Source: Can J Psychiatry  |  Posted 9 years ago

Some smokers may not develop chronic obstructive pulmonary disease (COPD) as a result of their dietary intake of fruit and vegetables.

According to investigators at the Primary Medical Care Department, University of Southampton, Aldermoor Health Centre, England, fruit and vegetable consumption is inversely associated with the disease. They point out that most smokers do not develop COPD and it is unclear why some do.

While protection against lung tissue injury may be due to antioxidants found in food, there are inconsistencies in earlier epidemiological studies which did not focus on smokers, who are most at risk of COPD.

In this case-controlled study measurements were made of dietary intake differences between smokers and ex-smokers with and without the disease.

Subject cases were aged over 45 years with more than ten years of smoking who had a forced expiratory volume in one second (FEV[_]1[])/forced vital capacity (FVC) of less than or equal to 70 percent and a FEV[_]1[] of less than or equal to 80 percent of predicted.

Control patients were also aged over 45 years with more than ten years of smoking but with a FEV[_]1[]/FVC greater than 70 percent and a FEV[_]1[] greater than 80 percent predicted.

Validate questionnaires were used to collect data and logistic regression analysis was used for an unmatched case-controlled study.

When other independent factors of COPD were controlled for, subjects with vegetable intake of more than or equal to one portion a day (-1)(93g) were found to be less likely to have the disease. So, too, were subjects who consumed fruit at more than or equal to one and a half portions a day (-1).

There were three reasons why this was not because of an overall reduction in food/calories intake caused by COPD. First, the estimates were not altered by adjusting for body mass index; second the effect was specific to fruit and vegetables and not to other food groups; and third, similar estimates were seen from incident cases.