Nutritional advice

Objectives:
The association between vitamin C intake and breast cancer is unclear. Therefore, this review article (meta-analysis) has been conducted.

Does a higher vitamin C intake reduce risk of breast cancer incidence, mortality and recurrence?

Study design:
This review article included 24 cohort studies and 30 case-control studies.

Results and conclusions:
The investigators found pooled results suggested that the highest versus lowest vitamin C intake was significantly associated with a 14% lower risk of breast cancer incidence [relative risk = 0.86, 95% = 0.81 to 0.92, I2 = 78.7%, p 0.00].
Sensitivity analysis indicated that the overall results remained consistent even after excluding studies individually.

The investigators found the use of random-effects model indicated that a 100-mg/day increment in vitamin C intake had no significant effect on breast cancer risk.

The investigators found stratification by study design showed a 26% lower risk of breast cancer incidence for vitamin C intake in case-control studies [RR = 0.74, 95% CI = 0.65 to 0.84, p 0.001]. However, a non-significant inverse association was found in cohort studies [RR = 0.96, 95% CI = 0.89 to 1.04, p = 0.295].

The investigators found when the studies were stratified by the source of vitamin C, a 11% lower risk of breast cancer incidence with dietary intake [RR = 0.89, 95% CI = 0.82 to 0.96, p = 0.004] but not with supplements [RR = 1.02, 95% CI = 0.94 to 1.10, p = 0.678].

The investigators found that the highest versus lowest vitamin C intake was significantly associated with a 22% lower risk of breast cancer mortality [HR = 0.78, 95% CI = 0.69 to 0.88, I2 = 2.6%].

The investigators found that the highest versus lowest vitamin C intake was significantly associated with a 19% lower risk of breast cancer recurrence [HR = 0.81, 95% CI = 0.67 to 0.99, p = 0.043, I2 = 0.0%].

The investigators concluded that higher vitamin C dietary intake is significantly associated with a reduced risk of breast cancer incidence, mortality and recurrence.

Original title:
Association of vitamin C intake with breast cancer risk and mortality: a meta-analysis of observational studies by Zhang D, Xu P, [...], Dai Z.

Link:
https://www.aging-us.com/article/103769/text

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Objectives:
Heated debates have been on-going about tea consumption and the incidence of cancer, especially in head and neck cancer types. Therefore, this review article (meta-analysis) has been conducted.

Does habitual tea consumption reduce risk of nasopharyngeal cancer?

Study design:
This review article included 6 articles.

Results and conclusions:
The investigators found that habitual tea consumption significantly reduced risk of nasopharyngeal cancer with 13.5% [OR = 0.865, 95% CI = 0.806 to 0.929].

The investigators concluded that habitual tea consumption is associated with prevention of nasopharyngeal cancer development. Additional studies are needed to further understand the molecular role of bioactive compound and potential health benefit of tea consumption in nasopharyngeal cancer prevention.

Original title:
The Association between Tea Consumption and Nasopharyngeal Cancer: A Systematic Review and Meta-Analysis by Okekpa SI, Basria R, […], Musa MY.

Link:
https://pubmed.ncbi.nlm.nih.gov/32856842/

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Objectives:
Probiotics are being used increasingly in pregnant women, whereas the efficiency on pregnancy outcomes is yet lacking. Therefore, this review article has been conducted.

Have probiotic supplements during pregnancy positive effects on pregnancy outcomes, such as eczema, gestational age?

Study design:
This review article included 18 RCTs with a total of 4,356 pregnant women.

Results and conclusions:
The investigators found probiotic supplementation during pregnancy significantly decreased risk of atopic eczema with 32% [RR = 0.68, 95% CI = 0.58 to 0.81, p 0.001, without significant heterogeneity].

The investigators found probiotic supplementation during pregnancy significantly decreased risk of eczema with 21% [RR = 0.79, 95% CI = 0.68 to 0.91, p = 0.002, without significant heterogeneity].

The investigators found probiotic supplementation during pregnancy was associated with a prolonged gestational age [WMD = 0.09, 95 % CI = 0.04 to 0.15, p = 0.001 with insignificant heterogeneity].
However, probiotic supplementation during pregnancy had no significant effect on birth weight [p = 0.851].

The investigators found probiotic supplementation during pregnancy significantly decreased risk of death with 66% [RR = 0.34, 95% CI = 0.13 to 0.91, p = 0.031, without evidence of heterogeneity].

The investigators found probiotic supplementation during pregnancy significantly decreased risk of necrotising enterocolitis (NEC) with 62% [RR = 0.38, 95% CI = 0.18 to 0.11, p = 0.012, without evidence of heterogeneity].

The investigators concluded probiotic supplementation in pregnant women is beneficial for atopic eczema, eczema, gestational age, death and necrotising enterocolitis.

Original title:
Effect of probiotic supplementation in pregnant women: a meta-analysis of randomised controlled trials by Kuang L and Jiang Y.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31856928

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Necrotizing enterocolitis (NEC) is a devastating disease that affects mostly the intestine of premature infants. The wall of the intestine is invaded by bacteria, which cause local infection and inflammation that can ultimately destroy the wall of the bowel (intestine). Such bowel wall destruction can lead to perforation of the intestine and spillage of stool into the infant’s abdomen, which can result in an overwhelming infection and death.
 

Objectives:
The number of cancer survivors is growing rapidly worldwide, especially long-term survivors. Although a healthy diet with a high vegetable and fruit consumption is a key factor in primary cancer prevention, there is a lack of specific dietary recommendations for cancer survivors, except in the case of breast cancer [World Cancer Research Fund (WCRF)/American Institute for Cancer Research (AICR) report]. Therefore, this review article (meta-analysis) has been conducted.

Does the general recommendation to consume ≥5 servings of vegetables and fruit per day (400 g/d) meet the needs of cancer survivors?

Study design:
This review article included 28 cohort studies.

Results and conclusions:
The investigators found a high vegetable intake before diagnosis significantly reduced overall mortality in survivors of head and neck cancer with 25% [HR = 0.75, 95% CI = 0.65 to 0.87].  

The investigators found a high vegetable intake before diagnosis significantly reduced overall mortality in survivors of ovarian cancer with 22% [HR = 0.78, 95% CI = 0.66 to 0.91].  

The investigators found a high fruit intake before diagnosis significantly reduced overall mortality in survivors of ovarian cancer with 18% [HR = 0.82, 95% CI = 0.70 to 0.96].  

The investigators found the evidence was insufficient for survivors of other cancers, although these associations generally tended to be protective. Therefore, more studies are needed to clarify the association between vegetable and fruit consumption and the prognosis of these different types of cancer.

The investigators concluded the general recommendation to consume ≥5 servings of vegetables and fruit per day (400 g/d) could underestimate the needs of cancer survivors, particularly those with ovarian tumors, in which the recommendation could increase to 600 g/d (i.e., 300 g/d of vegetables and 300 g/d of fruit).

Original title:
Vegetable and Fruit Consumption and Prognosis Among Cancer Survivors: A Systematic Review and Meta-Analysis of Cohort Studies by Hurtado-Barroso S, Trius-Soler M, […], Zamora-Ros R.

Link:
https://pubmed.ncbi.nlm.nih.gov/32717747/

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Find more information/studies on vegetables and fruit and cancer right here.

Objectives:
It is unclear how dietary intake influences the ovarian cancer. Therefore, this review article (meta-analysis) has been conducted.

Is there a relationship between dietary intake of different nutrients/food groups and ovarian cancer risk?

Study design:
This review article included 97 cohort studies.

Results and conclusions:
The investigators found no significant association between dietary intake and risk of ovarian cancer.

The investigators found in subgroup analyses that dietary intake of green leafy vegetables significantly reduced risk of ovarian cancer with 9% [RR = 0.91, 95% CI = 0.85 to 0.98].

The investigators found in subgroup analyses that dietary intake of allium vegetables significantly reduced risk of ovarian cancer with 21% [RR = 0.79, 95% CI = 0.64 to 0.96].

The investigators found in subgroup analyses that dietary intake of fiber significantly reduced risk of ovarian cancer with 11% [RR = 0.89, 95% CI = 0.81 to 0.98].

The investigators found in subgroup analyses that dietary intake of flavonoids significantly reduced risk of ovarian cancer with 17% [RR = 0.83, 95% CI = 0.78 to 0.89].

The investigators found in subgroup analyses that dietary intake of green tea significantly reduced risk of ovarian cancer with 39% [RR = 0.61, 95% CI = 0.49 to 0.76].

The investigators found in subgroup analyses that dietary intake of tota fat significantly increased risk of ovarian cancer with 10% [RR = 1.10, 95% CI = 1.02 to 1.18].

The investigators found in subgroup analyses that dietary intake of saturated fat significantly increased risk of ovarian cancer with 11% [RR = 1.11, 95% CI = 1.01 to 1.22].

The investigators found in subgroup analyses that dietary intake of saturated fatty acid significantly increased risk of ovarian cancer with 19% [RR = 1.19, 95% CI = 1.04 to 1.36].

The investigators found in subgroup analyses that dietary intake of cholesterol significantly increased risk of ovarian cancer with 13% [RR = 1.13, 95% CI = 1.04 to 1.22].

The investigators found in subgroup analyses that dietary intake of retinol (vitamin A) significantly increased risk of ovarian cancer with 14% [RR = 1.14, 95% CI = 1.00 to 1.30].

The investigators found, in addition, acrylamide, nitrate, water disinfectants and polychlorinated biphenyls were significantly associated with an increased risk of ovarian cancer.

The investigators concluded that dietary intakes of green leafy vegetables, allium vegetables, fiber, flavonoids and green tea reduce ovarian cancer.

Original title:
Association between dietary intake and risk of ovarian cancer: a systematic review and meta-analysis by Khodavandi A, Alizadeh F and Razis AFA.

Link:
https://pubmed.ncbi.nlm.nih.gov/32661683/

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Objectives:
Some evidence indicates that carotenoids may reduce the risk of bladder cancer (BC), but the association is unclear. Therefore, this review article (meta-analysis) has been conducted.

Do dietary carotenoid (β-cryptoxanthin, α-carotene, β-carotene and lutein and zeaxanthin) intakes or circulating carotenoid concentrations reduce bladder cancer risk in men and women?

Study design:
This review article included 22 studies (case-control and cohort studies), involving 516,740 adults.

Results and conclusions:
The investigators found no association for the highest compared with the lowest category of carotenoid dietary intake and reduced risk of bladder cancer [RR = 0.88, 95% CI = 0.76 to 1.03].
No association because RR of 1 was found in the 95% CI of 0.76 to 1.03. RR of 1 means no risk/association.

The investigators found no association for the highest compared with the lowest category of circulating carotenoid concentrations and reduced risk of bladder cancer [RR = 0.36, 95% CI = 0.12 to 1.07].

The investigators found for the highest compared with the lowest category of circulating lutein and zeaxanthin concentrations a significantly reduced risk of 47% for bladder cancer [RR = 0.53, 95% CI = 0.33 to 0.84].
Significant because RR of 1 was not found in the 95% CI of 0.33 to 0.84. RR of 1 means no risk/association.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 42% [RR = 0.58, 95% CI = 0.36 to 0.94] for every 1 mg increase in daily dietary β-cryptoxanthin intake.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 76% [RR = 0.24, 95% CI = 0.08 to 0.67] for every 1 μmol/L increase in circulating concentration of α-carotene.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 27% [RR = 0.73, 95% CI = 0.57 to 0.94] for every 1 μmol/L increase in circulating concentration of β-carotene.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 56% [RR = 0.44, 95% CI = 0.28 to 0.67] for every 1 μmol/L increase in circulating concentrations of lutein and zeaxanthin.

The investigators concluded dietary β-cryptoxanthin intake and circulating concentrations of α-carotene, β-carotene and lutein and zeaxanthin reduce risk of bladder cancer.

Original title:
Carotenoid Intake and Circulating Carotenoids Are Inversely Associated With the Risk of Bladder Cancer: A Dose-Response Meta-analysis by Wu S, Liu Y, […], Ramirez AG.

Link:
https://pubmed.ncbi.nlm.nih.gov/31800007/

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Objectives:
A growing number of epidemiological studies have suggested a possible association between long-chain omega-3 polyunsaturated fatty acid (PUFA) intake and the risk of cancers, but the results have been inconsistent. Therefore, this review article (meta-analysis) has been conducted.

Does dietary intake of omega-3 PUFAs reduce digestive system cancers?

Study design:
This review article included 8 case-control studies and 17 cohort studies, involving 1,247,271 participants and 23,173 patients with digestive system cancers.

Visual inspection of funnel plots and the Begg's and Egger's tests revealed no evidence of publication bias.

Results and conclusions:
The investigators found the risk of digestive system cancers significantly decreased by 17% in individuals who consumed omega-3 PUFAs [RR = 0.83, 95% CI = 0.76 to 0.91].

The investigators found the risk estimates of digestive system cancers varied by cancer sites, study location, study design, type of omega-3 PUFAs and other confounders (smoking, alcohol consumption, body mass index and physical activity).

The investigators concluded omega-3 PUFA is a healthy dietary component for the prevention of digestive system cancers. Cancer incidence decreases with increasing omega-3 PUFAs intake for most digestive system cancer sites. The relation between omega-3 PUFAs and digestive system cancers RR is similar among different populations.

Original title:
Omega-3 PUFA Intake and the Risk of Digestive System Cancers: A Meta-Analysis of Observational Studies by Jian J, Zhang and Zhao L.

Link:
https://pubmed.ncbi.nlm.nih.gov/32384489/

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Objectives:
Do higher gestational vitamin D levels (vitamin D levels of the mother during pregnancy) decrease risk of multiple sclerosis (MS) in offspring?

Study design:
This review article included 4 case-control studies of moderate to low risk of bias.

Factors identified as determinants of heterogeneity were the definitions of vitamin D deficiency, the characteristics of study participants and the quality of the study.

Results and conclusions:
The investigators found that higher levels of gestational vitamin D significantly reduced risk of multiple sclerosis in offspring with 37% [OR = 0.63, 95% CI = 0.47 to 0.84] in random effects models and in a stratified analysis based on study quality.

The investigators concluded higher levels of gestational vitamin D reduce risk of multiple sclerosis in offspring.

Original title:
Gestational vitamin D and offspring risk of multiple sclerosis: a systematic review and meta-analysis by Jasper EA, Nidey NL, […], Ryckman KK.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32014337

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Objectives:
Micronutrients’ deficiency is a common phenomenon among a majority of the population residing in the low- and middle-income countries (LMICs) especially among women and children. Given the widespread prevalence of micronutrients’ deficiency in LMICs, iron-fortified foods could be of potential benefits for both the mother and the development of fetus. Therefore, this review article has been conducted.

Does iron fortification increase hemoglobin (Hb) concentration during pregnancy and have iron fortification positive effects on specific maternal and pregnancy outcomes?

Study design:
This review article included 12 RCTs (n = 3,872).

The weighted mean difference (WMD) and relative risk (RR) were calculated using random-effects models. Sources of heterogeneity were explored through meta-regression.

The funnel plot was symmetrical, indicating that there was absence of any publication bias which was confirmed using Egger's weighted regression method [Egger test, ρ = 0.69].

Results and conclusions:
The investigators found the mean change in hemoglobin concentration was significantly higher in the group of mothers with iron fortification when compared with the control group [WMD = 4.45 g/L, 95% CI = 2.73 to 6.17 g/L, I2 = 83%, ρ 0.00001].

The investigators found in meta-regression analysis that the duration of feeding was positively associated with the effect size.

The investigators concluded iron fortification increases hemoglobin (Hb) concentration during pregnancy. Further research is required to explore the benefits of iron fortification on maternal and neonatal health outcomes during pregnancy.

Original title:
Meta-analysis Approach on Iron Fortification and Its Effect on Pregnancy and Its Outcome Through Randomized, Controlled Trials by Athe R, Dwivedi R, […], Banset U.  

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7114015/

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Objectives:
An increased risk of gastric cancer for pickled vegetable and salted fish intake has been suggested, yet the lack of a dose-response association warrants a quantitative analysis. Therefore, this review article (meta-analysis) has been conducted.

Do pickled vegetable and salted fish intakes increase risk of gastric cancer?

Study design:
This review article included 21 cohort studies with a total of 195,624 participants for the analysis of pickled vegetable intake and 16 cohort studies with a total of

196,384 participants for the analysis of salted fish intake.

Results and conclusions:
The investigators found in a dose-response meta-analysis of 6 studies, a significantly increased risk of 15% [combined RR = 1.15, 95% CI = 1.07 to 1.23, p for heterogeneity = 0.14] for gastric cancer incidence for a 40 g/day increment in pickled vegetable intake.

The investigators found in the categorical meta-analysis of 6 studies, a marginally significant increase in the risk of gastric cancer incidence, comparing the highest to the lowest intake of salted fish [RR = 1.17, 95% CI = 0.99 to 1.38, p for heterogeneity = 0.26].

The investigators concluded intake of 40 g/day of pickled vegetable increases risk of gastric cancer incidence.

Original title:
Pickled Vegetable and Salted Fish Intake and the Risk of Gastric Cancer: Two Prospective Cohort Studies and a Meta-Analysis by Yoo JY, Cho HJ, […], Park SK.

Link:
https://www.mdpi.com/2072-6694/12/4/996/htm

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Objectives:
Epidemiologic studies focusing on the association between 1-carbon metabolism-related vitamins (ie, folate, vitamin B6, vitamin B2, vitamin B12) and breast cancer risk have reported inconsistent findings. Therefore, this review article (meta-analysis) has been conducted.

Does higher dietary intake of folate (folic acid), vitamin B2, B6 or B12 reduce breast cancer risk?

Study design:
This review article included 27 studies (case-control and cohort studies) with a total of 49,707 cases (persons with breast cancer) among 1,274,060 individuals.

Results and conclusions:
The investigators found for the highest folate dietary intake compared with the lowest, a significantly reduced risk of 7% [pooled relative risk = 0.93, 95% CI = 0.88 to 0.99, p = 0.018] for breast cancer.

The investigators found for the highest vitamin B6 dietary intake compared with the lowest, a significantly reduced risk of 6% [pooled relative risk = 0.94, 95% CI = 0.89 to 1.00, p = 0.037] for breast cancer.

The investigators found for the highest vitamin B2 dietary intake compared with the lowest, a significantly reduced risk of 10% [pooled relative risk = 0.90, 95% CI = 0.82 to 0.99, p = 0.026] for breast cancer.

The investigators found no significant association between vitamin B12 and breast cancer risk [RR = 0.99, 95% CI = 0.94 to 1.04, p = 0.604].

The investigators found folate and vitamin B6 dietary intake significantly decreased the risk of estrogen receptor-negative (ER-)/progesterone receptor-negative (PR-) breast cancer but not ER+/PR+ breast cancer.

The investigators found an increment of 100 μg/d folate dietary intake corresponded to a 7% [RR = 0.93, 95% CI = 0.89 to 0.98, p = 9.007] deceased risk of ER-/PR- breast cancer.

The investigators concluded both higher folate, vitamin B2 and B6 dietary intake decreases risk of breast cancer, especially ER-/PR- breast cancer.

Original title:
Association Between One-carbon Metabolism-related Vitamins and Risk of Breast Cancer: A Systematic Review and Meta-analysis of Prospective Studies by Zeng J, Gu Y, […], Chang H.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32241696

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If breast cancer cells have estrogen receptors, the cancer is called ER-positive breast cancer. If breast cancer cells have progesterone receptors, the cancer is called PR-positive breast cancer. If the cells do not have either of these 2 receptors, the cancer is called ER/PR-negative.

Objectives:
The impact of light-intensity physical activity (LPA) in preventing cancer mortality has been questioned. Therefore, this review article has been conducted.

Does light-intensity physical activity reduce cancer mortality?

Study design:
This review article included 5 prospective cohort studies, in which the definition of light-intensity physical activity based on accelerometer readings was mainly set within 100 to 2,100 counts/min.

Results and conclusions:
The investigators found 30 min/day of light-intensity physical activity significantly reduced cancer mortality with 14% [summary HR = 0.86, 95% CI = 0.79 to 0.95, I2 1%] and the association between light-intensity physical activity and risk reduction in cancer mortality was linearly shaped [p nonlinearity = 0.72].

The investigators found light-intensity physical activity exhibited a comparable magnitude of risk reduction in cancer mortality of moderate-to-vigorous physical activity regardless of equal time-length [0.87 per 30 min/day vs. 0.94 per 30 min/day, p interaction = 0.46] or equal amount [0.74 vs. 0.94 per 150 metabolic equivalents-min/day, p interaction = 0.11].

The investigators found, furthermore, replacing sedentary time by light-intensity physical activity of 30 min/day significantly decreased the risk of cancer mortality by 9%.

The investigators concluded 30 min/day of light-intensity physical activity reduce cancer mortality.

Original title:
Objectively-Measured Light-Intensity Physical Activity and Risk of Cancer Mortality: A Meta-analysis of Prospective Cohort Studies by Qiu S, Cai X, […], Schumann U.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32303534

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Light intensity physical activity is an activity that is classified as 3 METS.

Objectives:
Previous studies have demonstrated some associations between dietary vitamin A intake and ovarian cancer risk with an inconsistent relationship. Therefore, this review article (meta-analysis) has been conducted.

Does higher dietary intake of vitamin A reduce ovarian cancer risk?

Study design:
This review article included 10 case-control studies and 5 cohort studies, involving 4,882 cases (persons with ovarian cancer) among 443,179 participants.

There was no publication bias.

Results and conclusions:
The investigators found higher dietary vitamin A intake significantly reduced ovarian cancer risk with 18.4% [RR = 0.816, 95% CI = 0.723 to 0.920, I2 = 48.4%, p for heterogeneity = 0.019].
Sensitivity analysis showed that no single study had a potential impact on the pooled RR.

The investigators found higher dietary vitamin A intake significantly reduced ovarian cancer risk with 23.1% [RR = 0.769, 95% CI = 0.655 to 0.902] in case-controle studies.
However, this reduced risk was not significant in cohort studies.

The investigators found higher dietary vitamin A intake significantly reduced ovarian cancer risk with 17.5% [RR = 0.825, 95% CI = 0.720 to 0.946] in North American populations.

The investigators concluded that higher dietary intake of vitamin A reduces ovarian cancer risk, especially among North Americans. As some limitations existed in this analysis, large scale studies with detailed amount of dietary vitamin A intake are needed to verify the results.

Original title:
Dietary vitamin A intake and the risk of ovarian cancer: A meta-analysis by Wang Q and He C.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7138903/

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Objectives:
Epidemiologic studies of the relationship between nitrite or nitrate consumption and risk of non-Hodgkin lymphoma (NHL) remain controversial. Therefore, this review article has been conducted.

Does dietary intake of nitrite or nitrate increase risk of non-Hodgkin lymphoma?

Study design:
This review article included 8 case-control and 4 cohort studies with a total of 8,067 cases of non-Hodgkin lymphoma that reported the correlation between nitrate or nitrite consumption and risk of non-Hodgkin lymphoma published between 1996 and 2013.

NOS scores ranged from 4 to 8 with a mean value of 6.
Information on nitrate and nitrite intake was obtained by personal interview, telephone interview or mailed questionnaires.

There was no evidence of publication bias.

Results and conclusions:
The investigators found that high levels of nitrite dietary intake was linked to a significantly elevated risk of non-Hodgkin lymphoma of 55% [OR = 1.55, 95% CI = 1.27-1.88, I2 = 41.8%, p = 0.161]. 

The investigators found, however, no connection between the risk of non-Hodgkin lymphoma and high levels of nitrate dietary intake [OR = 1.02, 95% CI = 0.94-1.10, I2 = 14.2%, p = 0.308].

The investigators found that the risk of non-Hodgkin lymphoma increased by 26% for each additional microgram of nitrite consumed in the diet per day [OR = 1.26, 95% CI = 1.09-1.42].

The investigators found data from the high-quality studies indicated that nitrite consumption was positively associated with carcinogenicity, leading to non-Hodgkin lymphoma [OR = 1.44, 95% CI = 1.17-1.77] and positively correlated with the development of diffuse large B-cell lymphoma [OR = 1.55, 95% CI = 1.07-2.26], but not other non-Hodgkin lymphoma subtypes.

The investigators found, in addition, high levels of nitrite dietary intake was linked to a significantly elevated risk of non-Hodgkin lymphoma of 50% [OR = 1.50, 95% CI = 1.15-1.95] in females.
However, this increased risk was not significant in males [OR = 0.84, 95% CI = 0.52-1.36].

The investigators concluded that nitrite dietary intake, but not that of nitrate, raises the risk of developing non-Hodgkin lymphoma, particularly diffuse large B-cell lymphoma in females. In the future, better designed prospective research studies should be conducted to confirm these findings, clarify potential biological mechanisms and instruct clinicians about non-Hodgkin lymphoma prophylaxis.

Original title:
The relationship between consumption of nitrite or nitrate and risk of non-Hodgkin lymphoma by Yu M, Li C, [...], Jin J.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6969097/

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The preservative sodium nitrite fights harmful bacteria in ham, salami and other processed and cured meats and also lends them their pink coloration.
 

Objectives:
Previous studies had been published to explore the association about carbohydrate intake on esophageal cancer risk, with inconsistent results. Therefore, this review article (meta-analysis) has been conducted.

Does dietary intake of carbohydrate reduce esophageal cancer risk?

Study design:
This review article included 13 case-control studies that assessed a total of 3,033 patients.
The quality evaluation scores of each study ranged from 6 to 9 and the methodological quality was higher.

In the publication bias assessment, the results from funnel plots and Egger’s test detected no publication bias.

Results and conclusions:
The investigators found in overall analysis for the highest category versus lowest category of dietary carbohydrate a significantly reduced risk of 37.3% [summarized OR = 0.627, 95% CI = 0.505 to 0.778, I2 = 59.9%, p for heterogeneity = 0.001] for esophageal cancer.
Sensitivity analyses showed no single study had essential effect on the overall result.

The investigators found for the highest category versus lowest category of dietary carbohydrate a significantly reduced risk of 43.1% [summarized OR = 0.569, 95% CI = 0.417 to 0.777] for esophageal adenocarcinoma.

The investigators found for the highest category versus lowest category of dietary carbohydrate a significantly reduced risk of 33.5% [summarized OR = 0.665, 95% CI = 0.453 to 0.975] for esophageal squamous cell carcinoma.

The investigators found in subgroup analysis by study design that the association was significant in population-based case-control studies, but not in the hospital-based case-control studies.

The investigators concluded that dietary intake of carbohydrate may contribute to the lower development of esophageal cancer. May contribute because this review article only included case-control studies and no cohort studies. As some limitations existed in tbjs meta-analysis, large scale prospective studies with detailed type of dietary carbohydrate intake are needed to verify these results.

Original title:
Dietary carbohydrate intake and the risk of esophageal cancer: a meta-analysis by Xuan F, Li W, […], Liu C.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7042123/

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The 2 main subtypes of esophageal cancer are esophageal squamous-cell carcinoma (often abbreviated to ESCC) and esophageal adenocarcinoma (EAC).
 

Objectives:
Omega-3 fatty acid and vitamin E or D co-supplementation may be an important approach to improve metabolic status in gestational diabetes, but the results are conflicting. Therefore, this review article has been conducted.

Do omega-3 fatty acid and vitamin E or D co-supplementation improve metabolic status in gestational diabetes?

Study design:
This review article included 4 RCTs.

Results and conclusions:
The investigators found omega-3 fatty acid and vitamin E or D co-supplementation was associated with a significantly reduced fasting plasma glucose level [MD = -10.47, 95% CI = -15.33 to -5.61, p  0.0001], homeostasis model of assessment-insulin resistance level [MD = -1.6, 95% CI= -2.44 to -0.77, p = 0.0002], malondialdehyde level [MD = -1.00, 95% CI = -1.05 to -0.95, p  0.00001] and triglycerides level [MD = 26.22, 95% CI = -38.94 to -13.51, p  0.0001].

The investigators found omega-3 fatty acid and vitamin E or D co-supplementation was associated with a significantly increased antioxidant capacity level [MD = 173.51, 95% CI = 164.72-182.30, p  0.00001].

The investigators found omega-3 fatty acid and vitamin E or D co-supplementation showed no effect on nitric oxide level [MD = 5.95, 95% CI = -7.48 to 19.37, p = 0.39] or total cholesterol level [MD = 1.63, 95% CI = -13.46 to 16.72, p = 0.83].

The investigators concluded omega-3 fatty acid and vitamin E or D co-supplementation have a favourable effect on metabolic status in gestational diabetes.

Original title:
Influence of omega-3 fatty acid and vitamin co-supplementation on metabolic status in gestational diabetes: A meta-analysis of randomized controlled studies by Li F, Pei L, […], Ye H.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32145487

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Objectives:
Does post-diagnosis dietary supplement use decrease total mortality, cancer mortality and recurrence among cancer survivors?

Study design:
This review article included observational studies and randomized clinical trials (RCT).

Results and conclusions:
The investigators found in 4 observational studies, compared to no supplementation, calcium supplementation significantly reduced total mortality with 12% [RR = 0.88, 95% CI = 0.77 to 1.00, I2 = 0%] among all cancer survivors.

The investigators found in 3 observational studies, compared to no supplementation, calcium supplementation significantly reduced cancer mortality with 29% [RR = 0.71, 95% CI = 0.53 to 0.95, I2 = 0%] among all cancer survivors.

The investigators found in 2 observational studies, compared to no supplementation, calcium supplementation significantly reduced cancer mortality with 34% [RR = 0.66, 95% CI = 0.47 to 0.94, I2 = 0%] among colorectal cancer survivors.

The investigators found in 2 observational studies and 2 RCT’s, compared to no supplementation, vitamin D supplementation significantly reduced total mortality with 14% [RR = 0.86, 95% CI = 0.76 to 0.99, I2 = 0%] among all cancer survivors.

The investigators found in 4 observational studies, compared to no supplementation, vitamin C supplementation significantly reduced total mortality with 21% [RR = 0.79, 95% CI = 0.68 to 0.92, I2 = 0%] among breast cancer survivors.

The investigators found in 2 observational studies, compared to no supplementation, vitamin D supplementation significantly reduced total mortality with 15% [RR = 0.85, 95% CI = 0.72 to 0.99, I2 = 0%] among breast cancer survivors.

The investigators found in 3 observational studies, compared to no supplementation, vitamin E supplementation significantly reduced total mortality with 24% [RR = 0.76, 95% CI = 0.64 tot 0.90, I2 = 0%] among breast cancer survivors.

The investigators found in 2 observational studies, compared to no supplementation, multivitamins supplementation significantly reduced cancer recurrence with 21% [RR = 0.79, 95% CI = 0.64 to 0.97, I2 = 0%] among breast cancer survivors.

The investigators found in 2 observational studies, compared to no supplementation, vitamin C supplementation significantly reduced cancer recurrence with 24% [RR = 0.76, 95% CI = 0.64 to 0.91, I2 = 0%] among breast cancer survivors.

The investigators found in 2 observational studies, compared to no supplementation, vitamin E supplementation significantly reduced cancer recurrence with 31% [RR = 0.69, 95% CI = 0.55 to 0.85, I2 = 0%] among breast cancer survivors.

The investigators concluded post-diagnosis dietary supplement use (particularly calcium, vitamin C, D and E) decreases total mortality, cancer mortality and recurrence among cancer survivors.

Original title:
Dietary Supplement Use after Cancer Diagnosis in Relation to Total Mortality, Cancer Mortality and Recurrence: A Systematic Review and Meta-Analysis by Kanellopoulou A, Riza E, […], Benetou V.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32148118

Additional information of El Mondo:
Find more information/studies on calcium, vitamin C, D, E, breast cancer and colorectal cancer right here.

Objectives:
Does high waist circumference increase liver cancer?

Study design:
This review article included  5 prospective cohort studies with 2,547,188 participants.
Participants were aged 46-58 years, with a mean age of 51 years.
The mean follow-up of participants in the studies was 7.8 years.
The mean quality (NOS scores) of the studies included was 7 (ranging from 5 to 9).

Funnel plots did not show significant asymmetry between the studies included.
Furthermore, Begg's and Egger's regression test did not show any significant publication bias (p = 0.62 and p = 0.60, respectively).

Results and conclusions:
The investigators found combined results of the studies included with random-effects model showed that the highest waist circumference category was significantly associated with an increased risk of 59% for liver cancer [HR = 1.59, 95% CI = 1.38-1.83, I2 = 0%, p = 0.42] compared to the lowest waist circumference category.

The investigators concluded that waist circumference is a significant risk factor related to the incidence of liver cancer.

Original title:
Waist Circumference and Risk of Liver Cancer: A Systematic Review and Meta-Analysis of over 2 Million Cohort Study Participants by Rahmani J, Kord Varkaneh H, [...], Zhang Y.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7024879/

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

Objectives:
The efficacy of n-3 fatty acids supplementation on the prevention of pregnancy-induced hypertension or preeclampsia remains unclear. Therefore, this meta-analysis (systematic review) has been conducted.

Does n-3 fatty acids supplementation (EPA and/or DHA and/or ALA) decrease risk of pregnancy-induced hypertension and preeclampsia during pregnancy?

Study design:
This review article included 14 RCTs.

Results and conclusions:
The investigators found that n-3 fatty acids supplementation significantly reduced risk of preeclampsia with 18% [RR = 0.82, 95% CI = 0.70 to 0.97, p = 0.024. I2 = 19.0%].
However, n-3 fatty acids supplementation did not associated with a reduced risk of pregnancy-induced hypertension [RR = 0.98, 95% CI = 0.90 to 1.07, p = 0.652, I2 = 0%].

The investigators concluded n-3 fatty acids supplementation (EPA and/or DHA and/or ALA)  reduces risk of preeclampsia during pregnancy.

Original title:
Efficacy of n-3 fatty acids supplementation on the prevention of pregnancy induced-hypertension or preeclampsia: A systematic review and meta-analysis by Bakouei F, Delavar MA, […], Taheri Z.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32039806

Additional information of El Mondo:
Find more information/studies on n-3 fatty acids, hypertension and pregnancy right here.

 

Objectives:
Epidemiologic studies have investigated the association between nut intake and risk for multiple cancers. However, current findings are inconsistent and no definite conclusion has been drawn from prospective studies. Therefore, this review article has been conducted.

Does nut consumption reduce cancer risk?

Study design:
This review article included 33 cohort studies with more than 50,000 cancer cases.

Results and conclusions:
The investigators found when comparing the highest with the lowest category of nut consumption, high consumption of nuts significantly decreased risk of overall cancer with 10% [RR = 0.90, 95% CI = 0.85-0.95].
Significant association was only obtained for intake of tree nuts.

The investigators found when comparing the highest with the lowest category of nut consumption, high consumption of nuts significantly decreased risk of cancer from the digestive system with 17% [RR = 0.83, 95% CI = 0.77-0.89].

The investigators found per 20 g/day increase in nut consumption was related to a 10% [RR = 0.90, 95% CI = 0.82-0.99] decrease in cancer risk.

The investigators concluded that consumption of 20 grams of tree nuts per day reduces cancer of the digestive system.

Original title:
Nut Consumption and Risk of Cancer: A Meta-analysis of Prospective Studies by Long J, Ji Z, […], Cheng L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32041895

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

Objectives:
Which factors are associated with the risk of stomach cancer?

Study design:
This review article included 232 observational studies involving 33,831,063 participants.

Results and conclusions:
The investigators found H. pylori infection significantly increased risk of stomach cancer with 156% [OR = 2.56, 95% CI = 2.18 to 3.00].

The investigators found formerly smoked significantly increased risk of stomach cancer with 43% [OR = 1.43, 95% CI = 1.29 to 1.59].

The investigators found currently smoking significantly increased risk of stomach cancer with 61% [OR = 1.61, 95% CI = 1.49 to 1.75].

The investigators found currently drinking significantly increased risk of stomach cancer with 19% [OR = 1.19, 95% CI = 1.10 to 1.29].

The investigators found formerly drank significantly increased risk of stomach cancer with 73% [OR = 1.73, 95% CI = 1.17 to 2.56].

The investigators found intake of fruits ≥3 times/week significantly decreased risk of stomach cancer with 52% [OR = 0.48, 95% CI = 0.37 to 0.63].

The investigators found intake of vegetables ≥3 times/week significantly decreased risk of stomach cancer with 38% [OR = 0.62, 95% CI = 0.49 to 0.79].

The investigators found using pickled vegetables significantly increased risk of stomach cancer with 28% [OR = 1.28, 95% CI = 1.09 to 1.51].

The investigators found green tea significantly decreased risk of stomach cancer with 12% [OR = 0.88, 95% CI = 0.80 to 0.97].

The investigators concluded that both smoking, drinking and H. pylori infection increase the risk of stomach cancer, while both ≥3 times/week fruit and vegetables and green tea reduce the risk of developing stomach cancer.

Original title:
Risk factors for stomach cancer: a systematic review and meta-analysis by Poorolajal J, Moradi L, [...], Gohari-Ensaf F.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/32023777

Additional information of El Mondo:
Find more information/studies on alcohol, tea, vegetable and fruit and cancer right here.

Objectives:
Does dietary intake of fiber reduce risk of endometrial cancer?

Study design:
This review article included 16 studies, involving 6,563 cases (persons with endometrial cancer).

Results and conclusions:
The investigators found dietary fiber intake significantly reduced risk of endometrial cancer with 14% [RR = 0.86, 95% CI = 0.78 to 0.93].
In stratified analysis, this trend was more pronounced in the case-control studies and in studies conducted in the Americas and Asia.

The investigators found dietary fiber intake significantly reduced risk of endometrial cancer with 26% after adjusting for education level [RR = 0.74, 95% CI = 0.60 to 0.88].

The investigators found dietary fiber intake significantly reduced risk of endometrial cancer with 30% after adjusting for age [RR = 0.70, 95% CI = 0.57 to 0.83].

The investigators found dietary fiber intake significantly reduced risk of endometrial cancer with 19% in studies with NOS scores of 6 (the higher the NOS scores, the more reliable the studies are) [RR = 0.81, 95% CI = 0.67 to 0.95].

The investigators found dietary fiber intake significantly reduced risk of endometrial cancer with 25% in studies with NOS scores of 7 [RR = 0.75, 95% CI = 0.62 to 0.88].

The investigators concluded dietary fiber intake reduces risk of endometrial cancer. Further efforts should be made to confirm these findings.

Original title:
Association between dietary fiber and endometrial cancer: a meta-analysis by Li H, Mao H, [...], Nan Y.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31584301

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Find more information/studies on fiber, significantly/review article and cancer right here

Objectives:
Does dietary intake of garlic reduce risk of colorectal cancer?

Study design:
This review article included 11 studies involving 12,558 cases (persons with colorectal cancer).

There was no notable evidence of publication bias.

Results and conclusions:
The investigators found for the highest versus the lowest garlic consumption categories, a significantly reduced risk of 20% [integrated relative risk = 0.80, 95% CI = 0.69 to 0.91] for colorectal cancer.
The sensitivity analysis revealed no notable alterations of the integrated results.
Significant means that there is an association with a 95% confidence.

The investigators found in case-control studies for the highest versus the lowest garlic consumption categories, a significantly reduced risk of 29% [relative risk = 0.71, 95% CI = 0.60 to 0.84] for colorectal cancer.
Significant because relative risk of 1 was not found in the 95% CI of 0.60 to 0.84. Relative risk of 1 means no risk/association.

The investigators found in cohort studies for the highest versus the lowest garlic consumption categories, a non-significantly reduced risk of 1% [relative risk = 0.99, 95% CI = 0.80 to 1.23] for colorectal cancer.
Non-significantly because relative risk of 1 was found in the 95% CI of 0.80 to 1.23. Relative risk of 1 means no risk/association.

The investigators concluded that dietary intake of garlic could reduce risk of colorectal cancer. Could reduce because the risk was not significant in cohort studies.

Original title:
Garlic intake and the risk of colorectal cancer: A meta-analysis by Zhou X, Qian H, […], Zeng L.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31895803

Additional information of El Mondo:
Find more information/studies on significantly/cohort studies, garlic consumption and colorectal cancer right here.

Objectives:
Does dehydroepiandrosterone (DHEA) supplementation improve the outcomes of in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) in women with diminished ovarian reserve (DOR) and/or poor ovarian response (POR)?

Study design:
This review article included 9 RCTs, published between 2010 and 2017.
The sample sizes ranged from 24 to 208, with a total of 862 patients.
All of included patients had been diagnosed with diminished ovarian reserve (DOR) and/or poor ovarian response (POR).

The treatment intervention was 75 mg daily DHEA versus placebo.

The lack of significant asymmetry of funnel plot indicated the lack of potential publication bias in the included studies.

Results and conclusions:
The investigators found in a pooled analysis using the random effects model revealed a statistically significant increase in retrieved oocytes in the DHEA group, compared to the control group [MD = 0.91, 95% CI = 0.23 -1.59, p = 0.009, I2  = 53%, p = 0.06].

The investigators found in 8 studies (405 in the DHEA group and 415 in the control group) a statistically significant increase in the clinical pregnancy rate in the DHEA group compared to the control group [RR = 1.27, 95% CI = 1.01 -1.61, p = 0.04, I2 = 0%, p = 0.57].

The investigators found in 5 studies (189 in the DHEA group and 190 in the control group) a statistically significant increase in the live birth rate in the DHEA group, compared to the control group [RR = 1.76, 95% CI = 1.17 -2.63, p = 0.006, I2  = 0%, p = 0.43].

The investigators found in 3 studies (96 in the DHEA group and 99 in the control group) no significant difference in the miscarriage rates between the DHEA and control groups [RR = 0.37, 95% CI = 0.12-1.13, p = 0.08, I2 = 25%, p = 0.26].

The investigators concluded 75 mg daily DHEA supplementation increases the retrieved oocytes, clinical pregnancy rate and live birth rate in women with diminished ovarian reserve and/or poor ovarian response, who are undergoing in vitro fertilization or intracytoplasmic sperm injection.

Original title:
The Effect of Dehydroepiandrosterone (DHEA) Supplementation on IVF or ICSI: A Meta-Analysis of Randomized Controlled Trials by Xu L, Hu C, […], Li Y.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6620181/

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Find more information/studies on pregnancy right here.

Your body naturally produces the hormone dehydroepiandrosterone (DHEA) in the adrenal gland. In turn, DHEA helps produce other hormones, like testosterone and estrogen. Natural dehydroepiandrosterone levels peak in early adulthood and then slowly fall as you age.

 

Objectives:
Some evidence indicates that carotenoids may reduce the risk of bladder cancer (BC), but the association is unclear. Therefore, this review article has been conducted.

Do carotenoids (β-cryptoxanthin, α-carotene, β-carotene and lutein and zeaxanthin) reduce risk of bladder cancer?

Study design:
This review article included a total of 22 studies (case-control and cohort studies) involving 516,740 adults.

Results and conclusions:
The investigators found for the highest compared with the lowest category of carotenoid dietary intake a non-significantly reduced risk of 12% [RR = 0.88, 95% CI = 0.76 to 1.03] for bladder cancer.
Non-significantly because RR of 1 was found in the 95% CI of 0.76 to 1.03. RR of 1 means no risk/association.

The investigators found for the highest compared with the lowest category of circulating carotenoid concentrations a non-significantly reduced risk of 64% [RR = 0.36, 95% CI = 0.12 to 1.07] for bladder cancer.

The investigators found for the highest compared with the lowest category of circulating lutein and zeaxanthin concentrations a significantly reduced risk of 47% [RR = 0.53, 95% CI = 0.33 to 0.84] for bladder cancer.
Significantly because RR of 1 was not found in the 95% CI of 0.33 to 0.84. RR of 1 means no risk/association.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 42% [RR = 0.58, 95% CI = 0.36 to 0.94] for every 1 mg increase in daily dietary β-cryptoxanthin intake.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 76% [RR = 0.24, 95% CI = 0.08 to 0.67] for every 1 μmol/L increase in circulating concentration of α-carotene.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 27% [RR = 0.73, 95% CI = 0.57 to 0.94] for every 1 μmol/L increase in circulating concentration of β-carotene.

The investigators found dose-response analysis showed that bladder cancer risk significantly decreased by 56% [RR = 0.44, 95% CI = 0.28 to 0.67] for every 1 μmol/L increase in circulating concentrations of lutein and zeaxanthin.

The investigators concluded dietary β-cryptoxanthin intake and circulating concentrations of α-carotene, β-carotene and lutein and zeaxanthin reduce risk of bladder cancer.

Original title:
Carotenoid Intake and Circulating Carotenoids Are Inversely Associated with the Risk of Bladder Cancer: A Dose-Response Meta-analysis by Wu S, Liu Y, […], Ramirez AG.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/31800007

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