This tab will answer the following nutritional question: How can nutrition contribute positively to my health?

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

Find scientific studies on vitamin A: type vitamin A in Search field.

Nutritional advice

20 mg/d isoflavones dieatary intake reduces risk of colorectal neoplasms in Asians

Objectives:
Epidemiological studies suggest that soya consumption as a source of phyto-oestrogens and isoflavones may be associated with a reduced risk of colorectal cancer. However, findings have not yet been synthesised for all groups of phyto-oestrogens. Therefore, this review article (meta-analysis) has been conducted.

Does soya consumption reduce colorectal cancer risk?

Study design:
This review article included 16 studies (case-control studies and cohort studies).

Results and conclusions:
The investigators found in case-controle studies a significant reduced risk of 24% [pooled RR = 0.76, 95% CI = 0.69-0. 84] for colorectal cancer when comparing the highest phyto-oestrogens with the lowest intake category. However, the reduced risk for colorectal cancer was not significant in cohort studies [pooled RR = 0.95, 95% CI = 0.85-1.06].

The investigators found in case-controle studies a significant reduced risk of 23% [pooled RR = 0.77, 95% CI = 0.69-0. 85] for colorectal cancer when comparing the highest isoflavones with the lowest intake category. However, the reduced risk for colorectal cancer was not significant in cohort studies [pooled RR = 0.94, 95% CI = 0.84-1.05].

The investigators found in case-controle studies a significant reduced risk of 30% [pooled RR = 0.70, 95% CI = 0.56-0. 89] for colorectal cancer when comparing the highest lignans with the lowest intake category. However, the reduced risk for colorectal cancer was not significant in cohort studies [pooled RR = 1.00, 95% CI = 0.64-1.57].

The investigators found dose-response analysis yielded an 8% reduced risk of colorectal neoplasms for every 20 mg/d increase in isoflavones intake in Asians [pooled RR = 0.92, 95% CI = 0.86-0.97].

The investigators found dose-response analysis showed a non-linear inverse association with colorectal cancer risk for lignans intake, but no association for circulating enterolactone concentrations was observed.

The investigators concluded every 20 mg/d increase in isoflavones dietary intake reduces risk of colorectal neoplasms with 8% in Asians.

Original title:
Phyto-oestrogens and colorectal cancer risk: a systematic review and dose-response meta-analysis of observational studies by Jiang R, Botma A, […], Chang-Claude J.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/28091359

Additional information of El Mondo:
Find more information/studies on isoflavones, colorectal cancer and cohort study/review article right here.

20 mg/d isoflavones dieatary intake reduces risk of colorectal neoplasms in Asians

Elevated serum selenium levels may decrease high-grade prostate cancer among current and former smokers

Objectives:
Some observational studies have shown that elevated serum selenium levels are associated with reduced prostate cancer risk. However, not all published studies support these results. Therefore, this review article (meta-analysis) has been conducted.

Does an elevated serum selenium level reduce prostate cancer risk?

Study design:
This review article included 12 case-control studies, 4 cohort studies and 1 RCT with 6,136 prostate cancer cases among 34,901 participants.

Results and conclusions:
The investigators found elevated serum selenium levels significantly decreased prostate cancer risk with 24% [pooled OR = 0.76, 95% CI = 0.64 to 0.91, I2 = 60.8%, p = 0.001]. Significant means that there is an association with a 95% confidence.

The investigators found in subgroup analysis, an inverse association between elevated serum selenium levels and prostate cancer risk in case-control studies, current and former smokers, high-grade cancer cases, advanced cancer cases and different populations. However, such correlations were not found among cohort studies, nonsmokers, low-grade cancer cases and early stage cancer cases.

The investigators concluded that elevated serum selenium levels may decrease high-grade prostate cancer among current and former smokers. May decrease because the inverse relationship between elevated serum selenium levels and prostate cancer risk was not significant among cohort studies. Therefore, further cohort studies and randomized control trials based on non-Western populations are required.

Original title:
Serum selenium levels and prostate cancer risk: A MOOSE-compliant meta-analysis by Cui Z, Liu D, […], Liu G.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5293444/

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