High Dietary Fiber Can Reduce Cough With Phlegm A diet high in fiber from fruit and soy foods can reduce the incidence of chronic respiratory symptoms, especially cough with phlegm production, according to data from the Singapore Chinese Health Study. Writing in the first issue for August 2004 of the American Thoracic Society's peer-reviewed American Journal of Respiratory and Critical Care Medicine, Lesley M. Butler, Ph.D., of the Department of Epidemiology and Preventive Medicine, University of California at Davis, Davis, California, along with four associates, studied the details from 571 cases of incident cough with phlegm, along with research information collected from 44,068 men and women who did not suffer from the respiratory problem. "Our prospective data support the role of diet in the etiology of cough with phlegm production," said Dr. Butler. "In particular, nonstarch polysaccharides, a major component of dietary fiber, and certain noncitrus fruits, including apples and grapes, were independently associated with reduced development of cough with phlegm." The researchers administered a 165-item quantitative food frequency questionnaire that was developed for and validated by the men and women in the study. With ages ranging from 45 to 74, they were all either permanent residents or citizens of Singapore and formed part of two major Chinese dialect groups. Their survey follow-up, completed in August 2003, assessed their usual diet over the past year. It contained 16 items on individual fruits and juices, 24 questions on 34 specific vegetables, and 7 queries on soy food items. Members of the cohort who suffered from incident phlegm were more likely to be male, older, and members of one dialect group, compared with noncases. The cases, regardless of symptom duration, were more likely to be current smokers, to have started smoking before age 20, and to be heavier smokers. The investigators noted that fruit, vegetable, and grain products were the major contributors of nonstarch polysaccharides in this population. (Polysacharides are carbohydrates composed of more than one monosacharide, but usually not more than four.) "The incidence of cough with phlegm was reduced with high intake of fruit, but not vegetable or grain products," said Dr. Butler. "It is possible that fiber from fruit may have physiologic effects that are more beneficial in reducing development of cough with phlegm than fiber from vegetables or grain products." The researchers believe that other components in fruit, in addition to fiber, such as individual flavonoids, could also have been important in protecting against chronic cough. Among the many properties of the aromatic compounds called flavonoids are those that account for the yellow, red, and blue pigmentation in fruit, plus its antioxidant and anti-inflammatory properties. The investigators noted that they observed an association between high consumption of fruits high in flavonoids such as apples, grapes, and pears and lower levels of incident cough with phlegm. They said that their data provides evidence that promoting a diet high in fiber and flavonoids, such as fruit and soy, might make an important contribution to primary prevention strategies for chronic respiratory symptoms, both in smokers and nonsmokers. Aug. 2, 2004 American Thoracic Society Thanks to Intelihealth.com Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.