Cutting edge

May 7, 1999

Consumers are eager to learn about what makes a healthy diet. They could take a look at flavanols' effect on free radicals

Public concern about food quality and safety is at an all-time high. Evidence shows that the overall food provision in Britain is not ideally suited to long-term health. Other countries - Finland, Norway and the Netherlands - have managed to generate changes over many years (reduced fat and saturated fat, reduced salt, more fruits, more vegetables, more fish) that have improved health. Cancer and heart disease, to which bad diet contributes about 30 per cent, was halved in Finland in 20 years.

Scotland has some of the worst health statistics in the world, but paradoxically Scottish food is internationally renowned for its quality. Beef, lamb, salmon, sea fish - Scotland produces the best. In potatoes, green vegetables and soft fruits, Scotland leads the world. What has gone wrong is that these quality foods are mainly exported and most food eaten (particularly by the more deprived) is processed to add in the fats, salt and sugar that contribute to ill health.

The problem of what gets into manufactured foods can only be solved by cooperation with the food industry (growers, processors, retailers, caterers). A Scottish Diet Action Plan, published in 1996, proposes this, with support from all political parties and branches of the food industry.

But consumers also need to eat more fruit and vegetables. The minimum target of five portions a day is twice the average. To achieve this target requires health education, but also production and provision changes.

Food retailers and growers want to know what characteristics fruits and vegetables should have. Taste, shelf life and yield are well-established factors for growing but even conventional plant breeding can select strains with higher nutrient contents.

The reason for wanting to eat at least five-a-day of fruit and vegetables has to do with the antioxidants. Most damage in the body, leading ultimately to heart disease, strokes, cancer, or Alzheimers', is the result of free radicals, highly reactive molecules that damage cells. The body produces antioxidants to combat free radicals - as do plants.

Until recently, vitamins A, C, and E were considered the main antioxidants, but research in Glasgow and elsewhere shows that plant foods contain more powerful antioxidants in a family of compounds called polyphenolics - which include flavonols.

The content of flavonols varies between common foods that look and taste the same. Red lollo-rosso lettuce, for example, has 100 times as much as a green lettuce.

The same variation is true for many others - onions, tomatoes, tea, red wines. Flavonol content can change after harvesting, so it may be that deep frozen foods (picked in their prime) are better than "fresh" foods.

These topics are all under research by Glasgow University's plant products and human nutrition research group, in collaboration with teams at Dundee, Aberdeen, London and laboratories in Sweden, Finland and Japan. Research is funded by the Ministry of Agriculture, Food and Fisheries, the Scottish Office's chief scientist office, fruit growers and retailers (Safeway). Long-term safety in food policy and industry is the aim.

The public need guidance. A recent BBC Radio Scotland programme on foods and antioxidants generated more than 400 letters. The previous record for requests on other lifestyle topics was 11.

Mike Lean, department of human nutrition, and Alan Crozier, division of biochemistry and molecular biology, University of Glasgow.

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