Eating Fruit High in Vitamin C May Help Children With Asthma
April 20, 2000 -- Children who eat fruit high in vitamin C may experience less wheezing and asthma, say the authors of a large study published in the medical journal Thorax. But other experts say parents might not want to go running to the fruit stand just yet.
Earlier studies have suggested that eating fresh fruit containing vitamin C is associated with improved lung function in both adults and children. Researchers believe that properties of vitamin C protect against inflammation in the lungs of people with asthma. But the theories about vitamin C's effect on asthma remain controversial, and many of these studies have been done only on adults.
To determine if vitamin C-rich fruit affects asthma symptoms in children, Italian researchers studied more than 18,000 children, 6 to 7 years old, in northern and central Italy. The researchers were led by Francesco Forastiere of the department of epidemiology, Regional Health Authority, Lazio, Rome.
The parents of these children were asked to complete questionnaires about their lifestyles, living conditions, and dietary habits, as well as the children's susceptibility to asthma and wheezing. The children were ranked by how frequently they ate citrus (oranges, tangerines, grapefruit) and kiwi fruit: less than once a week, 1-2 times per week, 3-4 times per week, or 5-7 times per week.
After accounting for factors such as household crowding, the parents' smoking habits, and dampness or mold in the child's bedroom, the researchers found that eating citrus or kiwi fruit was "a highly significant protective factor for wheeze."
In an one-year follow-up study of more than 4,000 of the children, researchers still found that eating fruit was associated with a lower occurrence of most asthma symptoms. They found this protective effect against wheezing even in children who ate fresh fruit only one or two times a week.
"This study is catchy but I think we need to look more closely at these data," pediatric allergist Michael Ruff, MD, tells WebMD. He questions the fact that it was a study based on questionnaires, and therefore the results are based on parents' observations. He also says that with so many factors affecting asthma symptoms, such as parental smoking, colds, and allergies to pets, "it is difficult to determine the contribution of just one." Ruff is an associate clinical professor in the allergy division at the University of Texas Southwestern Medical Center in Dallas.