Over the years, vitamin A has had many links with the dreaded C-word. In my second article in the series on vitamin A, let’s explore how it might help you prevent — and even treat — certain types of cancer.
First, vitamin A could help prevent breast cancer. Over a five-year study, retinoids were able to reduce the risk of second breast cancer in premenopausal women. They were given a synthetic vitamin A, called “fenretinide,” at a dose of 200 milligrams (mg) a day. The nutrient may also help protect the liver from cancer. Synthetic vitamin A, acyclic retinoid, prevented the development of a second liver cancer and improved survival in a Japanese report.
(It’s never a bad time for good news on the cancer front. Here is a recent story we did on cancer survivors: Know Who’s Growing Old? Cancer Survivors.)
It was thought that vitamin A could help prevent lung cancer, the world’s most fatal tumor. But it may in fact be the opposite. Most clinical studies failed to show that vitamin A protected against lung cancer. Then, in a large trial 10 years ago, about 9,000 smokers and people with asbestos exposure were randomized to received a daily dose of 25,000 international units (IU) of retinal and 30 mg of beta-carotene or placebo. Unbelievably, lung cancer was 28% higher among the supplemented group. Whether or not vitamin A has a deleterious effect in non-smokers is unknown, but if you smoke it would seem unwise to supplement here.
As for actually treating cancer, there is one decent connection for vitamin A: Acute Promyelocytic Leukemia (APL). This is the most curable type of adult forms of leukemia and that has much to do with vitamin A. Over the past decade, the use of all-trans retinoic acid (ATRA), the acid form of vitamin A, alone or alongside chemotherapy has been standard treatment for APL. And it has had great success. ATRA has significantly improved the prognosis and survival for these patients at two years (55%) and four years (85%). The overall survival rate is between 70% and 80% now.
In this regard, that is one powerful vitamin.