Beta-carotene is a red-orange pigment found in plants and fruits, especially carrots and colorful vegetables.
The name beta-carotene comes from the Greek "beta" and Latin "carota" (carrot). It is the yellow/orange pigment that gives vegetables and fruits their rich colors. H. Wachenroder crystallized beta-carotene from carrot roots in 1831, and came up with the name "carotene".
Beta-carotene's chemical formula - C40H56 - was discovered in 1907.
The human body converts beta-carotene into vitamin A (retinol) - beta-carotene is a precursor of vitamin A. We need vitamin A for healthy skin and mucus membranes, our immune system, and good eye health and vision.
Beta-carotene in itself is not an essential nutrient, but vitamin A is.
Here are some key points about beta-carotene. More detail and supporting information is in the main article.
- Beta-carotene is a red/orange pigment found in many fresh fruits and vegetables
- Beta-carotene is converted into vitamin A, an essential vitamin
- Vitamin A is toxic at high levels
- Beta-carotene is a carotenoid and an antioxidant
- Foods rich in vitamin A include onions, carrots, peas, spinach and squash
- One study showed that smokers with high beta-carotene intake might have an increased risk of lung cancer
- Some evidence suggests that beta-carotene might slow cognitive decline
- Beta-carotene supplements interact with certain drugs, including statins and mineral oil
- Beta-carotene might help older people retain their lung strength as they age.
Beta-carotene from food is a safe source of vitamin A
Vitamin A can be sourced from the food we eat, through beta-carotene, for example, or in supplement form. The advantage of dietary beta-carotene is that the body only converts as much as it needs.
Excess vitamin A is toxic. Toxic vitamin A levels can occur if you consume too many supplements.
Beta-carotene is an antioxidant
The flamingo's characteristic red-orange color is caused by beta-carotene in their diet.
Beta-carotene, like all carotenoids, is an antioxidant. An antioxidant is a substance that inhibits the oxidation of other molecules; it protects the body from free radicals.
Free radicals damage cells through oxidation. Eventually, the damage caused by free radicals can cause several chronic illnesses.
Some studies have suggested that those who consume at least four daily servings of beta-carotene rich fruits and/or vegetables have a lower risk of developing cancer or heart disease.
Which foods are rich in beta-carotene?
The following foods are rich in beta-carotene:
- Chinese cabbage
- Dandelion leaves
- Herbs and spices - chilli powder, oregano, paprika, parsley
- Many margarines
- Sweet potatoes.
If you follow a healthy diet rich in beta-carotene you do not need supplements. As mentioned above, supplements can lead to undesirable excesses in beta-carotene levels - this cannot occur if your source is from the food you eat.
Smokers and beta-carotene lung cancer risk
A French study involving adult females published in the Journal of the National Cancer Institute (September 2005 issue) found that smokers with high beta-carotene levels had a higher risk of lung cancer and other smoking-related cancers than other smokers. They also found that non-smokers with high beta-carotene intake had a lower risk of lung cancer.
They found that the risk of lung cancer over a ten-year period was:
- 181.8 per 10,000 women for non-smokers with low beta-carotene intake
- 81.7 per 10,000 women for non-smokers with high beta-carotene intake
- 174 per 10,000 women for smokers with low beta-carotene intake
- 368.3 per 10,000 women for smokers with high beta-carotene intake.
Further research has suggested that the high intake among smokers is nearly always due to supplements, and not food intake.
Beta-carotene may slow down cognitive decline
Carrots are an excellent source of beta-carotene.
Men who have been taking beta-carotene supplements for 15 or more years are considerably less likely to experience cognitive decline than other males, researchers from Harvard Medical School reported in Archives of Internal Medicine (November 2007 issue).
Oxidative stress is thought to be a key factor in cognitive decline, the researchers explained. Studies have shown that antioxidant supplements may help prevent the deterioration of cognition.
Their study, involving 4,052 men, compared those on beta-carotene supplements for an average of 18 years to others who were given placebo. Over the short-term, they found no difference in cognitive decline risk between the two groups of men, but in the long-term it was clear that beta-carotene supplements made a significant difference.
The researchers emphasized that there may have been other factors which contributed to the slower decline in cognitive abilities among the men in the beta-carotene group.
Beta-carotene drug interactions
Drug interaction refers to a substance interfering in how a medication works, by either making it less effective, increasing its potency, or changing what it is supposed to do.
The following drugs may be affected by beta-carotene supplements:
- Statins - the effectiveness of simvastatin (Zocor) and niacin may be decreased if the patient is taking beta-carotene with selenium and vitamins E and C.
- Some cholesterol-lowering drugs - cholestyramine and colestipol can reduce blood levels of dietary beta-carotene by thirty to forty per cent.
- Orlistat (Xenical, Alli) - this is a weight control medication. It can undermine the absorption of beta-carotene by up to 30%, resulting in lower blood beta-carotene levels. Those choosing to take a multivitamin while on orlistat should take them at least two hours before having their medication.
- Mineral oil - used for the treatment of constipation can lower blood levels of beta-carotene.
Long-term alcohol consumption can interact with beta-carotene, raising the chances of developing liver problems.
Beta-carotene slows down lung power decline as people age
The British Medical Journal published a report in March 2006 which showed that high blood beta-carotene levels compensate for some of the damage to the lungs caused by oxygen free radicals.
They measured the FEV1 of 535 participants and measured their beta-carotene blood levels. FEV1 measures how much air you can breathe out in one go. They found that those with high beta-carotene levels had much slower decline in FEV1 measures.
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