Adults who consume dairy products at least once daily have higher cognitive function than those who rarely or never drink milk or eat dairy foods, according to a new study by researchers from the University of South Australia and University of Maine.
Those who consumed the most dairy products had the highest scores in an extensive cognitive test battery that included multiple measures of visual-spatial ability, verbal memory, working memory, reasoning ability and executive functioning (the ability to plan, organize and integrate cognitive functions).
Those who seldom or never consumed dairy performed lower than average for this study population.
The research was led by doctoral student in nutrition and psychology Georgina Crichton of the University of South Australia, in collaboration with UMaine psychologist/epidemiologist Merrill Pete Elias, and psychologists Michael Robbins and Gregory Dore. It involved 972 adults free from stroke, dementia and kidney disease who participated in the community-based Maine-Syracuse Longitudinal Study at the University of Maine.
The 35-year Maine-Syracuse Longitudinal Study, initiated by Elias in 1975, is one of the longest-running NIH-funded scientific investigations relating aging, arterial blood pressure and cardiovascular disease risk factors to comprehensive measures of neuropsychological test performance. The longitudinal study focuses on relations among risk factors for cardiovascular disease and cognitive performance across the adult life span.
Beginning in 2001, data collected on participants in the Maine-Syracuse Longitudinal Study also included responses to the 41-question Nutrition and Health Questionnaire, which focuses on dietary intake and lifestyle.
More than a third of the 972 participants in the study of the relationship between dairy food intake and cognitive function reported eating milk products daily, and more than half reported consuming dairy between two and six times weekly.
Cheese was the most popular dairy product, most often eaten two to four times a week. Nearly a third of the participants said they drank at least two and a half cups (600 ml) of milk daily, mostly skim or reduced-fat.
This cross-sectional study is one of the few to investigate whether dairy food intake is associated with levels of cognitive function while controlling for multiple confounding variables, including cardiovascular disease risk factors such as blood pressure, obesity, cholesterol and other lipids. Previous investigations have focused on the benefits of milk products in relation to body weight and cardiovascular health and dementia.
The researchers point out that milk consumption has decreased worldwide in recent years. In the United States, the trend has coincided with a dramatic increase in soft drink consumption.
Diet modification to include more dairy products is one lifestyle change that could slow or prevent age-related cognitive impairment and decline, according to the researchers, who reported their findings in the International Dairy Journal.
The reality is that dairy has many benefits in those who are not restricted from consumption for health reasons, Elias says. We have learned in recent years that components of dairy calcium, whey protein, vitamin D and magnesium may play a role in reducing levels of obesity, diabetes and hypertension. Now we know that eating dairy also is positively associated with cognitive functioning.