More fruit could mean less asthma in adults

People with an antioxidant-rich diet could reduce their risk of developing asthma in adulthood, say Cambridge researchers - adding to a growing body of science on the subject.

“We have found symptomatic asthma in adults to be associated with a low intake of the dietary antioxidants vitamin C and manganese. The low intake of vitamin C appears to primarily associated with a diet deficient in fruit,” wrote corresponding auther Dr. Nick Wareham.

This study appears to support a growing body of science that has linked antioxidant intake, particularly vitamins C and E, to the incidence of asthma, a condition on the rise in the Western world and the most common long-term condition in the UK today. According to the charity Asthma UK, affecting over four million adults and over a million children.

The new study, published in the journal Thorax (Vol. 61, pp. 388-393), used a nested case-control design to investigate a potential relationship between fruit and vegetable intake, and corresponding antioxidant intake, and the incidence of both diagnosed and symptomatic asthma for 515 cases and 515 controls with average age 32.

Dr. Wareham and his colleagues found that dietary intake of vitamin C and manganese were inversely and independently linked to symptomatic asthma, with a 12 per cent reduction in incidence with increasing vitamin C intake, and a 15 per cent reduction in incidence with increasing manganese intake. The researchers divided intakes into five groups (quintiles) ranging from low to high intake, but no quantification of each cut-off point is made.

For diagnosed asthma, only manganese has an effect on the incidence of the condition. Increasing intake of manganese, as a per quintile measure, was associated with a 14 per cent reduction in the risk of diagnosed asthma.

When the researchers looked at the incidence and associated risks of both symptomatic and diagnosed asthma in terms of fruit and vegetable consumption, and particular types of each, it was reported that moderate consumption (between 0.7 and 46.2 grams per day) of citrus fruits decreased the risk of asthma by 12 per cent. High consumption (46.3 grams per day or more) decreased the risk by 41 per cent.

Apples consumption also reported a significant effect on the risk of asthma, both symptomatic and diagnosed, with high consumption (48.1 grams per day or more) associated with a 32 per cent reduction in risk.

There are several limitations however, as there are with all observational studies. The most notable being that cases may have altered their diets because of their asthma, although possible errors from this are reduced by the fact that only 22 cases reported such a change. There also exists the possibility that other, unaccountable confounders, may have affected the results.

Courtesy of nutraingredienets.com