Eating a Healthy Diet Now May Reduce Your Risk of Cognitive Decline Later

• A new study that tracked diet and cognitive ability across seven decades found that individuals with a healthier diet had better cognitive outcomes over time.
• The research involved a cohort of more than 3,000 individuals living in the UK born in 1946.
• The findings suggest that eating a healthy diet consistently in childhood and midlife is important to maintaining brain health in old age.

Diet is an important part of keeping your brain sharp as you age. New research indicates that the earlier you start eating healthy, the better.

In a first-of-its-kind study, researchers tracked the diet and eating habits of more than 3,000 individuals living in the UK and correlated it with their cognitive ability for seven decades. Those who had the highest-quality diets tended to have better cognitive ability over time compared to their peers who ate unhealthy diets.

“Cognitive decline can begin at age 65. But, there’s this long latency period, maybe 10 to 15 years prior to symptoms showing up, that those brain changes can already be happening. So our thinking was that diet much earlier than age 65 might be an important factor in what’s happening in our later life cognition. And our preliminary findings suggest that may be the case,” Kelly Cara, PhD, a recent graduate of the Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University and author of the research, told Healthline.

Cara presented her findings this week at NUTRITION 2024 , the annual meeting of the American Society for Nutrition. The findings have not yet been published in a scientific journal and are considered preliminary.

Nonetheless, they are compelling and have practical implications for anyone concerned about maintaining brain health through diet. Experts say eating a diet rich in fruits and vegetables, fish, and whole grains — such as the Mediterranean diet — is a good place to start.

“The findings are consistent with similar studies and truly exemplify the importance that diet plays early in life to impact health (in this case, cognitive health) later in life,” said Kristin Kirkpatrick, MS RD, a nutritionist at the Cleveland Clinic, and co-author of Regenerative Health . She was not affiliated with the study.

Seven decades of research suggests healthy diets boost brain health

Cara’s work is based on data from the Medical Research Council’s National Survey of Health and Development , which has collected health and medical information from British citizens for nearly 100 years.

The research looked at one specific cohort of 3,059 individuals born in 1946 and evenly split between men and women. Those alive today are 78 years old and are still involved in the study.

Members of the cohort reported their dietary information at five separate points (age 4, 36, 43, 53, and 63). They also recorded cognitive ability, based on standard testing, seven times during that time span, between age 8 and 69.

“I have never seen any cohort that has dietary measures as early as this cohort, where diet was first assessed at age four, and then again throughout middle adulthood and now into the later life years,” said Cara.

Diet was assessed using a standard measure known as the Healthy Eating Index (HEI) , which factors in 13 different components, including fruits, vegetables, whole grains, added sugars, and more to create a composite score of an individual’s diet.

The assessments also used diaries and took place over several days rather than just a single day, creating a more detailed picture of an individual’s diet quality.

“We have a better indication of what that person’s habitual diet was at that time, instead of just a single measure taken, we’re able to kind of average across those multiple days, essentially to represent their diet in that decade,” said Cara.

Those who ate healthier diets, particularly in mid-life (during the survey at age 43), were associated with better cognitive ability through age 69. Specifically, 47% of those with the lowest quality diets also had the worst cognitive outcomes. On the other hand, 48% of individuals with the highest quality diet also had the best cognitive outcomes.

“This means general ability across language and memory and reaction time and visual processing, all of those things,” said Cara.

Foods and diet types that support a healthy brain

The right foods can support your brain health by reducing oxidative stress and slowing age-related mental decline.

“Brain” foods are often high in antioxidants and healthy fats, such as berries, nuts, and fatty fish, including:

• Pumpkin seeds
• Coffee
• Salmon
• Herring
• Sardines
• Walnuts

“Focus on colorful fruits and vegetables in the diet (aim for at least 6 colors every single day), a serving of leafy greens daily, and limit alcohol and ultra-processed foods. If you do not enjoy fatty fish, then consider omega-3 supplementation as well,” said Kirkpatrick.

Both Cara and Kirkpatrick emphasize the importance of diet as a whole rather than thinking about specific individual components. Eating healthy over a lifetime is about consistency and finding the right balance of what works for you.

“The idea here is that if I can be inspired by knowing that what I eat today actually does have an impact on how my future might look in terms of my cognition, that might be one more reason that I can say this is worth doing,” said Cara.

The bottom line

A first-of-its-kind study tracked dietary information and cognitive ability in more than 3,000 individuals across seven decades.

Researchers found that those who tended to have higher-quality diets also showed better cognitive ability across time compared to those with an unhealthy diet.

Experts say that thinking about diet holistically and eating a diet rich in fruits, vegetables, whole grains, and fish, such as the Mediterranean diet, is important for brain health.