Vitamin D Deficiency: Symptoms, Causes, Test and Treatment

6 min read · Conditions · By the Asthra Health Care team

Why vitamin D matters

Vitamin D helps the body absorb calcium and phosphorus from food, which are needed for strong bones and teeth. It also supports muscle strength and plays a role in the immune system. Our skin makes vitamin D when it is exposed to sunlight, and a small amount comes from food.

Without enough vitamin D, bones can become soft and weak. In children this causes rickets, with bowed legs and delayed growth. In adults it causes osteomalacia, with bone pain and muscle weakness, and over time it adds to the risk of osteoporosis and fractures, especially in older people.

Why it is common in India

Although India is sunny, many people spend most of the day indoors in offices, schools, shops or homes, and travel in vehicles. Darker skin needs more sunlight to make the same amount of vitamin D. Covering most of the body, using sunscreen all the time, air pollution and a mostly vegetarian diet with few vitamin D foods also add to the problem.

• Older adults and people who rarely go outdoors
• Pregnant and breastfeeding women, and exclusively breastfed babies
• People who are overweight
• Those with kidney or liver disease, or conditions that affect gut absorption
• People taking some long-term medicines, such as certain anti-seizure drugs or steroids

Symptoms of vitamin D deficiency

Many people with low vitamin D have no symptoms, and it is found only on a blood test. When symptoms appear, they are often vague and easy to blame on work or age. They include tiredness, aches in the bones, especially the lower back, hips and legs, muscle weakness or cramps, and difficulty climbing stairs or getting up from a squatting position.

Children may have delayed walking, bowed legs, late teething or poor growth. Older people may have frequent falls. Low vitamin D is also linked with low mood, though this does not mean supplements alone will fix every such problem. If you have ongoing aches or weakness, see a doctor to rule out other causes.

The vitamin D blood test

The test used is 25-hydroxy vitamin D, often written as 25(OH)D. It shows how much vitamin D is stored in your body. Fasting is not needed. Your doctor will interpret the result along with your symptoms and risk factors, since the cut-offs for deficiency and insufficiency differ slightly between guidelines.

Your doctor may also check calcium, phosphorus, alkaline phosphatase and sometimes parathyroid hormone, as well as kidney function. Routine testing is not needed for everyone, but it is useful for people with symptoms, bone problems or high risk. Repeated tests at short intervals are usually not useful, since levels change slowly.

How vitamin D deficiency is treated

Vitamin D deficiency is treated with vitamin D3 (cholecalciferol) supplements, in the form of tablets, capsules, sachets, drops or chewable forms. The strength and schedule should be decided by your doctor based on your blood level, age and health. High-strength weekly or monthly doses are meant for a limited period only, followed by a smaller maintenance amount if needed.

Calcium may be added if your diet is low in calcium. Do not take high-dose vitamin D on your own for long periods. Too much can raise calcium in the blood, causing nausea, thirst, confusion and kidney stones. People with kidney disease, kidney stones or sarcoidosis need special care.

Sunlight and food

Short, regular periods of sun on the face, arms and legs can help the skin make vitamin D. Avoid sunburn and do not stay out long in the harsh afternoon heat, especially in summer. Sunlight through glass windows does not help, as glass blocks the rays needed.

Foods with vitamin D include oily fish such as sardines and mackerel, egg yolks, and fortified milk, oil or cereals. Vegetarians rely more on fortified foods and sunlight. Include calcium-rich foods like milk, curd, paneer, ragi, sesame seeds and green leafy vegetables.

Special groups and follow-up

Babies, especially those who are exclusively breastfed, are often given vitamin D drops, as advised by the paediatrician. Pregnant and breastfeeding women should take supplements only as their doctor advises. Older adults may need both vitamin D and calcium to prevent falls and fractures.

Your doctor may repeat the blood test after a few months of treatment to check the response. Keep all your supplements in a safe place away from children. For advice on which form suits you and how to take it, speak to your doctor or pharmacist.

This article is general health information, not medical advice. Do not start, stop or combine medicines on your own — always follow your doctor's prescription and ask your pharmacist if unsure.