Benefits of Vitamin D

The holidays are over and as we return to the routine of our daily lives we begin to remember that it is winter in northeast Ohio, the glow of sunshine is more difficult to find.  The days are shorter and sunshine is scarce. Most people retreat to the warmth of their homes, rarely venturing outside resulting in rare exposure to the sun. This deprivation of sunshine, besides affecting our mood, can cause vitamin D deficiency. Vitamin D plays a significant role in the normal functioning of all major organ systems and therefore its deficiency adversely affects our health.

The major source of vitamin D is through sunshine.  Dietary sources of vitamin D are through vegetables (vitamin D2) and animal source (vitamin D3).  Vitamin D3 is synthesized in the skin through exposure to ultraviolet-B (UVB) light.  The activated form of vitamin D3 binds to receptors in tissues throughout the body to influence their functioning and ability to repair itself. In modern society sunlight exposure is limited by design (fear of skin cancer) and necessity (most work now is done in doors). Studies on young professionals revealed that 32% are deficient in vitamin D.  Aging only worsens this problem. As we get older our skin has reduced ability to synthesize vitamin D; older adults require three-times the amount of sun exposure as younger adults to maintain normal vitamin D levels. Up to 90% of older adults are deficient in vitamin D. Why is this important?

Vitamin D has long been recognized as being important in skeletal health and prevention of osteoporosis. It helps with the absorption of calcium in the intestine and helps maintain steady blood levels of calcium. Some studies suggests it also has anti-proliferative effects on malignant cells meaning it prevents or slows the growth of cancer. This includes very common cancers such as cancer of the breast, prostate, colon, and leukemic cells. Many epidemiologic studies have shown reduced incidence and mortality from these cancers in areas with a sunny climate or in populations taking vitamin D supplements. Low vitamin D levels also have an adverse effect on the immune system. Inflammatory bowel disease and rheumatoid arthritis are examples of conditions of an abnormal immune system in which patients often have vitamin D deficiency. Vitamin D deficiency has an adverse effect on the cardiovascular system increasing risk for heart attacks and stroke. It also contributes to the development of diabetes by contributing to insulin resistance.  Vitamin D deficiency contributes to postmenopausal syndromes of osteoporosis, muscle weakness, falls, fractures, depression, cognitive impairment, and dementia.

Because vitamin D deficiency is associated with multiple significant health problems it is not unreasonable to measure its level once a year, especially in older individuals who live in a northern climate. A simple blood test for vitamin 25 (OH) D and parathyroid hormone (PTH) should be drawn. Normal levels for 25(OH) D is higher in older individuals than the young because resistance to its effect occurs as we age. This resistance is reflected by elevated levels of PTH. Achieving and maintaining normal levels of vitamin D may lower the risk for breast and colon cancer by as much as 80%. The daily requirement of total vitamin D is 3,000 to 5,000 units per day, most of which is obtained by the sun. As a generalization most adults should take 1,000 to 2,000 units (IU) of vitamin D3 daily. An individual’s exact amount of dietary supplement varies depending on age, sun exposure, and other health conditions. The required daily oral intake of vitamin D may range between 2,000 to 10,000 units per day. It is best to have testing done by your physician to help determine what is the correct amount for you.

Vitamin D is not the “magic” pill that will provide good health and prevent disease but it is an important part of the equation. As always a healthy lifestyle of a balanced diet, regular vigorous exercise, sufficient sleep, and avoidance of tobacco and excessive alcohol will give you the best chance of having a long and healthy life.  And here is hoping our mild winter lasts and the sun keeps shining!