What are Vitamin D functions in the body?

  • Main action of vitamin D is to help calcium and phosphorus in our diet to be absorbed from the gut and thus keep bones healthy and strong and prevent diseases such as rickets, osteomalacia and osteoporosis (see below for description)
  • Vitamin D seems to be important for muscles and general health
  • There is also some evidence that vitamin D may also help to prevent other diseases such as cancer (of colon, breast and prostate), diabetes and heart disease, but no conclusive evidence is yet available

Are there Vitamin D food sources, which can give all you need?

  • There are no rich dietary sources of vitamin D, you need exposure to sunlight for its synthesis in the body; fortified food stuff  (oils, breakfast cereal , milk etc.) is commonplace in western countries but is still not available freely in India
  • As per National Institute of Nutrition (NIN) India, Indians should try to get enough vitamin D by sun exposure. NIN reports that adequate amounts  of vitamin D can be synthesized in the body exposure to bright sunlight even for 5 min per day.  But the exposure should be on face, neck and arm, either without a sunscreen or with sunscreen of SPF factor less than 15
  • BUT season, time of day, length of day, cloud cover, smog, skin melanin content affect UV radiation exposure and vitamin D synthesis
  • THEREFORE if you doubt that you are not getting enough sun exposure, get your vitamin D blood levels checked. Or you can opt for supplements straight away:  10 mcg=400 IU of vitamin D/day is suggested by NIN
  • Fishes, fish oils, egg yolk, liver, and wild mushrooms contain only small quantities of vitamin D

Vitamin D deficiency

Symptoms of vitamin D deficiency

Vitamin D deficiency is widely reported in India and so is osteoporosis, which is a common manifestation of calcium and vitamin D deficiency. Vitamin D Deficiency causes following symptoms

  • In children:
    • Mild deficiency of vitamin D results in impaired growth especially height, irritability, unwillingness to walk, susceptibility to infections and delay in eruption of teeth
    • Children with severe deficiency may develop rickets: in which bones get soft and  children get knock knees and bow legs. They may also complain of bone pains, often in the legs, muscle pains or muscle weakness
  • In adults:
    • Complain of a general tiredness, vague aches and pains and a general sense of being unwell
    • Osteomalacia is a more severe deficiency where there may be more pain and weakness. Muscle weakness may cause difficulty in climbing stairs or getting up from the floor or a low chair, or can lead to the person walking with a waddling pattern
    • Bones can feel painful to moderate pressure (often more noticeable in the ribs or shin bones). Not uncommonly, people have a tiny fracture in the bone which is causing tenderness and pain. Bone pain often also occurs in the lower back, hips, pelvis, thighs and feet.
    • Osteoporosis : is the commonest manifestation of calcium and vitamin D deficiency, it affects one in three women over 50, one in five such men! It leads to bones that become weak and fractures happen in those bones with least injury or sometimes spontaneously. The common fractures include : fracture of spine, of femur (long bone of thigh)

People at risk for vitamin D deficiency

  • People with inadequate sun exposure
  • Pregnant or breastfeeding women
  • Breastfed babies whose mothers are lacking in vitamin D or who are exclusively breast fed for long
  • Elderly people
  • People with diseases of intestine and some types of liver and kidney disease
  • Obese people or who have undergone gastric bypass surgery
  • People taking certain medicines. E.g: epilepsy drugs (carbamazepine, phenytoin, barbiturates), steroids, weight loss drug orlistat and cholesterol lowering drug cholestyramine) and some anti-HIV medicines

Test for vitamin D deficiency

  • 25 OH Vitamin D levels in blood
  • Wrist X-ray is for children

Vitamin D Supplements

  • Vitamin D supplements are generally safe
  • Depending on your level of deficiency: you may need mega dosages for some time before you can continue with usual dose of vitamin D supplementation. Therefore, get vitamin D blood level tested
  • Doctors prescribe multiple doses of 60000 IU of Vitamin D3 supplements: once-twice  in a week for 2-3 months followed by once every month for life in case of severe deficiency, consult your doctor if test shows that you have vitamin D deficiency

To know more about supplements: go to “supplements: should you be taking any?” and “supplements: what cautions to take?”

CHECK OUT: Our references for recommendations on diet