Vitamin D Benefits and Supplements

Vitamin D has benefits across multiple body systems and organs, and even has a role to play in helping mental health. Here are just some of its proven jobs:

• keeping bones and teeth strong by helping us absorb calcium and phosphorus from our food

• maintaining healthy muscle function – too little vitamin D and muscles can become sore and weak

• keeping blood glucose levels constant by regulating insulin, and therefore helping prevent you from getting diabetes, or helping if you have been diagnosed

• keeping our heart and circulation healthy - vitamin D keeps belly fat and fat around internal organs in check by improving insulin sensitivity and reducing insulin resistance, plus it reduces high blood pressure and cholesterol, keeping the risk of heart disease at bay

• it's essential for a healthy immune system and some studies show that it may help in fighting respiratory infections and reducing the severity of colds and flu

• it may help low mood and depression – the exact mechanism is not yet understood, but the brain has been found to have lots of vitamin D receptors, and some think it may regulate mood-related hormones such as dopamine and serotonin

Your skin is the great vitamin D factory, using direct sunlight to convert it to a useful form in the body. To a lesser extent, certain foods contain vitamin D such as oily fish, egg yolk, red meat and some cereals and margarine, where they artificially add vitamin D.

Unfortunately, both of these sources have pitfalls. There's not enough sunshine in the winter months in northern countries such as the UK. And dietary sources provide only a small amount of the vitamin D we need to keep us in optimum health. That’s where supplements are essential, especially between October and April. The government recommends everyone buys supplements in these months.

Some people are at higher risk of deficiency, and it's recommended they take supplements all year round. These include those who don’t get outdoors much, or cover their face and neck when they go out, the elderly, and those with darker skin such as Asian, African or Caribbean background. This can lead to osteoporosis.

Those who are pregnant or breastfeeding have higher vitamin requirements, so they should take supplements before and throughout. Babies and children up to 4 years old are recommended to take supplements, and those on a vegan diet are also at risk of low levels.

Vitamin D supplements available at the pharmacy or health food stores, and this usually comes in a version called vitamin D3, or colecalciferol. You can buy this on its own, combined with other vitamins such as calcium, or as part of a multivitamin.

Vitamin D comes as tablets, capsules, oral sprays or oral liquids. You can take it daily or at a higher dose weekly. It comes in a variety of strengths, depending on your personal needs:

• 10 mcg (or 400 IU) for children over 4 years old

• 20-25 mcg (800-1000 IU) for women during pregnancy

• 25 mcg (1000 IU) for general year-round maintenance

• 50-100 mcg (2000-4000 IU) preparations for those at high risk of severe deficiencies such as the elderly, those with darker skin, vegans or those with dietary restrictions, and those who may be housebound or have little opportunity to get good sunlight during spring and summer

Vitamin D combined with calcium, where they work together to be properly absorbed and maintain healthy strong bones and teeth. In combination with vitamin K, it can help maintain a healthy circulation, as it mops up excess calcium in the bloodstream, which prevents it forming plaques to block arteries, which can lead to a heart attack or stroke.

Vitamin D is a fat-soluble vitamin, which means that you maximise absorption by taking it with healthy fats such as avocados, nuts, seeds, eggs, or a dressing made with olive oil.

If you are in a high-risk group or for anyone living in the UK in winter, you do not need to check vitamin D levels, you can just start taking supplements. If you have reason to be worried that levels are low, you can speak to your doctor. Alternatively, you can get your levels checked in a blood test from a private clinic or lab.

You should check with your doctor before taking supplements if you are on certain medications, such as digoxin or water tablets (diuretics), if you have liver or kidney disease, or if you are receiving treatment for osteoporosis or another bone condition.