Vitamin D: the new super-nutrient?

In the last two weeks alone three articles have appeared in the scientific press about new studies reporting on vitamin D’s many crucial roles in the body. Along with promoting strong bones, a healthy immune system and protection against some types of cancer, recent studies suggest vitamin D can treat heart failure, protect against heart attacks and reduce the risk of death from both cardiovascular and overall causes.

Back in April I wrote an article called “Throw Away Your Sunscreen” about the protective effects of exposure to sunlight against melanoma. Despite conventional wisdom that tells us to avoid sun exposure at all costs, it turns out that the vitamin D our bodies synthesize when exposed to UV light is a first line of defense against developing melanoma.

In an article published on June 9 in Archives of Internal Medicine, scientists reported that low levels of vitamin D are associated with a higher risk of myocardial infarction (heart attack) in men. The study showed that rates of cardiovascular disease-related deaths are increased at higher latitudes and during the winter months, and are lower at lower altitudes.

In an article published in the July issue of the Journal of Cardiovascular Pharmacology, on June 12, researchers found that vitamin D directly contributes to cardiovascular fitness. In fact, University of Michigan pharmacologist Robert U. Simpson, Ph.D. thinks it’s apt to call vitamin D “the heart tranquilizer”. Simpson and his team discovered that treatments with activated vitamin D prevented heart muscle cells from hypertrophy, a condition in which the heart becomes enlarged and overworked in people with heart failure.

Finally, in a study published on June 23 in the Archives of Internal Medicine, a team of Austrian scientists revealed that low blood levels of vitamin D appear to have an increased risk of death overall and from cardiovascular causes. Harald Donbig, M.D. and his colleagues studied 25-hydroxyvitamin D and 1,25 dihydroxyvitamin D levels in 3,258 consecutive patients (average age 62 years) who were scheduled for coronary angiography testing at a single medical center between 1997 and 2000.

During 7.7 years of follow-up, death rates from any cause and from cardiovascular causes were higher among individuals in the lower one-half of 25-hydroxyvitamin D levels and the lowest one-fourth of 1,25-dihydroxyvitamin D levels. These associations remained when researchers controlled for other factors such as coronary artery disease, physical activity and co-occurring diseases.

So what does all this mean to you? A recent consensus panel estimated that about 50 - 60 percent of older individuals in North America and the rest of the world do not have satisfactory vitamin D status, and the situation is similar for younger individuals. Blood levels of vitamin D lower than 20 to 30 nanograms per milliliter have been associated with falls, fractures, cancer, autoimmune dysfunction, cardiovascular disease and hypertension.

To put it blankly, that means half of all people around the world are deficient in vitamin D and therefore at increased risk for serious and potentially fatal conditions.

Low 25-hydroxyvitamin D levels are also correlated with markers of inflammation such as C-reactive protein, as well as signs of oxidative damage to cells, Donbig’s study revealed. In a previous article, I explained that inflammation and oxidative damage (not cholesterol) are the primary causes of the worldwide heart disease epidemic. Inflammation and oxidative damage are also contributing factors to diabetes, metabolic syndrome, cancer and many other diseases.

So how does vitamin D work its magic? It acts as a potent hormone in more than a dozen types of tissues and cells in the body, regulating expression of essential genes and rapidly activating already expressed enzymes and proteins. In the heart, vitamin D binds to specific vitamin D receptors and produces its “calming”, protective effects.

There are essentially three ways to obtain vitamin D: exposure to UV light, food and supplements. The most effective of all of these methods is exposure to sunlight. Full-body exposure of pale skin to summer sunshine for 30 minutes without clothing or sunscreen can result in the synthesis of between 10,000 and 20,000 IU of vitamin D. At most latitudes outside of the tropics, however, there are substantial portions of the year during which vitamin D cannot be obtained from sunlight; additionally, environmental factors including pollution and the presence of buildings can reduce the availability of UVB light.

In northern latitudes or during winter months when the sun isn’t shining, I recommend taking 1 tsp./day of high-vitamin cod liver oil (Green Pasture or Radiant Life are two brands I recommend) to ensure adequate vitamin D (and vitamin A) intake. You can also eat vitamin D-rich foods such as herring, duck eggs, bluefin tuna, trout, eel, mackerel, sardines, chicken eggs, beef liver and pork. If you follow this approach further supplementation should not be necessary.

Before closing, I must mention (briefly) the issue of vitamin D toxicity. Vitamin D is widely considered to be the most toxic of all vitamins, and dire warnings are often issued to avoid excess sun exposure and vitamin D in the diet on that basis. The discussion of vitamin D toxicity has failed to take into account the interaction between vitamins A, D and K. Several lines of evidence suggest that vitamin D toxicity actually results from a relative deficiency of vitamins A and K.
So, the solution is not to avoid sun exposure or sources of vitamin D in the diet. Rather, it ensure adequate vitamin D intake (through sunlight and food) and to increase the intake (through diet and/or supplements) of vitamins A & K. Stay tuned for a future post on the interaction between vitamins A, D & K and their relevance to human health.

Suggested Links

• The Vitamin D Miracle: Is it For Real?
• From Seafood to Sunshine: A New Understanding of Vitamin D Safety
• Vitamin D Toxicity Redefined

Popularity: 41%

Related posts

• The truth about statin drugs (6)
• Essential fatty acids: not so essential after all (0)