Advice for Picky Eaters: Liking a Variety of Foods Linked with Brain Health

Older people who aren’t picky eaters appear to have better brain health than those who prefer more limited diets, according to a large study of British adults.

The research tracked the dietary preferences of nearly 182,000 older adults in Britain. The study was unusual because rather than focusing on the health effects of a particular diet, it examined the link between the foods individuals liked and disliked and their mental well-being and cognitive health.

After parsing the data, the researchers noticed a trend: People who liked a variety of foods and flavors reported better mental health and well-being, and did better on cognitive tests than those with limited dietary preferences.

The findings suggest that preference for a limited diet – such as a vegetarian diet or a high-protein diet – may not always be best for overall well-being. Based on the results, people “need a more balanced diet to be better off,” said Jianfeng Feng, one of the study’s lead researchers, who works at both the Institute of Science and Technology for Brain-Inspired Intelligence at Fudan University in Shanghai and at the University of Warwick in Britain.

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Picky eaters vs. ‘balanced’ eaters

To conduct the research, which was published in the journal Nature Mental Health, the scientists from Britain and China looked at food preferences among participants in the U.K. Biobank study, one of the largest and longest health research studies in the world. The U.K. Biobank volunteers completed a “food-liking” questionnaire, ranking their preferences for 140 foods and beverages. The rankings were measured on a nine-point hedonic scale, in which 1 represents “extremely dislike” and 9 represents “extremely like.”

The ranked foods fell into 10 categories: alcohol, beverages, dairy, flavorings (such as black pepper, curry, ketchup and vinegar), fruits, fish, meat, snacks, starches and vegetables.

The researchers found that 57 percent of respondents showed a balanced preference across all 10 food categories, while others were more picky. One group (18 percent) preferred starch-free or reduced starch foods, another 5 percent preferred a vegetarian diet, while the last group (19 percent) preferred eating more protein and less fiber.

Some of the findings contradict conventional wisdom about healthy eating. For instance, individuals who preferred fruits and vegetables more than protein-rich foods – suggesting a more vegetarian diet – “exhibited a heightened susceptibility” to symptoms of anxiety, depression and other forms of mental distress, said Wei Cheng, a professor in the Institute of Science and Technology for Brain-Inspired Intelligence at Fudan University.

Other participants who favored diets high in protein and low in fiber were also more likely to report symptoms of anxiety and “diminished well-being,” he said.

It’s important to note that the data only show an association with certain food preferences and mental health. For instance, it may be that people who prefer certain food groups have other characteristics that could affect mental health scores.

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A link between food and brain health

The study adds to a growing body of research demonstrating the ways in which the food we eat may affect our brain health. High sugar, fatty diets – also known as a “Western diet” – have been associated with decreased cognitive performance. And a small study of Finnish men found a Western diet was associated with an increased prevalence of depressive symptoms. The Mediterranean diet, high in fruits, vegetables, fish and olive oil, has been linked with a lower risk of Alzheimer’s disease.

The study’s results “demonstrate that specific food preferences have significant associations with mental health, cognitive functions, blood and metabolic biomarkers and brain imaging,” Rebecca MacPherson, an associate professor at Brock University in Ontario, Canada, who studies how exercise and diet can improve a person’s metabolism and brain health, said in an email.

“There is a clear need for more preclinical studies investigating the underlying mechanisms,” as well as the short and long-term effects different nutrients can have “on the progression of disease,” said MacPherson, who was not involved in the study.

The observational study has several limitations, the researchers said. Ruohan Zhang, a doctorate student at the University of Warwick and the lead author, said the data is based on preference for various foods, not what an individual actually consumed day-to-day. Participants in the U.K. Biobank are known to be comparatively healthier than the general population.

In the study, the researchers described a “balanced” diet as one that includes vegetables, fruits, cereals, nuts, seeds, pulses, moderate dairy, eggs and fish. That’s “just a very, very healthy diet,” said Thomas M. Holland, a physician scientist at Rush University Medical Center in Chicago who was not involved in the research. “We know that diet impacts not only global cognition but a lot of different domains, being semantic memory, episodic memory, working memory, perceptual speed.”