A Powerful Antioxidant*
Lycopene is a bright red carotenoid pigment and phytochemical found in tomatoes and other red fruits. Its name is derived from the classification of tomatoes, Solanum lycopersicum (‘lyco’ is Greek for wolf and ‘persicum’ means peach, so tomato implies ‘wolf-peach’).
It is present in human serum and skin, as well as in the liver, adrenal glands, lungs, prostate and colon.
In plants, lycopene is an important intermediate in the biosynthesis of many carotenoids, including beta carotene, responsible for yellow, orange or red pigmentation. Lycopene also performs various functions in photosynthesis, and protects photosynthetic organisms from excessive light damage. Lycopene’s eleven conjugated double bonds give it its deep red colour and are responsible for its antioxidant activity. Due to its strong colour and non-toxicity, lycopene is a useful food colouring.
Fruits and vegetables that are high in lycopene include
ź Pink grapefruit
ź Pink guava
ź Papaya (Pawpaw)
ź Red capsicum (bell pepper)
ź Goji (a berry relative of tomato)
Tomatoes, tomato based sauces, juices and ketchup account for more than 85% of the lycopene dietary intake of most people. The lycopene content of tomatoes depends on species and increases as the fruit ripens.
Bioavailability of Lycopene
Unlike other fruits and vegetables, where nutritional content such as vitamin C diminishes on cooking, processing of tomatoes, including cooking, increases the concentration of bioavailable lycopene.
Lycopene is insoluble in water, and in the fruit or vegetable it is tightly bound to the plant fibre. In the processing of tomatoes, the lycopene is released from the fibre. Thus processed tomato products such as tomato juice, tomato soup and tomato sauce or ketchup contain the highest concentrations of bioavailable lycopene from tomato based sources. Lycopene in tomato paste is some four times more bioavailable than in fresh, raw tomatoes.
Absorption of Carotenoids, including Lycopene
Lycopene is fat-soluble, so oil, as present in a spaghetti sauce or pizza, is said to help absorption from the gastrointestinal tract.
Scientists studying the absorption of nutrients in people who ate “bowls of salad greens with tomatoes and various types of salad dressings”, recognised that those who had eaten fat-free or low-fat dressings had poor absorption of the beneficial carotenoids from the salad. Only in those who had eaten the oil-based dressings were the nutrients well-absorbed (based on blood samples) (Dr J.Mercola, October 2009).
It is therefore recommended that, in order to absorb its nutrients, you need to eat your tomatoes with a little fat. Olive oil, extra-virgin and cold-pressed, is an excellent choice for this purpose. (But note that olive oil should not be used for frying, as in stir-fry. Coconut oil is recommended for this purpose.)
Therapeutic Uses of Lycopene
Lycopene is an antioxidant, one of the most potent. It protects against free radical damage throughout the body.
The following are some of the uses of lycopene that are based on scientific evidence. The Mayo clinic indicates that although there is scientific support for these applications, at times this scientific evidence may not be strongly positive.
ź Asthma, exercise induced
ź Atherosclerosis and high blood cholesterol
ź Benign prostate hyperplasia (hypertrophy)
ź Cancer prevention (prostate, colorectal, lung and breast)
ź Coronary heart disease
ź Infertility (male)
ź Macular degeneration (age-related)
ź Sun protection
In laboratory (test tube) studies, lycopene has been shown to be a powerful antioxidant, being 100 times more efficient in action than vitamin E, which in turn has 125 times the effect than the action of glutathione (an antioxidant produced naturally by the body). As well as its powerful antioxidant properties, it also gives excellent protection against the effects of ultraviolet light on the skin, a primary cause of skin aging.
Because of lycopene’s antioxidant properties, substantial scientific and clinical research has been devoted to a possible correlation between its consumption and general health. It is this property of lycopene that accounts for many of the uses set out above.
There are many published studies on the effects of lycopene and health. The following three illustrate some of the findings:
ź One of the most influential pieces of research on tomatoes and cancer was a large Harvard study published in 1995. The eating habits of 47,000 men were followed for six years. Those who had at least 10 weekly servings of tomato-based foods were up to 45 percent less likely to develop prostate cancer.
ź Another study from the Harvard Medical School reviewed 72 studies that looked for a link between cancer risk and food made with tomatoes. In all, 57 linked tomato intake with a reduced risk, and in 35 of these, the association was strong enough to be considered statistically meaningful.
ź A study published in the journal Lipids in 1998 showed that daily consumption of tomato products providing at least 40 mg of lycopene was enough to substantially reduce LDL (low density lipoprotein) oxidation. High LDL oxidation is associated with increased risk of atherosclerosis and coronary heart disease.
Lycopene Content in Tomatoes
Two glasses of tomato juice a day will provide some 40 mg of lycopene. Fresh, red tomatoes have between 3 and 8 mg of lycopene per 100 grams. Peeled, processed tomatoes have 11 mg, and tomato paste, 30 mg. Tomato sauces have a variable level of lycopene up to 32 mg per 100 grams (Food Technology, 53(2): 38-45, 1999).
Lycopene is non-toxic and is generally well tolerated. Excessive and prolonged carotenoid intake may result in the skin taking on a yellowish colour. This rapidly settles with reduction of intake.
Lycopene should be avoided in individuals with a known allergy/hypersensitivity to lycopene or tomatoes.
There are other phytochemicals in tomatoes, and researchers have shown that these help boost the effectiveness of the lycopene. Thus it is unlikely you will obtain the same health benefits from lycopene supplements.
Lycopene is a proven antioxidant. Antioxidants neutralise free radicals, which may damage the body’s cells. Regular high consumption of fruit and vegetables is recommended as part of healthy eating. Epidemiological studies have shown that high intake of lycopene-containing foods is inversely associated with the incidence of certain cancers, including prostate, colorectal, lung, bladder, cervix and skin. Lycopene is also protective against eye diseases (macular degeneration and cataracts) and other degenerative diseases arising from free radical damage.
Include tomatoes, in some form, routinely in your diet.
*Copyright 2009: The Huntly Centre.
Disclaimer: All material in the Huntlycentre.com.au website is provided for informational or educational purposes only. Consult a health professional regarding the applicability of any opinions or recommendations expressed herein, with respect to your symptoms or medical condition.
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