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What happens if we don’t get enough vitamin D?

Severe deficiency of vitamin D leads to rickets in children and osteomalacia (softening of the bones) in adults. At the turn of the 20th century rickets was rampant in infants from poor homes living in industrialized cities of Northern United States, as well as in several heavily polluted cities in Europe. One post-mortem study in the early part of the 20th century found evidence of rickets in 96% (214 of 221) of children 18 months or less who had died from any cause (1). These observations led to the fortification of commonly consumed foods such as milk and margarine with vitamin D, and rickets was all but eliminated in western countries.

With the advent of sunscreen and concerns about skin cancer we are unfortunately seeing a return of rickets in N. America, especially in Afro-American and Hispanic children. Many children’s hospitals in affluent countries now have rickets clinic, something we once managed to relegate to the medical history books. In the UK, rickets has been identified in babies in utero as early as 19 weeks gestation (2).This appalling situation is easily prevented by ensuring that all infants and children receive a vitamin D supplement.

Vitamin D and disease

Apart from its requirement for bone health, recent research suggests a much wider role for vitamin D. It is involved in controlling blood pressure, cholesterol levels and the immune system. It is important for the production of insulin, and in maintaining the health of the brain. It is also intimately involved in the control of cell growth and replacement of normal tissues and is required to control the runaway abnormal cell growth we call cancer. Vitamin D is therefore involved in regulating the health of every tissue in the body.

An explosion of research in recent years has shown an association between vitamin D deficiency and a wide range of common health problems. These include osteoporosis (women and men), diabetes, rheumatoid arthritis, multiple sclerosis, and other autoimmune diseases, and muscle and bone pain and weakness (3). It has recently been suggested that many cases of fibromyalgia are actually misdiagnosed vitamin D deficiency (4). A new role for vitamin D is emerging in preventing the build-up of plaques in the brain that is the hallmark of Alzheimer’s disease, and older men and women with low levels of vitamin D don’t do as well on tests of reasoning, learning and memory as those with higher levels (5).

Vitamin D and cancer

Vitamin D is essential in surveillance against all types of cancer, including skin cancer. The association with skin cancer has led to fierce disputes between the dermatologists, some of whom insist that sun exposure alone causes skin cancer, while others say that we get skin cancer because we get burned by the sun when we are depleted of vitamin D (1).  Recent research suggests that both arguments are valid. Sun is a risk factor for skin cancer, but it is a catch 22 situation, because staying out of the sun will increase vitamin D deficiency and put us at risk of a whole host of diseases, including other cancers such as breast, colon, lung and prostate cancer (6,7,8). A compromise solution is to take vitamin D supplements, which are cheap and readily available.

Vitamin D and heart disease

Since geographic latitude, altitude and season are all associated with mortality from cardiovascular disease, it has recently been suggested that vitamin D deficiency plays a key role in heart health (9). The mechanisms whereby vitamin D deficiency might lead to heart disease are not thoroughly known, but one suggestion is that vitamin D prevents calcification (stiffening) of blood vessels, and reduces inflammation. It is interesting also that research studies have shown that blood pressure and cholesterol levels are lower in the summer months in those who are regularly outdoors (10,11).

Vitamin D, pregnancy and infant health

Canadian mothers and babies, especially those in northern Canada, don’t get enough vitamin D, according to the Canadian Pediatric Society (12).  They believe that vitamin D deficiency is widely prevalent among pregnant women and exclusively breastfed babies. In infancy, high dose supplementation may prevent disease in later life.

A Finnish study which followed up babies given 2000 IU vitamin D in infancy to adulthood found that they were protected against type 1 diabetes (13). Another Finnish study found that similar doses of vitamin D supplementation during the first year of life were associated with a reduced risk of schizophrenia, although only in males (14).

The Canadian Pediatric Society recommends that pregnant or breastfeeding women should talk to their doctor about taking a supplement of 2000 IU/day, and that all babies who are exclusively breastfed receive a supplement of 400 IU/day. Babies in the North (above 55 degrees latitude), they say, should get twice that amount during winter months (from October to April).

What are the physical signs of vitamin D deficiency?

Some of the most common signs of vitamin D deficiency involve its effects on muscle function and pain. Especially in the elderly, a reduction of muscle strength is common. Back, hip and leg pain as well as difficulty walking, going up and down stairs and getting up out of a chair are common manifestations of vitamin D deficiency. Another common finding is a pronounced body sway, when standing in the erect position. On the other hand, supplementation of vitamin D improves all these aspects of neuro-muscular functioning (15).

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Aileen Burford-Mason, PhD, is a biochemist, immunologist and cell biologist and a widely recognized expert in the field of vitamins and their appropriate use in health maintenance, healthy aging and the prevention and treatment of disease. Respected for her balanced and scientifically-based approach, Aileen is known for her ability to take the latest findings in diet and supplement research and translate them into practical evidence-based guidelines for both lay audiences and health professionals. A go-to person for radio, TV and print journalists, Aileen is in regular demand for media commentary on the latest research and controversies in the field of dietary supplements. She is the author of Eat Well, Age Better, with Judy Stoffman (2012, Thomas Allen Publishers). Learn more about Aileen at aileenburfordmason.ca.

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