Beta-carotene is a phytonutrient in the carotenoid family, which also includes alpha-carotene, beta-cryptoxanthin, lycopene, lutein, zeaxanthin. Beta-carotene is a provitamin A carotenoid, meaning it can be converted by the body to retinol (vitamin A).
Population studies suggest that diets high in carotenoid-rich fruits and vegetables are associated with reduced risk of cardiovascular disease and some cancers. However, four randomized controlled trials found no evidence that beta-carotene delivered in nutritional supplements was effective in preventing cardiovascular diseases.
Similarly, two randomized controlled trials found that high-dose beta-carotene supplements increased the risk of lung cancer in smokers. As with most nutrients, it is best to get beta-carotene in its natural form—from food sources.
Like its other carotenoid cousins, beta-carotene is lipid soluble and best used by the body when it is cooked and eaten with a small amount of healthy fat. Research shows as little as 3-5 g of fat in a meal helps to ensure carotenoid absorption.
Mannisto S, Smith-Warner SA, Spiegelman D, et al. Dietary Carotenoids and Risk of Lung Cancer in a Pooled Analysis of Seven Cohort Studies. Cancer Epidemiol Biomarkers Prev. 2004;13(1):40-48. The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers. The Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group. N Engl J Med. 1994;330(15):1029-1035.