Summer’s here and the time is right for getting out and soaking up
some healthy sunlight that will prompt your body to manufacture
vitamin D. The trick, however, is getting just the right amount of
sun exposure: enough to enhance your supply of D, but not so
much that you burn your skin. Inevitably, however, we sometimes
linger too long at the ballgame or the beach, and come home with a
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.
But a new study demonstrates that if you’re one of the millions
who have this sort of skin damage, you may substantially lower
your risk of developing skin cancer by increasing your intake of
one key vitamin.
Bumping up the dose
In a recent issue of 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
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 then again, one year later, at the end of the
The effects of one year of vitamin A supplementation were
- 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. But side effects sometimes occur with prolonged use of
vitamin A at very high doses, so usage should be monitored by a
doctor. Smokers and heavy drinkers are most susceptible to
vitamin A toxicity.
Checking the sources
In the e-Alert “Type Casting” (5/6/04), I told you about some of
the dietary and supplementary sources of vitamin A. But after
sending out that e-Alert I received messages from HSI members
who questioned some of the conclusions I came to.
After reviewing the research, I found that on a couple of points I
zigged when zagging would have been the better choice. So now
I’ll put the record straight with these simple guidelines for getting
adequate amounts of vitamin A:
- The problems with vitamin A toxicity are associated with
supplements of synthetic vitamin A taken in high doses
- 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
- Cod liver oil is an excellent natural source of vitamin A
If you follow these vitamin A basics, you can’t go wrong.
To Your Good Health,
Health Sciences Institute
“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,