Vitamin D supplementation
Most people don’t need vitamin supplements. Adults following a healthy and balanced diet get all the vitamins and minerals required for their bodies to function well from food. Nonetheless, vitamin D supplement is recommended by the NHS throughout autumn and winter. This week we explore the importance of vitamin D, the need for vitamin D supplementation and the consequences of vitamin D deficiency.
Vitamin D helps regulate the levels of calcium and phosphorous in the body which directly translates to maintaining healthy muscles, bones and teeth. In simple terms, it enables normal bone mineralization and helps prevent muscle spasms. However, recent studies show that vitamin D has other important functions in the body, too, including reduction of inflammation and support for immune function and glucose metabolism1. It is an essential vitamin for maintaining good health and strong muscles and bones.
Sources of vitamin D
Vitamin D is normally obtained through sun exposure (it is produced in the skin), from food and through vitamin D supplements.
Sun exposure is normally the biggest source of vitamin D for humans as there is very little of it in most foods. According to the NHS, the daily recommended intake of vitamin D for an adult is 10 micrograms a day. You can obtain this amount of vitamin D with just 15 minute exposure to full direct sunlight but that is without any sunscreen and with 18% of your bare skin exposed. Clearly, this isn’t a healthy way of obtaining vitamin D (remember to always use sunscreen to reduce the risk of skin damage or skin cancer!) and it is virtually impossible to complete in the winter months. Thus, between October and March, it is recommended that all adults supplement vitamin D.
A small amount of vitamin D (between 10-20%) can be obtained through your diet. The best sources of vitamin D in food are:
- oily fish
- red meat
- egg yolk
- vitamin D fortified foods – such as some fat spreads and breakfast cereals
To get the required 10 micrograms of vitamin D from food you would need to eat 10 eggs or 500g of beef liver or 3kg of yoghurt. Don’t do it! ?
It is extremely difficult to obtain your entire vitamin D requirement from food while maintaining a healthy and balanced diet. That’s why vitamin D supplements are recommended.
Vitamin D supplementation
Adults need approximately 10 micrograms of vitamin D a day, according to the NHS. During autumn and winter we cannot get enough sun exposure to produce the required amount of vitamin D naturally. As it is difficult to obtain the recommended levels from diet, too, the NHS recommends that from October to March all adults (and children over age of 4) supplement vitamin D. You should consider taking a daily supplement containing 10 micrograms of vitamin D.
Some people may need to supplement vitamin D all year round, and those include:
- those who are not often outdoors
- those who are in institutions like a care home
- those who usually wear clothes covering most of their skin therefore further reducing the exposure to sun.
Safety note from the NHS: Some people have medical conditions that mean they may not be able to safely take as much. If in doubt, you should consult your doctor.
If your doctor has recommended you take a different amount of vitamin D, you should follow their advice.2
Vitamin D deficiency
The main consequence of vitamin D deficiency can be observed in children whose bones don’t develop properly (rickets) and in adults whose bones become brittle. However, numerous studies have linked vitamin D deficiency to other long-term conditions including type 1 and type 2 diabetes, hypertension, glucose intolerance and multiple sclerosis3.
Vitamin D deficiency can occur in adults if they don’t follow a healthy diet, don’t have sufficient sun exposure and don’t take vitamin D supplements. It is worth noting that those following a vegan diet are more likely to obtain even less vitamin D from foods. The pigment melanin reduces the skin’s ability to make vitamin D in response to sunlight exposure so studies have shows that adults with darker skin may also be at a higher risk of vitamin D deficiency.
Vitamin D overdose
You cannot overdose vitamin D through exposure to sun. However, taking too much vitamin D supplement over a long period of time can lead to calcium build-up in the body. Only take the recommended daily dosage.
Remember, the advice above applies to healthy adults and if in doubt and for more information you should always consult your doctor.