Carotenoids
Where to Find It
Carotenoids are found in all plant foods. In general, the greater the intensity of color, the higher the level of carotenoids. In green leafy vegetables, beta-carotene is the predominant carotenoid. In the orange colored fruits and vegetables—such as carrots, apricots, mangoes, yams, winter squash—beta-carotene concentrations are high, but other pro-vitamin A carotenoids typically predominate. Yellow vegetables have higher concentrations of yellow carotenoids (xanthophylls), hence a lowered pro-vitamin A activity; but some of these compounds, such as lutein, may have significant health benefits, potentially due to their antioxidant effects. The red and purple vegetables and fruits—such as tomatoes, red cabbage, berries, and plums—contain a large portion of non-vitamin A–active carotenoids. Legumes, grains, and seeds are also significant sources of carotenoids. Carotenoids are also found in various animal foods, such as salmon, egg yolks, shellfish, milk, and poultry. A variety of carotenoids is also found in carrot juice and “green drinks” made from vegetables, dehydrated barley greens, or wheat grass.
Synthetic beta-carotene is available as a supplement. Mixed carotenoids (including the natural form of beta-carotene) are also available in supplements derived from palm oil, algae, and carrot oil.
How to Use It
Whether people who already consume a diet high in fruits and vegetables would benefit further from supplementation with a mixture of carotenoids remains unknown. While smokers clearly should not supplement with isolated synthetic beta-carotene, the effect in smokers of taking either natural beta-carotene or mixed carotenoids is not clear.
Nonetheless, based on health-promoting effects associated with these levels in preliminary research, some doctors recommend that most people supplement with up to 25,000 IU (15 mg) per day of natural beta-carotene and approximately 6 mg each of alpha-carotene, lutein, and lycopene.