Vitamin D: The “D” stands for definitely important

Nearly three out of four adults and teens may be deficient in vitamin D. Deficiency risk increases with age, skin pigment, and limited sun exposure. Current daily intake recommendations (400 IU to 600 IU) are primarily based on bone health, and it has been suggested that higher levels may be necessary to maintain optimum physical functions, muscle strength, and other health functions.

Vitamin D could be called “hormone D” due to its powerful effects.  It regulates more than 2,000 of the 30,000 genes in the human body.  We know that the major and most well-known function of vitamin D is to maintain the calcium and phosphorous balance and to promote bone mineralization.  However, its role has expanded to cover medical and health conditions such as muscle function, falls, immunity, glucose balance, and cardiovascular diseases.

Vitamin D is sometimes referred to as the “sunshine” vitamin because it is created in the skin.  However, if you remain indoors all day, 15 minutes of sunshine can be difficult to come by; in fact, we need sunlight when the UV index is greater than 3.  This occurs daily within the tropics, during the spring and summer seasons within the temperate regions, and almost never within the arctic circles.  Therefore, supplementation is the answer.

Vitamin D’s influence on key biological functions is vital to one’s health and well-being and is essential to bone and cartilage health.  A deficiency in vitamin D can increase the risk of osteoporosis, inflammatory bowel disease, Type 1 and Type 2 diabetes, metabolic syndrome, and hypertension. 

Studies have also shown that the use of vitamin D has shown positive effects on osteoarthritis (OA), such as helping prevent the breakdown of cartilage.  Low intake of vitamin D may be linked to greater risk of hip osteoarthritis in older women and OA-related joint changes in both men and women. 

Vitamin D may also protect against heart attack.  Men classified as deficient in vitamin D are about 2.5 times more likely to have a heart attack than those with higher levels.  Researchers compared those deficient in vitamin D (no more than 15 ng/mL of blood) to men in the lower-end of the normal range (at least 30 ng/mL of the blood).  Higher levels of the vitamin reduce the risk of cardiovascular disease and could help protect against Crohn’s disease and other inflammatory bowel disease. More importantly, a substantial study presented at the annual meeting of Pediatric Academic Societies in Vancouver, BC in early 2010 concluded that raising the amount of vitamin D intake daily is not only safe for pregnant women, but may reduce risk of complications and made women less likely to go into labor early, give birth prematurely or develop infections.  However, as with all supplements and medications, pregnant women should not change their intake without consulting their physicians. 

In another study that was published in Spine magazine in 2003, vitamin D was credited with relieving chronic low-back pain (subjects were given either 5000 IU or 10,000 IU daily).  Another study from the University of Minnesota concluded that when combined with a reduced-calorie diet, supplementation with vitamin D helps to accelerate weight loss.

Vitamin D is not only helpful in obtaining optimum health, it can also benefit the active individual as well.  A recent study in adolescent females found that vitamin D was significantly associated with muscle power and force in adolescent girls and is, therefore, important for promoting muscle and strength.  In May, 2009, a publication in Medical Science Sports Exercise concluded that “vitamin D may improve athletic performance in vitamin D deficient athletes.  The Chicago Blackhawks have become the first modern sports team to supplement with vitamin D.

Unfortunately, good sources of vitamin D may be hard to find.  Our bodies manufacture vitamin D3 when skin is exposed to the sun’s ultraviolet-B rays, which can be blocked by both windows and sunscreen.  Furthermore, vitamin D is only found naturally in a few foods (fish, eggs, mushrooms), which is why products like milk are vitamin D-fortified, sometimes with the less absorbable vitamin D2 form.  Dietary supplements are often recommended, but they vary in quality and may be made from vitamin D2 or D3.  D3 supplements may be 3 times more effective than D2 at increasing vitamin D levels in the body. The supplement delivery form and manufacture may also influence absorption potential, so it’s just as important with this “basic” vitamin to seek higher quality for maximum benefits.

To ensure these benefits, I recommend the combination of vitamin D with soy isoflavones.  This combination is designed to support optimal metabolism of vitamin D to its most active form.  My recommendation is for 2000 IU per day. 

Finally, it is essential that individuals assess their vitamin D levels through a blood test.  What is considered normal range is 32 to 100 ng/mL.  My recommendation is that optimum levels should be 50 to 60 ng/mL, and high-functioning athletes should be between 60 to 80 ng/mL.  Please follow my recommendation of 2000 IU per day and evaluate your vitamin D levels.