CAROTENES AS ANTIOXIDANT
Carotenes are a highly colored group of fat-soluble plant pigments ranging from red to violet. Due to their antioxidant effects, carotenes play a crucial role in protecting organisms against damage. Preliminary and experimental studies suggest that a high intake of carotenes offers protection against developing certain cancers, such as lung, skin, uterine, cervix, and gastrointestinal tract; heart disease, macular degeneration; cataracts; and other health conditions linked to ixidative or free-radical damage. Carotenes that are converted in the body to vitamin A are called "provitamin A" carotenes.
The best-known carotenes without provitamin A activity but with very high antioxidant activity are lutein, lycopene, and zeaxanthin.
Lycopene exibits the highest free-radical-scavenging activity which is roughly double that of beta-carotene. Furthermore, lycopene may exert even more impressive anticancer effects.
According to a detailed analysis of the levels of carotenoids in 120 fruits and vegetables, very few contained lycopene. The table below illustrates lycopene levels in some of those foods. Tomatoes are the primary dietary source of lycopene. These values indicate that food processing does not destroy lycopene levels.
Milligrams of Lycopene per 100 Grams of Fruit or Vegetable
| Food Name |
Amount of Lycopene
|
| Apricot, canned | 0.06 |
| Apricot, dried | 0.8 |
| Grapefruit (pink and raw) | 3.4 |
| Guava juice | 3.3 |
| Tomato, raw | 3.1 |
| Tomato juice, canned | 8.6 |
| Tomato paste, canned | 6.5 |
| Tomato sauce, canned | 6.4 |
| Watermelon, raw | 4.1 |
Oleoresins are naturally occurring mixtures of an oil and a resin in various plants. Studies show that tomato-oleoresin supplementation increases lycopene concentrations in blood serum, tissues and skin [8].
Studies regarding the protective role of lycopene against prostate cancer are inconsistent. One study conducted at the National Cancer Institute showed that among men with a family history of prostate cancer, risks were decreased in relation to increased consumption of lycopene and specific tomato-based foods commonly eaten with fat (spaghetti, pizza, lasagna). This large study does not support the hypothesis that greater lycopene/tomato product consumption protects from prostate cancer. Researchers concluded that evidence for protective associations in people with a family history of prostate cancer required further corroboration.
However, two other relevant dietary studies found that consumption of two to four servings of tomato sauce per week was associated with about a 35% risk reduction of total prostate cancer and a 50% reduction of advanced prostate cancer [11]. The results were particularly apparent for aggressive cancer and for men not consuming beta-carotene supplements [11],[12].