A pilot dose–response study of the acute effects of haskap berry extract (Lonicera caerulea L.) on cognition, mood, and blood pressure in older adults

Haskap (Lonicera caerulea L. or blue honeysuckle) is a plant native to the low-lying wet areas and mountains of Siberia and northeastern Asia, but is now cultivated in Canada. The dark blue berries are rich in anthocyanins, particularly cyanidin-3-O-glucoside. Previously, anthocyanin-rich fruits have been observed to benefit cognitive performance during the immediate postprandial period following a single acute dose. However, no study has currently examined the potential for haskap berries to influence cognitive performance. Here, we investigate the acute cognitive benefits of an anthocyanin-rich haskap berry extract. A double-blind, counterbalanced, crossover intervention study compared the acute effects of three separate haskap berry extract doses, containing 100 mg, 200 mg, and 400 mg anthocyanins, with a sugar-matched placebo. Participants were an opportunity sample of 20 older adults, aged 62–81 years. Measures of cognition, mood, and blood pressure were recorded at baseline and 1.5 h postprandially. Compared to placebo, the 400 mg dose elicited significantly lower diastolic blood pressure and heart rate. Both 200 mg and 400 mg doses elicited significantly higher word recall, with the 400 mg dose also significantly improving word recognition scores, on an episodic memory task. However, mood, working memory and executive function task results were more equivocal. The findings provide evidence for improvements in episodic memory and blood pressure following acute supplementation with haskap berry extract, with higher doses appearing most effective. The cognitive findings concur with previous literature that suggests episodic memory effects, and not executive function effects, are most prevalent in older adults following anthocyanin-rich berry supplementation. The blood pressure outcome is consistent with a vasodilatory mechanism of action.