These precursors of vitamin A are sometimes called provitamin A. Bright orange beta-carotene is the most important carotenoid for adequate vitamin A intake because it produces more vitamin A than alpha or gamma carotene.
Some carotenoids, like lycopene, do not convert to vitamin A at all. However, lycopene, the orange-red pigment found in tomatoes and watermelon, is still valuable because it is an even more powerful antioxidant than beta-carotene. The other carotenoids are also valuable antioxidants. Antioxidants help the body reduce the inflammatory action of singlet oxygen or free radicals. Oxygen atoms like to combine in pairs. Singlet oxygen atoms are unstable and interact with lipids found in cell walls causing inflammation and damage. Sometimes your own body uses these free radicals to fight infection and abnormal cells. Most of the time, these free radicals cause inflammation and damage to cells. , like those that line the arteries.
Orange and yellow fruits and vegetables have high vitamin A activity due to the carotenoids they contain. Generally, the deeper the color of the fruit or vegetable is an indication of a higher concentration of carotenoids. Carrots, for example, are especially good sources of beta-carotene. Green leafy vegetables like spinach, asparagus, and broccoli also contain large amounts of carotenoids, but their deep green pigment, courtesy of chlorophyll , masks the telltale orange-yellow color. (See the table on page 194 for a list of good food sources of vitamin A.)
Most of the other carotenoids, such as alpha and gamma carotene, plus cryptoxanthin and beta zeacarotene have less vitamin A activity than beta carotene, but offer extensive cancer prevention. Some carotenoids, such as lycopene, zeaxanthin, lutein, capsanthin, and canthaxanthin, do not convert to vitamin A in the body. But again, they are powerful cancer fighters, predominant in fruits and vegetables. There is abundant evidence that lycopene in particular helps reduce the risk of prostate cancer.
Carotenes are also valuable preventive medications. Research shows that people who eat a lot of foods rich in beta-carotene, the carotenoid with the highest vitamin A value, are less likely to develop lung cancer. Even among smokers, lung cancer is less likely to occur in those who eat a diet that includes lots of vegetables and fruits that contain beta-carotene. However, taking a beta-carotene supplement in pill form does not always have the same effect. Perhaps this is because in these foods there may be other substances that also offer protection. In three studies with 69,000 participants, many of them smokers, beta-carotene supplements increased the rate of lung cancer. Lutein / zeaxanthin,
Many experts now believe that the protective effect of carotenoids depends on when you take them. If you take beta-carotene before your cells have undergone precancerous changes, the antioxidant action of carotenoids can help reduce the likelihood of mutations occurring. Carotenoids at this point can prevent free radicals from damaging cells and the DNA within cells, both of which can initiate cancerous growth. But if you take supplemental beta-carotene AFTER the cells have already mutated, the beta-carotene can protect the mutated cells from being destroyed by your own immune system .
Some of the most powerful cancer-fighting cells in your body use free radicals to fight infection and destroy precancerous cells. So eating carotenoid-rich foods or taking supplements helps with what’s called primary protection against cancer – cancer never starts. But after you have a growing colony of cancer cells in your system, beta-carotene supplements can prevent your own system from fighting cancer, making carotenoid supplements significantly less safe for what is called secondary prevention – stopping the cancer. cancer recurrence.
In addition to their role in cancer prevention, carotenes also offer us protection against heart disease. Again, it is its antioxidant behavior that protects the lining of the arteries and the fats in the blood from oxidative damage from free radicals. And age-related macular degeneration of the eye, which leads to vision loss , can be counteracted by the antioxidant power of carotenes.
Beta carotene is used to treat skin problems caused by sun exposure. Some people have conditions in which swelling, redness, itching, and pain develop after exposure to the sun. Usually this is the result of excessive free radical damage due to a cellular problem. Beta-carotene supplementation helps alleviate these symptoms by protecting cells from damage.
Carotenes, like vitamin A, support immune function, but in a different way. They stimulate the production of special white blood cells that help determine the general immune status. They also improve communication between cells, resulting in fewer cell mutations. White blood cells attack bacteria , viruses , cancer cells, and yeast. Women with high levels of carotenes in their blood tend to have fewer incidences of vaginal yeast infections.
While the liver stores retinol, excess carotenoids accumulate in the fat just under the skin. If you eat a lot of foods rich in carotene, you may notice yellowing of your skin, especially on the palms of your hands and the soles of your feet. This is generally considered harmless, although carotene-containing tanning pills used in Europe cause infertility in women.
There is no known carotenoid deficiency state. Instead, deficiency symptoms are related to vitamin A deficiency. While carotenoids can help prevent vitamin A deficiency, people with impaired thyroid function are less able to convert beta-carotene to vitamin A ( retinol).
Taking more than 100,000 IU of beta-carotene per day sometimes gives the skin a yellow-orange hue, which may look like jaundice but is not harmful. People who take beta-carotene for long periods should also supplement with vitamin E, as beta-carotene can lower vitamin E levels. Supplementation with doses of more than 50,000 IU beta-carotene can also lower blood levels of lutein, lycopene, and others. carotenoids.
Vitamin A and carotenoids are vital to your overall health, especially good eyesight. Just make sure you’re getting the right amounts of this nutrient and protect yourself against overdosing to avoid toxic levels, and the vitamin A will work to keep your body running smoothly.