- What is vitamin D?
Vitamins are compounds that our bodies need to grow and remain healthy. Vitamin D is one of fat soluble vitamin which primarily helps regulate the amount of calcium and phosphate in the body. Calcium and phosphate are needed to help keep bones and teeth healthy. Vitamin D may also help to keep us healthy in other ways, for example by helping the immune system.
- Where do we get vitamin D from?
The main source of vitamin D is made in the skin with the help of sunlight (UVB rays). Unlike other vitamins, only a small amount comes from the food we eat, even if we have a healthy diet.
- How much sun exposure you need for adequate synthesis of vitamin D in your body?
During summer, two or three exposures each week (of at least the face and arms without sunscreen and not behind glass; each exposure lasting 10 to 15 minutes), between 10 AM and 3 PM, should provide adequate amounts of vitamin D. Older people and those of non‐white ethnicity will have higher requirements. Darker-skinned individuals may need 5-10 times more exposure than a fair-skinned person to make the same amount of vitamin D. During winters vitamin D synthesis may be very poor because of lack of UV B in sunlight.
In order to maximise the benefit of sunlight, please ensure:
- Expose bare face, arms or legs (exposure through glass window is not adequate) to sunlight at least 2‐3 times per week
- Best time is between 10 AM and 3 PM
- Each episode should last 10‐15 minutes e.g. out in the garden, walking to the shops or school
- People with pigmented skin absorb less sunlight and therefore need to spend more time in the sun.
- Avoid sunscreen application during the above times of sunlight exposure as sunscreen may block the making of vitamin D in the skin. Ensure adequate sun protection measures are followed after this time to avoid sunburn. Additional sun exposure without sunscreen has no added benefit on vitamin D synthesis.
- What are the dietary sources of Vitamin D?
Vitamin D is found in a small number of foods. Good food sources are oily fish and cod liver oil. Small amount is also present in mushrooms and egg yolk. Some food sources may be fortified with vitamin D such as margarine, breakfast cereals and powdered milk.
- How much vitamin D do I need?
The latest recommendations suggest that 600 IU (international units) of vitamin D each day is enough for nearly all adults and children over 1 year old. Older adults (over 70 years of age) need about 800 IU daily.
- What causes vitamin D deficiency?
Low level of vitamin D (vitamin D deficiency) in the body is caused mainly by the lack of adequate sunlight. This is compounded by the often cloudy weather and long winter. Adults and children with pigmented skin and those who cover up their body with traditional clothes or attire are also more prone to vitamin D deficiency. Infants born to vitamin D deficient mothers have very low body stores of vitamin D at birth. Adults that are housebound or have limited mobility e.g. wheelchair bound are also at risk of vitamin D deficiency.
- How common is vitamin D deficiency?
Viamin D deficiency is highly prevalent all over the world. In Delhi and other parts of India too, almost 80-90% of population is vitamin D deficient. This deficiency is prevalent to the same tune in all age groups from neonates to elderly.
- Does vitamin D deficiency affect other family members?
If one family member has low vitamin D, it is highly likely that the rest of the family have the same problem. It is essential that the whole family has adequate sunlight exposure as mentioned above and discuss with your doctor about a suitable supplement.
- What are the symptoms of vitamin D deficiency?
Adults with very low levels of vitamin D for a long time develop a condition called osteomalacia. In this condition, calcium is lost from the bones. The bones become softened and painful and broken bones (fractures) can occur without an injury. In osteomalacia, the muscles also become weak making it hard to walk.
Children with severe deficiency may have soft skull or leg bones. Their legs may look curved (bowlegged). They may also complain of bone pains, often in the legs, and muscle pains or muscle weakness. This condition is known as rickets. Children may also present with poor growh, tooth delay and increased irritability.
- May I have vitamin D deficiency; if I don’t have any of these symptoms?
Many people have no symptoms, or only vague ones such as tiredness or general aches and pains. Because symptoms of vitamin D deficiency are often very nonspecific or vague, the problem is often missed.
- Does vitamin D deficiency associated with increased risk of diabetes?
Obsevational epidemiological studies have shown increased risk of insulin resistance and type 2 diabetes in people with vitamin D deficiency. Viamin D supplementaion may improve insulin secretion and pancreatic function in people with diabetes as shown in multiple studies.
- What are the other diseases associated with vitamin D deficiency?
Low vitamin D status leads to muscle weakness, falls, and potentially a multitude of nonskeletal morbidities. Epidemiological studies have shown increased risk of certain cancers like breast, colon and prostate cancers in association with vitamin D deficiency. Also, risk of certain autoimmune diseases like multiple sclerosis and rheumatoid arthritis may be increased in association with vitamin D deficiency. Vitamin D deficiency has also been linked to increased risk of high blood pressure and cardiovascular disease in multiple studies.
- How is vitamin D deficiency diagnosed?
A simple blood test for vitamin D level can make the diagnosis. Blood tests for calcium and phosphate levels and liver function may also show changes linked to a low level of vitamin D. Sometimes, a wrist X-ray is done for a child. This can assess how severe the
problem is by looking for changes in the wrist bones.
- What is the treatment of vitamin D deficiency?
Correction of vitamin D deficiency requires higher daily doses of vitamin D. These doses can either be delivered on a daily basis or an equivalent dose calculated and provided on weekly basis. For infants and children, both the daily dose (2000 IU /day) or a weekly calculated dose (60,000 IU per week for 6 weeks followed by 1500–200 units per day) are acceptable. In adults, the commonest strategy is to give 60,000 units per week for 8 weeks followed by 2000 IU per day or an equivalent weekly or monthly dose.
- Are there any side‐effects from vitamin D treatment?
It is very unusual to get side‐effects from vitamin D if taken in the prescribed dose. Doses up to 4000 IU daily are considered safe and most people need much less than this to keep their bones healthy. In the event of taking too much, symptoms are due to raised calcium levels in blood and these include nausea, vomiting, increased thirst, passing a lot of urine and headache. If these symptoms are noted, please report to your doctor immediately so that blood test for serum calcium can be done.
Care is needed with vitamin D supplements in certain medical conditions like patients with kidney stones, some types of kidney disease, liver disease or hormonal disease. Specialist advice may be needed in those persons. Vitamin D should not be taken by people who have high calcium levels without specialist advice.