Role of Folate or Folic Acid in Cancer Prevention

Several large observational studies have shown a decrease in risk of colorectal and other cancers with dietary folate, while other randomized trials of folic acid supplementation have raised the possibility of increased cancer risk from folic acid supplementation.

In the largest meta-analysis of individual patient data from randomized trials of folic acid for the prevention of cardiovascular disease (10 trials, n = 49,969) and colorectal adenoma (3 trials, n = 2652), during an average of 5.2 years of treatment, there was no significant difference in overall cancer incidence for patients assigned to folic acid or placebo.

There was also no significant effect on the incidence of specific cancers, including cancers of the large intestine, prostate, lung, or breast. (Lancet 2013;381:1029)

Fish oil and cardiovascular mortality

The Risk and Prevention Study enrolled patients with multiple cardiovascular risk factors or known vascular disease and, after a median follow-up of five years, found no reduction in coronary heart disease death with n-3 polyunsaturated fatty acid supplementation compared with placebo.  [N Engl J Med 2013;368:1800]

Breastfeeding and obesity

There is increasing evidence that breastfeeding does not reduce the risk of obesity in the offspring. A follow-up study from a cluster-randomized trial of over 17,000 breastfeeding mother-infant pairs reported on outcomes of children at 11.5 years of age, and confirmed findings from 5 years earlier that there were no differences in the body mass index or rates of obesity and overweight.  Population strategies to increase the duration and exclusivity of breastfeeding are unlikely to impact the obesity epidemic.  (JAMA 2013;309:1005.)