Beta-cryptoxanthin
Beta-cryptoxanthin, along with the alpha and beta carotenes, is a pro-vitamin A carotenoid. This means it can be converted by the body into Vitamin A. It is one of six hundred or so carotenoids found in nature. Carotenoids are a fat soluble pigment in the red, orange and yellow color range. Vitamin A is essential for normal growth and development, immune system function, and vision. Of the three pro-vitamin carotenoids, beta carotene is the strongest, with a conversion to retinol (Vitamin A) of 1/12. Beta-cryptoxanthin and alpha carotene have a conversion ratio of 1/24. Beta-cryptoxanthin is also classified as a Xanthophyll. This is a long hydrocarbon chain, which differs from the other two pro-vitamin A carotenoids by the presence of a hydroxyl group containing oxygen.
Good sources of beta-cryptoxanthin include pumpkin, papayas, sweet red peppers, oranges, tangerines, nectarines, carrots, yellow corn and paprika. Chopping, pureeing or otherwise breaking up the cells of the plants, and cooking them in at least a small amount of oil makes the beta-cryptoxanthin more usable by the body.
Vitamin A is an essential nutrient with many health benefits, and of course beta-cryptoxanthin is important for its precursor properties. However it may have health benefits of its own that are independent of its Vitamin A status. A 2005 study in American Journal of Clinical Nutrition showed that an increase in beta-cryptoxanthin intake may reduce the risk of developing inflammatory disorders such as rheumatoid arthritis. Beta-cryptoxanthin is a strong antioxidant which can prevent free radicals from damaging your cells. Studies have shown that this phytonutrient may also reduce the risk of colon and lung cancer. These benefits may be due to its antioxidant activity, and to the fact that it stimulates expression of the RB gene, which prevents cells from becoming cancerous. A 2004 study in Cancer Epidemiology Biomarkers and Prevention showed that beta-cryptoxathin decreased risk of lung cancer by 30%.
Other studies done with smokers and former asbestos workers found that supplementing with 20-30 mg/day of beta-carotene for 4-6 years was associated with significant increases in the risk of lung cancer. Therefore it's not recommended that smokers or people at a risk of lung cancer start taking supplements of carotenoids, which are available without a prescription. Vitamin A can be toxic if you take too much, especially if you are pregnant or breastfeeding. Therefore it's best to get these phytonutrients by including some good food sources in your diet. When your body has adequate Vitamin A from food it will simply stop converting the precursors, so you don't have to worry about getting toxic levels that way.
The information on this page is not meant to be used in treatment of medical conditions. Please seek the advice of a physician about any medical condition or symptom. Those with medical conditions should consult a medical professional about the appropriateness of taking dietary supplements or diet therapy, and how these methods will interact with their medications.
LINKS
A September 2005 study published in the European Journal of Clinical Nutrition showing how Dietary Recalls and Food Questionnaires can accurately predict plasma levels of carotenoids.
More about beta-cryptoxanthins, including molecular structure.