Fri | Dec 8, 2023

Vitamin D: The sunshine vitamin

Published:Tuesday | April 30, 2013 | 12:00 AM

VITAMIN D is perhaps the single most underrated nutrient in the world. Maybe because it's freely made by your body from sunshine, its health benefits are not widely promoted.

Vitamin D is, in fact, more like a powerful hormone than a vitamin. It controls the activity of over 2,000 of our genes and there are receptor sites for vitamin D in virtually every cell in the human body. The term vitamin D includes a family of several substances, but vitamin D3 (cholecalciferol) is the most active and useful form.

The vitamin is found naturally in only a few foods such as fish liver oils, fatty fish, mushrooms, egg yolks and liver. Food manufacturers now fortify some foods like dairy products with this vitamin. But it is nearly impossible to get enough vitamin D from your diet. For example, an individual would have to drink 10 large glasses of vitamin D-fortified milk each day just to get the minimum recommended amount of vitamin D.

Vitamin D and the sun

Mankind's main source of vitamin D comes from sunshine. When the UVB rays of the sun strikes the skin, it converts cholesterol in the epidermal skin cells into vitamin D. Dark skin, old age and the use of sunblock greatly reduces the production of this vitamin from sunshine.

Vitamin D is also available as a safe and inexpensive supplement while providing many benefits for all, particularly women. Sadly, the research indicates that most of us are deficient in vitamin D. Although there is much publicity about the need for vitamin D to protect women's bones against osteoporosis, this vitamin has many other important uses.

Sunlight exposure is the most reliable way to generate vitamin D in your own body. In a one-hour sunbath, the body can manufacture up to 10,000 units of vitamin D. That is more than five times the recently increased recommended daily allowance for the vitamin. This is another example of how wrong 'health authorities' can be about vitamins. It is impossible for your body to generate too much vitamin D from sunlight exposure: your body self-regulates and only produces what it needs.

Black people need more sunshine

The darker your skin colour, the more sunshine you need to make vitamin D. People with dark skin pigmentation may need 20 to 30 times as much exposure to sunlight as fair-skinned people to generate the same amount of vitamin D. Because of this, many black persons are vitamin D deficient.

Research shows that over 90 per cent of African Americans are vitamin D deficient. Many Jamaicans also have this deficiency. Almost all of the patients who I have tested have low levels of vitamin D in their blood although they live in sunny Jamaica. Also, the further you live from the equator, the more sunshine you need in order to generate vitamin D.

Vitamin D and cancer

Contrary to the propaganda, sunlight does not cause cancer. In fact, compelling medical evidence indicates that vitamin D could prevent close to 80 per cent of all types of cancer. The research results clearly demonstrate that the lower your vitamin D levels in your blood, the higher your risk of developing several cancers.

Fifteen cancers have been identified as vitamin D sensitive: colon, stomach, oesophagus, gallbladder, rectum, small intestine, bladder, kidney, prostate, breast, endometrium, ovary, Hodgkins and non Hodgkins lymphoma.

The researchers reliably predicted that hundreds of thousands of cancers could be prevented around the world by raising the vitamin D levels in entire populations.

There is very good evidence that vitamin D lowers the risk of breast cancer. Studies of vitamin D levels in women diagnosed with breast cancer show that the risk of breast cancer decreases rapidly as vitamin D levels increase.

Research at Georgetown University Medical Center, Washington, DC, revealed an impressive link between high vitamin D intake and a reduced risk of breast cancer. Their findings reveal that high doses of vitamin D caused a 50 per cent reduction in breast tumours, and a 75 per cent decrease in cancer spread among those who already have the disease.

Vitamin D and fibroids

Over two thirds of our women have uterine fibroids. A new study published in the journal Biology of Reproduction has found that vitamin D may effectively reduce the size of existing uterine fibroids, and may even help prevent them from forming in the first place.

Dr Louis de Paolo of the National Institutes of Health suggests that this research provides a promising new approach in the search for a non-surgical treatment for fibroids. Rather than waiting to have a surgery, women with fibroids (or who may develop them later) may benefit greatly from simply exposing themselves more regularly to natural sunlight and/or by supplementing with vitamin D3.

Vitamin D and bones

Much is made of the need for sufficient dietary calcium to ensure strong bones and to prevent osteoporosis. It should, however, be equally emphasised that vitamin D is critical for calcium to be absorbed in the intestines. Without sufficient vitamin D, your body cannot absorb calcium, rendering calcium supplements useless. Much of the current epidemic of osteoporosis is related to vitamin D deficiency. Optimal vitamin D levels reduce the risk of hip fractures in the elderly by 25 per cent.

Vitamin D and infections

Vitamin D improves immune system function, thus providing protection against infections. Influenza outbreaks are seasonal in part due to variations in sunshine levels and vitamin D. Both bacterial diseases like pneumonia, gingivitis, septicaemia and tuberculosis, as well as viral diseases like influenza and the common cold, influenced by vitamin D. The vitamin also had a protective effect against auto-immune disorders, particularly type 1 diabetes and multiple sclerosis.

Vitamin D and metabolic diseases

Growing evidence indicates that vitamin D reduces the risk of the common metabolic diseases, including coronary heart disease, type 2 diabetes, hypertension and stroke. This may be part of the reason why these disorders are so prevalent in black populations like African Americans and Caribbean peoples. However, controlled trials have not yet been reported.

Increase your vitamin D level

Chronic vitamin D deficiency cannot be reversed overnight. It takes months of sunlight exposure and vitamin D supplementation to build up the body's levels. I strongly recommend a daily sunbath whenever possible for everyone. Ideally one should try to expose at least 50 per cent of one's skin directly to the sun for at least 30 to 60 minutes. The healing UVB rays of natural sunlight that generate vitamin D in your skin cannot penetrate glass, so you don't make vitamin D when sitting behind the window in your car or home.

Even weak sunscreen blocks your body's ability to generate vitamin D by 95 per cent. Although the sunscreen industry doesn't want you to know, sunscreen products may actually contribute to disease by creating a critical vitamin deficiency in the body.

Vitamin D is 'activated' in your body by your kidneys and liver before it can be used. Therefore, individuals with kidney or liver damage may have decreased ability to activate vitamin D. The skin of the elderly is also less efficient in making vitamin D. These people need more sunshine and would benefit from taking vitamin D supplements.

What about sunburn, skin damage and skin cancer? This is a problem only when your nutrition is poor and your skin is deficient in antioxidants. Antioxidants greatly boost your body's ability to handle sunlight without damage or burning. So, in addition to sunbathing, take enough vitamins A, C and E and eat lots of fresh fruit and vegetables. This is particularly important if you have sensitive skin.

You may email Dr Tony Vendryes at or listen to 'An Ounce of Prevention' on POWER 106FM on Fridays at 8 p.m. His new book 'An Ounce of Prevention, Especially for Women' is available locally and on the Internet.