The importance of vitamin D and your bones

You’ve likely heard of vitamin D, in some way or another. Maybe you’ve eyed it on your smoothie bottle, or pondered what it was doing in your moisturiser, but never really known exactly why we need it, and what role it performs in our bodies. Dr Taher Mahmud of the London Osteoporosis Clinic gives us the basics of vitamin D, and why it’s necessary for us and our bone health. 

What is vitamin D?

Vitamin D is sometimes nicknamed ‘the sunshine vitamin’, as our skin produces it naturally in a direct response to sunlight. Vitamin D can be made by the skin, but only in temperate climates. The UK winters don’t exactly stimulate the process – although (at times) the weather is sunny, there is not enough UVB light, essential in vitamin D production in the body. So even if you’re outside in winter, your body cannot produce the vitamin D it needs.  

The vitamin is fat-soluble, meaning it dissolves in fat and is stored throughout the body. Fat soluble vitamins, like vitamin A, D, E and K, are absorbed into the body through the lymphatic system, then finally into the blood circulation, where they are beneficial in different ways.

Vitamin D has several important functions, but one of the most important is regulating the body’s absorption of calcium. You can be taking in enough calcium through your diet, but all this will be wasted if you aren’t getting the right amount of vitamin D. Calcium can only help to build bones at full potential if the body has enough vitamin D. Lack of vitamin D results in a vitamin D deficiency – a problem in the UK, as the weather prevents a high amount of the population from getting the vitamin D they need.

What are the symptoms of a vitamin D deficiency?

In adults, symptoms may manifest in the following ways:

• Through tiredness, feeling aches and pains, and generally feeling lethargic or unwell
• Bone pain
• Muscle weakness
• Excessive sweating

In children, as bones are forming and developing, vitamin D deficiency may lead to ‘softer’ bones, resulting in conditions like rickets, or skeletal deformities such as knock knees and bow legs. Low vitamin D can also cause low calcium levels, which can cause muscle cramps and seizures in the very young. 

What problems can vitamin D deficiency cause in adults?

Low levels of vitamin D are linked to bone conditions such as osteomalacia, where bones become soft or weak due to loss of calcium and other minerals, and osteoporosis, where bone density decreases, bones become more porous, and break due to weakness over time.

How can we increase vitamin D intake?

Vitamin D levels can be checked through a blood test, and there are ways other than being exposed to sunlight to make sure that you get the right amount.

Some foods and drinks are fortified with vitamin D, especially in countries in the northern hemisphere. Cereals, margarine, and some dairy products such as milk may have vitamin D added to them. There are also foods in which vitamin D naturally occurs, such as egg yolks and fatty/oily fish.

However, it is difficult for children, and sometimes adults, to get the right amount of vitamin D through food alone. There are many multi-vitamin supplements on the market that can help increase vitamin D levels, and calcium supplements may also contain vitamin D.

Those with low vitamin D also require more calcium in their diet. Calcium-rich foods include dairy products such as yoghurt, milk, and cheese, or tofu, which can be important for those who avoid dairy products.

It is also important to stress that while sunlight exposure plays a key role in vitamin D production, you shouldn’t be reaching for your beach towel and deck chair with abandon. Ten minutes exposure is usually enough, as any more can cause reddening and burning. Too much sun exposure is linked to skin cancer, so as with most things in life, getting the balance right is essential.

Getting enough calcium and vitamin D is an essential part of prevention of osteoporosis and other related conditions. Talk to your doctor or health specialist about the best ways to include these nutrients in your diet, and daily routine.