The effect of flaxseed on physical and mental fatigue in children and adolescents with overweight/obesity.

Anti-inflammatory agents such as long-chain ω-3 fatty acids have been recognized to improve disease-related fatigue. We hypothesized that α-linolenic acid may also benefit in reduction of fatigue in low-grade inflammation such as overweight/obesity. Seventy two healthy children and adolescents with body mass index (BMI) >25 kg/m2 were randomized to flaxseed (n=38) and puffed wheat (n=34) groups. Participants consumed isocaloric amounts of either 20 g/day flaxseed or 25 g/day puffed wheat for 4 weeks. Fatigue, mood feelings (depression, anxiety, and stress), appetite, energy intake, weight, height, and waist circumference were measured. Analysis was performed based on per-protocol (PP) and intention-to-treat (ITT) approaches. Consumption of flaxseed decreased mental fatigue and caused a significant between-group difference (P<0.001). Although no significant change in physical and total score of fatigue was observed in either group, a significant between-group difference occurred due to a more remarkable change in these parameters in flaxseed group. General fatigue, motivation, activity, and mood feelings did not change significantly between groups. Flaxseed showed less benefit than puffed wheat on anthropometric measures as it caused smaller increase in height (0.53±0.89 vs. 1.09±0.87, P=0.03) and reduction in BMI (-0.25±0.63 vs. -0.67±0.56, P=0.01) than puffed wheat. Appetite and waist circumference decreased in both groups but no significant difference was observed between groups. In ITT analysis, only alteration in mental fatigue was significant. In conclusion, consumption of flaxseed may improve mental fatigue in children with overweight/obesity. However, because of smaller increase in height it is better to hinder administration of flaxseed in growth ages.