in order to analyze primary breast cancer prevention.

Original title:
Folate Intake and the Risk of Breast Cancer: A Dose-Response Meta-Analysis of Prospective Studies by Zhang YF, Shi WW, […], Zhou YH.

Link:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4059748/

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

Objectives:
Increasing evidence suggests that the Mediterranean diet can reduce the risk of cardiovascular disease. Olive oil is the hallmark of this dietary pattern. Therefore, this review article has been conducted.

Does olive oil consumption reduce risk of cardiovascular disease?

Study design:
This review article included case-control, prospective cohort studies and a randomised controlled trial investigating the specific association between olive oil consumption and the risk of cardiovascular disease (101,460 participants) or stroke (38,673 participants). The results of all observational studies were adjusted for total energy intake.

Evidence of heterogeneity was apparent for cardiovascular disease, but not for stroke. Both the Egger test (p = 0.06) and the funnel plot suggested small-study effects.

Results and conclusions:
The investigators found in case-controle studies a non-significant reduced risk of 27% [relative risk = 0.73, 95% CI = 0.44-1.21] for cardiovascular disease for a 25g increase in olive oil consumption.

The investigators found in cohort studies a non-significant reduced risk of 4% [relative risk = 0.96, 95% CI = 0.78-1.18] for cardiovascular disease for a 25g increase in olive oil consumption.

The investigators found in cohort studies olive oil consumption significantly reduced risk of stroke with 26% [relative risk = 0.74, 95% CI = 0.60-0.92].

The investigators found random-effects model showed a significant reduced risk of 18% [RR = 0.82, 95% CI = 0.70, 0.96] for combining all cardiovascular events (CHD and stroke).

The investigators concluded available studies support an inverse association of olive oil consumption with stroke and with stroke and cardiovascular disease combined. This finding is in agreement with the recent successful results of the PREDIMED randomised controlled trial.

Original title:
Olive oil consumption and risk of CHD and/or stroke: a meta-analysis of case-control, cohort and intervention studies by Martínez-González MA, Dominguez LJ and Delgado-Rodríguez M.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/24775425

Additional information of El Mondo:
Find more studies/information on cardiovascular disease right here.

Objectives:
What is the impact of antioxidants (N-acetylcysteine (NAC), polyunsaturated fatty acids (PUFAs) and vitamins) on incidence of postoperative atrial fibrillation (POAF) and duration of length of hospital stay?

Study design:
This review article included 23 RCTs that reported outcomes of 4278 patients undergoing cardiac surgery.
A total of 10 RCTs with 1,026 patients (513 cases were allocated to the NAC and 513 cases to the control group, with a mean age of 63.2 years and 76.8% being males), 8 RCTs with 2,687 patients (with a mean age of 64.17 years and 77.6% being males), and 5 RCTs with 565 patients (with a mean age of 65.17 years and 73.6% being males) investigated the effect of NAC, PUFA and antioxidant vitamins on POAF, respectively.

There was no publication bias.

Results and conclusions:
The investigators found pooled effects estimates on postoperative atrial fibrillation showed a significant reduction after:
NAC [OR = 0.56, 95% CI = 0.40-0.77, p 0.001, I2 = 15%, p = 0.3];
PUFA [OR = 0.84, 95% CI = 0.71-0.99, p = 0.03] and;
Vitamin C treatment [OR = 0.50, 95% CI = 0.27-0.91, p = 0.02, I2 = 50%].

The investigators found hospital length of stay was not significant reduced after NAC therapy [SMD = 0.082, 95% CI = -0.09 to 0.25, p = 0.3, I2 = 0.0%, p = 0.7], but could be significant decreased with PUFA [SMD = -0.185, 95% CI = -0.35 to -0.018, p = 0.03, I2 = 11%, p = 0.3] and vitamin C [SMD = -0.325, 95% CI = -0.50 to -0.14, p 0.01, I2 = 60.4%, p = 0.056].
Significant because the p-values were less than the p-value of 0.05.

The investigators concluded perioperative antioxidant supplementations with N-acetylcysteine, polyunsaturated fatty acids and vitamin C prevent atrial fibrillation after cardiac surgery. Moreover, polyunsaturated fatty acids and vitamin C are capable to reduce hospital stay, whereas N-acetylcysteine lacks this capacity.

Original title:
Antioxidant supplementations for prevention of atrial fibrillation after cardiac surgery: an updated comprehensive systematic review and meta-analysis of 23 randomized controlled trials by Ali-Hassan-Sayegha S, Mirhosseinia SJ, […], Liakopoulose OJ.

Link:
http://icvts.oxfordjournals.org/content/early/2014/02/19/icvts.ivu020.long

Additional information of El Mondo:
Find more studies on cardiovascular diseases, antioxidants, NAC, PUFA, vitamin C and p-value of 0.05/95% CI right here. 

Objectives:
Does niacine supplementation reduce blood lipids levels in patients with type 2 diabetes mellitus?

Study design:
This review article included randomized controlled trials.

The meta-analysis showed the absence of publication bias and any dose-response relations between niacin and effect size.

There was a significant heterogeneity for the impact of niacin on LDL cholesterol and fasting plasma glucose.

Results and conclusions:
The investigators found niacin supplementation significantly increased HDL cholesterol with 0.27 mmol/L [95% CI = 0.24 to 0.30, p 0.001] in patients with type 2 diabetes mellitus.

The investigators found niacin supplementation significantly reduced LDL cholesterol with 0.250 mmol/L [95% CI = -0.47 to -0.03, p 0.05] in patients with type 2 diabetes mellitus.

The investigators found niacin supplementation significantly reduced triglycerides with 0.39 mmol/L [95% CI = -0.43 to -0.34, p 0.001] in patients with type 2 diabetes mellitus.

The investigators found niacin supplementation significantly increased fasting plasma glucose with 0.085 mmol/L [95% CI = 0.029 to 0.141, p 0.05] compared with controls in patients with long term treatment.

The investigators concluded niacin alone or in combination improves lipid abnormalities in patients with type 2 diabetes mellitus, but requires monitoring of glucose in long term treatment.

Original title:
Effect of niacin on lipids and glucose in patients with type 2 diabetes: A meta-analysis of randomized, controlled clinical trials by Ding Y, Li Y and Wen A.

Link:
http://www.ncbi.nlm.nih.gov/pubmed/25306426

Additional information of El Mondo:
Find more information on niacin (vitamin B3) and diabetes.

Objectives:
Observational studies suggest an association between dietary fiber intake and risk of type 2 diabetes, but the results are inconclusive. Therefore, this review article (meta-analysis) has been conducted.

Does dietary fiber intake reduce risk of type 2 diabetes?

Study design:
This review article included 17 prospective cohort studies of dietary fiber intake and risk of type 2 diabetes involving 19,033 cases and 488,293 participants.

Results and conclusions:
The investigators found total dietary fiber intake significantly reduced risk of type 2 diabetes with 19% [combined RR = 0.81, 95% CI = 0.73-0.90].

The investigators found dietary cereal fiber intake significantly reduced risk of type 2 diabetes with 23% [combined RR = 0.77, 95% CI = 0.69-0.85].

The investigators found dietary fruit fiber intake significantly reduced risk of type 2 diabetes with 6% [combined RR = 0.94, 95% CI = 0.88-0.99].

The investigators found dietary insoluble fiber intake significantly reduced risk of type 2 diabetes with 25% [combined RR = 0.75, 95% CI = 0.63-0.89].

The investigators found a nonlinear relationship of total dietary fiber intake with risk of type 2 diabetes [p for nonlinearity 0.01].

The investigators found dietary fiber intake of 15g per day non-significantly reduced risk of type 2 diabetes with 2% [combined RR = 0.98, 95% CI = 0.90-1.06].

The investigators found dietary fiber intake of 20g per day non-significantly reduced risk of type 2 diabetes with 3% [combined RR = 0.97, 95% CI = 0.87-1.07].

The investigators found dietary fiber intake of 25g per day significantly reduced risk of type 2 diabetes with 11% [combined RR = 0.89, 95% CI = 0.80-0.99].

The investigators found dietary fiber intake of 30g per day significantly reduced risk of type 2 diabetes with 24% [combined RR = 0.76, 95% CI = 0.65-0.88].

The investigators found dietary fiber intake of 35g per day significantly reduced risk of type 2 diabetes with 34% [combined RR = 0.66, 95% CI = 0.53-0.82].

The investigators found that the risk of type 2 diabetes decreased by 6% [combined RR = 0.94, 95% CI = 0.93-0.96] for 2 g/day increment in cereal fiber intake.

The investigators concluded that the intakes of dietary fiber, at least 25g total dietary fiber intake per day reduce risk of type 2 diabetes.

Original title:
Dietary fiber intake and risk of type 2 diabetes: a dose–response analysis of prospective studies by Yao B, Fang H, […], Zhao Y.

Link:
http://link.springer.com/article/10.1007/s10654-013-9876-x

Additional information of El Mondo:
Find more information on fiber and type 2 diabetes right here.