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Vitamin D deficiency is both highly prevalent and highly misdiagnosed in our world today. A deficiency of this vitamin can have dire health consequences ranging from osteoporosis, to increased risk of some common cancers, to increased risk of type 1 diabetes and cardiovascular disease (1).
There are several reasons that a deficiency of D is so prevalent. Very few foods contain appreciable quantities of vitamin D. In fact, other than oily fish and foods which are fortified with vitamin D (milk, some orange juice), one would be hard pressed to consume adequate vitamin D (1). Vitamin D can be synthesized in our skin, but this requires direct sunlight. In recent years the knowledge that sunlight can increase the incidence of skin cancer and will prematurely “age” the skin (cause wrinkles etc.) has lead to the increasing use of sunscreen lotions and the virtual avoidance of direct sunlight. Locale can also have a bearing on D deficiency. Above 35 degrees of latitude the rays of the sun hit the earth at such an angle during the winter months as to preclude the adequate production of vitamin D in the skin (1). Finally, obesity can be a cause of D deficiency. Vitamin D is very efficiently deposited into our bodyfat stores. With a greater and greater percentage of the population in the developed world becoming obese, the aforementioned causes of vitamin D deficiency are being even further exacerbated.
Vitamin D is integral to our absorption of dietary calcium (1). Without adequate levels of vitamin D our absorption of calcium is reduced dramatically. This can lead to a weakening of the bones and, if the deficiency were serious enough, can interfere with the proper functioning of our nervous system.
As already mentioned in the beginning of this article, vitamin D can also play a role in the reduction of risk for several common cancers. This wonderful feat is accomplished due to a little know biologic function of vitamin D (1). Vitamin D has the ability to down-regulate, or slow down, hyperproliferative cell growth (1). Out of control cell growth is one of the hallmarks of cancer. Most of our bodily tissues and cells contain vitamin D receptors (1). Both normal and cancer cells often respond to the active form of vitamin D, 1,25(OH)2D by decreasing their proliferation and maturing more quickly (1). Immune T and B lymphocytes also have D receptors and treatment with D has been shown (in mice) to be of help against the common autoimmune diseases like type 1 diabetes, rheumatoid arthritis, and multiple sclerosis (1). In short, the health consequences of a vitamin D deficiency can be dire and far reaching in scope.
Some common symptoms of vitamin D deficiency are listed below (2):
- Paleness due to lack of sun exposure
- Fragile bones in adults and rickets in children
- Arthritis (some cases)
- Soft teeth, cavities, and pyorrhea
- Nervousness, irritability and tension
- Sensitivity to pain
- Insomnia
- Tuberculosis type of infection of skin and psoriasis (some cases)
- Nearsightedness (some cases) and conjunctivitis
- Muscle spasms or cramps
- Bronchitis
- Nosebleed and some other types of hemorrhage
- Restlessness and fast heart beat
- Delayed healing
As you can see the symptoms are varied and some are non-specific (you could experience them for other reasons). However, if you have many of these symptoms, live in a Northern area, are older, have darker pigmented skin, do not get much direct sun exposure, or do not consume the foods listed earlier as being good sources of vitamin D on a regular basis (3-4 times per week), it is quite possible you are deficient in vitamin D. In fact, the chances that you are deficient are quite good in general.
I am sure by now that you want to know what to do in order to avoid a vitamin D deficiency. This is a debatable topic, but I will try to give you the best answer possible. First, it should be noted that excess vitamin D can be toxic to the body, thus care must be taken if a vitamin D supplement is to be used. In the absence of reasonable exposure to sunlight, 1000 IU of supplemental vitamin D daily has been shown to raise plasma levels to an acceptable level (1). When you are able to get out in the sun, a moderate dose of it will do the trick (1). What is a moderate dose? According to Michael F. Holick it is about 25% percent of the exposure time it would take to cause a light pinkness in the skin (1). Remember, this had to be unadulterated exposure to the sun, no sunscreen. After the period of time has elapsed, you can go back inside or apply sunscreen. Finally, you can increase your intake of the foods listed earlier as being rich in vitamin D (oily fish such as salmon, mackerel, and sardines, cod-liver oil, fortified milk and orange juice) (1).
The choice of how you increase your vitamin D level is yours, just make sure you make the choice and do something.
References:
1. Holick, MF. Vitamin D: importance in the prevention of cancers, type 1 diabetes, heart disease, and osteoporosis. Am J Clin Nutr 2004;79:362-371.
2. Clark, Linda. Know Your Nutrition: the complete guide to good health through natural living. Keats Publishing, Inc. 1973
Written by Chris Mason
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