Effect of Milk and Other Dairy Products on the Risk of Frailty, Sarcopenia, and Cognitive Performance Decline in the Elderly: A Systematic Review

Nutrition is a modifiable factor potentially related to aging. Milk and other dairy products may contribute to the prevention of physical and cognitive impairment. We conducted a systematic review to investigate the effectiveness of dairy product intake for preventing cognitive decline, sarcopenia, and frailty in the elderly population. A systematic search for publications in electronic databases [MEDLINE via PubMed, Embase, Scopus, the Cochrane Central Register of Controlled Trials (CENTRAL), and the Cochrane Database of Systematic Reviews] from 2009 to 2018 identified observational and interventional studies in English and Spanish that tested the relation between dairy product consumption and cognitive decline, sarcopenia, and frailty in community-dwelling older people. We assessed the participants, the type of exposure or intervention, the outcomes, and the quality of evidence. We screened a total of 661 records and included 6 studies (5 observational prospective cohort studies and 1 randomized controlled trial). Regarding cognitive impairment, the relation cannot be firmly established. Consumption of milk at midlife may be negatively associated with verbal memory performance. In older women, high intakes of dairy desserts and ice cream were associated with cognitive decline. On the other hand, 1 study demonstrated a significant inverse relation between dairy intake and development of Alzheimer disease among older Japanese subjects. The consumption of dairy products by older people may reduce the risk of frailty, especially with high consumption of low-fat milk and yogurt, and may also reduce the risk of sarcopenia by improving skeletal muscle mass through the addition of nutrient-rich dairy proteins (ricotta cheese) to the habitual diet. Despite the scarcity of evidence on the topic, our systematic review shows that there are some positive effects of dairy products on frailty and sarcopenia, whereas studies concerning cognitive decline have contradictory findings.