Vitamin D: What Do I Need to Know?

Vitamin D is an essential vitamin, as it helps with the absorption of calcium from the digestive system. It also assists in regulating the loss of calcium from bones. Calcium of course, is necessary for strong healthy bones.

Vitamin D is needed throughout life to maintain strong healthy bones. Deficiency of vitamin D in children may lead to a condition called Rickets, where bones become weakened and in some cases deformed. In adulthood, particularly in the older population, vitamin D deficiency can lead to the development of osteoporosis, a chronic degenerative condition where bone becomes weakened and more likely to fracture. Osteoporosis is a significant health problem in western countries, so preventative measures such as increasing the awareness about the importance of adequate vitamin D intake are becoming more apparent in public health programs.

There is some new research emerging showing that vitamin D may also have a role in protecting against some other chronic diseases such rheumatoid arthritis, multiple sclerosis and autoimmune diseases to name a few. However this research is in its infancy, so more studies will be needed to further define the role of vitamin D in these conditions.

Unlike many other vitamins and minerals, vitamin D is not something most of us are likely to get from our regular diet. Vitamin D mainly comes from the sun, by exposing the skin to direct sunlight (so not through glass or clothing). Not many foods contain vitamin D, and those that are have usually been artificially fortified with vitamin D. Certain dairy products (milk, cheese, cream, yoghurt) may contain added vitamin D. Oysters, eggs and fatty fish (salmon, mackerel) are natural sources of vitamin D. Many multivitamins contain some vitamin D, and there are a number of single ingredient vitamin D products on the market. Note that there are two forms of vitamin D, vitamin D3 (cholecalciferol) which is from the sun and vitamin D2 (ergocalciferol), which is from dietary sources.

When UV rays (the light from the sun) hit the skin, the skin uses the UV light to make vitamin D3 (cholecalciferol) which then gets processed by the liver and kidney to its active hormone form. In this form, it assists with calcium absorption from the digestive system and regulates the loss of calcium from bone. When vitamin D is obtained from the diet (in the form vitamin D2, or ergocalciferol), it is converted in the body to vitamin D3. The same process of conversion to the active hormone form occurs.

This depends on your age, gender and general health. For most people, 10-15 minutes of unprotected exposure to the sun three times a week would be sufficient to produce the body’s vitamin D needs. Care needs to be taken to avoid prolonged unprotected exposure to the sun, as this greatly increases the risk of skin cancer.

Factors such as staying indoors all day, being darker skinned, high levels of air pollution being present, cloud cover and shade can all affect vitamin D needs.

As a general rule, older people, darker skin people and those that are housebound will need more vitamin D (from supplemental sources), as they cannot produce it as effectively from sunlight.

The following are recommendations for daily vitamin D intake, assuming minimal sun exposure:

Children 1 year – 18 years: 600 IU (15 micrograms)

Adults 19- 70 years: 600 IU (15 micrograms)

Adults >71 years: 800 IU (20 micrograms)

Pregnancy and Breastfeeding: 600 IU (15 micrograms)

Are there any side effects of vitamin D?

Taking too much vitamin D, which is possible if taking too many supplements, can cause side effects. Excessive sun exposure (whilst not good for you due to the risk of skin cancer) cannot cause vitamin D overdose. Too much vitamin D can lead to your body having too much calcium in the blood. This can cause symptoms such as confusion, kidney problems, constipation, nausea, vomiting, loss of appetite, weakness and weight loss. It may even lead to calcium going where it shouldn’t, depositing in heart and lung tissue which can cause additional problems.

Some prescription medicines for osteoporosis come with vitamin D in them, so check with your doctor or pharmacist if you are unsure, before taking a vitamin D supplement. If you take multiple vitamin products, always read the labels to make sure you are not taking too much vitamin D.

So now that you know a little more about the importance of vitamin D, take the opportunity now to go and enjoy a stroll outside in the sunshine!