“Carrots make your buttocks pink” they say, or “to see well, you have to eat carrots”. There would be some truths behind it if we believe the properties of carrots. Indeed, they are full of carotenoids, natural pigments responsible for the colors ranging from orange-yellow to purple-red of a large number of fruits and vegetables. These colors are not only a pleasure for the eyes, they protect the skin from aging, limit the risk of prostate cancer and the occurrence of AMD and cataracts.
The word carotenoid is derived from the Latin name for the carrot (Daucus carota) from which beta-carotene (or pro-vitamin A), the most widespread carotenoid in our diet, was isolated for the first time. Carotenoids represent a very large family of molecules, with over 600 distinct members identified in a wide variety of foods.
Humans, like animals in general, are unable to manufacture carotenoids and these molecules must therefore come from our diet. Fortunately, the sources of carotenoids are multiple and the abundant consumption of plants allows an adequate supply of these molecules. In general, it is estimated that the human diet allows the absorption of about fifty distinct carotenoids, the most important being beta-carotene (carrots), lutein (spinach) and lycopene (tomatoes) which represent the three of them nearly 80% of the population’s carotenoid intake.
Pro-vitamin A protects skin from sun, UV and aging
Adequate intake of carotenoids, or pro-vitamin A, is important because these pigments perform multiple positive health functions. Most carotenoids are also powerful antioxidants capable of protecting our cells from damage caused by free radicals. This protective effect is particularly important in the skin, an organ that contains large amounts of carotenoids provided by food.
Studies have reported that an increased dietary intake of carotenoid-rich foods is associated with better UV protection. Of all the carotenoids, lycopene, a molecule present in large quantities in tomatoes, is by far the most effective in neutralizing free radicals produced by the action of UV rays, an action that could slow down the aging of the skin. For example, one study showed that daily consumption of tomato paste was associated with an increase of about 30% in the degree of skin protection against the sun, as well as a significant increase in collagen levels, two factors crucial to maintaining the integrity of
25% reduction in the risk of prostate cancer
In addition to their antioxidant action, carotenoids also exert several cellular effects that could participate in the prevention of chronic diseases. The best characterized example is undoubtedly that of tomato lycopene, this molecule possessing the ability to block the growth of several types of cancerous cells, in particular those originating from prostate cancer.
In the latter case, studies have shown that regular consumption of tomato-based products results in an accumulation of lycopene in the prostate as well as a significant reduction in the risk of prostate cancer. For example, a study of 47,000 Americans indicates that a regular intake of tomato products reduces the risk of cancer of this organ by approximately 25%.
Reduce the risk of AMD and cataracts
Certain carotenoids such as beta-carotene and cryptoxanthin are converted into vitamin A, an essential vitamin for vision, this role of beta-carotene in vision is also the origin of the saying that carrots are good for eyesight. Thus, lutein and zeaxanthin, two molecules abundant in green vegetables, are concentrated in the central part of the retina (the macula) to form a protective layer that absorbs high-energy (blue) light.
Studies suggest that the formation of this layer exerts a protective effect against the risk of age-related macular degeneration; for example, regular consumption of important sources of lutein and zeaxanthin, including spinach and corn, is correlated with a reduced risk of macular degeneration as well as cataracts.
The multiple health benefits of carotenoids are another good reason to eat a wide variety of plants, especially colorful plants, on a regular basis.
Giovannucci et al. A prospective study of tomato products, lycopene, and prostate cancer risk. J Natl Cancer Inst; 94:391-8.
Carpentier et al. Associations between lutein, zeaxanthin, and age-related macular degeneration: an overview. Crit Rev Food Sci Nutr; 49: 313-26.