Cooked tomatoes
"The bright red colour of tomatoes is supplied by a photochemical called lycopene, which is in the same family of carotenoids [natural fat-soluble pigments] as the orange-coloured betacarotene in carrots," says nutrition consultant Lorraine Perretta (myvitality.com). Research shows that lycopene can be absorbed more efficiently by the body if processed into ketchup, juice, sauce and paste.
A proven antioxidant, lycopene appears to be different from other carotenoids because its concentration in body tissue tends to be higher. Lycopene is deposited in the liver, lungs, prostate gland, skin and colon. Research has suggested that frequent consumption of tomato products or lycopene may be associated with a lower risk of prostate cancer. A study of more than 47,000 men, conducted by Harvard Medical School, concluded that those who ate tomato sauce or other types of cooked tomatoes two or more times a week had a 20% less chance of developing prostate cancer.
Turmeric
Curcumin is a compound found in turmeric. The Alzheimer's Society reports that research from the University of California in Los Angeles has suggested the idea that curcumin might play a role in slowing the progression of this disease. Mice were injected with amyloid proteins to create conditions similar to those in patients suffering from dementia. They suggested this key ingredient of curry helped to clear amyloid from the brain and that its relative lack of side effects and combination of anti-inflammatory and antioxidant properties could be beneficial. "It's too soon to say curcumin, or drugs based on it, could be potential preventive treatments," says Clive Ballard, director of research for the Alzheimer's Society, "but if you like spicy Indian food, enjoy it."
Blueberries
"New research has declared red, purple and blue fruits - blackberries, blueberries, cranberries, black grapes included - to be the anti-ageing food of the 21st century," says Perretta. "The active ingredient is a plant chemical group called anthocyanidins, which are powerful antioxidants." Anthocyanidins have been found to prevent collagen from breaking down - the elastic protein in skin, joints and veins and arteries that carry nutrients to the brain. They are thought to be 50 times more powerful than vitamin E.
"They are robust nutrients and survive various food processes, so when fresh berries are not available, canned and frozen berries are nutritious alternatives," says Perretta.
Wheatgrass
Chlorophyll, the substance that makes green plants green, is seen as a useful blood tonic. "Foods such as wheatgrass, algae, seaweeds and green vegetables help to 'build' the blood," explains Patrick Holford in his book The Optimum Nutrition Bible (Piatkus). "Research has shown that components of chlorophyll found in foods, when taken in very small purified amounts, may stimulate the production of red blood cells in the bone marrow." Rich in enzymes, vitamins, minerals and trace elements, this highly nutritious substance also contains useful detoxification and cleansing properties.
Broccoli sprouts
"Glucosinolates are phytochemicals that were once thought to be toxic to humans and act as natural pesticides," says nutrition expert Judith Wills and author of The Food Bible (Quadrille). "They are found mainly in cruciferous and green vegetables - cabbage, brussels sprouts, kale and cauliflower - where the stronger the taste, the higher the potency of the chemicals. Broccoli is a particularly rich source of glucosinolates which breaks down into a substance called sulphoraphane that appears to have a strong anti-cancer effect by stimulating our natural defences."
Sulphoraphane is a compound that was recognised in broccoli spouts by researchers at the Johns Hopkins University School of Medicine in Baltimore and the French National Scientific Research Centre. They discovered it kills the bacterium Helicobacter pylori, the bug widely thought to be responsible for the majority of cases of stomach ulcers and stomach cancer.
Grapefruit
"Bioflavonoids act as potent antioxidants which can bind to toxic metals and escort them out of the body," says Holford. "They have a synergistic effect on vitamin C, stabilising it in human tissue. Furthermore, they have an antibiotic effect which accounts for their anti-infection properties and are also anti-carcinogenic." Bioflavonoids usually appear to be most powerful in fruit, probably because the sugars help the flavonoids to be absorbed. Taxifolin and rutin are two important flavonoids found in citrus fruit, including grapefruit. "Many years ago, bioflavonoids were classed as vitamin P and then more or less dismissed as of no significance," says Wills. "Now we know better."
Onions
"There is a subgroup of flavonoids called flavonols, one of which - the most researched, and probably the most abundant in foods - is quercetin," says Wills. Found not only in the skins of onions but also in apples, black tea and red wine, Wills says a high quercetin intake has been linked with a lower risk of coronary heart disease and may also help to prevent cataracts. This antioxidant also boosts antihistamine properties which may help to relieve allergic and asthma symptoms.
