Research suggests this snack may benefit brain health – but only for some people

Prediabetes is a condition in which blood sugar levels are higher than usual, but not high enough for a diagnosis of type 2 diabetes. It is often seen as a prompt to take steps to manage blood sugar, but it has also been linked with a higher risk of cognitive decline and changes in brain health.

Now, a small randomised trial suggests that eating almonds may support cognitive health among people with prediabetes.

The study, published in The Journal of Nutrition, suggests that noshing on almonds is associated with better performance on cognitive tests in people with prediabetes. But because researchers only tested the impact of almonds on cognitive health, it's tough to say whether this is an overall nut thing or limited to almonds – and what we can extrapolate for almond-eaters who don’t have prediabetes.

Here’s what the researchers found, plus what a neurologist and dietitian want you to keep in mind.

Researchers recruited 60 people with prediabetes aged between 40 and 60, and divided them into two groups. One group received standard dietary and exercise counselling. The other received the same counselling, but was also asked to eat a daily serving of raw, unroasted almonds for six months.

The almonds provided 20% of participants’ calorie needs, which worked out at around 28–40g a day. Participants in the almond group were also asked to replace some cooking fats and carbohydrate-rich cereals in their diet with almonds.

Researchers assessed the participants' cognitive performance at the start of the trial and again after six months. They used online tests that required participants to match patterns, follow visual cues, and complete spatial arrangements. They also took blood samples to track blood sugar, insulin production, inflammation, and cellular stress.

At the end of the study, the researchers found that people in the almond group performed better on executive function tasks and visual problems compared to those in the control group. They also had faster processing speeds and reacted more quickly to tests compared to when they started the trial. (People in the control group didn’t see a change in reaction times.) Not only that, people in the almond group lost weight and had better blood sugar management compared to the start of the study.

‘These findings suggest that almonds provide dual cognitive and metabolic benefits in this high-risk population,’ the researchers wrote in their conclusion.

There are a few important caveats to flag here. The study was funded by the Almond Board of California, although the organisation did not play a role in how the study was designed or how the data were collected and analysed.

That said, experts have a few theories about what might be behind the findings.

‘Prediabetes is associated with impaired glucose regulation and insulin resistance, which can affect the body’s ability to efficiently provide energy to the brain,’ says Anna Hohler, MD, director of neurology for Northwell in Westchester, chair of neurology at Northern Westchester Hospital in Mount Kisco and chief of neurology at Phelps Hospital in Sleepy Hollow.

Almonds are rich in fibre, protein, healthy unsaturated fats, magnesium, and antioxidants, nutrients that may help improve blood sugar management, reduce inflammation, and lower oxidative stress, she points out.

‘By improving metabolic health, almonds may indirectly help to protect neurological functioning,’ Dr Hohler says.

Keri Gans, dietitian and the author of The Small Change Diet, agrees that all of these elements may help.

‘That said, this is one study, so it’s too soon to conclude that eating almonds daily will prevent cognitive decline,’ she says. ‘It’s another piece of evidence suggesting that overall diet may play an important role in brain health.’

Possibly. ‘The nutrients found in almonds, including vitamin E, healthy fats and antioxidant compounds, are beneficial for overall brain health regardless of diabetes status,’ Dr Hohler says.

However, she stresses that because the study looked specifically at people with prediabetes, it is difficult to know how far its findings apply to everyone else.

‘That said, a diet rich in nuts, fruit, vegetables and other nutrient-dense foods has consistently been associated with better cognitive ageing and brain health,’ Dr Hohler says.

It is likely, according to Dr Hohler. ‘Walnuts are particularly noteworthy because they contain alpha-linolenic acid (ALA), a plant-based omega-3 fatty acid associated with brain health,’ she says. ‘Pistachios, hazelnuts, pecans and peanuts also provide healthy fats, antioxidants and nutrients that support vascular and metabolic health.’

There is no single ‘superfood’ snack that will dramatically alter your brain health, Gans points out. ‘But nutrient-rich choices can certainly contribute to an overall brain-healthy eating pattern,’ she says. ‘The goal is variety and consistency, not reliance on any one “superfood”.’

Reviewed byCarina Hsieh, MPH

Deputy Features Editor

Carina Hsieh, MPH, is the deputy features editor of Women’s Health. She has more than a decade’s worth of experience working in media and has covered everything from beauty, fashion, travel, lifestyle, pets, to health.

She began her career as an intern in the fashion closet at Cosmopolitan where she worked her way up to Senior Sex & Relationships Editor. While covering women’s health there, she discovered her passion for health service journalism and took a break to get her Masters in Public Health. Post-grad school, she worked as a freelance writer and as The Daily Beast’s first Beauty, Health, and Wellness Reporter.

Carina is an alum of the Fashion Institute of Technology and the Yale School of Public Health. She and her French Bulldog, Bao Bao, split their time between Brooklyn and Connecticut. She enjoys reformer Pilates, (slow) running, and smelling the fancy toiletries in boutique fitness class locker rooms.