Lycopene from the neo-Latin lycopersicum, the tomato species, is a bright red carotene and carotenoid pigment and phytochemical found in tomatoes and other red fruits and vegetables, such as red carrots, watermelons, gac, and papayas, although not in strawberries, or cherries. Although lycopene is chemically a carotene, it has no vitamin A activity. Foods that are not red may also contain lycopene, such as asparagus and parsley.[no_toc]
Lycopene is not an essential nutrient for humans, but is commonly found in the diet mainly from dishes prepared from tomatoes. When absorbed from the intestine, lycopene is transported in the blood by various lipoproteins and accumulates primarily in the blood, adipose tissue, skin, liver, and adrenal glands, but can be found in most tissues.
Fruits and vegetables that are high in lycopene include Autumn Olive, Gac, Tomatoes, watermelon, pink grapefruit, pink guava, papaya, Seabuckthorn, Wolfberry (goji, a berry relative of tomato), and rosehip. Although gac (Momordica cochinchinensis Spreng) has the highest content of lycopene of any known fruit or vegetable, up to 70 times more than tomatoes for example, due to gac’s rarity outside its native region of southeast Asia, tomatoes and tomato-based sauces, juices, and ketchup account for more than 85% of the dietary intake of lycopene for most people. The lycopene content of tomatoes depends on species and increases as the fruit ripens.
Unlike other fruits and vegetables, where nutritional content such as vitamin C is diminished upon cooking, processing of tomatoes increases the concentration of bio-available lycopene. Lycopene in tomato paste is up to four times more bio-available than in fresh tomatoes.
While most green leafy vegetables and other sources of lycopene are low in fats and oils, lycopene is insoluble in water and is tightly bound to vegetable fibre. Processed tomato products such as pasteurised tomato juice, soup, sauce, and ketchup contain the highest concentrations of bio-available lycopene from tomato-based sources.
Cooking and crushing tomatoes (as in the canning process) and serving in oil-rich dishes (such as spaghetti sauce or pizza) greatly increases assimilation from the digestive tract into the bloodstream. Lycopene is fat-soluble, so the oil is said to help absorption. Gac is a notable exception, containing high concentrations of lycopene and also saturated and unsaturated fatty acids.
Lycopene may be obtained from vegetables and fruits such as the tomato, but another source of lycopene is the fungus Blakeslea trispora. Gac is a possible commercial source of lycopene for the purposes of extraction and purification, as its seed content of lycopene is high.
The cis-lycopene from some varieties of tomato is more bio-available.
Note that there are some resources which make the mistaken assumption that all red fruits contain lycopene, when in fact many are pigmented by other chemicals. An example is the blood orange, which is coloured by anthocyanins, while other red coloured oranges, such as the Cara cara navel, and other citrus fruit, such as pink grapefruit, are coloured by lycopene.
In addition, some foods that do not appear red also contain lycopene, e.g., asparagus, which contains approximately 30μg of lycopene per 100 gram serving (0.3μg/g) and dried parsley and basil, which contain approximately 3.5-7 μg of lycopene per gram.
Potential Health Effects
Lycopene from tomatoes has been tested in human studies for cardiovascular diseases and prostate cancer. These studies, however, did not attain sufficient scientific agreement to conclude an effect on any disease. The FDA, in rejecting manufacturers’ requests in 2005 to allow “qualified labeling” for lycopene and the reduction of various cancer risks, stated:
…no studies provided information about whether lycopene intake may reduce the risk of any of the specific forms of cancer. Based on the above, FDA concludes that there is no credible evidence supporting a relationship between lycopene consumption, either as a food ingredient, a component of food, or as a dietary supplement, and any of these cancers.
A 2011 Cochrane review found insufficient evidence for any effect lycopene might have on prostate symptoms, PSA levels or prostate cancer.
Many studies suggest that eating lycopene-rich foods or having high lycopene levels in the body may be linked to reduced risk of cancer, heart disease, and age-related eye disorders. However, measures of lycopene intake have been based on eating tomatoes, not on the use of lycopene supplements. Since tomatoes also contain other nutrients, such as vitamin C and potassium, the potential benefits of lycopene alone are still unclear.
Lycopene deficiency is not considered a medical condition. There is a lack of evidence on whether increasing low lycopene levels may benefit health.
Source : Mayo Clinic