AS YOU stir more turmeric into the vindaloo or grate ginger into the stir-fry, it's good to know these ingredients not only make food taste good but they also may be working inside your body to protect you from disease.
Spices and herbs make up one of the newer pieces in the complex jigsaw of nutrition science, says Professor Linda Tapsell, director of Wollongong University's Smart Foods Centre. But while scientists have a good grasp of how vitamins and minerals work and how much we need, they're only beginning to understand the role of the thousands of phytochemicals in plant foods.
"Some of these phytochemicals are thought to help prevent chronic diseases like heart disease, cancer and Alzheimer's by targeting two underlying problems these diseases have in common - one is oxidation that can damage cells or cause bad LDL cholesterol to oxidise and damage arteries, and the other is inflammation," Tapsell says.
What makes spices special, apart from their big flavours, is that they contain concentrated amounts of some of these chemicals, says Tapsell, whose review of research into the health effects of spices and herbs will appear in the journal Nutrition Today next month.
The spices currently attracting research interest include ginger for its anti-inflammatory properties, cinnamon for controlling blood sugar and, especially, turmeric, which contains curcumin, a phytochemical from a family of powerful antioxidants called phenolics. Animal and lab studies suggest curcumin may protect against cancers of the stomach, colon, prostate and skin, as well as Alzheimer's.
But one small study in humans by Johns Hopkins University in 2006 found that when doses of both curcumin and quercetin (a phenolic found in red onions) were given to five patients with inherited pre-cancerous polyps over six months, the number of polyps shrank by 60 per cent.
What's intriguing about curcumin is that we absorb it better when it's combined with piperine, a substance found in pepper - a combination cooks have used instinctively for thousands of years. Still, regular doses of turmeric are no guarantee against cancer, as Tapsell stresses. There is much to learn about the potential benefits of spices and herbs for human health, she says.
"It's one thing to get promising results in test tubes and with mice, but humans are more complex - because people are different not only in their genes but in how they live their lives, they can respond to these substances in different ways," she says.
She's cautious, too, about the weight loss benefits often attributed to eating chilli.
"Again, it's one part of the jigsaw puzzle - one of many things that can help weight loss, but in a small way. But you can't take one single element and pin your hopes of weight loss on it - at the end of the day it's the total diet and exercise that counts," she says.
But while we're a long way from knowing how much of the compounds in spices we need to protect our health, there's an argument for using them generously: it's an easy way to boost the variety of nutrients in your diet - and reduce the salt as well.
Sydney Morning Herald
Thursday May 15, 2008