What Is Vitamin D Deficiency? Mixed Messages About Sun Exposure

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Main Category: Nutrition / Diet
Also Included In: Dermatology
Article Date: 10 Jun 2010 - 0:00 PST

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Vitamin D deficiency is when your body, more specifically your blood, does not have enough vitamin D. This can be caused by the following factors:

• Inadequate exposure to the right kind of sunlight
• Inadequate intake from foods and supplements
• Disorders in the gastrointestinal tract that limit absorption
• Liver disorders
• Kidney disorders
• Some hereditary disorders (very rare)

Vitamin D deficiency can lead to the following conditions and illnesses:

• Rickets - a disease of children and infants that interferes with normal bone formation - a failure to mineralize bone. Bones become distorted and bend wrongly because they are soft. During the first three decades of the 20th century rickets was mainly caused by lack of direct exposure to sunlight. The ultraviolet rays necessary for vitamin D synthesis do not pass through ordinary window glass.
• Osteomalacia - softening of the bone caused by demineralization (loss of mineral), mainly loss of calcium from bone. This disorder only affects adults and can cause severe musculoskeletal pain.
• Osteoporosis - reduced bone mineral density and increased bone fragility.

Vitamin D deficiency has also been linked to the following diseases:

• Hypertension (high blood pressure)
• Heart failure, according to US researchers.
• Ischemic heart disease
• TB (tuberculosis)
• Cancer
• Periodontal disease
• MS (multiple sclerosis)
• Chronic pain
• SAD (seasonal affective disorder)
• Peripheral artery disease
• Cognitive impairment
• Cardiovascular disease among patients with diabetes
• Parkinson's disease (possibly: we are not sure whether Parkinson's causes low vitamin D levels, or whether low vitamin D causes Parkinson's)
• Alzheimer's disease, suspected by researchers from the Sunlight, Nutrition, and Health Research Center.
• Immune system problems - a University of Missouri nutritional sciences researcher found that vitamin D deficiency is associated with inflammation, a negative response of the immune system, in healthy women.
• Bacterial vaginosis - a common vaginal infection that increases a pregnant woman's risk of preterm delivery, according to scientists at the University of Pittsburgh.

Mixed messages regarding sun exposure

For decades we have been told to stay out of the sun, to wear hats and cover ourselves with sun block to protect against skin cancer - and also significantly reducing our levels of vitamin D. Add to that a growingly sedentary lifestyle where we and our children spend more time indoors either watching TV or in front of a computer monitor, and it is not surprising that millions of people have excessively low levels of vitamin D in our system.

Then we are told that sunlight can rapidly make up for any vitamin D shortfall, while at the same time the American Academy of Dermatology continues to recommend that the public obtain vitamin D from nutritional sources and dietary supplements, and not from unprotected exposure to ultraviolet radiation because of the skin cancer risk (article), and we despair.

Telling people to get their vitamin D from just food and supplements obviously does not work. People have been told that for the last twenty years and vitamin D deficiency or insufficiency has increased significantly. It is estimated that 50% of American elderly women consume far less vitamin D in their diet than recommended. Consequently, vitamin D deficiency is a serious problem among the elderly in the USA.

It is understandable why a dermatologist, who is in direct contact with skin cancer patients, advises people to stay out of the sun. However, millions of people are and will develop other very serious diseases because their vitamin D levels are too low. Skin cancer is one factor, but there are many other factors.

Large studies are required that can clearly tell us:

1. Why is the current policy of telling people to get just their vitamin D from nutritional sources not working?
2. Is the current vitamin D problem greater than the skin cancer problem?
3. Is it possible to estimate what the impact of recommending 15 minutes twice a week of sun exposure would be on skin cancer numbers, and the health benefits from a resulting lower incidence of vitamin D deficiency in the population?

Some health authorities are starting to change their recommendations. Here is a quote from the Cancer Council, Australia (2009):

Sun exposure is the cause of around 99% of non-melanoma skin cancers and 95% of melanomas in Australia. However, exposure to small amounts of sunlight is also essential to good health. A balance is required between avoiding an increase in the risk of skin cancer by excessive sun exposure and achieving enough exposure to maintain adequate vitamin D levels.

Further reading

• What Is Vitamin D? What Are The Benefits Of Vitamin D?

Written by Christian Nordqvist
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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