Alpita Das was surprised when a minor accident led to her fracturing her thumb. She was already on Vitamin D supplements, which the doctor had suggested as she was planning to conceive. “Women are generally deficient in Vitamin D. It is one of the supplements you should start having now. Continue to have calcium tablets and Vitamin D supplements after the delivery,” her gynaecologist had told her.

How could she suffer such a serious injury from a minor fall? A recent report published in the journal, Lancet Diabetes & Endocrinology, provides the answer. The study says that taking Vitamin D supplements does not help prevent fractures or falls or increase mineral bone density in adults. In other words, despite what you read on social media, Vitamin D supplements cannot boost bone health.

“Patients these days rely a great deal on what they read on the Internet. I have patients who happily tell me that they are keeping well because they are on Vitamin D supplements,” says orthopaedic surgeon Dr Tanmay Datta. “In one case, when we got his serum vitamin levels checked, we found that it had shot up to 200 nanogram per ml, way higher than normal (between 30 to 50 nanogram per ml),” adds the associate professor of the Institute of Post-Graduate Medical Education and Research (IPGMER) in Calcutta. Incidentally, what Vitamin D is known to do is help in absorption and utilisation of calcium.

“It is a misconception that having Vitamin D supplements prevents one from suffering a fracture. There are other hormonal factors linked to it,” says Dr Ranjini Datta, dietician and head of the department of clinical dietetics and community nutrition, KPC Medical College and Hospital, Calcutta.

The study in Lancet Diabetes & Endocrinology is based on the analysis of data from about 80 random controlled trials of nearly 53,000 people. The researchers believe that clinical guidelines should be revised to discourage use of Vitamin D supplements.

“It is always better to increase your Vitamin D level in nutraceutical instead of pharmaceutical ways. Vitamin D can be found in milk, fish liver oil, beef liver and so on. And it is best absorbed when it is consumed with some amount of fat,” says dietician Datta.

You need to worry about your Vitamin D level only if you are deficient in it. “Deficiency is prevalent in people who have a strictly vegetarian diet, in new-born babies who

are exclusively breast-fed, in the elderly whose skins have lost the capacity to synthesise sunlight and convert it into Vitamin D

as well as in people with dark skin as melanin reduces the capacity of the skin to produce Vitamin D,” says Dr Tanmay Datta.

The lead author of the paper, Dr Mark J. Bolland, is also an associate professor at the University of Auckland. He is of the opinion that anyone taking Vitamin D without needing it will not derive any benefit from it. In fact, having Vitamin D supplements without needing them — or having more than the prescribed dosage — may lead to unnecessary complications.

Dr Tanmay Datta agrees that, in many cases, excess consumption of Vitamin D is known to have had an adverse effect on the body. “If one has an excess of Vitamin D, the calcium levels will also increase. This is dangerous as the person may then develop something called hyper vitaminosis D. It is a condition where the toxicity level in the body tends to rise,” he adds.

This would lead to problems such as an increased appetite and thirst, the tendency to urinate more, constipation and also some cognitive impairment. “In some cases, excess of vitamin D can even increase the chances of having renal stones or renal colic,” says Dr Tanmay Datta.

However, Dr Ranjini Datta says, “Sometimes the body does require Vitamin D — such as elderly men or women suffering from osteoporosis or women who have had menopause. It is because the hormonal changes are such that there is a need to have supplements over and above a Vitamin D-rich diet.”

In these cases, Dr Tanmay Datta says, “It is extremely important to check the serum calcium or Vitamin D levels in the blood

and consume only the quantity prescribed by a registered practitioner. It is also important to buy products from reputed manufacturers to avoid improper labelling and accidental over dosage.”

Food sources of vitamin D

• Oily fish, cooked, 3 ounces (85gm) *444
  
• Tuna fish, canned in oil, drained, 3 ounces (85gm) 229
  
• Sardines, canned in oil, drained, 3 ounces (85gm) 165
  
• Milk, skimmed, fortified, 8 ounces (236.5ml) 116
  
• Orange juice, fortified, 8 ounces (236.5ml) 100
  
• Egg, whole, cooked, scrambled, 1 large 44
  
• Cheddar cheese, 1 ounce (28gm) 7
  

*All figures in International Units

Source: USDA National Nutrient Database for Standard Reference