Study links organic food consumption to better cognitive function in older adults

Older adults who eat more organic food tend to have better cognitive performance, according to a new study published in the European Journal of Nutrition. The researchers also found that organic food consumption was associated with a reduced risk of mild cognitive impairment among women, but not among men.

Mild cognitive impairment refers to a noticeable decline in memory and thinking skills that is greater than expected for a person’s age but does not interfere significantly with daily life. It is often viewed as a transitional stage between normal aging and dementia. Research shows that between 10 and 20 percent of individuals with mild cognitive impairment progress to dementia each year, and about half make this transition within five years.

Since there are currently no effective treatments to reverse or stop this progression, strategies aimed at preventing cognitive decline have gained increasing attention. Lifestyle factors such as diet, exercise, and cognitive training have shown promise, but findings remain mixed.

Diet is believed to influence brain health in part through anti-inflammatory effects of certain nutrients and by promoting a healthier gut microbiome, which may communicate with the brain through what is known as the brain–gut axis. Organic foods, grown without most synthetic pesticides and fertilizers, have been suggested to contain higher levels of beneficial nutrients like polyphenols, magnesium, and essential fatty acids. However, few studies have directly examined whether organic food consumption influences cognitive health in aging adults.

In light of these gaps, researchers from Southern Medical University in China set out to examine the relationship between organic food intake and cognitive function. They used data from two large surveys: the Health and Retirement Study, a nationally representative study of older Americans, and its sub-study, the Health Care and Nutrition Study. Participants completed questionnaires about their food consumption and underwent cognitive assessments.

The researchers analyzed data from 6,077 adults for a cross-sectional analysis and 4,882 adults for a longitudinal analysis over a median follow-up of 3.7 years. Participants were considered organic food consumers if they reported eating any certified organic foods over the past year, based on United States Department of Agriculture standards. Organic foods were grouped into animal-based products, such as milk, eggs, and meat, and plant-based products, including fruits and vegetables. The researchers also calculated a dietary diversity score based on the number of different organic foods consumed.

Cognitive function was assessed using a telephone-based test that measured memory, attention, and processing speed. Higher scores indicated better cognitive abilities. Participants were also classified as having normal cognition, mild cognitive impairment, or dementia based on their test performance. The researchers controlled for a wide range of factors that could influence cognition, such as age, sex, race, education, wealth, physical activity, smoking, alcohol use, body mass index, depression, diabetes, hypertension, other chronic diseases, total energy intake, and overall diet quality.

Across the entire sample, older adults who consumed organic food had significantly higher cognitive scores than those who did not. This association was observed for both men and women. Consumption of both organic animal products and organic plant foods was independently linked to better cognitive function. Each additional type of organic food consumed was also associated with slightly better cognitive performance.

When examining changes over time, the researchers found that organic food consumption was associated with a lower risk of developing mild cognitive impairment — but only among women. Women who ate organic foods had about a 20 percent lower risk of mild cognitive impairment compared to women who did not, even after adjusting for multiple confounding factors. Eating organic animal products was associated with a 27 percent lower risk, while eating organic plant foods was associated with a 20 percent lower risk.

In contrast, no significant relationship between organic food consumption and mild cognitive impairment risk was found among men. Analyses suggested that organic meat, fruits, and vegetables were particularly important for reducing risk among women.

The researchers offered some potential explanations for the findings. Organic foods tend to have lower levels of potentially harmful substances, such as pesticide residues and heavy metals, and higher concentrations of protective nutrients like polyphenols, vitamins, and omega-3 fatty acids. These nutrients are believed to support cognitive health by reducing inflammation, promoting beneficial gut bacteria, and directly protecting brain cells from oxidative stress.

Despite the strengths of the study, including its large sample size and detailed adjustment for potential confounders, the researchers acknowledged several limitations. The measure of organic food consumption relied on self-report and did not capture the frequency or quantity of organic foods eaten. Occasional and regular organic food consumers were grouped together, which may have led to an overestimation or underestimation of the associations. Additionally, although the researchers adjusted for many factors, residual confounding cannot be ruled out, and the observational design means that no conclusions can be drawn about cause and effect.

The study’s authors noted that more research is needed, especially long-term randomized controlled trials that directly compare the effects of organic and conventional diets on cognitive outcomes. They also emphasized the importance of considering sex differences in future studies of diet and brain health.

The study, “Organic food consumption is positively associated with cognitive function among middle‑aged and older adults: cross‑sectional and longitudinal analyses,” was authored by Shiyu Li, Haowen Chen, Ruxun Zhao, Tingyu Wang, and Jufeng Ye.