The pigments that give some fruits and vegetables their rich red, orange and yellow colours are called carotenoids. These natural compounds are also potent disease fighters. If your diet doesn’t contain enough of them, supplements are a handy option.
What they are
Although more than 600 carotenoid pigments have been identified in foods, it appears that only six are used in significant ways by the blood or tissues of the body. Besides beta-carotene, which is probably the best-known carotenoid, these include alpha-carotene, lycopene, lutein, zeaxanthin and cryptoxanthin.
Carotenoids are found in various fruits and vegetables, but the foods that are the most concentrated sources may not be part of your daily fare. Alpha-carotene is found in carrots and pumpkin; lycopene is abundant in red fruits, such as watermelon, red grapefruit, guava and, especially, processed tomatoes. Lutein and zeaxanthin are plentiful in dark green vegetables, pumpkin and red capsicums, while cryptoxanthin is present in mangoes, oranges and peaches. Supplements providing a mixture of the six key carotenoids may be the best option.
What they do
The primary benefit of carotenoids lies in their antioxidant potential. Antioxidants are compounds that protect body cells from damage by unstable oxygen molecules called free radicals. Although the carotenoids are similar, each acts on a specific type of body tissue. In addition, alpha-carotene and cryptoxanthin can be converted into vitamin A in the body, but not to the same extent as beta-carotene.
Carotenoids may guard against certain types of cancer, apparently by limiting the abnormal growth of cells. Lycopene, for instance, appears to inhibit prostate cancer formation. Researchers at Harvard Universiy found that men who ate 10 or more servings a week of tomato-based foods – tomatoes are the richest dairy source of lycopene – cut their risk of prostate cancer by nearly 45%. Lycopene may also be effective against cancers of the stomach and digestive tract. Studies show that high intakes of alpha-carotene, lutein and zeaxanthin decrease the risk of lung cancer, and that cryptoxanthin and alpha-carotene lower the risk of cervical cancer.
In addition, carotenoids may fight heart disease. In a survey of 1300 elderly people in the US, those who ate the greatest amount of carotenoid-rich foods had half the risk of developing heart disease and a 75% lower risk of heart attack than those who ate the least of these foods. This was true even after the researchers took other heart-disease risk factors – such as smoking and high cholesterol levels – into account. Scientists believe that all carotenoids, particularly alpha-carotene and lycopene, block the formation of LDL (‘bad’) cholesterol, which can lead to heart attacks and other cardiovascular problems.
The carotenoids lutein and zeaxanthin promote clear vision by absorbing the sun’s harmful ultraviolet rays and neutralising free radicals in the retina (the light-sensitive portion of the eye). This may help to reduce the risk of macular degeneration, an age-related vision disorder that is the leading cause of blindness in older adults. Other carotenoids may prevent damage to the lens of the eye and so decrease the risk of cataracts.
Preliminary studies also indicate that there may be a link between low levels of carotenoids and menstrual disorders. And other studies show that, even after the onset of cancer, a diet high in carotenoids may improve the prognosis.
- May lower the risk of certain types of cancers, including prostate and lung cancer.
- May provide protection against heart disease.
- Slow down the development of macular degeration.
- Enhane immunity.
How to take them
If you don’t eat a wide variety of foods rich in carotenoids, take a supplement that containsmixed carotenoids – alpha-carotene, beta-carotene, lycopene, lutein, zeaxanthin and cryptoxanthin – and supplies a minimum of 25 000 IU vitamin A activity each day. Higher doses of mixed carotenoids may be recommended for the prevention of specific disorders.
Guidelines for use
Take carotenoid supplements with foods that contain a bit of fat, which helps the body absorb the carotenoids more effectively. Some experts also believe that your body will absorb more of these nutrients if you divide the total daily amount of carotenoids you plan to take in half and have them at two different times during the day.
Possible side effects
Large doses of carotenoids (through food or supplements) can make your skin turn orange, especially the palms of your hands and the soles of your feet. This effect is harmless and will gradually go away if you reduce your intake of carotenoids. though there are no other known side effects associated with large amounts of mixed carotenoids, taking high doses of individual carotenoids may interfere with the workings of the other carotenoids.
Reminder: If you have a medical condition, talk to your doctor before taking supplements.