The important plant-based pigment lycopene is found mainly in tomatoes. This carotenoid is just one of the approximately six hundred members of the family of carotenoid compounds. These beneficial phytochemicals are very good for health and are found in abundant quantities in many common fruits and vegetables consumed daily. The humble tomato and products made from tomato form the best source of lycopene.
The most famous carotenoid is, of course, beta-carotene, found in carrots. This compound has stoked the curiosity of researchers for a long time due to its role as a pro-vitamin A in the body – it undergoes chemical conversion to form vitamin A, whenever the supply of the vitamin runs low. The majority of clinical research has focused on the effects of a few beneficial carotenoids including the much-studied beta-carotene, at the same time, the often ignored lesser carotenoids like lycopene, that does not show pro-vitamin A-like activity, has been sidelined. In previous decades, scientist believed that these other carotenoids like lycopene were mere “junk” carotenoids, which had little purpose in the body other than their role as natural pigments lending color to fruits and vegetables. As time has passed, however, the unique and beneficial roles that carotenoids like lycopene play in the body has been realized following a more thorough clinical investigations. Now, most researchers are of the opinion that lycopene has a much more potent antioxidant effect than beta-carotene in the body; it is also believed to be a strong anti-carcinogen.
Lycopene has been tested on human and animal cancer cells every since the first positive results of its anti-carcinogenic action came out. In these second series of confirmatory trials, the results obtained hold great potential and promise for the future treatment strategies. In clinical reports, the ability of lycopene to suppress the growth of cancer cells from cancerous breast, lung, and endometrial tissues has been announced by the researchers. In fact, the potent effect of lycopene was further confirmed in laboratory animals that were fed potent carcinogens, in these animals the administration of high levels of lycopene helped to suppress all the cancerous growths resulting from the forced use of carcinogens. One relationship was clear, the effectiveness of the lycopene in suppressing cancer was greater the higher the doses administered. Researchers have also confirmed the great effectiveness of lycopene in dealing with the chemical carcinogens found in tobacco smoke. In one more study, results indicated that the use of lycopene can possibly give a protective effect to skin against the photo damage from long exposure to ultraviolet light – long exposure to sunlight during a lifetime can increase wrinkles and causes skin cancer in many people.
As a human grows older they become more susceptible to diseases, as the levels of all nutrients in the blood decline with old age. Lycopene supplements are ideal as a potent nutrient for all individuals who are 50 or older, particularly if such individuals do not consume at least one tomato dish on a daily basis. The ideal way to get lycopene in the diet is not by drinking a glass of tomato juice, even consuming a fresh tomato a day will not be sufficient in the long run – supplements must be taken to ensure adequate amounts in the body. The human body does not absorb the lycopene present in tomatoes well, if the vegetable is not heated or mixed with a little fat, like olive oil. Therefore, supplemental lycopene is the best to get adequate amounts of the lycopene.
Studies have established that individuals, who consume diets rich in tomatoes, have a lower risk of suffering from certain types of cancer. The lycopene in the tomatoes seemed to suppress the cancers of the lung, prostate, and the stomach, particularly well. The effect of lycopene and its preventive role against cancer or its potential use in treating cancers requires further clinical research. One can be certain, that with the beneficial and preventive effect of human diets that are rich in fruits and vegetables is not simply explainable on one single component of the diet.
At the same time, some proponents of lycopene as a supplement claim that it can help reduce the risk of heart disease by preventing the hardening of the arteries in the heart, they also suggest that lycopene can prevent macular degenerative disease in old people; this is a common age-specific illness leading to blindness. These people also suggest that lycopene plays a role in the regulation of lipid oxidation, a chemical damage that affects normal fat molecules leading to inflammation and disease in some individuals. Lycopene has also been suggested as being capable of lowering the elevated levels of the “bad” cholesterol known as low-density lipoprotein – or LDL cholesterol. It is said to boost the functioning of the immune system and of supporting the body defenses against pathogens. Lycopene may also protect enzymes, DNA, and cellular fats according to some proponents of this supplement. The biggest support for lycopene is for its use in treating cancers of the lung, the prostate gland, the stomach, the urinary bladder, the cervix, and the skin. Some of these claims may have a basis in fact while other need further study and confirmation.
Based on clinical studies, some researchers are of the view that lycopene may possibly prevent the spread and slows the growth of cancerous tissues in case of prostate, lung, and stomach cancers. The researchers attribute such beneficial effects of the lycopene to its potency as an antioxidant, which are organic compounds that help blocks the action of activated oxygen molecules called free radicals which are released in the cells as a part of normal metabolism – the action of these free radicals can severely damage cells in the body. Indeed, lycopene is a very active and effective antioxidant molecule, with an activity said to be equal or double that of beta-carotene – the other well-known carotenoid anti-oxidant that is also believed to be potent cancer-preventing nutrient obtainable from the diet. As the nutrient, the lycopene is regarded as being one of the most effective of the antioxidant compounds as it does not undergo chemical conversion to vitamin A in the body, following its consumption. The chemical conversion of beta-carotene to vitamin A limits its use as an antioxidant compound.
The highest levels of dietary lycopene are found principally in tomatoes; however, other fruits also contain high levels of the compound including guava, apricots, watermelons, papayas, and pink grapefruit. As tomatoes are readily available and often used as food, they are the best food source for lycopene – tomatoes are also cheaper than other costly fruits. In clinical studies, it has been confirmed that the lycopene levels in the blood were higher in the blood of people who consumed cooked tomatoes than in the body of those who consumed raw tomatoes or drank tomato juice alone. What this result suggests is that dietary tomato sauce or paste might be the ideal source for the lycopene contained in tomatoes than the consumption of raw tomatoes itself. In most health food stores, the supplements of lycopene are sold in the form of soft gel capsule supplements. The dosages of lycopene differ and different manufacturers may give different dosage regimens in the product label.
The proof that diets high in lycopene lead to a reduced incidence of cancer has come from the long-term scientific observation of the nutritional pattern of groups of individuals from many countries across the world. In these populations, a diet high in tomato products translated into high levels of lycopene in the blood is associated with the lowest chance of developing certain cancers. These nutritional studies all suggests that in general diets that are rich in tomatoes might be the possible reason for the reduction in the risks of developing several different kinds of cancer across any population.
Lycopene may also possibly have a beneficial protective effect against the chance of cancers of the cervix and breast in women, and cancers of the mouth, the pancreas, the esophagus, as well as those of the colon, and the rectum in men and women.
Tomatoes in the diet have been linked to lowered risk of prostate cancer in some nutritional studies that observed large groups of people – this is said to be due to the diet high in lycopene from the tomato based foods taken in the diet. This connection between tomato-based foods and lowering of prostate cancer risk is disputed by the other researchers, however, in these studies, some researchers have found no concrete link between the consumption of large amounts of tomato-based food products and a lowering in prostate cancer risk. There may be a genetic factor behind all this, as the results from one recent study show. These results suggest that the form or variation in a particular gene called XRCC1, which codes for proteins that help repair damaged DNA damage influences the effectiveness of lycopene. This gene may be affecting the chances of whether a high intake of lycopene will influence the risk of prostate cancer in men.
Lycopene in itself may not be the sole agent in tomatoes that lowers the risk of cancer. Many other important nutrients such as vitamins, the mineral potassium, pigments like the carotenoids, and other classes of antioxidants, and many other beneficial compounds are found in tomatoes, these acting alone or affecting a combined effect with the lycopene, may be the agent or agents that induce the protective effects attributed solely to lycopene by some researchers. In studies in which the researchers have analyzed the dietary habits of large groups of people all with varied lifestyles and habits, it might be the case that also the effect in lowered cancer risk attributed to certain diets is induced in fact, by other factors that were never examined in the study.
In a scientific review of a study published in 2004, it was stated that in a study in which eleven observational and ten cases control studies were analyzed, it did seem that tomato based products give a weak but protective effect over the chance of prostate cancer – this results in a lowered risk of prostate cancer according to the conclusion based on the study. It is important to state here, that this analysis of the study results did not involve the use of any lycopene supplements whatsoever, only tomato and tomato-based food products were utilized. However, lycopene levels in the blood were indeed considered in some of the individual studies. In the review, the analyst suggested that the protective effect was indeed somewhat stronger when cooked tomato products were consumed. It was also noted that the addition of small quantities of fat improved the absorption of lycopene in the body.
In fact, the role of lycopene possibly preventing or treating cancers completely has been investigated in a few experimental studies. In one of these experiments, animals given supplements of lycopene displayed reductions in the growth rate of induced brain tumors – this is a significant result. Administration of high doses of lycopene to test mice studied in another experimental study showed that the high levels of lycopene in the body of the animal led to the suppression of induced breast tumor growth to a very significant extent. The insight gained from this particular study may not be applicable to human disease states, as at least ninety-five percent of all the human breast cancers cases are different to the form of breast cancers seen in mice and other mammals.
In addition, supplements of lycopene have been shown to actively suppress the growth of a variety of human cancer cell lines under laboratory conditions. This ability of lycopene to interfere and disrupt cancer cell growth was particularly potent in cancers that grow in response to the insulin-like growth factor I – a growth factor in mammals. Therefore, at least in the animal and laboratory studies, lycopene has shown a certain promise for the treatment of cancer. However, its application to human cancers requires further studies and long term testing, before it can be used on humans.
In one test, to assess the fact about lycopene as a principal cancer-fighting compound in tomatoes, animals given lycopene supplements were compared to those given powdered tomatoes as a supplement. The group of laboratory rats were fed tomato powder and analytically compared to rats given just lycopene supplements over a long period of time. There was a significant lowering of risk for cancer in the rats that received tomato powder while it was noticed, that the rats administered only lycopene supplements had no more significant lowering of risk for cancers from the group that was given only powdered tomatoes.
Human tests have also been conducted to check the possibility of lycopene use in the treatment of cancer. In one particular controlled study that checked a small group of men affected by prostate cancer, it was discovered that the use of lycopene supplements seemed to result in a reduction of rapid growth in prostate cancer cells normally seen in such affected men. This result is disputed and a more recent clinical study has indicated that lycopene supplements induced no significant healing effect on prostate cancer affected men who had all failed hormone therapy as part of an earlier treatment. At any rate, human tests of this type are just in the starting stage, and it is necessary to conduct more controlled studies that test larger groups of patients, before the benefits of lycopene in dealing with cancer if any, are known. Currently, individuals with cancer are being tested in a number of smaller studies now underway to check if any tomato products or supplements lycopene can be used in treating cancer states.
Since it is a natural organic compound, there are no safety issues connected to the intake of lycopene from the consumption of fruits and vegetables. High levels of the compound are also not known to induce any significant side effects and lycopene is believed to safe for human use – unless such people are allergic to the fruit or vegetable itself. Supplemental lycopene is a different matter though the potential side effects of such supplements if any is still not fully known due to the scarcity of reports. Lycopene and its potential side effects were studied in a group of test patients, who all received a supplement rich in tomato-based lycopene at doses of fifteen mg two times every day. In these patients, the supplement induced some type of intestinal side effects including spells of nausea and vomiting, persistent diarrhea, indigestion, abdominal gas and bloating of the stomach. Therefore, lycopene supplements are comparatively safe and side effects are considered mild. Consuming large amounts of tomato-based products for prolonged periods of time is also known to bring out an orange color in the skin, with no other symptoms.
If they are used during the course of a radiation or chemotherapy regimen, then antioxidant supplements may interfere with the actual killing of the cancer cells in the body – therefore, antioxidants must be avoided during such treatments. This area of research is still unclear and more studies in humans are required to find out the exact manner in which antioxidants might interfere in such cases. It is suggested, however, that supplements of vitamins, minerals, or nutrient supplements taken by cancer patients undergoing therapy must be only under medical supervision, a qualified doctor must be consulted by the patient before such supplements are used to avoid possible problems. On the other hand, fresh fruits and vegetables, which are all high in antioxidants, can be safely eaten by the patient during the radioactive or drug-based chemotherapy treatment of cancer without fear of a possible interference in the treatment.