Most of the press from the past few years has been focused on vitamin D and the integral role of its deficiency on human health and disease. Much less focus has been given to any of the other fat soluble vitamins.
Vitamin A sits on the same nuclear receptor as vitamin D and, much like vitamin D, vitamin A acts more like a hormone than it does a vitamin. For this reason, supplementation of vitamin A along with vitamin D is probably a very good idea. Luckily, both are easily taken and very inexpensive.
Of course, levels of supplementation vary between D and A. Supplementation of D usually starts around 2,000 IU per day, while vitamin A can be used at much higher dosages, sometimes up to 25,000 IU per day.
Vitamin A, much like vitamin D, has many functions in the body, although the first few to jump to mind are always vision, immune support and skin support. It is not unusual to have patients who are unsuccessfully fighting off respiratory infections to do much better with the addition of both vitamins A and D. Vitamin A is also essential for healthy skin, and has even shown some very strong benefits on lowering precancerous skin lesions in sun exposed area of the skin.
This particular study gives some new insight into some less well known benefits of vitamin A. Researchers used mice to see what effect giving retinoic acid (a metabolite of vitamin A) had on the development of new fat cells. They found that, in the presence of a high fat diet that would normally cause obesity in the mice, the retinoic acid was able to lower the production of new fat cells. Pretty neat.
Good food sources of vitamin A are the usual players…broccoli, sweet potatoes, dandelion greens (ok…so maybe not usual for most…), spinach, kale and pumpkin.