by William M. Healy, M.D.
Vitamin D, known as “the sunshine vitamin,” functions as both a hormone and a vitamin in our bodies. Many of us already know we need Vitamin D to help in the absorption of calcium responsible for maintaining strong bones and teeth. However, the list of attributes for Vitamin D appears to grow almost daily. Vitamin D promotes muscular strength we need for activities such as walking and also helps to support a healthy immune system. Low levels of Vitamin D have been associated with higher blood pressure, an increased risk for diabetes mellitus, arthritis, multiple sclerosis, and perhaps cancers of the breast, colon, prostate, ovaries, esophagus and the lymphatic system. New research published this year in the journal Neurology, links low Vitamin D levels with dementia.
Vitamin D is found in food, and good sources include cod liver oil, cooked salmon, eggs, and fortified milk and cereal. Additionally, the absorption of sunlight upon our skin can stimulate the production of our own Vitamin D. Despite these sources, Vitamin D deficiency is common and estimates range from 40 to 75%. During Western New York winters, the sun doesn’t rise high enough to allow for natural Vitamin D production and thinner, aging skin can limit production as well. Not long ago, I had a Vitamin D level return “undetectable” in an elderly patient.
Risk factors for Vitamin D deficiency include lack of adequate sun exposure, using sunscreen on a regular basis, age over 65, dark-colored skin, restriction to indoor activity such as living in a nursing home, being overweight, certain medications such as anti-seizure medications, bowel diseases, and poor nutrition. Symptoms of Vitamin D deficiency include bone pain, feelings of depression, muscle weakness, fatigue, and excessive sweating.
So, how much Vitamin D do we need? In 2010, new recommended daily allowances (RDA) were published. For ages one through 70, the recommended daily dose is 600 IU. For ages 71 and older, 800 IU is recommended. Many physicians and health professionals advise their patients to take 1000 IU per day. Higher doses are given in cases of deficiency and in certain disease states. Since one cup of fortified milk contains about 100 IU and just 20 IU per one whole egg, meeting these daily requirements with food alone can be difficult.
Fortunately, Vitamin D supplements in the form of Vitamin D2 and Vitamin D3 are readily available and come in a variety of doses. Side effects from these supplements are unusual at the recommended doses. Doses above 4000 IU should be monitored by your health professional.
So, should everyone be tested for Vitamin D levels? Blood testing is readily available, but testing everyone has been controversial. Individuals with risk factors and complaints suggestive of Vitamin D deficiency should strongly consider being tested. Here in Western New York, low Vitamin D levels are common, yet treatable.
