Vitamin D – is it Really?

20111216-105412.jpgHave you ever wondered about the importance of vitamin D. Certainly with all the publicity regarding the beneficial effects of vitamin D, knowing the levels in your own body and supplementing properly can give you great beneficial effects regarding your future health. Vitamin D is technically not a vitamin. Its active metabolite, calcitriol (1, 25 dihydroxyvitamin D), is actually a secosteroid hormone that targets over 1000 genes. Every cell in our body has a vitamin D receptor that responds to calcitriol.

Vitamin D is available in two forms: vitamin D3, (also known as cholecalciferol), and vitamin D2, (known as ergocalciferol). Vitamin D3 is the form of vitamin D that is created in the skin during exposure to sunshine. The darker your skin the more likely you’ll have less vitamin D produced. Other causes which reduce vitamin D production in the skin is clothing, sunscreen, body fat, and certain drugs such as anticonvulsants and corticosteroids. Vitamin D2 is the form obtained from our food ingestion. Supplementation can be in either form, however, the D3 form is preferred. Both forms can be converted to active metabolites. Vitamin D deficiency is becoming pandemic. In the United States, all age groups are prone to vitamin D deficiency. Vitamin D deficiency is noted when calcidiol levels are less than 20 ng/mL. It is estimated that over 40% of Americans are vitamin D deficient. European studies show deficiencies which range between 30 and 90% of healthy adults. High rates of vitamin D deficiency is worldwide and has been reported in the United States, Mexico, Middle East, India, Asia, Europe, and Australia. Anyone who does not get lots of sunshine or ingest at least will 2000 to 10,000 international units per day is at high risk for vitamin D deficiencies and secondary health consequences. One whole egg is equivalent to 20 international units of vitamin D, 1 cup of fortified milk is equivalent to 100 international units of vitamin D, while cod liver oil delivers 1,360 international units per tablespoon. Other foods which contain vitamin D include tuna, mackerel, salmon, herring, and sardines. Severe vitamin D deficiency leads to an unfortunate disease called Rickets. This is when children develop poor bone formation which leads to deformities from poor mineralization. The growth area in maturing bone is called a growth plate, which becomes widened resulting in severe bone deformation. Secondary hyperparathyroidism is often the result. Adults with severe vitamin D deficiency also develop secondary hyperparathyroidism which leads to increased bone loss, a reduction in bone mineral density, and the development of osteoporosis.

When vitamin D is measured, the storage form must be measured called calcidiol (or 25 -hydroxy vitamin D). Both vitamin D2 and vitamin D3 is converted in the liver to calcidiol. Calcidiol is then converted to the active form of calcitriol mainly in the kidneys. It is this active form of vitamin D that has such tremendous beneficial effects in disease prevention and health maintenance. Optimization of vitamin D has been shown to protect against a variety of cancer, heart disease, stroke, autoimmune diseases, diabetes, mental health, depression, and osteoarthritis. Studies show that levels of calcidiol greater than 50 ng/ml reduce breast cancer and endometrial cancer by 50%. Levels over 40 reduce ovarian cancer by over 20%. There are many myths regarding proper vitamin D supplementation. The body can synthesize as much as 25,000 international units per day in the sunshine. The lowest intake of vitamin D that is associated with hypercalcemia(high calcium) in controlled studies is 40,000 international units per day for several months. Supplementing with adequate amounts of vitamin D3 while following serum laboratory values and keeping these values controlled has shown to be safe and effective. I frequently supplement my patients with vitamin D3 ranging between 3000 and 10,000 international units to get adequate serum levels of vitamin D3. This has been shown to be highly effective in cancer prevention. Vitamin D has been shown to reduce metastasis (the spreading of cancer), increased cancer cell death (known as apoptosis), and initiate gene transcription in cancer modulation (control cancer growth). Vitamin D has also been shown to greatly reduce inflammation and oxidative stress within our body. Levels of vitamin D are inversely associated with levels of CRP (which is an inflammatory marker within the body). Vitamin D3 inhibits NFKB which directly influences inflammation. Multiple studies have shown the importance of vitamin D in reduction of cardiovascular risk and coronary heart disease. Vitamin D insufficiency is linked to hypertension, diabetes, heart failure, and chronic vascular inflammation. Calcitriol has also been shown to increase the production of LL – 37 which is a polypeptide that fights against infectious disease. Calcitriol can help fight both bacterial and viral infections.

Knowing the importance of vitamin D in both disease prevention and control, evaluating your serum levels is paramount. Keeping 25 hydroxy D in the reference range of 60 to 80 ng/mL is important. No toxicity has been reported with serum levels under 150 ng/mL. Check serum calcium levels to avoid hypercalcemia (high calcium), as well as parathyroid hormone levels on an intermittent basis. Optimal doses of vitamin D three range between 3000 and 15,000 international units per day while serum levels are followed. Weekly doses of vitamin D3 is appropriate if desired. Vitamin D3 may not be needed if excessive sun exposure exists. So get your vitamin D checked, supplement appropriately, and you’ll have gone a long way in optimizing your health and preventing a multitude of diseases.


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