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Ounce of Prevention | Sunshine is very important for your health

Published:Tuesday | August 7, 2018 | 12:00 AMDr Tony Vendryes

With the intense heat and sunlight of our current summer, health authorities have been warning people to stay indoors as much as possible to reduce the possibility of heat stroke and dehydration, and rightly so.

But exposure to sunlight is the only reliable way for you to generate vitamin D in your body, as vitamin D is produced by your skin in response to exposure to ultraviolet radiation (UVB) from natural sunlight. UVB converts cholesterol in the skin into vitamin D3 and this vitamin is perhaps the single most underrated nutrient in the world.

It is hardly promoted, probably because it's free, made by your body from sunshine. Drug companies can't sell sunlight, so its health benefits are not highlighted.

In the United Kingdom (UK), several health groups, including the Cancer Research UK, National Osteoporosis Society, Multiple Sclerosis Society, British Association of Dermatologists, Diabetes UK, National Heart Forum and the Primary Care Dermatology Society have now joined forces to promote the benefits of sunshine and vitamin D.




A person would need to drink ten large glasses of vitamin D fortified milk every day just to get minimum levels of vitamin D into their diet.

On the other hand, a one-hour sunbath can provide more than five times the recommended daily allowance for the vitamin. Please note that your body will not generate too much vitamin D from sun exposure, as your body self-regulates and only produces what it needs. Vitamin D toxicity is extremely rare in the medical literature.




The darker your skin color, the more sunshine you need to manufacture vitamin D. People with dark skin may need as much as 20 times more 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 ninety percent of African Americans are low in vitamin D. Even in sun-drenched Jamaica, many black persons also have this deficiency




Sunlight does not cause cancer, even skin cancer. In fact, compelling evidence indicates that vitamin D could help prevent close to 80 per cent of all types of cancer. The studies clearly demonstrate that the lower your blood vitamin D level, the higher your risk of developing cancer.

Fifteen cancers are identified as vitamin D sensitive: colon, stomach, oesophagus, gallbladder, rectum, small intestine, bladder, kidney, prostate, breast, endometrium, ovary and lymphomas.

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




Much is made of the need for sufficient dietary calcium to ensure strong bone and to avoid osteoporosis. It should, however, be emphasized that vitamin D is critical for calcium absorption from the diet. Your body cannot absorb calcium without vitamin D and 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 improves immune system function, thus providing protection against infections. Both bacterial diseases like pneumonia and Tuberculosis as well as viral diseases like Influenza and the common cold are influenced by vitamin D.

Flu outbreaks are seasonal in part due to variations in sunshine levels and vitamin D. The vitamin also had a protective effect against autoimmune disorders particularly type1 diabetes and multiple sclerosis.




Growing evidence indicate that vitamin D reduces the risk of the common metabolic diseases including coronary heart disease, type 2 diabetes, hypertension and stroke. This may partly explain why these disorders are so prevalent in black populations like African Americans and Caribbean peoples. More research on this is needed.




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 your 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. If fact, there is evidence that the sunlight that comes through glass may actually lower your vitamin D level and increase your risk of cancer.

Sunscreen lotions block your body's ability to generate vitamin D by up to 95 per cent, and may actually help create a vitamin deficiency in the body. Of, course the sunscreen industry doesn't want you to know that.

Vitamin D is "activated" in your body by your kidneys and liver before it can be used and individuals with kidney or liver damage have a decreased ability to activate vitamin D. The elderly also makes less vitamin D. These people need more sunshine and should take vitamin D3 supplements.

I believe that in today's world most people need to take vitamin D3 supplements - at least 5000 IU per day. It is also good to test vitamin D blood levels, as this is a useful guide to how much vitamin D you need to take.

What about sunburn, skin damage and skin cancer? This is a problem when your nutrition is poor, your skin is deficient in antioxidants and your sun exposure has been excessive.

Antioxidants greatly boost your body's ability to handle sunlight without damage or burning. In addition to sunbathing take enough vitamins A, C and E and eat lots of fresh fruit and vegetables, especially if you have sensitive skin.

- You may email Dr Vendryes at or listen to An Ounce of Prevention on POWER106FM on Fridays at 9:10 pm. Visit for details on his books and articles.