Annual Report: CIRAD 2006

Polyphenols have been the object of growing interest over the past decade or so, on the part of nutritionists, epidemiologists, agrifood firms and consumers. They have much better antioxidant properties than vitamins, and could play a role in preventing numerous degenerative diseases such as cancer and cardiovascular disease. However, there had never been an overall study of total polyphenol intake in the daily fruit and vegetable diet in France. A vast project was thus launched in order to compile a polyphenol database and composition table.

Health benefits that are difficult to estimate

Researchers have only recently shown an interest in the health benefits of polyphenols. One of the major obstacles to studies is their significant structural diversity. Several thousand molecules have been identified in higher plants. Several hundred are found in the edible parts, which mostly contain one or more generally several phenolic molecules.

Moreover, the data currently available on food polyphenol composition are both sketchy and scattered. It was thus impossible for the researchers to estimate daily polyphenol consumption in France from dietary surveys.

The assumption that polyphenol consumption could reduce the risk of chronic disease has been looked at in several prospective studies, albeit only concerning consumption of certain types of flavonoids. While several studies have observed a beneficial effect on cardiovascular disease and cancer, others have failed to see any impact. However, it may be that the flavonols and flavones studied did not fully reflect the whole range of flavonoids consumed, much less the whole range of polyphenols. There were thus not enough data to draw any conclusions, hence the need for a composition table containing data on the total intake of polyphenols in the daily fruit and vegetable diet.

A better understanding of consumption

In all, 162 vegetable, 71 fruit and 85 tea samples were analysed for total polyphenol content. The results were added to a database that was subsequently used to establish a composition table for fresh foodstuffs, with a value for each product.

One of the first studies conducted using the table concerned daily polyphenol consumption in France, which was estimated based on existing data from the Secodip database on fruit and vegetable purchases by a panel of 2 000 households, and the Suvimax database on actual fruit and vegetable consumption in the country. The analysis revealed that the main fruit sources of polyphenols in the French diet are apples, strawberries and grapes, while the main vegetable sources are potatoes, lettuce and onions. Total polyphenol consumption from fruit is two to three times higher than from vegetables, while apples and potatoes combined account for almost half the polyphenols consumed in France.

Contact

Pierre Brat, e-mail , UMR: Integrated Food Quality System (QUALISUD)

Partners

• Agence française de sécurité sanitaire des aliments (AFSSA, France),
• Agence pour la recherche et l’information en fruits et légumes frais (APRIFEL, France),
• Centre technique de conservation des produits agricoles (CTCPA, France),
• Centre technique interprofessionnel des fruits et légumes (CTIFL, France),
• Conservatoire national des arts et métiers (CNAM, France),
• Institut national de la recherche agronomique (INRA, France),
• Institut national de la santé et de la recherche médicale (INSERM, France),
• Unilever-Bestfoods (France),
• Vilmorin-Clause (France).

For further information

• Brat P., George S., Bellamy A., Du Chaffaut L., Mennen L., Scalbert A., Amiot M.J., 2005. Polyphenol fruits and vegetables database: determination of the French polyphenol intake. In : Fruit, vegetable and health congress, Québec.
• Brat P., George S., Bellamy A., Du Chaffaut L., Scalbert A., Mennen L., Arnault N., Amiot M.J., 2006. Daily polyphenol intake in France from fruits and vegetables. Journal of Nutrition, 136 : 2368-2373.
• George S., Brat P., Alter P., Amiot M.J., 2005. Rapid determination of polyphenols and vitamin C in plant-derived products. Journal of Agricultural and Food Chemistry, 53 : 1370-1373.