In 2017, a two-year study by Dubai Health Authority found that around 90 per cent of the UAE population are vitamin D-deficient.
Professor Abdul Jabbar, Consultant Endocrinologist, Medcare Hospital Dubai, and former head of the Diabetes/Endocrine section at AKUH, Karachi, says that an insufficiency or deficiency is when there is less than 30ng/ml of vitamin D in the bloodstream.
He questions why the prevalence exists even after the introduction of fortified foods. “Vitamin D has long been associated with calcium metabolism and bone health,” he says. “Over the years, especially in colder countries where the sunlight is not very good, people started to recognise vitamin D deficiencies in children.
In the case of cancer, there are studies that have associated sufficient levels of vitamin D with a 30-50 per cent decreased risk of colon, prostate and breast cancer.
“Once this was recognised, vitamin D fortification began and it was added to dairy products and the problem diminished.” Despite the fortification of foods, in recent years, regionally and globally there has been a significant spike in the prevalence of vitamin D deficiencies. One explanation could be people’s growing awareness of sunscreen and skin cancer. “When you wear sunblock, it prevents the sun from going into your skin and manufacturing vitamin D,” says Prof. Jabbar.
He doesn’t however believe that the spike is related to people consuming less fortified dairy products, suggesting instead that it is probably related to body fat.
“The most important thing, which appears to be very realistic but is still to be 100 per cent proven, is that it’s related to body fat, because vitamin D is a fat soluble vitamin. For example, if I’m an average person with a 70kg bodyweight and 30kg of fat in my body, my vitamin D will be stored in the fat and the rest will be in the bloodstream. But, if I weigh 120kg and my body fat is raised from 30kg to 60kg, the amount of vitamin D stored in the fat is doubled, which means that less is circulating in the bloodstream. It is called a vitamin D fat bone excess in humans.”
Prof. Jabbar reasons that, in the past 10 years, our eating habits and exposure to sunlight haven’t changed significantly enough to explain global rise in vitamin D deficiencies.
While Prof. Jabbar says that the causes of vitamin D deficiencies and the extent to which they can affect our health are still not 100 per cent conclusive, he also refers to how its role is far more significant than just bone health and calcium levels.
“Now, we have identified that there are so many tissues in the body including the brain, kidney, fatty tissue and the heart, where vitamin D plays a role. We have also identified cancer cells that have vitamin D receptors.
“In the case of cancer, there are studies that have associated sufficient levels of vitamin D with a 30-50 per cent decreased risk of colon, prostate and breast cancer.”
He refers to a number of studies and his own professional experience as mounting evidence that the vitamin’s role in our health and well-being is multifaceted. “We found that if we give patients with type 2 diabetes vitamin D, then their neuropathic [nervous system] pain was less, so it could be related to nerve health.
“There are still factors that are under the research portfolio because we don’t have conclusive data. For example, there was a study of 10,366 children in Finland, where type 1 diabetes is very common and they were given 2,000 units of vitamin D per day. They followed the diet from the first year of birth for 31 years and the risk of type 1 diabetes was reduced by approximately 80 per cent.
“An important Nurses’ Health Study cohort [of 32,826 patients], found that the ratio for colorectal were inversely associated with a median vitamin D level.”
Prescribing vitamin D
Prof. Jabbar advocates the prescription of vitamin D and believes that it is inexpensive and relatively risk-free. “The problem is that the test for vitamin D is expensive, but a vitamin D pill is not expensive.
If you strongly suspect that someone is low on vitamin D and you are unable to check, I would suggest just prescribing them the recommended dose for their age.
“The only thing you would need to worry about in terms of the harmful effects of vitamin D can be if calcium levels become too high or if there is a history of kidney stones. But checking for calcium is inexpensive, so if a vitamin C check is not possible, it’s a practical alternative.”
In the coming months, Prof. Jabbar is hoping to publish a review of vitamin D in the UAE. In the meantime, the high prevalence of vitamin D deficiency means that it could feasibly be associated with the majority of common health issues.
The emphasis is on finding the conclusive evidence to prove beyond question that vitamin D plays a significant role in these issues.