Vitamin D Deficiency: Signs, Causes, and What to Do

Why does your body need vitamin D?

Vitamin D is not just another vitamin. It works in the body more like a hormone, regulating many functions. Its most important job is helping your gut absorb calcium from food, which keeps your bones and teeth strong. Without enough of it, the calcium in your meals passes through without doing your body much good.

Vitamin D also supports your muscles so they can work properly, and it plays a part in regulating the immune system that defends you against infection. That is why a long-standing deficiency can affect your general health, not just your bones.

Because food contains relatively little of this vitamin, your body relies mainly on sunlight to make it in the skin. And that is where the story begins of why deficiency is so common in our region, despite all the sunshine around us.

Signs that may point to vitamin D deficiency

The tricky part is that vitamin D deficiency rarely announces itself clearly. Many people feel nothing at all and only discover it by chance on a blood test done for another reason. When symptoms do appear, they are vague and can have many other causes.

Remember that these signs alone are not enough for a diagnosis. Tiredness, for example, can come from anaemia, poor sleep, or a thyroid problem. Still, the signs most often linked to deficiency include:

• Ongoing tiredness and low energy with no clear cause
• Aching bones, especially in the lower back
• Muscle weakness or aches, and sometimes cramps
• Low mood or feeling down for no obvious reason
• In children, severe deficiency can show up as slow growth or bowed legs

Why is deficiency so common here despite the sunshine?

It sounds strange: how can a shortage of the sunshine vitamin be widespread in countries that are sunny most of the year? The answer is that your body makes vitamin D when sunlight touches the skin directly, and our daily routines leave very little room for that.

Most of us spend the day indoors, at home, in the office, or in the car, and we avoid going out in the intense heat. Clothing that covers most of the body blocks sunlight from reaching the skin, and window glass filters out the rays the skin needs, so sitting by a sunny window does not help here.

On top of that, darker skin contains more melanin, the pigment that gives skin its colour, so it needs longer in the sun to make the same amount of vitamin D as lighter skin. Put these factors together and you can see why deficiency is common in our communities despite the abundant sun.

Who is more at risk?

Anyone can develop a deficiency, but some groups are more likely to than others. If you see yourself in one of these groups, it is worth paying attention and raising it with your doctor at your next visit.

• People who spend most of their time indoors
• People whose clothing covers most of the body
• People with darker skin
• Older adults, because the skin makes less vitamin D with age
• Pregnant and breastfeeding women, because the body's needs increase
• People who are overweight
• People with conditions that affect fat absorption in the gut, or chronic kidney or liver disease

How is vitamin D deficiency diagnosed?

The diagnosis is simpler than you might think: a single blood test that measures the level of the vitamin in your body, known as the 25-hydroxyvitamin D test. This is the standard test doctors request, because it reflects your body's actual store of the vitamin.

There is no need to keep testing yourself repeatedly on your own. If you have troubling symptoms, or you belong to one of the higher-risk groups, talk to your doctor first. They will decide whether you need the test at all.

The result usually appears as a number alongside a reference range showing whether your level is low or adequate. Do not rush to judge the number yourself. Interpreting it depends on your age, your health, and your medicines, so let your doctor explain what it means for you.

Where can you get vitamin D?

The first source is the sun. Exposing your arms or legs to sunlight several times a week helps your body make the vitamin. Choose milder times of day, away from the scorching midday hours, and never stay out long enough for your skin to redden. The right amount of time varies from person to person depending on skin tone and where you live, so ask your doctor what suits you.

Food provides a limited but still useful amount. The best sources are oily fish such as salmon, sardines, and mackerel, along with egg yolk and foods fortified with vitamin D, including some milks, dairy products, and breakfast cereals. Look for the word fortified on the packaging when you shop.

If a test confirms a genuine deficiency, your doctor may prescribe vitamin D supplements for a set period. The key point is not to start high doses on your own. Your doctor will decide the right dose and how long to take it, because too much from supplements can harm you as well.

When should you see a doctor?

See your doctor if tiredness or aching bones and muscles persist and interfere with your daily life, or if you belong to a higher-risk group and want peace of mind. Do not rely on guesswork or on other people's experiences, because what suits someone else may not suit you.

The good news is that vitamin D deficiency is common and, in most cases, easy to treat once it is properly diagnosed. And remember, this article is for general awareness only. It is not a substitute for advice from your doctor or pharmacist.