Vitamin D Deficiency: A Worldwide Epidemic
Donald Aulds, M.D.
Although vitamin D is called a vitamin, it’s not really a vitamin. It’s actually a prohormone, a substance that the body changes to a type of hormone utilized in almost every tissue of the body. At one time, a deficiency of vitamin D was known to produce a bone disorder called rickets. But rickets is only the tip of the iceberg when you consider all the problems that are now associated with vitamin D deficiency.
So what has led to this deficiency in vitamin D? There are several factors that can be considered including the fact that people have reduced their exposure to the sun by now working indoors more than outdoors, by reducing intake of milk and milk products, by using sunscreens to reduce risk of skin cancers, and the government’s recommendations on intake of vitamin D at 200 IU for children and 400 IU for adults being too low to prevent the deficiency. So our low exposure to sunlight and our low intake of vitamin D have produced a society suffering from epidemic vitamin D deficiency. Studies are now showing that, in certain populations, as high as 70 percent of adults may be deficient and, in the US, the rate is approximately 50 to 60 percent of all adults. The body makes its own vitamin D after exposure to sunlight, but as the exposure to sunlight has decreased, our body is now producing less vitamin D.
What are the main sources of vitamin D for our bodies?
- Sun exposure – As we work indoors and decrease exposure to the sun through less outdoor activities and more sunscreens, vitamin D production by our bodies has decreased. There has to be a balance between the exposure and lack of exposure. Also people with dark skin tend to produce less vitamin D due to the blockage of UV light by melanin in the skin.
- Eggs – Some Vitamin D is present in the egg yolk – about 25 IU - which is only a small amount of what is needed.
- Essential fatty acids from fish – Salmon is a fairly good source of vitamin D, but it would require nearly ¾ of a salmon filet daily to get the recommended amount of vitamin D.
- Vitamin D enriched milk – You can get 100 IU of vitamin D in an eight ounce glass of milk.
- Vitamin D supplements – These are beneficial only if they contain more than the federal recommended daily allowance.
What are the risks of vitamin D deficiency?
- The most commonly talked about risk for the deficiency of vitamin D has been the effects on the bones. For years, rickets was known about in children, but now research has shown that the deficiency has been associated with osteopenia and osteoporosis. Bone fractures have increased with the lack of vitamin D. Vitamin D assists with the absorption of calcium and phosphorus, minerals that are vital for bone health.
- Muscles have vitamin D receptors and require the vitamin for optimum function. In the presence of a lack of vitamin D, muscle weakness occurs resulting in a decrease in performance speed and muscle strength. A recent study showed that 400 IU of vitamin D was insufficient in increasing muscle strength and function.
- Directly or indirectly, vitamin D regulates more than 200 genes in our cells, including genes responsible for cell growth and regeneration after a cell dies. It has been shown to work as an inhibitor of the proliferation of cancer cells.
- Vitamin D has been shown to help in the control of the spread and severity of psoriasis.
- Studies have indicated that vitamin D deficiency has been associated with a higher risk of developing colon, prostate and breast cancers. The lack of the vitamin has also been associated with increased deaths from these cancers.
- Autoimmune diseases have been shown to be increased in the presence of vitamin D deficiency.
- Chronic diseases such as type I diabetes, multiple sclerosis, and Crohn’s disease are seen more frequently in people with a deficiency in vitamin D. A study in Finland was done giving women vitamin D during pregnancy. After birth, the children were given 2000 IU of vitamin D. Thirty-one years later, the children showed an 80 percent decrease in type I diabetes. In teenagers, vitamin D deficiency showed an increase in insulin resistance, a decrease in insulin production that can lead to metabolic syndrome. A recent study showed that taking 800 to1000 IU of vitamin D decreased one’s risk of developing type II diabetes by 33 percent.
- A recent study done in Europe showed that increasing blood levels of vitamin D decreased blood pressure and decreased inflammation factors such as C-reactive protein which is associated with heart disease.
- Adequate levels of vitamin D during pregnancy have been associated with brain development and maintenance of mental function in later life. Deficiency has been linked to increased risk of depression and schizophrenia.
- Inadequate levels of vitamin D during pregnancy has been associated with increased risk of development of asthma in children and increased risk of lung problems in later life.