A healthy diet can reduce brain aging

Obesity is known to negatively impact a variety of bodily systems, including the brain, with many studies providing neuroscientific evidence of accelerated brain aging in obese individuals. 

Recently, a team of researchers led by the Ben-Gurion University of the Negev in Israel has tested the effect of weight loss following 18 months of lifestyle intervention in a sub-study of 102 participants from the large-scale, long-term clinical trial The Dietary Intervention Randomized Controlled Trial Polyphenols Unprocessed Study (DIRECT-PLUS). 

What the researchers discovered 

The analysis revealed that as little as one percent of body weight loss induced by following a “Green Mediterranean diet” resulted in an 8.9 months’ reduction of brain age, which was significantly associated with improved liver biomarkers and decreased liver fat.

DIRECT-PLUS is the first study to examine how a green-Mediterranean, high polyphenols diet impacts brain health in a cohort of 300 participants followed during a period of 18 months. This diet is distinct from the traditional Mediterranean one due to its more abundant dietary polyphenols (secondary metabolites of plant compounds providing a variety of health benefits) and lower red and processed meat. 

Besides a daily intake of 28 grams of walnuts, the green-Mediterranean dieters had to consume 3-4 cups of green tea and one cup of Wolffia-globosa (Mankai) plant green shake of duckweed per day during the length of the study. According to the scientists, this aquatic green plant can be a better substitute for meat since it contains high amounts of bioavailable iron, B12 vitamin, 200 kinds of polyphenols, and protein.

Weight loss and brain age

In the sub-study investigating the relationship between diet-induced weight loss and brain age, the participants received a brain scan at the beginning and end of the trial, along with other tests and measurements capturing biological processes affected by obesity, such as liver health. 

The investigations revealed that a diet-induced reduction in body weight of one percent led to the participants’ brain age – a measurement showing how old their brain appears on detail scans, regardless of its chronological age – being nearly nine months younger than at the beginning of the study. This attenuated aging was linked to changes in other biological measures, such as decreased liver enzymes and liver fat.

“Our study highlights the importance of a healthy lifestyle, including lower consumption of processed food, sweets, and beverages, in maintaining brain health,” said lead author Gidon Levakov, who conducted the study during a doctoral studentship in Cognitive and Brain Sciences at Ben-Gurion.

More research is needed

These findings provide clear evidence that lifestyle interventions which promote weight loss can have a highly beneficial impact on the aging trajectory of the brain witnessed in obesity. With rates of obesity rising worldwide, identifying efficient interventions to promote brain health in obese individuals could have major clinical, educational, and social impacts. 

However, further research is needed to examine to what extent slowing down obesity-driven brain aging can result in better clinical outcomes for patients. The study is published in the journal eLife.

More about brain aging

The human brain is an incredibly complex organ that changes throughout our lives. However, as we age, our brains undergo a variety of alterations that can affect our cognitive abilities, memory, and other mental functions. 

Brain aging is a natural process, but its impact can vary greatly between individuals due to factors like genetics, lifestyle, and environment. Here’s a brief summary of what happens to the brain as we age:

Shrinkage

Starting around the age of 60, the brain tends to lose volume, particularly in the prefrontal cortex and hippocampus, which are areas involved in higher cognitive function and encoding new memories. The ventricles, which are fluid-filled spaces in the brain, also tend to enlarge.

Reduced blood flow

Aging can result in reduced blood flow to the brain, limiting the supply of oxygen and nutrients.

Neurotransmitter changes

Levels of certain neurotransmitters – the chemicals that transmit signals between neurons – change as we age. This can affect a wide range of functions including sleep, mood, and mental alertness.

Neuron loss

Neurons, or nerve cells, do not regenerate as other cells in our body do. With age, we may lose neurons in certain parts of the brain, which can affect various cognitive functions.

Changes in synaptic density

Synapses are the points of communication between neurons. Synaptic density, or the number of synapses, tends to decline with age, particularly in the prefrontal cortex. This could potentially contribute to declines in cognitive function.

Increased inflammation and oxidative stress

Aging is associated with increased inflammation and oxidative stress in the brain, which can damage cells.

Buildup of protein aggregates

Proteins such as beta-amyloid and tau can build up in the brain, forming “plaques” and “tangles,” respectively. While these are most commonly associated with Alzheimer’s disease, some degree of these changes are often found in the brains of older adults with no cognitive impairment.

White matter changes

White matter in the brain is composed of myelinated axons, which facilitate the communication between different brain regions. Aging is associated with changes in white matter, including loss of myelin, which can slow down the speed of communication between neurons.

However, it’s important to note that brain aging isn’t synonymous with cognitive decline or dementia. Many people maintain their cognitive function well into old age, thanks to factors like cognitive reserve (the brain’s resilience to damage) and neuroplasticity (the brain’s ability to reorganize itself by forming new neural connections). 

Additionally, there are strategies to promote healthy brain aging, including maintaining a balanced diet, regular physical and mental exercise, adequate sleep, and social engagement.

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By Andrei Ionescu, Earth.com Staff Writer

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