Asthma and dietary intake: an overview of systematic reviews

Abstract

Epidemiological research on the relationship between diet and asthma has increased in the last decade. Several components found in foods have been proposed to have a series of antioxidant, anti-allergic and anti-inflammatory properties, which can have a protective effect against asthma risk. Several literature reviews and critical appraisals have been published to summarize the existing evidence in this field. In the context of this EAACI Lifestyle and asthma Task Force, we summarize the evidence from existing systematic reviews on dietary intake and asthma, using the PRISMA guidelines. We therefore report the quality of eligible systematic reviews and summarize the results of those with an AMSTAR score ≥32. The GRADE approach is used to assess the overall quality of the existing evidence. This overview is centred on systematic reviews of nutritional components provided in the diet only, as a way to establish what type of advice can be given in clinical practice and to the general population on dietary habits and asthma.

Diet and asthma: need to account for asthma type and level of prevention

“…To our knowledge, only one longitudinal study on dietary patterns and asthma has been published and reported a small positive association between adherence to a Western diet and incident wheezing in children [23]. Regarding diet during adulthood, the few longitudinal studies show, overall, no association [11].…”

“…Regarding diet during childhood, few longitudinal studies have been published. The association between diet and childhood asthma is moderate, at best, with observational studies reporting 'protective' associations for fruits and vegetables, and fish intake [11,22]. To our knowledge, only one longitudinal study on dietary patterns and asthma has been published and reported a small positive association between adherence to a Western diet and incident wheezing in children [23].…”

“…Overall, few studies have been performed on primary prevention of asthma with diet, and all of them have considered asthma as a binary (yes/no) outcome (wheezing in early childhood, childhood-onset asthma, or adult-onset asthma) [11].…”

“…Regarding maternal diet during pregnancy, a small number of cohort studies have highlighted associations between wheezing in the first years of life and reduced maternal intake of vitamins E and D, zinc, and omega-3 PUFAs during pregnancy [11,21]. The few longitudinal studies conducted on associations between maternal dietary patterns during pregnancy and wheeze/asthma in the offspring reported, overall, no association [21].…”

“…Over the last 20 years, the role of diet in asthma has gained interest in the international literature, and a substantial number of papers have been published on this topic [11]. Taken together, the literature is inconclusive, probably due to the complexity of both the exposure and outcome and, consequently, of their association.…”