Plant Compounds Keep Disease Away: Study

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Plant Compounds Keep Disease Away: Study

Tue Sep 10, 1:29 PM ET

By Merritt McKinney

NEW YORK (Reuters Health) - An apple a day may indeed keep the doctor away,

new findings from Finland suggest.

In a study of more than 10,000 men and women, individuals who consumed more

of plant compounds called flavonoids--especially one type that is most

abundant in apples--were less likely to die from heart disease or develop a

variety of chronic diseases, including lung cancer, asthma, stroke and

diabetes.

" The message of our study is that individuals consuming fruits and

vegetables rich in different flavonoids have a reduced risk of overall

mortality and of several chronic diseases, " Dr. Knekt of the National

Public Health Institute in Helsinki told Reuters Health.

Compared to other fruits and vegetables, apples " showed the strongest and

most consistent effects, " Knekt said. He added, " This study underlines the

suggestion that a healthy diet should include plenty of fruits and

vegetables, " including apples.

Flavonoids, which are found in a variety of fruits and vegetables as well as

in tea and red wine, are thought to boost health in part by combating

oxidation, a process in which cell-damaging substances called free radicals

accumulate. Oxidative damage can be caused by outside factors, such as

cigarette smoking, or by factors on the cellular level. Oxidation is

suspected of increasing the risk of heart disease, stroke and several other

diseases.

Some studies have shown that the risk of cardiovascular disease and cancer

decline as consumption of flavonoids rises, but other studies have failed to

show a protective effect of the plant compounds.

In the current study, participants filled out a questionnaire and completed

an interview to find out what they had eaten during the previous year. Based

on average flavonoid contents of foods available in Finland, the researchers

estimated each person's flavonoid intake. Through national prescription and

disease registries, the researchers tracked the development of disease in

the participants for up to 28 years after the initial interview.

The results of the study suggest that the risk of several chronic

diseases--including heart disease, stroke, lung and prostate cancer ( news -

web sites), type 2 diabetes and asthma--drops as the consumption of

flavonoids rises, Knekt and his colleagues conclude in a report in the

American Journal of Clinical Nutrition ( news - web sites). Most of the

benefits seemed to stem from quercetin, a powerful antioxidant that is

plentiful in apples, although several other flavonoids seemed to be

protective as well.

For instance, greater consumption of apples, which are the main source of

quercetin in Finland, and onions, which contain a flavonoid called

kaempferol, were both linked to a reduced risk of dying from heart disease.

Likewise, the risk of stroke was 30% lower in people who ate the most

kaempferol than in those who ate the least. And in men, higher levels of

quercetin were linked to lower risks of lung cancer and prostate cancer.

Eating lots of foods rich in quercetin also seemed to provide some

protection against type 2 diabetes, although the risk reduction was small

enough that it could have resulted from chance.

Although the researchers suspect that the antioxidant properties of

flavonoids account for some of the benefits of the compounds, they call for

additional research in other groups of people who consume different

varieties of flavonoid-rich foods. They suggest that such studies, which

should take into account factors that might influence the connection between

flavonoids and good health--such as lifestyle--may help draw conclusions

about the antioxidant compounds.

SOURCE: American Journal of Clinical Nutrition 2002;76:560-568.