In a recent study, on the role of diet in modifying risk of Alzheimer’s Disease led by Dr William B. Grant, director of Sunlight, Nutrition and Health Research Center at San Francisco and Dr Steven M. Blake, of director of Nutritional Neuroscience at Maui Memory Clinic, Hawaii, published in  the Journal of Alzheimer's Diseases shedding light on diets that can reduce the risk of developing Alzheimer’s disease the researchers  focussing on the role of diet and its modification in influencing the risk of Alzheimer’s disease, comparing various dietary patterns, the researchers found that with a higher emphasis on plant-based foods, such as the Mediterranean diet and traditional diets in China, Japan, and India, show a reduced risk of Alzheimer’s disease, particularly when compared to the Western diet. 

The study further suggested that as countries transi to a Western diet, Alzheimer’s disease rates tend to rise.

Certain dietary patterns, including increased consumption of saturated fats, red meat, processed meats, and ultra-processed foods with high sugar and refined grains, tend to increase the risk for dementia. 

The study elucidated the impact of specific foods on the risk of Alzheimer’s disease, associating meat with heightened risk factors such as inflammation, insulin resistance, oxidative stress, saturated fat, advanced glycation end products, and trimethylamine N-oxide. 

Conversely, green leafy vegetables, colorful fruits and vegetables, legumes, nuts, omega-3 fatty acids, and whole grains were identified as protective foods.

The research emphasised the adverse effects of ultra-processed foods, which can increase the risk of obesity and diabetes, both recognised risk factors for Alzheimer’s disease. 

The researchrs opined that these highly processed foods often lack essential components found in whole plant foods, such as anti-inflammatory compounds and antioxidants.

The study also pointed out the role of socio-economic factors, noting that poverty can contribute to Alzheimer’s disease as ultra-processed foods and meat are more affordable sources of energy compared to fruits, vegetables, and whole grains.

Furthermore, the researchers predicted that a 50% increase in Alzheimer’s disease rates in the United States by 2038 based on trends in obesity. 

According to them, this projection aligns closely with the estimate published by the Alzheimer’s Association in 2018, suggesting a 56% increase. 

The study suggests that the rising trend of obesity, driven by the consumption of meat and ultra-processed foods, is a significant force behind the increasing prevalence of dementia.

The researchers advocate for a balanced diet containing fruits, vegetables, legumes, nuts, and whole grains, and reducing meat, especially red meat, saturated fats, and ultra-processed foods to lower the risk of Alzheimer’s disease. 

While acknowledging the need for further research, the study underscored the likelihood that dietary and lifestyle factors associated with diseases like diabetes and cardiovascular issues influence the risk of Alzheimer’s disease. 

Commenting on the finding of the study, Professor Edward Giovannucci, of Harvard University said, “Grant and Blake comprehensively review and synthesise the role of dietary factors in Alzheimer’s disease.”

Pointing out that evidence from diverse perspectives support that balanced diet he added, “A diet that emphasises fruits, vegetables, legumes, nuts, whole grains, and…de-emphasizes meat, especially red meat, saturated fats, and ultra-processed foods is associated with lower risk of Alzheimer’s disease.”

He emphasised that physical inactivity and obesity also contribute to higher risk of Alzheimer’s disease saying “In addition, the dietary and lifestyle patterns associated with higher risk of Alzheimer’s disease are known to affect the constellation of mechanisms believed to increase risk, including inflammation, insulin resistance and oxidative stress, among others.”

“Grant and Blake make a strong case that, while further research is needed to better understand the mechanisms, diet and lifestyle factors linked to diabetes, cardiovascular disease and some cancers are likely to influence risk of Alzheimer’s disease,” Professor Edward Giovannucci concluded.

Pointing out that the study team provide a comprehensive review on the dietary and other factors that affect the risk of Alzheimer's disease, Dr Paul Marik, Chairman and Co-Founder of Front Line COVID-19 Critical Care Alliance said, “Apart from the particular type of diet they demonstrate that the consumption of red meat, insulin resistance, obesity, reactive oxygen species, and oxidative stress, phytochemicals and homocysteine amongst other factors interact with neuroinflammation and play a major role in the aetiology of AD.”