What Are They?
Carotenoids are the pigments that color some fruits and vegetables red, orange and yellow. Recent research has shown that, acting as antioxidants, these natural plant compounds can boost the immune system and possibly lower the risk of heart disease, prevent the onset of some cancers, and protect against such age-related diseases as cataracts and macular degeneration.
While more than 600 carotenoids have been identified in foods, surprisingly only six of them are used in significant ways by the body: alpha-carotene, lycopene, lutein, zeaxanthin, cryptoxanthin and the best-known, beta-carotene. Alpha-carotene is plentiful in carrots and pumpkin. Lycopene is found in red fruits, such as watermelon, guava, red grapefruit, and especially processed tomatoes. Lutein and zeaxanthin are present in red peppers, pumpkins and dark green vegetables (the yellow-orange pigments are masked by green chlorophyll). Cryptoxanthin is abundant in peaches, mangoes and oranges. And beta-carotene shows up in all these foods, as well as in sweet potatoes and cantaloupes.
If fruits and vegetables are not a regular part of your diet, you should consider taking a mixed carotenoid supplement, which contains a combination of the key carotenoids.
As antioxidants, carotenoids protect cells from damage by unstable oxygen molecules called free radicals. Though similar in structure, each carotenoid acts on a different type of body tissue. Certain carotenoids, including beta-carotene, alpha-carotene and cryptoxanthin, are converted by the body into vitamin A, but only as the body requires it.
Specifically, carotenoids may help to:
• Lower the risk of certain types of cancer. Carotenoids may inhibit the growth of cancer cells. In the well-known Framingham Nurses study, where 83,000 women were followed for 14 years, researchers found that high supplemental intakes of lutein, zeaxanthin, beta-carotene and high food intakes of vitamin A (along with a diet generally high in fruits and vegetables) reduced the risk of premenopausal breast cancer. This was especially true in women more likely to develop this disease due to family history or alcohol consumption. Other studies link high intakes of alpha-carotene, lutein, and zeaxanthin to a reduced risk for lung cancer. Cryptoxanthin and alpha-carotene have been shown to decrease the chance of developing cervical cancer. Lycopene appears to be particularly effective at inhibiting prostate cancer. Research conducted at Harvard University found that men who ate 10 or more servings of tomato-based foods a week lowered their risk of prostate cancer by almost 45%. Lycopene may also protect against cancers of the digestive tract, stomach, and lungs.
• Boost the immune system in those undergoing cancer therapy. Lycopene and beta-carotene, taken along with vitamins C and E, may help protect the body against the effects of chemotherapy or radiation. Both procedures can damage healthy cells as they attack cancer cells.
• Protect against heart disease. Experts believe that all carotenoids–but especially alpha-carotene, lycopene, and beta-carotene–help to prevent heart disease and heart attack by inhibiting the formation of harmful LDL cholesterol. A study of 1,300 older people found that those who ate the most foods rich in carotenoids were half as likely to develop heart disease, and 75% as likely to have a heart attack, as those who ate the least amount of carotenoids; the results included people who smoked and had high cholesterol levels. In a major European study, men who ate a lot of lycopene-rich food were 50% less likely to have a heart attack than men who consumed little lycopene. Nonsmokers experienced the most benefit.
• Prevent cataracts and macular degeneration. By filtering out the sun’s harmful ultraviolet (UV) rays and by keeping free radicals from damaging the retina–the light-sensitive part of the eye–lutein and zeaxanthin may help to protect against macular degeneration, the progressive loss of vision that is the leading cause of blindness in older adults. Other carotenoids may help preserve the eye’s lens, decreasing the risk of cataracts.
• Combat chronic fatigue syndrome. Because carotenoids can enhance immunity, taking a mixed carotenoid supplement along with vitamin C and echinacea may help the body fight the persistent tiredness and flulike symptoms associated with this ailment.
• Reduce the risk of developing diabetes. In a recent study conducted by the Centers for Disease Control, researchers found that those with high levels of beta-carotene, lycopene, and cryptoxanthin had normal glucose tolerance; those with the lowest levels of these compounds were often newly diagnosed with type 2 diabetes. In another study, people with type 2 diabetes were found to be far more likely to have a carotenoid deficiency than those without the disease.
• Fight the onset of Alzheimer’s disease and provide anti-aging actions. The antioxidant properties of carotenoids, in combination with vitamins C and E, may help keep nerve cells in the brain from deteriorating. This may help guard against the effects of aging in general as well as the more specific memory loss and disorientation associated with Alzheimer’s disease.
• Treat male infertility. Mixed carotenoids, taken with vitamins C and E, may help protect sperm from damage by free radicals.
Note: Carotenoids have also been found to be useful for a number of other disorders. For information on these additional ailments, see our Dosage Recommendations Chart for Carotenoids.
–If you don’t eat at least five servings of fruits and/or vegetables daily, take a mixed carotenoid supplement that supplies at least 25,000 IU vitamin A activity per day. Higher doses may be needed to protect against specific ailments.
–Women taking oral contraceptives or who use estrogen-based hormone replacement therapy–both of which reduce blood levels of carotenoids–should consider taking 1 pill mixed carotenoids daily that supplies approximately 25,000 IU vitamin A activity.
• For cancer and diabetes prevention: Take 1 pill mixed carotenoids a day, supplying at least 25,000 IU vitamin A activity.
• For cancer treatment: Take 3 pills mixed carotenoids a day; each pill should supply at least 25,000 IU vitamin A activity.
• To treat male infertility: Take 1 pill mixed carotenoids twice a day; each pill should supply at least 25,000 IU vitamin A activity.
• For cataracts, macular degeneration, chronic fatigue syndrome, or for prevention of heart disease: Take 2 pills mixed carotenoids a day; each pill should supply at least 25,000 IU vitamin A activity.
• For prevention of Alzheimer’s disease: Take 1 pill mixed carotenoids, supplying at least 25,000 IU vitamin A activity, along with 2,000 mg vitamin C and 400 IU vitamin E, a day.
Be sure to check out our Dosage Recommendations Chart for Carotenoids, which lists therapeutic dosages for specific ailments at a glance.
Guidelines for Use
• Taking carotenoid supplements with foods that contain some fat helps the body absorb these compounds more readily.
• There are no known drug or nutrient interactions associated with carotenoids.
Possible Side Effects
• If you ingest high levels of carotenoids from either foods or supplements, the palms of your hands and soles of your feet may turn orange. Stop taking extra carotenoids if this occurs and consult your doctor.
• Avoid taking large amounts of any one carotenoid; doing so, may decrease the usefulness of other carotenoids to the body.
Alzheimer’s Disease 1 pill mixed carotenoids each morning with food along with 2,000 mg vitamin C and 400 IU vitamin E. Each pill should supply 25,000 IU vitamin A activity.
Cancer 1 pill mixed carotenoids(usually 10,000 IU) twice a day
Cancer Prevention 1 pill mixed carotenoids with lycopene each morning with food. Each pill should supply 25,000 IU vitamin A activity.
Cataracts 2 pills mixed carotenoids each morning with food. Each pill should supply 25,000 IU vitamin A activity.
Chronic Fatigue Syndrome 2 pills mixed carotenoids each morning with food. Each pill should supply 25,000 IU vitamin A activity.
Heart Disease Prevention 15,000 to 25,000 IU day; may be partially covered by your daily antioxidant complex
Infertility, Male 1 pill mixed carotenoids each morning with food. Each pill should supply 25,000 IU vitamin A activity.
Macular Degeneration 2 pills mixed carotenoids each morning with food.
David Edelberg, MD