Turmeric
Turmeric is used both as a spice and as a colorant in food preparations. There is also a major constituent of curry (curry), a special mixture of spices used in Indian cooking. Yet few studies have evaluated the effects of consumption of turmeric. Moreover, most of them have used turmeric (or its active ingredients) in quantities exceeding what could be commonly used, then falling more than supplement the usual spice
Active and properties
Antioxidants
Antioxidants are compounds that protect body cells from damage caused by free radicals. These are highly reactive molecules that are involved in the development of cardiovascular disease, certain cancers and other diseases related vieillissement1. In one study, turmeric is the fifth largest in its content of antioxidants among over 1 000 food analysés2 (calculated from 100g diet). As usual a portion of turmeric is closer to 2 g (5 ml), it still contributes less than other foods to our daily intake of antioxidants. Turmeric contains flavonoids and compounds phenoliques, but curcumin is considered the main antioxidant compound.
Curcumin
Curcumin is a compound of the family curcuminoides. It presents various properties which have mainly been demonstrated by studies in vitro and in the animal. Among others, the antioxidant effect of curcumin suggests a protective effect against diseases associated with oxidative stress (such as cardiovascular disease and Alzheimer’s disease). Curcumin also has anti-inflammatory properties and may help prevent cancer at various stages of développement. These beneficial effects have not all been studied in humans and quantities of turmeric necessary to observe them are not always specified.
Cancer
Turmeric occupies an important place in the diet of people in India, which consume up to 2 g per day. Although no study demonstrated directly, there seems to be a link between consumption of turmeric particularly high and low incidence of certain cancers (eg colorectal cancer) in India and other countries asiatiques6. Among smokers, a clinical trial showed that daily consumption of 1.5 g of turmeric for 30 days decreased the carcinogenic compounds present in the organisme. Other preliminary studies show a potential anticancer activity of curcumin when consumed in quantities often exceeding what could be consumed daily as curcuma. Several studies in animals and in vitro support this protective effect of curcumin, particularly against gastro-intestinal and colorectal, 10. Although the mechanisms of action remain to be élucidés is by its antioxidant and anti-inflammatory curcumin may exert its effects anticancer. Some authors assume that the consumption of 1 v. Tea (5 ml) turmeric per day could provide the necessary amount of curcumin to exert a preventive effect against the cancer.
Gastro-intestinal
Turmeric is traditionally used to treat various gastrointestinal disorders such as inflammation and ulcers in the stomach. In this sense, it has been demonstrated that a turmeric extract inhibits gastric acid secretion in animals and may decrease the formation of ulceres. Curcumin does not appear to be responsible for these effects, further studies should be made to find out what active ingredients contribute to these effets. Moreover, daily consumption of 3 g of turmeric for 12 weeks resulted in complete regression of stomach ulcers in 75% of sujets. By cons, this study did not use a control group (placebo) and other studies in animals have shown effects opposes. Thus, better controlled clinical studies must be performed before encouraging the use of turmeric to treat stomach ulcers.
Cardiovascular system
Some studies have demonstrated the effectiveness of turmeric extract in preventing oxidation of LDL cholesterol ( “bad” cholesterol) and to decrease total cholesterol in the animal. It is increasingly clear that curcumin and its metabolites (obtained during the conversion of curcumin in other compounds in the body) would be partly responsible for these effets. These results suggest that turmeric might prevent the development of atherosclerosis and other risk factors for cardiovascular disease, but more human studies are requises.
Alzheimer’s disease
Epidemiological studies have shown that the prevalence of Alzheimer’s disease was lower in some populations of India compared to other countries. One reason given for this observation was the higher consumption of turmeric in India, but this explanation is still not supported by scientific data. It has been demonstrated in animals that consumption of curcumin improved the cognitive deficits associated with Alzheimer’s disease, by mechanisms still poorly connus. Probably the different properties of curcumin (such as antioxidant properties, anti-inflammatory and cholesterol-lowering) could be associated with this effet. A study is underway in patients suffering from Alzheimer’s disease to assess the effectiveness of curcumin in slowing this maladie.
Other effects
Turmeric is traditionally used to protect the liver against various agressions. Some studies have demonstrated a hepatoprotective effect of turmeric in vitro and in animals, but no data in humans is available actuellement. In addition, extracts of turmeric have demonstrated antimicrobial properties against a variety of bacteria, parasites and fungal pathogens in vitro and in animal.