Dietary strawberry improves cognition in a randomized, double-blind, placebo-controlled trial using older adults

Authors: MILLER, MARSHALL - Former ARS Employee; THANGTHAENG, NOPPORN - Former ARS Employee; SCOTT, TAMMY - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; Rutledge, Grant; Shukitt-Hale, Barbara

Submitted to: British Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/6/2021
Publication Date: 6/9/2021
Citation: Miller, M.G., Thangthaeng, N., Scott, T.M., Rutledge, G.A., Shukitt Hale, B. 2021. Dietary strawberry improves cognition in a randomized, double-blind, placebo-controlled trial using older adults. British Journal of Nutrition. 126(20):253-263. https://doi.org/10.1017/S0007114521000222.
DOI: https://doi.org/10.1017/S0007114521000222

Interpretive Summary: Changes in the brain during aging can decrease memory and mobility, which leads to problems with thinking or to injurious falls among older adults. Dietary supplementation with strawberry has been associated with positive outcomes in rodent models of aging. In this study, older men and women consumed about 2 cups of fresh strawberries or a strawberry-flavored placebo for 3 months. Participants consuming strawberries showed some improvement in measures of learning/memory, relative to the placebo group. No improvements in measures of reasoning, or gait or balance, were observed. These findings show that the addition of easily achievable quantities of strawberry to the diets of older adults may improve some aspects of learning and memory, but more evidence is required in order to draw definitive conclusions.

Technical Abstract: Purpose: Functional changes in the brain during aging can alter learning and memory, gait, and balance - in some cases leading to early cognitive decline, disability, or injurious falls among older adults. Dietary interventions with strawberry have been associated with improvements in neuronal, psychomotor, and cognitive function in rodent models of aging. We hypothesized that dietary supplementation with strawberry would improve mobility and cognition among older adults. Methods: In this study, 22 men and 15 women, between the ages of 60 and 75 years, were recruited into a randomized, double-blind, placebo-controlled trial in which they consumed either freeze-dried strawberry (24g/d, equivalent to 2 cups of fresh strawberries) or a strawberry placebo for 90 days. Participants completed a battery of balance and gait measures, and six cognitive tests at baseline and again at 45 and 90 days of intervention. Results: Significant supplement group by study visit interactions were observed on two of three tests which assessed the cognitive domains of learning and memory. Specifically, participants in the strawberry group showed significantly shorter latencies in a virtual spatial navigation task (p = 0.020, 'p2 = 0.106, and increased word recognition in the California Verbal Learning test (p = 0.014, 'p2 = 0.159), across study visits, relative to controls. However, no improvement in three tests of executive function, another cognitive domains, or on measures of gait or balance, were observed. Conclusions: These findings show that the addition of easily achievable quantities of strawberry to the diets of older adults can improve some aspects of cognition, but not gait or balance.