date:May 07, 2019
und only 20 articles (eight randomized trials and 12 cohort studies) eligible for further review. Of the 20 articles found eligible, five studies were conducted in North America, two in Finland, and one in Australia.
The participants in the studies were over the age of 40. Researchers reviewed six trials for vitamin E supplements and four trials compared the effects of beta-carotene with a placebo. The researchers provided study participants with food frequency questionnaires as an assessment.