## 3 Results
### Respiratory Tract Infections Incidence and Duration and Severity of Related Symptoms  
Table 2 shows the incidence of respiratory infections during the intervention period (14 weeks). The incidence of total respiratory infections and common colds was 9.4% and 25.0% lower in the extract group than in the control group, but the differences were not significant (\(p\) = 0.728 and \(p\) = 0.508, respectively), whereas the incidence of ILI was very similar in both groups (\(p\) = 0.978). However, the duration and severity of the respiratory infections seemed to be lower in the group that received the extract than in the control group. Common cold events mean duration were significantly lower in the extract group than in the control group (\(2.5\pm 1.0\) vs. \(4.8\pm 1.4\) days, \(p\) = 0.033), although we found no differences in ILI events (\(6.5\pm 3.1\) vs. \(5.7\pm 2.1\) days, \(p\) = 0.399) (Figure 2a). When common cold and ILI events were classified as mild or high severity according to the number of simultaneous symptoms, we observed that subjects in the extract group presented a significantly lower probability of having a high severity ILI event [OR (95% CI) 0.227 (0.054-0.961), \(p\) = 0.039], although this was not significant in common cold events [OR (95% CI) 0.714 (0.086-5.959), \(p\) = 0.755] (Figure 2b). \begin{table}
\begin{tabular}{l c c c} \hline \hline  & **Control Group (n = 30)** & **Extract Group (n = 30)** & \(p\) **between Groups** \\ \hline Age (years) & \(82.7\pm 9.2\) & \(85.9\pm 7.8\) & 0.155 \\ Sex & & & 0.739 \\ Men & 5 (16.7\%) & 6 (20\%) & \\ Women & 25 (83.3\%) & 24 (60\%) & \\ Weight (kg) & \(68.1\pm 13.9\) & \(63.6\pm 10.9\) & 0.176 \\ BMI (kg/m\({}^{2}\)) & \(26.1\pm 4.6\) & \(25.4\pm 3.8\) & 0.478 \\ Smoking habit & & & 0.109 \\ Current smoker & 4 (13.3\%) & 2 (6.7\%) & \\ Former smoker & 1 (3.3\%) & 6 (20\%) & \\ No smokers & 25 (83.3\%) & 22 (73.3\%) & \\ Physical activity & & & 0.519 \\ Very low & 23 (76.7\%) & 25 (83.3\%) & \\ Low & 7 (23.3\%) & 5 (16.7\%) & \\ Systolic BP (mm Hg) & \(126.2\pm 14.7\) & \(130.3\pm 10.4\) & 0.218 \\ Diastolic BP (mm Hg) & \(70.7\pm 10.2\) & \(71.8\pm 9.4\) & 0.667 \\ Sleeping medication & \(10\) (33.3\%) & 8 (26.7\%) & 0.389 \\ Hypertension medication & \(19\) (63.3\%) & 18 (60.0\%) & 0.518 \\ \hline \multicolumn{3}{l}{Values are mean \(\pm\) SD for continuous variables and n (\%) for categorical variables. \(p\) indicates differences between groups.} \\ \end{tabular}
\end{table} 
Table 1: Baseline characteristics of the subjects participating in the study. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **Control Group** & **Extract Group** & & & \\  & **IR (SD)** & **IR (SD)** & **IR Ratio (95\% CI)** & **IR Decrease, \%** & **\(p\) Value** 1  \\ \hline Common cold & 0.321 (0.188) & 0.240 (0.135) & 0.750 (0.320–1.759) & 25.0 & 0.508 \\ ILI a  & 0.494 (0.188) & 0.523 (0.174) & 1.059 (0.514–2.182) & \(-\)0.06 & 0.978 \\ Respiratory infections b  & 0.921 (0.273) & 0.834 (0.224) & 0.906 (0.523–1.570) & 9.4 & 0.725 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Incidence of respiratory tract infections. Finally, the incidence of sore throat was significantly lower in the extract group, presenting the volunteers that consumed the extract an incidence ratio decreased by 69.8% compared to the control group., (\(p\) = 0.043, Table 3). With respect to other symptoms related to respiratory infections,  
Figure 2: Duration and severity of respiratory tract infections. (**a**) Duration in days of common cold and influenza-like illness (ILI) events according to intervention groups. Values are represented as mean \(\pm\) standard error of mean (SEM) (light grey bars for control group and dark grey bars for extract group). \(p\)-value indicates differences between groups for the duration of common cold or ILI events (univariate model adjusted by sex, age and smoking habits).