Vitamin D in health and Disease

What is vitamin D?

Vitamin D is a fat-soluble vitamin. The fact that it dissolves in fat is important, because it means the body can store it for future use. Ultraviolet B (UVB) in sunlight rays convert cholesterol in the skin into vitamin D. Darker skins need more sun to get the same amount of vitamin D as a fair-skinned person. The sunlight needed has to fall directly on to bare skin (through a window is not enough). Traditionally it is thought that 2-3 exposures (each one 30 min) of sunlight per week in the summer months (April to September) are enough to achieve healthy vitamin D levels that last through the year. This does not seem to be true at present.

The main action of vitamin D is to help calcium and phosphorus in our diet to be absorbed from the gut. The calcium and phosphorus are essential for the structure and strength of our bones. So, vitamin D is really important for strong bones. In addition, vitamin D seems to be important for muscles/ligaments, also this is supposed to improve quality of life. Scientists have also found that vitamin D may also help to prevent other diseases such as cancer, diabetes and heart disease.

 Which foods contain vitamin D?

Surprisingly few foods contain vitamin D — unless it’s added to the food. That’s because your body is built to get vitamin D through your skin (from sunlight) rather than through your mouth (by food).

There are three vitamin D super foods:

  • Salmon (especially wild-caught), Mackerel (especially wild-caught) , Mushrooms exposed to ultraviolet light to increase vitamin D

Other food sources of vitamin D include:

  • Cod liver oil , Tuna canned in water, Sardines canned in oil, Milk or yogurt — regardless of whether it’s whole, non-fat, or reduced fat — fortified with vitamin D, Beef or calf liver, Egg yolks, Cheese.

How much vitamin D do I need?

This is tough question, we always thought the correct amount is what is need to prevent Rickets, now we know we need much more as vitamin D has more role in our good health. So you will be seeing our daily requirement is being increased depending on newer research coming day by day. A few years back, we told 400 iu is all that we need, but now we tell in adults around 2000 units is what is good for health.

Who gets vitamin D deficiency?

A very significant percentage of us is becoming vitamin deficient, this is mainly our indoor life-style (particularly urban population) there-by reducing the sunlight exposure, our dresses, use of Borkha in Muslim women, our skin which is not as good as white skin for making vitamin D. It is not clear atmospheric pollution has a role to play or not.

Particularly vulnerable people are growing children, pregnant and breast-feeding women, those in hospital for a long time, or housebound people, people using a lot of sunscreen (sun protection factor – 15 or above), elderly people (due to thinner skin than younger people) and some medical conditions like Crohn’s disease, coeliac disease, liver and kidney disease.

Vitamin D deficiency can also occur in people taking certain medicines – carbamazepine, phenytoin, primidone, barbiturates and some anti-HIV medicines.

What are the symptoms of vitamin D deficiency?

Many people have no symptoms, or only vague ones such as tiredness or general aches. Because symptoms of vitamin D deficiency are often very non-specific, the problem is often missed. The diagnosis is more easily reached in severe deficiencies with some of the classical (typical) symptoms and bone deformities.

Symptoms in adults

  • General vague aches and pains are the common symptoms.

  • In more severe deficiency, there may be more severe pain and also weakness. This may lead to difficulty standing up or climbing stairs, or can lead to the person walking with a ‘waddling’ pattern. This is known as osteomalacia.

  • Bone pains may develop and are typically felt in the ribs, hips, pelvis, thighs and feet.

How is vitamin D deficiency diagnosed?

It may be suspected from your medical history, symptoms, or lifestyle. A simple blood test for vitamin D level can make the diagnosis. Blood tests for calcium and phosphate levels 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 for vitamin D deficiency?

The treatment is to take vitamin D supplements. Vitamin D can be given as an injection or as a medicine (liquid or tablets). Your doctor will discuss the dose, and best treatment schedule, depending on your situation, age, severity of the deficiency, etc. Briefly, one of the following may be advised

Injection – This is a very effective and convenient treatment. It is useful for people who do not like taking medicines by mouth, or who are likely to forget to take their tablets.

Oral preparation – Vitamin D preparation is available in granules to take by mouth mixing with fruit juice or milk. Recently we have tablet preparation available in India which can be swallowed. Usual strength of tablet or granules is 60,000 units.

It is good to remember that we need to continue maintenance dose after deficiency is corrected. The exact dose is not clear, recommendation is changing everyday as all of us are learning; possibly we need around 2000 units daily for good health.

Our Experience and Protocol

In our department we are following a protocol to find out the correct supplement schedule of vitamin D, in case of severe deficiency we are giving initially injection every 2 weeks for 8 injections, and then checking level to continue replacement by oral tablet or granules. Most of the people in our protocol treatment are achieving expected level of vitamin D, till now we have not seen a single case of toxicity using our protocol.

How high should my vitamin D level be?

The recommended minimum vitamin D level is at least 32 ng/ml, best level is 40-80. The average 25(OH)D concentration of the confirmed cases of vitamin D toxicity reported in literature is 214 ng/ml.

Are there any side-effects from vitamin D supplements?

It is very unusual to get side effects from vitamin D if taken in the prescribed dose. However, very high doses can raise calcium levels in the blood. This would cause symptoms such as thirst, passing a lot of urine, nausea or vomiting, dizziness and headaches. If you have these symptoms, you should see your GP promptly, so that your calcium level can be checked with a blood test.

Outlook of vitamin D deficiency

The outlook for vitamin D deficiency is usually excellent. Both the vitamin levels and the symptoms generally respond well to treatment. However, it can take time (months) for bones to recover and symptoms such as pain to get better or improve.

Vitamin D is increasingly being linked to other diseases and illnesses. In recent years there have been associations with conditions such as cancer, heart disease, infectious disorders, autoimmune disease and diabetes. This does not mean that all people with vitamin D deficiency will get these problems. Nor does it mean that if you have one of these illnesses, a vitamin D deficiency is the cause. In these cases, vitamin D replacement is being shown beneficial.

DrSwaraj(swaraj_amit@yahoo.com), DrShailaB(Shailashamanur@gmail.com)

and DrArpandevBhattacharyya(Arpan@DiabetesEndocrinology.in),

Department of Diabetes and Endocrinology, Manipal Hospital, Bangalore.