Winter 2000 Issue — The Colourful World of Nutraceuticals

Andrew Kenrick

Overseal Foods Ltd

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Introduction

Epidemiological studies have shown that diets rich in fruit and vegetables are associated with the low incidence of life threatening diseases such as athersclerosis and cancer. Phytochemicals such as carotenoids and flavonoids are increasingly viewed as the active components within such diets. Interestingly these compounds are also responsible for the vibrant colours in nature, which give credence to the old adage that to stay healthy you should "eat colour". The colouring of foods using phytochemical based formulations is well established in a wide array of applications. Functional foods created using these phytochemicals offer the advantage that many food chemistry hurdles have already been overcome. It is beyond the scope of this article to exhaustively review the scientific literature pertaining to these functional ingredients. What is presented is a brief description of the most exciting points of what is a fascinating and ever evolving field of scientific research.

Carotenoids

Carotenoids are naturally occurring red, orange and yellow pigments. Of the 600 isolated 50 can be converted into Vitamin A within the body. Vitamin A is required for correct visual function, cell growth, cell differentiation, reproduction and embryonic development. As antioxidants carotenoids protect from diseases that are propagated by the action of free radicals such as cancer; atherosclerosis, premature ageing, arthritis, cataract formation and other degenerative diseases. Many studies have correlated high dietary consumption of carotenoids to the low incidence of cancer. More specifically a cocktail of carotenoids given to non-smokers demonstrated a decrease in the incidence of cellular DNA damage, which is seen as a precursor to tumour growth. A study over 6 years on 333 people with signs of coronary disease showed that *-carotene supplements decreased the incidence of major coronary events by 50%. Dietary supplementation with *-carotene decreases the reddening of the skin and loss of skin immune function after exposure to sunlight. It has been proposed that sunscreens should be used in conjunction with carotenoids to protect from UVB (burning rays) and UVA (ageing rays). Lycopene from tomatoes was first highlighted as a protective agent against prostrate cancer following a review of 46 fruits and vegetables in the diets of 47,000 men. Only tomato products could be shown to have a protective effect. Lycopene has also been linked with specific protection of 9 other organs from cancer.

Xanthophylls

Xanthophylls e.g. lutein are oxygenated carotenoids that are found in green leafy vegetables such as spinach and also marigold flowers. In cultured cells lutein is more effective than *-carotene at protecting cells from free radical induced cell damage. In humans dietary lutein had been correlated to a greater expression of oestrogen receptors in breast cancer cells and consequently greater survival rates following hormone therapy Lutein stimulates immune response in mice by enhancing lymphocyte proliferation and also by activation of a gene responsible for lymphocyte activity. Age Related Macular Degeneration (AMD) is the leading cause of blindness in people over 65 with a detrimental impact on the quality of life of those effected. The presence of dark green leafy vegetables in the diet has been shown to lead to a 43% reduction in the incidence of AMD. Such vegetables are rich in lutein. AMD is disease of the yellow spot, a depression in the retina directly behind the lens that is rich in xanthophylls, hence its colour and name. Cataracts are another major chronic disease, which although treatable by surgery the increasing number of operations performed strains the healthcare system. The formation of cataracts results from a clouding of the lens caused by protein clumping. The consumption of dark green leafy vegetables rich in lutein decreases the incidence of cataracts by 40%. The mode of protection for both AMD and cataracts is believed to be due to antioxidant activity and the filtering of harmful wavelengths of light.

Anthocyanins

Anthocyanins are responsible for the red, pink, blue and violet pigments of many flowers, fruits and vegetables. A major source of anthocyanins is black grape skin but they are also prevalent in elderberries, bilberries, black carrot and red cabbage. The French have a low incidence of heart disease despite having lifestyle factors suggesting the opposite such as a diet high in saturated fat and a high incidence of smoking. The antioxidant activity of a group of compounds found in red wine known as flavonoids has been proposed as the protective factor. Anthocyanins are themselves a type of flavonoid. Historically flavonoids were known as Vitamin P but the vitamin status was removed as no deficiency syndrome could be demonstrated. Anthocyanins from bilberry are used pharmacologically to control capillary permeability and fragility. Anthocyanins are 10 times more effective than Aspirin at inhibiting the enzymes responsible for inflammation. Anthocyanins have also been isolated from traditional remedies such as Cranberries that have been used as medicinal plant in the prevention and relief of urinary tract infections. Flavonoids such as resveratol, quercitin, kaempferol and myricetin protect cells from the actions of carcinogens and consequent development of tumours. Grape phenolics especially caffeic acid, (-)-epicatechin and chiorogenic acid have anti-bacterial and anti-viral activity. However the anti-microbial activity of grape phenolics is considerably lower than traditional antibiotics.

Curcumin

Curcumin is the yellow pigment in turmeric, a spice that has long been used to treat wound and injuries in India. Curcumin is a potent antioxidant and therefore protects against oxidative damage to cellular components. Curcumin enhances hepatic detoxification by increasing the activity of phase I and phase II enzyme systems. Curcumin inhibits the procarcineogenic action of the oxygenated species produced by arachidonic acid metabolism in response to inflammation. In this role it acts as both an antioxidant and anti-inflammatory agent. In mice curcumin has been shown to prevent cancer of the skin, stomach, breast, liver, colon and duodenum by inhibiting the initiation, promotion and progression of the disease. Curcumin impedes the action of and reverses the damage caused by Aflatoxins, a class of naturally occurring toxin that primarily attack the liver. The chemical induction of cataracts is inhibited in rats fed a diet supplemented with curcumin. Curcumin protects as an antioxidant and also through the induction of a specific protective enzyme. Curcumin can kill bacteria responsible for food poisoning such as Escherichia coil and Salmonella typhimurium in the presence of light and oxygen. The formation of cholesterol gallstones in mice and hamsters is inhibited by curcumin and it also causes pre-existing gallstones to regress. It has been found that curcumin enhances the activities of digestive enzymes in the small intestines of rats which explains the traditional belief that spices aid digestion.

Chlorophyll

Chlorophyll is responsible for the ubiquitous green colour of plants. All planetary life is dependent on the actions of chlorophyll within the series of reactions collectively known as photosynthesis for the generation of bioavailable oxygen and carbon. Chlorophyll is a powerful antioxidant and as such protects cells from the attack of free radicals. Approximately 2% of oxygen in human lungs is converted to a potentially harmful reactive form. This process is referred to as the "respiratory burst". The "respiratory burst" of smokers is greater thar that of non-smokers due to the high content of free radicals within cigarette smoke. Chlorophyll lowers the "respiratory burst" of smokers more efficiently than either *- carotene or vitamin C. The mutagenic activity of hetrocyclic amines, potent carcinogens formed within the cooking process, is inhibited by chlorophyll. Chlorophyll protects animal and plant extracts from the mutagenic effects of diesel coal dust, tobacco and cigarette smoke. The inclusion of chlorophyll in a diet containing dioxins caused an 11 fold increase in the excretion of the dioxins over that in a control group that was not given chlorophyll. The wound healing properties of chlorophyll have long been recognised. Since World War I chlorophyll has been used to stimulate healing and minimise scar formation. Chlorophylls are also reported to reduce or eliminate body odour and bad breath.

Conclusion

The phytochemicals described are prevalent in diets rich in fruit and vegetables and are therefore associated with prolonged good health. Scientific evidence is emerging as their efficacy in isolation as opposed to within a food matrix. As established natural colorants these photochemicals represent exciting nutraceuticals with known characteristic when used as ingredients.

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