Have you ever lain awake in bed, staring at the ceiling and wondering how it is that all plant life on earth does not burn to a crisp shortly after sunrise? Despite growing in full exposure to the relentless overhead sun, plants remain completely undamaged. The answer, in a word, is carotenoids.
Carotenoids are plant antioxidants that protect plants from damage from UV light. They are able to absorb the harmful chemicals produced during photosynthesis, the process whereby plants make energy from sunlight.
When we eat plants that contain carotenoids, they pass on this built-in protection mechanism. It is a beautiful example of the circular nature of life, of which we are an integral part.
After all, staying out of the sun is counterintuitive. Frolicking al fresco is a perfectly normal human activity, one to be encouraged. Most of us crave sunlight if we are deprived of it for too long. Yet no sooner has the sun got his hat on, we are solemnly reminded of the dangers of exposure. There is an urgent need to swaddle ourselves against the detrimental effects of the sun.
The thing is, the experts and medics do have a point. Non-melanoma skin cancer is the most common type of cancer in the UK, accounting for 20% of all new malignancies. Even so, it is considered much under-reported. That is an alarming figure, so of course we should do whatever we can to avoid being part of that statistic.
But that leaves us with a vitamin D-shaped dilemma. The problem with relying on sunscreens for protection, as we are advised to do, is that they block the rays that are needed to make vitamin D in the skin. Even factor 15 sunscreen blocks approximately 99% of vitamin D production in the skin.
Because of this, Public Health England has changed its longstanding advice for instant sunscreen slathering. It now recommends that everyone should have a short daily burst of sun exposure, without the use of sunscreen. What they don’t mention is the benefit of combining these short bursts with a regular diet of carotenoid-rich foods.
Carotenoids take the form of an orange pigment, so foods that contain them are easily identifiable: sweet potato, carrots, bell peppers, pumpkin, squash, cantaloupe melon, mango and apricots are good examples. Less identifiable are the carotenoid-rich, dark leafy greens whose green pigment camouflages the orange. These include kale, spinach, greens, broccoli and the like.
There are many different types of carotenoid, the best known being beta carotene (carrots), lycopene (tomatoes), alpha carotene (pumpkin and carrots), lutein, and zeaxanthin (kale and spinach). See table below for more details.
Common Carotenoids And Their Sources
|Alpha carotene||Carrots, pumpkin, squash|
|Beta carotene||Carrots, sweet potato, tomato, squash, pumpkin, kale, spinach, broccoli, cress, cantaloupe, apricot, mango|
|Beta cryptoxanthin||Dill, mango, orange, red pepper, pineapple|
|Lutein||Kale, spinach, sprouts, broccoli, carrot, pumpkin, squash, basil, parsley, red pepper, yellow pepper|
|Lycopene||Tomato and tomato products, water melon, pink grapefruit, apricot|
|Zeaxanthin||Kale, spinach, sprouts, broccoli, carrot, pumpkin, squash, basil, endive, parsley, red pepper, yellow pepper|
|Astaxanthin||Salmon, prawns, lobster|
Consuming carotenoid-rich food significantly lowers your risk of sun damage and skin cancer. Both animal and human studies have consistently shown that eating carotenoid-rich foods protects against damage from ultraviolet irradiation from the sun. A diet rich in lycopene in particular has been found to significantly lower the risk of burns to the skin. Beta carotene and lycopene have been found to significantly reduce the effects of sun-related skin damage, especially when vitamin E (tocopherol) is included. Beta carotene also works by creating an immune response to fight tumour cells.
So carotenoids are effective against burning – what about skin cancer? Well, animal studies have confirmed that carotenoids protect against skin cancer, but as far as humans go we don’t know. Randomised, controlled trials of humans are lacking, not surprisingly.
Sunlight has two ultraviolet rays: UVA and UVB. UVB is the one needed to make vitamin D, but it can also cause your skin to burn. UVA is more damaging as it can penetrate the outer skin and reach the cells that can become cancerous. Sunscreen protects against burning, but when it comes to preventing skin cancer, that’s quite another matter.
There are three main types of skin cancer associated with excessive sun exposure – cutaneous melanoma (the most lethal), basal cell carcinoma (the most common form) and squamous cell carcinoma. And the truth is, there is no evidence that they (sunscreens) protect against basal cell carcinoma or melanoma …. sunscreen companies have emotionally and inaccurately promoted the use of sunscreens.
According to the World Health Organization, malignant melanoma from sun exposure is relatively rare, compared to the number of diseases caused by lack of exposure. That’s quite a statement, when you think about it.
They might not prevent cancer, but sunscreens block the formation of vitamin D. Ironically, vitamin D is known to be protective against all sorts of cancers, including breast, colon, prostate and ovarian. It also protects against heart disease.
We need vitamin D, but the fact is that vitamin D deficiency is highly prevalent – deficiency is now described as a world-wide pandemic. The further away from the equator you live, the greater the risk of deficiency. The darker your skin, the more exposure to sunlight you need.
No one is suggesting that you strip off and toil semi-naked under a high sun all day, pausing only to eat carrots and drink tomato juice. We are all adults here, and know that it would be foolhardy to exposure ourselves to sunlight for prolonged periods. But brief, daily exposure is to be encouraged to ensure adequate vitamin D manufacture.
Common sense is required, and a daily helping of carotenoids to wash down that common sense. And not just the day before the summer holidays. Studies which have demonstrated the protective effects of carotenoids have also shown that they have to be consumed regularly, in high amounts over weeks and months, not just days.
The odd tomato or carrot is not going to cut it. The carotenoids that you eat from fruit and vegetables are distributed around the body, with higher concentrations found in the skin and the eye. Sometimes you can tell when you’ve eaten a lot as they affect skin colour, making it appear more yellow.
It is possible – just possible – that the alarming increase in skin cancer rates in the UK and Ireland is related to the equally alarming low level of fruits and vegetables, and therefore carotenoids, in the average diet. Data from the latest National Diet and Nutrition Survey for adults reveal that in Great Britain, just 7% of girls and 22% of boys aged 11 to 18 years, and 33% of women and 37% of men are meeting the five-a-day guidelines for fruit and vegetable consumption. With so little carotenoid consumption we really are at risk, especially the fair-skinned, whose defences are already down.
So get eating your carotenoids now. And here’s an extra tip. Carotenoids are fat soluble so put some butter on those carrots, and extra virgin olive oil on those greens. Importantly, bear in mind that these carotenoids are much more readily absorbed from cooked food, not raw. Indeed, very little is absorbed from raw plants, so cooking is essential.
If you’re wondering what to have for dinner tonight, how about a nice red pepper and tomato stew, with steamed spinach on the side ….. to go with grilled wild salmon, one of the few dietary sources of vitamin D. The perfect way to finish off a sunny day.
To learn more about vitamin D, and how to ensure you get enough during the winter months, read the article Ten Reasons Why You Must Start Taking Vitamin D Now!
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