The Sunshine Vitamin
by Dr. Janet McKenzie, ND, MBA, BSn

Vitamin D has become highly newsworthy over the last few years as it has been suggested as a preventative aid for many common health conditions for adults, ranging from cancer to high blood pressure to multiple sclerosis, and the supportive research for larger RDA’s continues to grow. Most of what we have heard is helpful to adults but what about children? How much Vitamin D do they need, and is it advisable to provide them with supplements too?

Vitamin D is a hormone-like substance that our bodies will manufacture when the skin is directly exposed to strong sunlight. This is the most efficient way to obtain Vitamin D because a brief exposure can provide up to 10,000 International Units (IU) per day. Depending on factors such as the degree of UV light exposure and the amount of pigment contained in the skin – people with dark complexions usually need more light exposure than people with light complexions.

Sun exposure is a challenge these days because the amount of UV light is higher now than in the past, and because of the connection between UV exposure and the subsequent development of skin cancer. Recognizing this connection, medical experts advise us to minimize our exposure to the sun, regardless of the climate in which we live and how darkly pigmented our complexions might be.

This good advice inadvertently creates a problem with respect to our Vitamin D status. When sun exposure is lacking because of climate, skin pigmentation or sunscreen use, we need to make sure we get Vitamin D from other sources, such as the foods and supplements we consume.

Vitamin D plays many roles in the development and maintenance of our bodies. Where children are concerned, Vitamin D is very important for the development of healthy bones and teeth as well as healthy immune function.

Vitamin D influences bone development by regulating the behaviour of bone cells and the process of bone mineralization. It affects immunity through the presence of Vitamin D receptors located on many white blood cells. When these receptors are activated, they influence the reproduction and specialization of immune cells. There are various types of immune cells that can arise from a common “parent” cell. Vitamin D is somehow involved in the process that guides the development of the “daughter” cells into different types. More recently, research has implicated Vitamin D deficiency in the development of severe asthma, obesity and diabetes in children, so it is clear that ensuring an adequate intake of this vitamin is critically important for their overall health.

Consequences of Too Little or Too Much
When we fail to get enough Vitamin D over an extended period of time, Vitamin D deficiency can develop.

Signs of Vitamin D deficiency in children include:
■ impaired bone development and growth, especially of the long bones in
the legs and arms (rickets)
■ dental problems
■ muscle spasms
■ muscle weakness

Vitamin D is a fat-soluble vitamin. This means we can build up stores of Vitamin D in the fatty tissues of our bodies. Because we can store it, it is possible to experience a toxic level of Vitamin D if we get too much of it. This is typically the result of over-supplementing.

Signs and symptoms of too much Vitamin D may include:
■ loss of appetite, nausea, vomiting
■ excessive thirst
■ excessive urination, chemical changes in the urine, possible kidney failure
■ weakness, nervousness, itching

Other dietary and health considerations can complicate the picture further. Remember, Vitamin D is a fat-soluble vitamin. As such, fat must be present in the diet for proper absorption to occur. People who do not consume enough fat from their food or who have conditions like Crohn’s disease, celiac disease or cystic fibrosis will be at risk of developing a Vitamin D deficiency. Children with epilepsy are also vulnerable to Vitamin D deficiency because anti-convulsant medications.