Nutritional advice

Objectives:
Does consumption of fruits and vegetables reduce risk of endometrial cancer?

Study design:
This review article included  of 21 case-control studies and 6 cohort studies.

Results and conclusions:
The investigators found that vegetables consumption significantly reduced risk of endometrial cancer with 24% [pooled odds ratio [OR], relative risk [RR], hazard ratio [HR] = 0.76, 95% CI = 0.63 to 0.91].

The investigators found that cruciferous vegetables consumption significantly reduced risk of endometrial cancer with 19% [pooled OR = 0.81, 95% CI = 0.70 to 0.94].

The investigators found that dark green and yellow/orange combined vegetables consumption significantly reduced risk of endometrial cancer with 36% [pooled OR = 0.64, 95% CI = 0.42 to 0.97].

The investigators found that fruits consumption significantly reduced risk of endometrial cancer with 19% [pooled OR = 0.81, 95% CI = 0.70 to 0.92].

The investigators found these results were primarily based on studies of high quality and exhibited either by case-control only or a combination of case-control and cohort studies. Additionally, the results varied by geographic location, such as Western areas, the US and Italy.

The investigators concluded that consumption of fruits and vegetables has beneficial effects on endometrial cancer risk and that specific kinds of fruits and vegetables should be recommended differently due to their outstanding bioactive components.

Original title:
The influence of dietary vegetables and fruits on endometrial cancer risk: a meta-analysis of observational studies by Lu YT, Gunathilake M and Kim J.

Link:
https://pubmed.ncbi.nlm.nih.gov/36151331/

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

Objectives:
There is keen interest in better understanding the impacts of alpha-linolenic acid (ALA), a plant-derived n-3 fatty acid, in ameliorating the development of cancer. However, results of several prospective cohort studies present an inconsistent association between ALA intake and the incident colorectal cancer (CRC). Therefore, this review article has been conducted.

Does a high dietary intake of alpha-linolenic acid or a high level of alpha-linolenic acid in blood reduce risk of colorectal cancer (colon and rectal cancer)?

Study design:
This review article included 15 cohort studies (11 studies on diet and 5 studies on biomarkers including 4 on blood and 1 on adipose tissue) with 12,239 colorectal cancer cases occurred among 861,725 participants.
The mean follow-up was 9.3 years (ranging from 1 to 28 years).
Among all of the included studies, quality scores assessed by the 9-star NOS ranged from 7 to 9, with a median quality (≤7 stars) in 2 studies and high quality (≥ 8 stars) in 13 studies.

There was no publication bias.

Results and conclusions:
The investigators found higher level of alpha-linolenic acid in blood significantly reduced risk of colorectal cancer with 17% [summary RR = 0.83, 95% CI = 0.69 to 0.99, I2 = 0.0%].

The investigators found each 0.1% increase in the level of alpha-linolenic acid in blood was significantly associated with a 10% reduction in colorectal cancer risk [summary RR = 0.90, 95% CI = 0.80 to 0.99, I2 = 38.6%].

The investigators no significant dose-response association between dietary intake of alpha-linolenic acid and the incident colorectal cancer [p for non-linearity = 0.18; p for linearity = 0.24].

The investigators concluded that higher blood levels of alpha-linolenic acid reduce risk of colorectal cancer while higher dietary intake of alpha-linolenic acid does not reduce risk of colorectal cancer. Encouraging the consumption of foods rich in alpha-linolenic acid to improve its levels in the blood may potentially decrease the risk of colorectal cancer. Nevertheless, well-designed and large-scale cohort studies with biomarkers are still needed for better reconfirming the potential impacts of alpha-linolenic acid intake in the primary prevention of colorectal cancer.

Original title:
Association of Dietary Intake and Biomarker of α-Linolenic Acid With Incident Colorectal Cancer: A Dose-Response Meta-Analysis of Prospective Cohort Studies by Dai ZB, Ren XL, […], Xu L.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9301188/

Additional information of El Mondo:
Find more information/studies on colorectal cancer and alpha-linolenic acid consumption right here.

Objectives:
Colorectal cancer is one of the most commonly diagnosed and deadly cancers worldwide. Epidemiological studies on the relationship between folate intake and the risk of colorectal cancer have reported inconsistent findings since folate fortification in the USA. Therefore, this review article has been conducted.

Does a high folate (folic acid) ietary intake reduce risk of colorectal cancer (colon and rectal cancer)?

Study design:
This review article included 24 cohort studies involving 6,165,894 individuals, of which 37,280 persons with colorectal cancer.

Results and conclusions:
The investigators found compared with the lowest dietary intake, the highest folate dietary intake significantly reduced risk of colorectal cancer with 12% [combined relative risk (RR) = 0.88, 95% CI = 0.83 to 0.92, p = 0.0004].
Significantly means that there is an association with a 95% confidence.

The investigators found compared with the lowest dietary intake, the highest folate dietary intake significantly reduced risk of colorectal cancer with 3% among persons witih medium alcohol consumption [RR = 0.97, 95% CI = 0.96 to 0.99, p = 0.008].
Significantly because RR of 1 was not found in the 95% CI of 0.96 to 0.99. RR of 1 means no risk/association.

The investigators found compared with the lowest dietary intake, the highest folate dietary intake significantly reduced risk of colorectal cancer with 5% among persons witih high alcohol consumption [RR = 0.95, 95% CI = 0.92 to 0.97, p = 0.003].

The investigators found compared with the lowest dietary intake, the highest folate dietary intake did not reduce risk of colorectal cancer among non-drinkers [RR = 1.00, 95% CI = 0.98 to 1.02, p = 0.827].

The investigators found compared with the lowest dietary intake, the highest folate dietary intake significantly reduced risk of colon cancer with 14% [RR = 0.86, 95% CI = 0.81 to 0.92, p = 0.0004].
Significantly because the calculated p-value of 0.0004 was less than the p-value of 0.05.

The investigators found compared with the lowest dietary intake, the highest folate dietary intake did not reduce risk of rectal cancer [RR = 0.92, 95% CI = 0.84 to 1.02, p = 0.112].

The investigators found compared with the lowest dietary intake, the highest folate dietary intake significantly reduced risk of colorectal cancer in USA and Europe but not in other regions.

The investigators concluded that high folate dietary intake reduces risk of colon cancer, particularly in people with medium or high alcohol consumption, but it still needs to be further confirmed.

Original title:
Folate intake and risk of colorectal cancer: a systematic review and up-to-date meta-analysis of prospective studies by Fu H, He J, […], Chang H.

Link:
https://pubmed.ncbi.nlm.nih.gov/35579178/

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Colorectal cancer starts in the colon or the rectum. These cancers can also be called colon cancer or rectal cancer, depending on where they start.

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

Does a higher dietary intake of meat increases the risk of hepatocellular carcinoma?

Study design:
This review article included 17 observational studies involving 2,915,680 participants, of which 4,953 cases of hepatocellular carcinoma.

10 studies reported red meat intake, 9 reported white meat intake, 9 reported fish intake, 7 reported processed meat intake and 5 reported total meat intake.

Results and conclusions:
The investigators found results showed that the consumption of red meat [relative risk = 1.04, 95% CI = 0.91 to 1.18, I2 = 50.50%, p = 0.033] and total meat intake [relative risk = 1.01, 95% CI =  0.90 to 1.13, I2 = 15.50%, p = 0.316] were not significantly associated with risk of hepatocellular carcinoma.

The investigators found, however, a higher dietary intake of processed meat significantly increased the risk of hepatocellular carcinoma with 20% [relative risk = 1.20, 95% CI = 1.02 to 1.41, I2 = 26.30%, p = 0.228].
Significant because relative risk of 1 was not found in the 95% CI of 1.02 to 1.41. Relative risk of 1 means no risk/association.

The investigators found, in contrast, a higher dietary intake of white meat significantly decreased the risk of hepatocellular carcinoma with 24% [relative risk = 0.76, 95% CI = 0.63 to 0.92, I2 = 68.30%, p = 0.001].

The investigators found, in contrast, a higher dietary intake of fish significantly decreased the risk of hepatocellular carcinoma with 9% [relative risk = 0.91, 95% CI = 0.86 to 0.96, I2 = 40.90%, p = 0.095].

The investigators concluded that a higher dietary intake of processed meat increases the risk of hepatocellular carcinoma, while a higher dietary intake of both white meat and fish decrease the risk of hepatocellular carcinoma. Therefore, these findings suggest that dietary intervention may be an effective approach to preventing hepatocellular carcinoma. These need to be verified with further well-designed observational studies and experimental clinical research.  

Original title:
Meat Intake and the Risk of Hepatocellular Carcinoma: A Meta-Analysis of Observational Studies by Yu J, Liu Z, […], Chen W.

Link:
https://pubmed.ncbi.nlm.nih.gov/35583453/

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Processed meats are meats that have been preserved by smoking or salting, curing or adding chemical preservatives. They include deli meats, bacon and hot dogs.

Objectives:
Evidence associating diet with the incidence of renal cell carcinoma (RCC) is inconclusive. Therefore, this umbrella review article has been conducted.

What is the association between diet and renal cell carcinoma incidence?

Study design:
This umbrella review article included 22 meta-analyses with a total of 502 individual studies and 64 summary hazard ratios (HRs) for renal cell carcinoma incidence: dietary patterns or dietary quality indices (n = 6), foods (n = 13), beverages (n = 4), alcohol (n = 7), macronutrients (n =15) and micronutrients (n =19).

No meta-analyses had high methodological quality.

59% of these 502 individual studies were cohort studies (n = 298), 39% were case-control studies (n = 196) and 2% were pooled studies (n = 8).

Sixty (94%) exposures in the included meta-analyses had more than 1,000 cases or 20,000 participants.

Results and conclusions:
The investigators found no dietary factors showed convincing or highly suggestive evidence of association with renal cell carcinoma incidence in the overall analysis.

The investigators found in the overall analysis that dietary intake of vegetables significantly reduced risk of renal cell carcinoma with 26% [summary HR = 0.74, 95% = 0.63 to 0.86, suggestive evidence].

The investigators found in the overall analysis that dietary intake of vitamin C significantly reduced risk of renal cell carcinoma with 23% [summary HR = 0.77, 95% = 0.66 to 0.90, suggestive evidence].

The investigators found in the overall analysis that moderate drinking significantly reduced risk of renal cell carcinoma with 23% [summary HR = 0.77, 95% = 0.70 to 0.84, convincing evidence] in Europe and North America.

The investigators found in the overall analysis that dietary intake cruciferous vegetables significantly reduced risk of renal cell carcinoma with 22% [summary HR = 0.78, 95% = 0.70 to 0.86, highly suggestive evidence] in North America.

The investigators concluded dietary intake of vegetables and vitamin C could reduce renal cell carcinoma risk. Moderate drinking might be beneficial for Europeans and North Americans and cruciferous vegetables might be beneficial to North Americans, but the results should be interpreted with caution because no meta-analyses had high methodological quality. More researches are needed in the future.

Original title:
The role of diet in renal cell carcinoma incidence: an umbrella review of meta-analyses of observational studies by Liao Z, Fang Z, […], Luo Z.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8812002/

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An umbrella review article is a scientific article which only includes meta-analyses (also called review articles). The results found in an umbrella review article are more reliable than found in an individual review article.

One swallow does not make a summer. A famous Dutch saying that could not be any more obvious. Just because one single scientific study about a certain topic makes certain claims, it does not necessarily mean it is true. On the other hand, a review article (a collection of scientific studies on a certain topic) of randomized, placebo-controlled double blind clinical trials (RCTs) will answer the following question:
"Do taking dietary supplements make sense?" Yes for a positive conclusion and no for a negative conclusion.

One swallow does not make a summer. A famous Dutch saying that could not be any more obvious. Just because one single scientific study about a certain topic makes certain claims, it does not necessarily mean it is true. On the other hand, a review article (a collection of scientific studies on a certain topic) of (prospective) cohort studies or case-control studies will answer the following question:
"Should I change my diet?".

Objectives:
Does a high olive oil consumption reduce cancer risk?

Study design:
This review article included 37 case-control studies with 17,369 cases (persons with cancer) and 28,294 controls (persons without cancer) and 8 cohort studies with 12,461 incident cases among 929,771 subjects (participants).

Significant publication bias was detected via Egger’s test in the analysis on overall cancer risk [p 0.001], breast cancer [p = 0.013] and gastrointestinal cancer risk [p = 0.048].

Results and conclusions:
The investigators found in pooled analysis of case-control and cohort studies that highest olive oil consumption was significantly associated with a 31% lower risk of any cancer [pooled RR = 0.69, 95% CI = 0.62 to 0.77].  
Significantly means that there is an association with a 95% confidence.

The investigators found subgroup analyses showed that the protective effect of high olive oil consumption in terms of cancer risk was also significant in case-control studies [37 study arms, RR = 0.65, 95% CI = 0.57 to 0.74] but not in cohort studies [8 study arms, RR = 0.90, 95% CI = 0.77 to 1.05].
Furthermore, the protective association was also found in a multivariate analysis [32 study arms, RR = 0.72, 95% CI = 0.65 to 0.81], a high study quality analysis [RR = 0.72, 95% CI = 0.64 to 0.81], Mediterranean participants [RR = 0.69, 95% CI = 0.60 to 0.79] and non-Mediterranean participants [RR = 0.49, 95% CI = 0.34 to 0.71].

The investigators found in pooled analysis of case-control and cohort studies that highest olive oil consumption was significantly associated with a 33% lower risk of breast cancer [pooled RR = 0.67, 95% CI = 0.52 to 0.86].  
Significantly because RR of 1 was not found in the 95% CI of 0.52 to 0.86. RR of 1 means no risk/association.

The investigators found subgroup analyses showed that the beneficial effect was reproducible in case-control studies [RR = 0.63, 95% CI = 0.45 to 0.87] but not in cohort studies.
Furthermore, high olive oil consumption was linked to a reduced breast cancer risk in Mediterranean [RR = 0.67, 95% CI = 0.49 to 0.92] and non-Mediterranean populations [RR = 0.25, 95% CI = 0.07 to 0.89].

The investigators found in pooled analysis of case-control and cohort studies that highest olive oil consumption was significantly associated with a 23% lower risk of gastrointestinal cancer [pooled RR = 0.77, 95% CI = 0.66 to 0.89].  
Subgroup analyses showed an inverse relationship between highest olive oil consumption and risk for esophageal cancer [RR = 0.47, 95%CI = 0.24 to 0.93] and pancreatic cancer [RR = 0.58, 95% CI = 0.35 to 0.97].
Furthermore, significant effects were also found in case-control studies [RR = 0.72, 95% CI = 0.61 to 0.85), studies within the Mediterranean area [RR = 0.77, 95% CI = 0.67 to 0.88], multivariate analyses [RR = 0.76, 95% CI = 0.63 to 0.90] and high quality studies [RR = 0.73, 95% CI = 0.62 to 0.86].

The investigators found in pooled analysis of case-control and cohort studies that highest olive oil consumption was significantly associated with a 26% lower risk of upper aerodigestive cancer [pooled RR = 0.74, 95% CI = 0.60 to 0.91].  
Subgroup analyses showed results remained significant for case-control studies [RR = 0.74, 95% CI = 0.60 to 0.91], multivariate analyses [RR = 0.75, 95% CI = 0.66 to 0.86] and studies of high quality [RR = 0.68, 95% CI = 0.52 to 0.89].

The investigators found in pooled analysis of case-control studies that highest olive oil consumption was significantly associated with a 54% lower risk of urinary tract cancer [pooled RR = 0.46, 95% CI = 0.29 to 0.72].  
Subgroup analyses showed results remained significant for studies of high quality [RR = 0.46, 95% CI = 0.32 to 0.66].

The investigators concluded highest versus lowest olive oil consumption is associated with 31% lower cancer risk, especially for breast, overall gastrointestinal, upper aerodigestive and urinary tract cancer. Additional prospective cohort studies on various cancer types, especially in non-Mediterranean regions, as well as large randomized trials, seem desirable in order to provide further insight into the role of olive oil in preventing cancer.

Original title:
Olive oil intake and cancer risk: A systematic review and meta-analysis by Markellos C, Ourailidou ME, […], Psaltopoulout T.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8751986/

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The conclusions in scientific studies are even more reliable when they are also found in cohort studies, multivariate analyzes (studies where adjustments were made for multiple confounding factors) and high-quality studies.
 

Objectives:
Does postoperative coffee or caffeine consumption causally reduce risk of postoperative ileus (POI) in patients undergoing elective colorectal surgery?

Study design:
This review article included 4 RCTs with 312 subjects.

Results and conclusions:
The investigators found postoperative coffee or caffeine consumption significantly decreased the time to first bowel movement [MD = -10.36 h, 95% CI = -14.61 to -6.11], shortened the length of hospital stay [MD = -0.95 days, 95% CI = -1.57 to -0.34] and was significantly  associated with a 36%-decreased risk of the use of any laxatives after the procedure [RR = 0.64, 95% CI = 0.44 to 0.92].

The investigators found the time to first flatus, time to tolerance of solid food, risk of any postoperative complication, postoperative reinsertion of a nasogastric (NG) tube and anastomotic leakage showed no statistical differences between groups.

The investigators concluded postoperative coffee or caffeine consumption causally improves bowel movement and decreases the duration of hospital stay in patients undergoing elective colorectal surgery. This method is safe and can prevent or treat postoperative ileus (POI).

Original title:
The effect of coffee/caffeine on postoperative ileus following elective colorectal surgery: a meta-analysis of randomized controlled trials by Yang TW, Wang CT, […], Tsai MC.

Link:
https://pubmed.ncbi.nlm.nih.gov/34993568/

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Find more information/studies on caffeine and cancer right here.

Postoperative ileus is a prolonged absence of bowel function after surgical procedures, usually abdominal surgery.

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

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

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:
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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