To Beta Carotene or Not To Beta Carotene
Should you or your child take beta carotene? If so, how much? Are there side effects? What are the potential benefits? If you or a member or your family has XP or a related disorder, these are questions worth considering.
It's common knowledge that eating lots of yellow vegetables can turn one's skin a little yellow. About twenty years ago, it was reported that beta carotene, one of the substances that makes these vegetables yellow, offered a notable measure of photoprotection to individuals with porphyria. The effect in other photosensitivity disorders such as XP has not been well-studied, but the benefit does not appear as substantial.1
It's also common knowledge that increased consumption of fruits (apricots have more beta carotene than carrots) and vegetables is associated with a lower risk of cancer. What's not so clear is if taking large doses of beta carotene offers similar reduced risk.2 It seems that other substances in veggies (e.g. lutein, lycopene)3 might be what really lowers the risk.
No one has ever overdosed on sweet potatoes. The yellow skin color that comes from consuming beta carotene is not jaundice (the eyes do not turn yellow). In fact, beta carotene is remarkably safe and free of side effects. Beta carotene is closely related to vitamin A, but there is a big difference. Large doses of vitamin A definitely can cause health problems.
If one chooses to take supplemental beta carotene, it is hard, if not impossible, to achieve the blood levels that have proven helpful in porphyria by diet alone. Beta carotene comes in a 30mg pill. Some must take ten or more per day to see benefit. This would be like eating about 2 lbs. of carrots every day.
The decision to take supplemental beta carotene is not an easy one. It might be something to consider during the summer months, if your skin is quite fair, if sun exposure is unavoidable, and/or if your disease is severe. Although available without a prescription, it would be important to discuss the matter with your doctor, who likely would monitor blood levels periodically. Interest in systemic photoprotection continues to develop. Last year, a substance called PL was found to triple tolerance to UV light in healthy volunteers.5 In the meantime, eat your vegetables!
Dr. Malak is Physician Manager in Pediatrics, Kaiser Permanante, Hudson Valley Region.
1 Mathews-Roth MM. Systemic Photoprotection. Dermatol Clinics. 1986;4:335-39
2 Omaye ST, et al. Beta carotene: friend or foe. Fundam Appl Toxicol. Dr Joseph Malak 1997;40:163-74
3 Nishino H. Cancer prevention by natural carotenoids. J Cell Biochem Suppl. 1997;27:86-91
4 Mangles AR, et al. Carotenoid content of fruits and vegetables: an evaluation of analytic data. JADA. 1993;93:284-296
5 Gonzalez S, et al. Topical or oral administration with an extract of Polypodium leucotomos prevents acute sunburn. Photodermatol Photoimmunol Photomed. 1997;13:50-60