Six Reasons Vitamin D Is So Important

David Juan, MD

Vitamin D, what have you not done for us lately? The sunshine vitamin, constantly in health news, continually being at the heart of health breakthroughs, and the king of natural supplements, plays six intricate roles in your body. Its functions are essential and, without the vitamin, many bodily processes would cease and many diseases could linger. Let's take a look at those six important roles:

1. It metabolizes calcium. Vitamin D and calcium are closely linked in your body. Calcium levels are tightly regulated by two hormones -- the parathyroid hormone (PTH) and 1,25 dihydroxyvitamin D (1,25 D). When calcium levels drop, PTH rises, which eventually gets calcium back to proper levels. One of the ways it does so is by triggering your kidneys to synthesize 1,25 D. And that increases calcium absorption in the guy and kidney.

2. Your immune system needs it. 1,25 D exerts a variety of effects on your immune system, which has the potential to fight infections and stop a variety of autoimmune disease from developing. These include type 1 diabetes and rheumatoid arthritis. So, your body's main defense system requires vitamin D to fight.

3. It regulates blood sugar levels. Your pancreas, which makes insulin, contains vitamin D. Insulin is needed to move sugar from the bloodstream to the cells. In studies, 1,25 D actually boosts insulin secretion in situations when there is a greater need for insulin. Vitamin D deficiency has been linked to the development of type 2 diabetes.

4. It helps make your heart run smoothly. Vitamin D is important to defend against plaque build-up, called "atherosclerosis." The sunshine vitamin does so by affecting muscles in artery walls, preventing inflammation, and decreasing the production of "renin" -- a key chemical in high blood pressure.

5. It improves your muscle function. Vitamin D regulates calcium movement and increases protein synthesis in muscle. It indirectly impacts muscle contraction. When you flex, vitamin D is at work.

6. It helps cells grow. This is a key to vitamin D's cancer- preventing abilities. Unregulated cell growth is characteristic of cancer. There is solid animal evidence that vitamin D suppresses cell growth, increases cell death and prevents the breakdown of DNA. All of these help shield you from tumors.

Source:
1. Kadowaki, S., and Norman, A.W., "Time Course Study of Insulin Secretion after 1,25-Dihydroxyvitamin D2 Administration." Endocrinology, 1985; 117: 1,765-77.

2. Ozfirate and Chowdhury, "Vitamin D deficiency and type 2 diabetes," Postgrad Medical Journal, 2010;86: 18-25.

3. Li, Y.C., et al., "1,25-Dihydroxyvitamin D(3) is a negative endocrine regulator of the renin-angiotensin system," Journal Clinical Investigation, 2002; 110: 229-38.

4. Vazquez, G., et al., "Involvement of Calmodulin in 1 alpha, 25-Dohydroxyvitamin D3 Stimulation of Store-operated Ca2+ Influx in Skeletal Muscle Cells," Jnl Biological Chemistry. 2000; 275: 16,734-38.

5. Chung, I., et al., "Differential Antiproliferative Effects of Calcitriol on Tumor-Derived and Matrigel-Derived Endothelial Cells," Cancer Research., 2006; 66: 8,565-73.

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