# Diet and Asthma: A Narrative Review
## 4 Diet and Asthma
### Nuts  
Nuts are a rich source of nutrients, healthy fats, and fiber, and have been widely studied for their potential health benefits [70]. While the consumption of nuts has been associated with a lower risk of chronic disease [70], some studies suggest that nut consumption may be linked to the exacerbation of asthma symptoms, as nuts are common food allergens that may induce an allergic response in the respiratory system [71]. Nonetheless, in a cross-sectional study, a high dietary intake of nuts appeared to exert a protective role on the prevalence of wheeze in children (OR = 0.46; 95% CI 0.20; 0.98) [72]. Peanuts, another common source of food allergens, even though being a legume, from a nutritional perspective, their contents are similar to tree nuts. [PERSON] et al., in a randomized trial, \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Fiber** & & & \\ \hline
**Author, Year,** & **Sample, Age** & **Dietary Assessment/Intervention** & **Results** \\ \hline
**[PERSON] et al., 2017,** & \begin{tabular}{c} Twenty-nine subjects with \\ stable asthma, \\ mean age: \\ \end{tabular} & \begin{tabular}{c} Effect of a single meal rich in \\ soluble fiber (175 g yogurt with \\ 3.5 g inulin and probiotics) \\ compared with a simple \\ carbohydrate meal (200 g of \\ 4.0 \(\pm\) 4.6 y. \\ \end{tabular} & \
\begin{tabular}{c} Effect of a single meal rich in \\ soluble fiber (175 g yogurt with \\ 3.5 g inulin and probiotics) \\ compared with a simple \\ carbohydrate meal (200 g of \\ 4.0 \(\pm\) 4.6 y. \\ \end{tabular} &
\begin{tabular}{c} Whole grain \\ products intake: \\ (+) asthma prevalence. \\ \end{tabular} \\ \hline
**[PERSON] et al., 2006,** & \begin{tabular}{c} A total of 598 children, with \\ 39 asthmatics, \\ mean age: 10.4 \(\pm\) 1.2 y. \\ \end{tabular} & \
\begin{tabular}{c} Dietary intake was estimated using \\ a semi-quantitative FFQ. \\ \end{tabular} &
\begin{tabular}{c} Whole grain \\ products intake: \\ (+) asthma prevalence. \\ \end{tabular} \\ \hline
**[PERSON] et al., 2013,** & \begin{tabular}{c} In total, 202 participants, with \\ 137 stable asthmatics. \\ Mean age: \\ healthy controls: 46.7 \(\pm\) 17.4 y; \\ intermittent, mild, and moderate \\ persistent asthma: 54.5 \(\pm\) 15.5 y; \\ severe persistent asthma: 57.8 \(\pm\) 14.4 y. \\ \end{tabular} & \
\begin{tabular}{c} Dietary intake was estimated \\ through a 186-item \\ semi-quantitative FFQ. \\ \end{tabular} &
\begin{tabular}{c} Less fiber intake: \\ (-) forced volume in \\ 1 s (FEV1); \\ (-) airway eosinophil. \\ \end{tabular} \\ \hline
**[PERSON] et al., 2015,** & \begin{tabular}{c} A total of 678 children, with \\ 351 asthmatics. \\ Mean age: \\ controls: 10.5 \(\pm\) 2.7 y. \\ asthma: 10.0 \(\pm\) 2.6 y. \\ \end{tabular} & \
\begin{tabular}{c} Dietary intake was assessed \\ through a 75-item questionnaire \\ regarding the child’s food \\ consumption, including \\ sublograins in the prior week. \\ \end{tabular} &
\begin{tabular}{c} High consumption \\ of wholegrains: \\ (+) asthma prevalence. \\ \end{tabular} \\ \hline \hline \end{tabular}  
Notes: Age is described as mean age \(\pm\) standard deviation (SD) in years, unless stated otherwise. N/R, Not reported; FFQ, food frequency questionnaire; GPR, G protein-coupled receptor; and FEV1, forced expiratory volume in 1 s. (+) stands for significant and positive effects on asthma outcomes; (=) stands for no significant effects on asthma outcomes; and (–) stands for negative effects on asthma-related outcomes.  
\end{table} 
Table 2: Studies evaluating effects of fiber intake on asthma and asthma-related outcomes. found no significant differences in risk of asthma events at 5 years of age between infants who were randomly ascribed either to consume peanuts, or to avoid peanut intake from 4 to 60 months old (_p_-value = 0.230) [73]. Additionally, there were no significant differences found in the severity of asthma events (_p_-value = 0.839) [73]. Accordingly, [PERSON] et al.