Seasonal decline in UVB radiation and low nutritional intake of vitamin D could compromise the bodys immune system.

Vitamin D isn’t exactly a vitamin but rather a group of fat-soluble vitamins formed by sunlight through a kind of dermal synthesis.

Activation requires conversion in the liver and kidney.

Essentially what we’ve always known Vitamin D to do is aid in the absorption of calcium, iron, magnesium, phosphate and zinc to build strong bones and the like.

Because of the high risk of skin cancer in South Africa, there has never been any official recommendation for how much sunlight we need to make substantial amounts of vitamin D.

And although vitamin D supplementation is relatively cheap, few people take it, because testing for a deficiency in the first place is costly.

But research suggests many South Africans are vitamin D deficient and that its role in the immune system has been underestimated.

This is according to Associate Professor at the Durban University of Technology, Morgan Chetty, who is also the Chairman of KwaZulu-Natal Doctors Healthcare Coalition and of the Independent Practitioners Association Foundation.

Chetty says: “The role vitamin D plays in the body is not as certain as other vitamins. However, there is a growing body of research suggesting that vitamin D plays an integral part in the proper function of the immune system.

“Work done at Queen Mary University of London suggests vitamin D regulates the expression of specific endogenous antimicrobial peptides in immune cells of the body, modulating the immune response to various infectious diseases. Basically is seems to assist treatment.

“This is relevant to our context; widely considered the epicentre of HIV and Aids, where compromised immune systems are common.

“In fact, recent collaborative research by academics from the University of Cape Town, University of Stellenbosch and University of Pennsylvania, has shown the supplementation of vitamin D slows down the progression of Aids in HIV-positive patients by boosting white blood cells. This research has important implications for health care policy-makers and clinicians in Southern Africa. Vitamin D supplementation could potentially be a relatively cost-effective way in helping to prolong the lives of HIV-positive individuals.”

Chetty says patients on ARVs, particularly tenofovir and efavirenz, have been found to have low levels of vitamin D.

In South Africa, this is compounded by the fact that darker skin seems to compete with the sun, and does not absorb helpful rays well, thus reducing the amount of vitamin D one might think the body could produce here.

“While melanin protects the dermis from radiation, it also competes with a special form of cholesterol for UVB, reducing the amount of light available to produce 
vitamin D. Except in the case of albinism, all people have certain concentrations of melanocytes in the dermis of their skin. Skin pigmentation regulates the penetration of UV radiation. However, a high concentration of melanin in the African skin prevents the body from making sufficient vitamin D, resulting in a deficiency, particularly in winter,” says Chetty.

“We know, too, that the obese and those with breast cancer, colon cancer, high blood pressure and cardiovascular disease also often present with vitamin D deficiency.

“When supplemented, it reduces inflammation and improves the efficacy of other drugs such as antibiotics.

“Biomedical researchers are postulating the possible benefits of using a vitamin D supplement in conjunction with other forms of antimicrobial therapy for pneumonia, sepsis and other lung infections. “Unfortunately, the only way to know if you are vitamin D deficient is to test.

“There are no signs.” Chetty warns against going out to purchase it over the counter without a doctor’s advice to ensure you are taking the correct, therapeutic amount and to avoid any negative effects.

* Professor Morgan Chetty is speaking at the Health Management Conference, which forms part of the 6th annual Africa Health Exhibition and Congress that began yesterday and is on until tomorrow in Johannesburg. More than 7 000 health care professionals and medical experts are expected to attend.