Getting enough sun exposure

Line of Defense

If you live just a few miles north of Quito, Ecuador, the equator may run right through your back yard. In that case, you probably get enough daily sun exposure to qualify as one of the least vitamin D deficient people on Earth.

The downside: You might easily get too much sun.

Last week, in the e-Alert “No Shrinking Violet” (6/14/05), I told you about research that indicates the amount of sun exposure we need in order for the body to manufacture adequate amounts of vitamin D. And in that same e-Alert I noted the three nutrients that relieve stress to the skin (vitamins C and E, and folic acid) and could even help prevent the development of skin cancer.

But for many, the time for initial precaution has long passed; those sunburns they experienced as children in Ecuador, or Phoenix, or Miami, or any spot on the globe where sunshine is abundant, laid the groundwork for precancerous lesions. For these folks the nutrients mentioned above are still very important. But if another vitamin is added, there’s a chance that skin cancer can still be avoided.

Covering the spread

When skin is damaged by occasional sunburns the stage is set for the development of actinic keratoses (AK) later in life. AK shows up as lesions that are precursors of the two most common types of cancer: nonmelanoma squamous cell or basal cell cancer. More than a million new cases of these cancers are diagnosed in the U.S. every year.

But a new study demonstrates that if you’re one of the millions who have AK skin damage, you may substantially lower your risk of developing skin cancer by increasing your intake of vitamin A.

In the journal Clinical Cancer Research, scientists at the Arizona Cancer Center, University of Arizona (UA), note that a previous study conducted at UA showed that vitamin A supplements significantly reduced the risk of squamous cell skin cancer in patients with moderately severe AK. The vitamin A dose used in that study was 25,000 IU. So the UA team designed another study to test higher doses for both safety and efficacy. Nearly 130 subjects with severely sun-damaged skin on their forearms were divided into four groups to receive daily doses of 25,000, 50,000, or 75,000 IU of vitamin A, or a placebo. Biopsies were conducted on the damaged skin of each patient before the study period began, and again one year later at the end of the study.

The effects of vitamin A supplementation were dramatic:

Placebo subjects: 25 percent had less skin damage when their pre-test and post-test biopsies were compared
25,000 IU subjects: 65 percent had less skin damage
50,000 IU subjects: 81 percent had less skin damage
75,000 IU subjects: 79 percent had less skin damage

Needless to say, the researchers concluded that 50,000 IU of vitamin A is the maximum daily dose required for the most effective protection for sun-damaged skin. No significant toxic reactions were reported in any of the four groups.

It’s an A thing

Vitamin A is essential to the health of your eyes, bones, skin and immune system. Growth and healing also benefit from the antioxidants that this key vitamin supplies. Here are some vitamin A basics:

Fruits and vegetables with orange and yellow coloring, and green leafy vegetables contain beta-carotene, a precursor of vitamin A
The body poorly converts beta-carotene into vitamin A
The best source of vitamin A is animal products, such as eggs and liver
Cod liver oil is an excellent natural source of vitamin A
The problems with vitamin A toxicity are associated with supplements of synthetic vitamin A taken in high doses

Studies show that smokers with a high intake of beta-carotene are at greater risk of developing lung cancer. As for just about everyone else, it’s almost impossible to overdo vitamin A consumption, according to HSI Panelist Allan Spreen, M.D. In fact, Dr. Spreen tells me there are only about two-dozen recorded cases of people who took too much vitamin A and suffered any distress whatsoever. Dr. Spreen suggests that 10,000 IU of beta-carotene vitamin A per day is adequate for most people.

If you have questions about vitamin A, consult with your doctor or a dependable nutritionist to determine a dosage that’s right for you.

Sources:
“Safety and Efficacy of Dose-Intensive Oral Vitamin A in Subjects with Sun-Damaged Skin” Clinical Cancer Research, Vol. 10, No. 6, 3/15/04, ncbi.nlm.nih.gov
“Vitamin A: Natural Skin Repair from Sun Damage” Maureen Williams, ND, Healthnotes Newswire, 6/24/04, pccnaturalmarkets.com