As you guiltily tuck into a cream-laden, calorie-rich chicken korma, it may seem hard to imagine that wolfing down a curry should have any health benefits. But that would be to miss a nutritional trick. The spices used in traditional Asian dishes are increasingly attracting attention for their potential healing properties, not least because of the slug of salicylic acid that they deliver.

Salicylic acid, as well as being found in spices, is also a breakdown product of aspi- rin, commonly prescribed by doctors for its anti-inflamma- tory effects; and there is now a growing body of evidence suggesting that aspirin may also help to prevent cancer, especially of the colon.

Given the particularly low rates of colon cancer in rural India, it is tempting to speculate that this may in part be due to the regular, high consumption of spices, and thus, salicylic acid, in this area of the world.

Experimental work certainly looks encouraging. Professor Garry Duthie, of the Rowett Research Institute in Aberdeen, explains: “Our question was: because regular intakes of aspirin seem to protect against colon cancer, could you get this effect through regular intakes of salicylic-rich foods? The first hurdle to cross was to find out whether this plant compound is bioavailable; in other words, do we absorb it from spices once eaten?”

Researchers at Dumfries and Galloway Royal Infirmary suggest that we may well do. Having calculated that a portion of vindaloo curry weighing 545g (1.2lb) supp- lied a total of 94mg of salicylic acid — similar, they say, to a low dose of aspirin — they then fed the curry to an individual who had fasted for ten hours. Levels of salicylic acid in his blood were found to increase significantly two hours after eating, with around 3 per cent of the salicylic acid appearing to be absorbed.

“You certainly get much less salicylic acid from foods than you get from taking an aspirin,” says Duthie. “But in food it seems the salicylic acid makes changes to key enzymes that are linked with cancer.

“There are no intervention studies yet, but from the experimental work that we have to date, there is reason to think that regularly eating salicylic acid-rich foods may reduce the risk of colon cancer, although this effect could in part also be down to capsaicin, the hot substance that gives chillies their bite.”

Experimental work, says Duthie, shows that capsaicin appears to cause apoptosis, a fancy word for cell death. If cancerous cells are not hanging around for too long then, the theory goes, there is less chance of them becoming cancerous. “Obviously spices are not a magic bullet, but they may contribute to protecting against colon cancer.”

Chillies may also play another role in our diets, whether in a curry or simply served with meals in a chilli sauce, as Jeya Henry, professor of nutrition at Oxford Brookes University, discovered. “We found that adding 20g of either chilli or mustard sauce to a meal raises your metabolism by up to 20 per cent for two hours after eating. What this means is that over time, if all other parameters such as calorie intake and exercise levels remained constant, you would burn more fat by eating such sauces with meals than if you did not.

“I’m not saying chilli and mustard are a panacea for weight loss, but over time small things like this have an accumulative effect. The metabolism-boosting effects have been identified as being the capsaicin in chillies and the isothiocynates in mustard, which dilate blood vessels and increase levels of the fat-burning hormone ephedrine.”

Research continues to come up with scientific rationale for the roles spices can play in health, such as the work from the Beltsville Human Nutrition Research Centre in Maryland, which recently found that incorporating as little as half a teaspoon of powdered cinnamon a day in the diet helped to control blood sugar in those with type 2 diabetes.

But it is important to remember that we also have at our fingertips a wealth of traditional medicinal and health-promoting roles for spices.

Ginger, for instance, as Ann Walker, medical herbalist and doctor of nutrition at the University of Reading, explains, has long been known for its stomach-settling properties among doctors from Ancient India and China to Greece and Rome.

“Ginger works primarily in the digestive tract, boosting digestive fluids and neutralising acids, so it is sometimes used as an alternative to anti-nausea drugs,” says Walker. It seems that the extra acid absorbs toxins caused by motion sickness, thus blocking the signals of nausea they would otherwise send to the brain.

Meanwhile, cloves have a slightly numbing effect (put it down to their volatile oils), which explains why tincture of cloves rubbed directly on to gums has long been promoted as a way of relieving toothache.

As far back as the 7th century, Chinese doctors used nutmeg to regulate and warm the stomach and fennel seeds to improve “reproductive disharmonies”.

Spices, it seems, are one area in which hard science rubs with traditional usage — in all but one area.

As Duthie points out: “I’ve had a lot of interest from people thinking that the aspirin-like effect of spices make curries an ideal hangover cure — I can tell you from experience, this is not the case.”

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