What is the right amount of vitamin D you need? Can too much hurt you?

A recent issue of BMJ Case Reports journal has said that “overdosing” on Vitamin D supplements is both possible and harmful and is sadly on the rise. It reported the case of a middle-aged man who had been taking high doses of more than 20 over the counter supplements every day along with other vitamin, mineral, nutrients and probiotic supplements. According to Vaman Khadilkar, who was the convener for the Indian Academy of Paediatrics IAP vitamin D and calcium guideline 2017 and past president Indian Society for Pediatric and Adolescent Endocrinology, “Hypervitaminosis is a condition caused by excess intake or injections of vitamin D. Serum level of more than 100 ng/ml is considered a toxic level.” Taking 60,000 international units (IU) a day of vitamin D for several months has been shown to cause toxicity. This level is many times higher than the US Recommended Dietary Allowance (RDA) for most adults of 600 IU of vitamin D a day. “Some adventurous people just keep popping pills without any moderation,” says Dr Tickoo.

Doses higher than the RDA are sometimes used to treat medical problems such as vitamin D deficiency, but these are given only under the care of a doctor for a specified time frame. Blood levels should be monitored while someone is taking high doses of Vitamin D to avoid any eventuality.
“There are no major warning signs of hypervitaminosis. You end up at the hospital to diagnose the condition,” says Dr Khadilkar.

Symptoms of hypervitaminosis

Neuro-psychiatric features include drowsiness, confusion, apathy, psychosis, depression, stupor, and coma. “There is general confusion, nausea, abdominal pain, vomiting and sometimes pancreatitis. Hypertension and arrhythmias are signs of vitamin D intoxication. Then there is polyuria, polydipsia, dehydration, calcification in the kidneys and renal failure,” says Dr Tickoo.

In children, Vitamin D toxicity “presents as high levels of calcium in the blood, vomitting, irritability and dehydration,” says Dr Khadilkar. However not all patients with high vitamin D serum values (> 100 ng/ml) will have symptoms.

What is the right amount of Vitamin D that should be taken?

The recommended daily amount of vitamin D is 400 international units (IU) for children up to 12 months, 600 IU for people ages 1 to 70 years, and 800 IU for people over 70 years.

Vitamin D is a fat-soluble vitamin that is essential for the proper functioning of the body. It is important for muscles, immune system and cell growth, according to experts. “Vitamin D deficiency in a sun-drenched tropical country like India is surprising,” says C V Harinarayan from the Institute of Endocrinology, Diabetes, Thyroid and Osteoporosis Disorders, Bengaluru, who has written the guidelines on “How to treat Vitamin D deficiency in sun-drenched India” in the Sri Venkateshwara Institute of Medical Sciences’ “Journal of Clinical and Scientific Research.”

Serum 25-hydroxyvitamin D (25(OH)D) level is the major circulating form providing Vitamin D status of an individual. Levels between 20 and 30 ng/mL are defined as insufficient, experts say. As per recommendations of IAP-2021,Vitamin D supplementation in doses of 400 IU/day is recommended during infancy. However, the estimated average requirement in older children and adolescents (400-600 IU/day, respectively) should be met from diet and natural sources like sunlight. Healthcare providers should be aware of various vitamin D preparations available in India and counsel patients regarding desirable doses and variability among formulations.

Universal Vitamin D is not recommended for the following

As per the revised IAP Vitamin D guidelines 2021, Universal Vitamin D supplementation is not recommended in childhood pneumonia, diarrhoea, TB, HIV and non-infectious conditions like asthma, atopic dermatitis and developmental disorders. Serum 25-hydroxy Vitamin D level of >20ng/mL should be maintained in children with conditions at high risk for vitamin deficiency, like nephrotic syndrome, chronic liver disease, chronic renal failure and others.

How much exposure to sunlight is required?

Both vitamin D and calcium intake are crucial for optimal bone health. Sunlight exposure increases serum 25(OH)D levels and is recommended for children and adolescents across all regions of India to prevent vitamin D deficiency. A daily sunlight exposure of 17-30 minutes in infants and 30-45 minutes in older children over 15-40 per cent body surface area is recommended at least five times a week during midday and afternoon (between 11 am and 3 pm) for preventing vitamin D deficiency across different regions and seasons, as per IAP guidelines.

Why do you need vitamin D?

Apart from bone health, reduction in the incidence of metastatic cancer is one of the many reasons you need to take supplements of Vitamin D. “Vitamin D contributes to the healthy functioning of our immune system. It improves resistance against certain diseases and helps us have strong bones and teeth. It also protects against respiratory infections, heart disease and stroke, reduces the risk of diabetes and prevents cognitive decline and dementia,” says Dr Tickoo. “For best results, you should take a combination of Vitamin D and Vitamin K. Both are fat-soluble vitamins that work together to replenish calcium in the body. Vitamin D accelerates the production of certain proteins that in turn need vitamin K to maximise their functioning,” he adds.

Dr Tickoo also suggests taking Vitamin D syrups as they can be absorbed better in the body. “Since Vitamin D is fat-soluble and syrups are already mixed with fat, they are better to increase absorption of the vitamin. You can take it once a week for eight to 12 weeks, and then once a month,” he adds. Always check with your doctor before taking Vitamin D supplements.