The Nutritional Institute

Vitamin D is a fat-soluble vitamin, meaning that it can be stored in our body’s fat tissues. It is also the only vitamin that our body can make itself, by converting a form of cholesterol when your skin is exposed to sunlight: this makes vitamin D more of a steroid hormone than a vitamin. Historically, vitamin D deficiency was linked to rickets in children, so it is better known for maintaining bone health by regulating calcium and phosphate levels.

However, we now know that vitamin D receptors are found everywhere in the body and active areas of research have shown that the right amount of vitamin D fulfils other vital bodily functions, such as preventing cardiovascular disease, maintaining optimal immune function and skeletal muscle health, as well as reducing the risk of all cancers.

It is well known that your geographic region plays a significant role in how much vitamin D you can get from sun exposure. That is why people from countries in higher latitudes, such as the UK, tend to be more deficient in vitamin D. Nevertheless, people from sunny countries, such as those in the Middle East, are also sometimes deficient in vitamin D, possibly because they conceal their bodies and there is UVB insulation due to dust particles in the atmosphere. The prevalence of vitamin D deficiency also increases as we move into the winter months, and the colour of your skin is also a key factor. If you have darker skin, you are at a greater chance of being deficient. However, I think anyone in modern society is at a greater risk than before because a large portion of today’s workforce lead a sedentary lifestyle in office-based settings and tend to eat convenience foods, often sacrificing nutritional quality.

When sun exposure is not an option, the only way to get your healthy dose of vitamin D is by consuming natural food sources, vitamin D fortified foods and/or supplementation. Two forms of vitamin D exist: vitamin D3 (the animal form) and vitamin D4 (the plant form). Vitamin D3 is known to be more effective, but there are not many natural food sources and it can be hard to get enough vitamin D from your diet. The best source is cod-liver oil (1 tbsp provides 1350 IU) as it provides more than double the amount of your recommended dietary allowance (RDA 600 IU, aged 1 to 70).

However, newer research is showing that the vitamin D RDA is inadequate for optimum health and we actually need more than stated. Oily fish, such as salmon, mackerel and sardines, and vitamin D fortified foods provide a reasonable amount of vitamin D, while egg yolks, liver and beef provide a small amount. You would need to consume a great amount of the latter foods to cover your needs.

My advice is to get your vitamin D levels checked, especially if you do not get much sun exposure - it is a cheap test from common pathology labs. This will help you to decide whether you need to consider supplementing with vitamin D3. The required dose will depend on your needs and should be monitored over time. As supplementing may interact with certain medications and is contraindicated for certain conditions, such as elevated blood calcium levels, you should consult with your doctor or other health practitioner if this is the case.

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