Nutrition and health

Objectives:
Even though many studies have examined the possible effect of low-fat diet on breast cancer survival, the relationship remains unclear. Therefore, this review article has been conducted.

Does low-fat diet reduce risk of recurrence of breast cancer?

Study design:
This review article included 2 randomized controlled trials (RCTs) and 1 large multi-center prospective cohort study with 9,966 breast cancer patients.

Results and conclusions:
The investigators found post-diagnostic low-fat diet significantly reduced risk of recurrence of breast cancer by 23% [HR = 0.77, 95% CI = 0.63 to 0.94, p = 0.009] and all cause mortality of breast cancer by 17% [HR = 0.83, 95% CI = 0.69 to 1.00, p = 0.05].

The investigators concluded post-diagnostic low-fat diet reduces risk of recurrence of breast cancer. However, more trials of the relationship between low-fat diet and all-cause mortality of breast cancer are still needed.

Original title:
Effect of low-fat diet on breast cancer survival: a meta-analysis by Xing MY, Xu SZ and Shen P.

Link:
https://pubmed.ncbi.nlm.nih.gov/24606431/

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

A low-fat diet is a diet with maximum 30 En% fat and maximum 7 En% saturated fat.  
30 En% fat means that the amounts of fat contribute 30% to the total calories (kcal) of the diet.
If the diet contains 2000 kcal, 66.7 grams of fat contribute 30% to this 2000 kcal.
1 gram of fat gives 9 kcal. Thus, 66.7 grams of fat provide 600 kcal and 600 kcal is 30% of 2000 kcal.

The most easy way to follow a diet a diet with maximum 30 En% fat and maximum 7 En% saturated fat is to choose only meals/products with maximum 30 En% fat and maximum 7 En% saturated fat. Check here which products contain maximum 30 En% fat and maximum 7 En% saturated fat.

However, the most practical way to follow a diet with maximum 30 En% fat and maximum 7 En% saturated fat is, all meals/products that you eat on a daily basis should contain on average maximum 30 En% fat and maximum 7 En% saturated fat.

To do this, use the 7-points nutritional profile app to see whether your daily diet contains maximum 30 En% fat and maximum 7 En% saturated fat.

Objectives:
Lung cancer is the most common cause of cancer death. Fruits and vegetables containing carotenoids and other antioxidants have been hypothesized to decrease lung cancer risk. Therefore, this meta-analysis (systematic review) has been conducted.

Do fruits and vegetables reduce lung cancer risk?

Study design:
This review article included prospective cohort studies up to December 2014.

Results and conclusions:
The investigators found in 18 studies, when comparing the highest fruits and vegetables with the lowest intakes, a significantly reduced risk of 14% for lung cancer [summary RR = 0.86 [95% CI = 0.78-0.94].

The investigators found in 25 studies, when comparing the highest vegetables with the lowest intakes, a significantly reduced risk of 8% for lung cancer [summary RR = 0.92 [95% CI = 0.87-0.97].

The investigators found in 29 studies, when comparing the highest fruits with the lowest intakes, a significantly reduced risk of 18% for lung cancer [summary RR = 0.82, 95% CI = 0.76-0.89].

The investigators found the association with fruit and vegetable intake was marginally significant in current smokers and inverse but not significant in former or never smokers.

The investigators found in 4 studies for each 100 g/day increase of fruits and vegetables, a significantly reduced risk of 4% for lung cancer [RR = 0.96, 95% CI = 0.94-0.98, I2 = 64%, n (cases) = 9,609].

The investigators found in 20 studies for each 100 g/day increase of vegetables, a significantly reduced risk of 6% for lung cancer [RR = 0.94, 95% CI = 0.89-0.98, I2 = 48%, n (cases) = 12,563].

The investigators found in 23 studies for each 100 g/day increase of fruits, a significantly reduced risk of 8% for lung cancer [RR = 0.92, 95% CI = 0.89-0.95, I2 = 57%, n (cases) = 14,506].

The investigators found the results were consistent among the different types of fruits and vegetables. However, the strength of the association differed across locations.

The investigators found evidence of a non-linear relationship [p 0.01] between fruit and vegetable intake and lung cancer risk showing that no further benefit is obtained when increasing consumption above ∼400g per day.

The investigators concluded fruits and/or vegetables intakes reduce risk of lung cancer with no further benefit when increasing consumption of fruits and vegetables above ∼400g per day.

Original title:
Fruits, vegetables and lung cancer risk: a systematic review and meta-analysis by Vieira AR, Abar L, […], Norat T.

Link:
http://www.ncbi.nlm.nih.gov/pubmed/26371287

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

Objectives:
Evidence shows cruciferous vegetables exhibit chemoprotective properties, commonly attributed to their rich source of isothiocyanates. However, epidemiological data examining the association between cruciferous vegetable intake and colorectal neoplasms have been inconclusive. Therefore, this review article (meta-analysis) has been conducted.

Does cruciferous vegetable intake decrease colon cancer risk?

Study design:
This review article included 33 articles.
Subgroup analysis for individual cruciferae types (n = 8 studies) and GST polymorphism (n = 8 studies) were performed. Pooled adjusted odds ratios (ORs) comparing highest and lowest categories of dietary pattern scores were calculated.

Results and conclusions:
The investigators found when comparing highest with lowest categorie, cruciferous vegetable intake significantly reduced risk of colon cancer with 16% [OR = 0.84, 95% CI = 0.72-0.98, p value heterogeneity 0.001].

The investigators found when comparing highest with lowest categorie, broccoli intake significantly reduced risk of colorectal neoplasms with 20% [OR = 0.80, 95% CI = 0.65-0.99, p value heterogeneity = 0.02].

The investigators found stratification by GST genotype showed that the GSTT1 null genotype confered a reduction in colorectal neoplasms risk of 22% [OR = 0.78, 95% CI = 0.64-0.95, p value heterogeneity = 0.32].

The investigators concluded this meta-analysis provides support to the hypothesis that cruciferous vegetable intake protects against cancer of the colon. This meta-analysis also demonstrates the significance of gene-diet interactions and the importance of assessing individual cruciferous vegetables.

Original title:
Cruciferous vegetables and risk of colorectal neoplasms: a systematic review and meta-analysis by Tse G and Eslick GD.

Link:
http://www.ncbi.nlm.nih.gov/pubmed/24341734

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Objectives:
Does physical activity reduce gastric cancer risk?

Study design:
This review article included 7 cohort studies (with mean reported follow-up ranging from 6 to 18.8 years) and 9 case control studies reporting 11,111 cases of gastric cancer among 1,606,760 patients.

There was no evidence of publication bias, both quantitatively [Begg and Mazumdar rank correlation test, p = 0.62] and qualitatively, on visual inspection of the funnel plot.

Results and conclusions:
The investigators found the risk of gastric cancer was 21% [OR = 0.79, 95% CI = 0.71-0.87, I2 = 55%]  lower among the most physically active people as compared with the least physically active people, after adjustment for important confounders, including age, obesity, and other risk factors for gastric cancer (smoking, alcohol, dietary patterns and socioeconomic status).
This protective effect was seen for gastric cancers in the cardia [OR = 0.80, 95% CI = 0.63-1.00, 4 studies] and distal stomach [OR = 0.63, 95% CI = 0.52-0.76, 5 studies].

The investigators found increasing physical activity was associated with a reduced risk of gastric cancer in both men [OR = 0.86, 95% CI = 0.75-0.99, 10 studies] and women [OR = 0.72, 95% CI = 0.55-0.94, 3 studies].

The investigators found in 12 studies that increased recreational physical activity showed an 18% reduction in gastric cancer risk [OR = 0.82, 95% CI = 0.72-0.94].

The investigators found the effect size was significantly smaller in high-quality studies [OR = 0.86, 95% CI = 0.75-0.99, 6 studies] as compared with low-quality studies [OR = 0.74, 95% CI = 0.69-0.81, 10 studies]. The results were consistent across sex, study quality, study design and geographic location.

The investigators concluded physical activity - especially recreational physical activity - is associated with reduced risk of gastric cancer. Lifestyle interventions focusing on increasing physical activity may decrease the global burden of gastric cancer, in addition to a myriad of other health benefits with being physically active, which include cardiovascular, metabolic and psychologic wellbeing.

Original title:
Physical Activity Is Associated with Reduced Risk of Gastric Cancer: A Systematic Review and Meta-analysis by Singh S, Varayil JE, […], Iyer PG.

Link:
http://cancerprevention.aacrjournals.org/content/7/1/12.abstract

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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

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Objectives:
Does allium vegetable consumption reduce gastric cancer risk?

Study design:
This review article included 22 case-control and 4 cohort studies with more than 10,000 cases.

Results and conclusions:
The investigators found in 10 case-control and 4 cohort studies for the highest versus lowest allium vegetables intake category a significant reduced risk of 22% for gastric cancer [OR = 0.78, 95% CI = 0.67-0.91].

The investigators found in 12 case-control studies for the highest versus lowest garlic intake category a significant reduced risk of 40% for gastric cancer [OR = 0.60, 95% CI = 0.47-0.76].

The investigators found in 13 case-control studies for the highest versus lowest onion intake category a significant reduced risk of 45% for gastric cancer [OR = 0.55, 95% CI = 0.41-0.73].

The investigators found in 4 cohort studies for the highest versus lowest allium vegetables intake category a non-significant increased risk of 2% for gastric cancer [RR = 1.02, 95% CI = 0.88-1.18]. Non-significant means no association with 95% confidence.

The investigators concluded high allium vegetable consumption, like garlic and onion is likely to reduce gastric cancer risk. Likely because this evidence is derived mainly from case-control studies. Therefore, further data from large cohorts are desirable for conclusive confirmation.

Original title:
Allium vegetable intake and gastric cancer: a case-control study and meta-analysis by Turati F, Pelucchi C, […], Galeone C.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/25215621

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Objectives:
There are conflicting reports on the correlation between manganese (Mn) levels and breast cancer. Therefore, this review article (meta-analysis) has been conducted.

Does manganese deficiency increase risk of breast cancer?

Study design:
This review article included 11 case-control studies involving 1302 subjects.

There was no evidence of publication bias. Sensitivity analysis showed that excluding any one study from the pooled analysis did not vary the results substantially.

Results and conclusions:
The investigators found the random-effects meta-analysis results indicated that subjects with breast cancer had lower manganese levels in serum and hair than healthy controls [SMD = -1.51, 95% CI = -2.47 to -0.56, I2 = 97.8%, p 0.001].

The investigators found in subgroup analysis that subjects with breast cancer had lower manganese levels than healthy controls in China [SMD = -1.32, 95% CI = -2.33 to -0.32] and Korea [SMD = -4.08, 95% CI = -4.63 to -3.54], but not in Turkey [SMD = -0.96, 95% CI = -3.19 to 1.27].

The investigators found in subgroup analysis that the differences of manganese levels between patients with breast cancer and healthy controls were similar in different sample specimens:
serum [SMD = -1.24, 95% CI = -2.31 to -0.16];
hair [SMD = -1.99, 95% CI = -3.91 to -0.06] and;
different types of manganese measurement:

ICP-AAS [SMD = -1.14, 95% CI = -2.24 to -0.04];
GFAAS [SMD = -1.94, 95% CI = -2.38 to -1.49];
ICP-AES [SMD = -3.77, 95% CI = -4.70 to -2.85]. These findings can well explain that  the between-study variability was the main source of heterogeneity.

The investigators concluded there is an association between deficient manganese concentration and breast cancer. However, the subgroup analysis found that there was contradiction regarding races and geography, like China and Turkey. Thus this finding needs further confirmation by trans-regional multicenter, long-term observation in a cohort design to obtain better understanding of causal relationships between manganese levels and breast cancer, through measuring manganese at baseline to investigate whether the highest manganese category versus lowest was associated with breast cancer risk.

Original title:
The association between deficient manganese levels and breast cancer: a meta-analysis by Shen F, Cai WS, [...],Xu B.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4443096/

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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

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Objectives:
Is there an association of intake of different vitamins and multiple-vitamin supplements and the incidence of colorectal cancer?

Study design:
This review article included 47 articles (cohort studies).

There was unacceptable heterogeneity for studies of multiple-vitamin supplements, so findings were inconclusive.

Results and conclusions:
The investigators found a significant reduced risk of 12% [multivariable-adjusted RR = 0.88, 95% CI = 0.81-0.95] for colorectal cancer when comparing the highest versus lowest dietary vitamin B9 (folate) intake. Significant means that there is an association with a 95% confidence.

The investigators found a significant reduced risk of 13% [multivariable-adjusted RR = 0.87, 95% CI = 0.77-0.99] for colorectal cancer when comparing the highest versus lowest dietary vitamin D intake. Significant because RR of 1 was not found in the 95% CI of 0.77 to 0.99. RR of 1 means no risk/association.

The investigators found a significant reduced risk of 12% [multivariable-adjusted RR = 0.88, 95% CI = 0.79-0.99] for colorectal cancer when comparing the highest versus lowest dietary vitamin B6 intake.

The investigators found a significant reduced risk of 14% [multivariable-adjusted RR = 0.86, 95% CI = 0.76-0.97] for colorectal cancer when comparing the highest versus lowest dietary vitamin B2 intake.

The investigators found, however, no association between both dietary vitamine A, C, E, B3 and B12 and the risk of colorectal cancer.

The investigators concluded high dietary vitamin B9 (folate), D, B6 and B2 intake reduces risk of colorectal cancer, but further study is needed.

Original title:
Vitamin and multiple-vitamin supplement intake and incidence of colorectal cancer: a meta-analysis of cohort studies by Liu Y, Yu Q, […], Li K.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/25491145

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Objectives:
Red meat intake has been associated with risk of colorectal cancer, potentially mediated through heterocyclic amines. The metabolic efficiency of N-acetyltransferase 2 (NAT2) required for the metabolic activation of such amines is influenced by genetic variation. The interaction between red meat intake, NAT2 genotype and colorectal cancer has been inconsistently reported. Therefore, this review article has been conducted.

Is there an interaction between red meat intake, NAT2 genotype and colorectal cancer?

Study design:
This review article included 11 retrospective case-control studies with 8,290 colorectal cancer cases and 9,115 controls (subjects without colorectal cancer).

Results and conclusions:
The investigators found the highest quartile of red meat intake was associated with a 41% increased risk of colorectal cancer compared with the lowest quartile [OR = 1.41, 95% CI = 1.29-1.55].
However, a significant association was observed only for studies with retrospective diet data, not for studies with diet prospectively assessed before cancer diagnosis.

The investigators found when combining all studies, high red meat intake was similarly associated with colorectal cancer in those with a rapid/intermediate NAT2 genotype [OR = 1.38, 95% CI = 1.20-1.59] as with a slow genotype [OR = 1.43, 95% CI = 1.28-1.61, p interaction = 0.9].

The investigators concluded high red meat intake was associated with increased risk of colorectal cancer only from retrospective case-control studies and not modified by NAT2 enzyme activity.

Original title:
Red Meat Intake, NAT2, and Risk of Colorectal Cancer: A Pooled Analysis of 11 Studies by Ananthakrishnan AN, Du M, […], Chan AT.

Link:
http://cebp.aacrjournals.org/content/cebp/24/1/198.full.pdf

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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/

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