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Ah, summer; a blessing for some, misery for others. When summer hits, some people come alive, spending hours outdoors, while others dread the heat and glaring sunlight of the lazy days. Without a doubt, the increased sunshine has a number of benefits for your health and mental outlook. One of these benefits is the production of vitamin D in your skin.

Vitamin D is a fat soluble vitamin essential to many functions. Without vitamin D, the human form wouldn’t be possible. Vitamin D has been a superstar among nutrients in the news lately. Study after study has come out extolling the virtues of this little miracle vitamin. Unfortunately, however, it has also come to light recently that many people are actually deficient in this essential nutrient. According to a 2005 study, a high number of people in North America have vitamin D insufficiency.

Vitamin D insufficiency is a form of deficiency with no external symptoms, but the dangers are real. That’s what this article is about. We want to identify the dangers of vitamin D insufficiency and describe who is at risk.  We want to identify ways you can determine your vitamin D status and what you can do if, in fact, insufficiency is present.

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Vitamin D—its actions.

Vitamin D is a prohormone, meaning it has no hormone properties itself but converts to a hormone with specific actions in the body. For anybody who cares to know, 1,25-dihydroxycholecalciferol is the hormone form of vitamin D. It binds to a receptor called the vitamin D receptor (VDR) which is present in numerous cells including the brain, heart, skin, gonads, prostate, and breast. When activated, this receptor triggers a biochemical cascade that varies from cell to cell.

In the intestine, bone, kidney, and parathyroid gland, vitamin D maintains calcium and phosphorous levels in the blood (along with parathyroid hormone and calcitonin), as well as maintaining bone content. Because calcium is so important to cell function, from neurotransmitter release to muscle contraction, vitamin D is essential in regulating these functions. And since our bones and teeth store 99% of the body’s calcium, it shouldn’t be too surprising to know how important vitamin D is to that process.

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Vitamin D also plays a role in cell differentiation. When cells divide, it is called cell proliferation; when cells develop into different types with different functions, it’s called cell differentiation. When cells differentiate, proliferation slows down—in other words, specialized cells don’t grow in number too quickly. Vitamin D actually stimulates differentiation and inhibits proliferation. Although proliferation is vital to wound healing, it can get out of control. Uncontrolled cell growth is the hallmark of cancer. Vitamin D has been shown to affect a gene that plays a role in the suppression of colon cancer. It does so by preventing the proliferation of colon cancer cells. Not bad for a simple nutrient.

Vitamin D also regulates your immune system. The immune system cells, most notably the T-cells, carry the VDR. Vitamin D acts as an autoimmune suppressor—that is, it helps regulate the immune system, particularly in disorders where the body attacks itself, like rheumatoid arthritis, lupus, or inflammatory bowel disease. A 2007 study showed that vitamin D significantly enhanced the immune response against tuberculosis.

beverly hills chiropractorThe VDR is abundantly found in the pancreatic insulin-secreting cells. Vitamin D plays an important role in insulin secretion when blood sugar levels go up (e.g., after a meal). Vitamin D insufficiency can lead to glucose tolerance in type 2 diabetes, so proper vitamin D levels in the body can prevent the development of diabetes.

The VDR is also closely tied to the renin-angiotensin system, which regulates blood pressure. It acts as an inhibitor to the production of renin which starts a cascade that eventually raises blood pressure by constricting blood vessels; so vitamin D actually works to lower blood pressure, or at the very least maintain a healthy level.

Sources of Vitamin D


As I pointed out earlier, the sun is our body’s first and primary source of vitamin D.  The deepest layers of the epidermis of the skin produce a compound called 7-dehydrocholesterol, or pre-vitamin D.  Pre-vitamin D is then acted upon photochemically by UV radiation, or sunlight, producing vitamin D.  The whole process is dependent on the concentration of melanin, which is a pigmentation compound in the skin meant to filter UV light.

beverly hills chiropracticThe darker the skin, the greater the concentration of melanin, and higher melanin levels mean that it takes the body longer to produce vitamin D simply because less sunlight gets through to make the chemical conversion of pre-D into vitamin D.  This has implications for darker people, as it has been found that black people have lower circulating blood D levels than the general population. This puts black people at a higher risk for vitamin D insufficiency and the health hazards that come along with it.

Black people, however, are not the only at-risk group. People in northern climates are at greater risk, too, simply because the amount of sunlight they receive annually is limited. For these people, the best source of vitamin D is food. Natural sources of vitamin D are fish liver oils (e.g., cod liver oil), fatty fish (herring, mackerel, catfish, salmon, sardines, eel, and tuna), whole eggs, beef liver, and UV-irradiated mushrooms.

Food and Supplements:

Since the 1930s, foods have been fortified with vitamin D.  This practice came about as a way to combat the prevalence of Ricketts, the childhood bone disease caused by more people working indoors during the Industrial Revolution. Typically fortified foods include milk, yogurt, breakfast cereals, and bread. For example, milk is generally fortified with 100 IU, one-fourth of the RDA level for vitamin D.

The third source of vitamin D is supplementation. Supplements might be the best and most effective way to increase vitamin D levels since many people are afraid to get too much sunlight, which is understandable, given the risk of skin cancer looming. Further, supplementing can give optimal vitamin D levels year-round for black people and in regions with sparse sun.

Some confusion revolves around what the proper vitamin D levels actually are.  The RDA is set at 400 IU per day.  If you have read my article on vitamin B deficiency, you will recall that the RDA levels are set to prevent deficiency diseases (see below) from occurring.  But that does not mean those levels are optimal for proper health and functioning.  In light of the newest findings on vitamin D insufficiency, experts now believe that 1,000 IU is necessary for optimal health.  Some experts feel that 5,000-50,000 IU can be safely taken without toxicity (see below).

West Hollywood ChiropacticIn my West Hollywood and Palm Desert chiropractic offices, I highly recommend vitamin D supplementation to my clients, even in a sunshine region like Southern California. I do this because I know that not everyone spends hours in the sun. Even in our warm weather climate, we tend to huddle indoors in the air conditioning and may not get sufficient sun exposure on a daily basis to maintain our healthy vitamin D levels.

I carry an excellent brand of vitamin D in my office. As I always say, I want to be the health product resource for my clients. As a chiropractor, I know how important nutrition is to healing. Even better is preventing diseases before they happen, so taking a vitamin D supplement is a must. Let’s talk about some diseases that vitamin D deficiency can lead to.

Vitamin D Deficiency Leads to Ill Health

Vitamin D deficiency is also known as hypovitaminosis D.  Poor nutritional intake of vitamin D coupled with lack of sun exposure can lead to the following illnesses:

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These major types of vitamin D deficiency disease are the extreme. Simply following the RDA will prevent these diseases from happening. Many more disorders are possible, though, and vitamin D insufficiency is just the starting point. Low vitamin D levels can lead to high blood pressure, tuberculosis, cancer, periodontal disease, multiple sclerosis, chronic pain, seasonal affective disorder (SAD), peripheral artery disease, cognitive impairment, including memory loss and foggy brain, and several autoimmune diseases, including diabetes. The RDA may simply not be enough. Remember, getting 1,000 IU of vitamin D daily might be necessary to ward off these other dangerous conditions.

Those at Risk for Vitamin D Insufficiency

I have already touched on some of the common risk factors for vitamin D insufficiency—dark skin, poor nutrition, and living in regions of low sunlight at various times of the year can all have a negative impact on vitamin D levels.  Some other risk factors include:

Testing Vitamin D Levels

So how can you know if your vitamin D levels are up to par?  Obviously, symptoms will alert you to any deficiency, but in their absence, how would you know if you are in the realm of insufficiency?  And if you are relatively healthy, perhaps even taking vitamin D supplements regularly, how would you know if you are at optimum levels? The best way to do it is through a blood test.

At my Los Angeles and Coachella Valley chiropractic offices, you can have your blood drawn by a registered nurse. We send your blood samples to a lab, where they assess your vitamin D levels through radioimmunoassay from Diasorin labs—the most effective way to assess vitamin D in the body.

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Once the lab results return, we will know whether you are deficient, insufficient, normal, or optimal. If you are suffering from insufficiency or worse, we can recommend proper supplements and activities to bring your vitamin D levels up to optimum. This is the only way to accurately and definitively know whether you are in vitamin D balance, and I cannot recommend it enough.


Everyone needs to know one more piece of information: Because vitamin D is a fat-soluble vitamin, there is a risk for toxicity, also known as hypervitaminosis D. Too much vitamin D is not a good thing—it can cause high blood pressure, digestive problems (anorexia, nausea, and vomiting), polyuria (excessive production of urine), polydipsia (increased thirst), weakness, nervousness, pruritus (itch), and eventually renal failure. It can also cause heart disease.

Toxicity is hard to develop. At one time, 2,000 IU was thought to be the upper limit for daily vitamin D intake, but now that limit is far too restricting and baseless. Today, experts believe that people can take up to 10,000 IU without toxicity. This is not what I am recommending here. I think 1,000-5,000 IU per day is plenty (it depends—the best practice is to have a professional check your blood levels). However, let it be known that toxicity and overdose are usually the result of manufacturing and industrial accidents and not from supplements. Furthermore, extended sun exposure is very unlikely to cause symptoms of toxicity.

This article should give you a better idea of how important vitamin D is to health and life. The primary source of vitamin D is our life-giving sun (even fish need vitamin D, which they get from eating photosynthesizing algae).  When vitamin D levels get too low, breakdown and illness can happen. Supplementing with vitamin D is the best adjunct to getting adequate daily sun and proper nutrition. However, not everybody has the luxury of 365-day sunlight like this Los Angeles chiropractor. Even more reason to supplement. And anyway, not all of us love being in the sun all that much. For those people, eating healthy foods rich in vitamin D or fortified and supplementing can go a long way. To find out where you stand on the vitamin D spectrum, come into my Beverly Hills and Palm Desert chiropractic offices and get tested today—you’ll get a whole new sunny perspective.

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-July 13, 2009