- Previous research shows that following a healthy diet may help lower a person’s risk for Alzheimer’s disease.
- Past studies have linked specific diets, such as the Mediterranean, DASH, and MIND diets, to a lower Alzheimer’s disease risk.
- A new review of the existing evidence found that following an Alzheimer’s-preventive diet is about more than just the foods you eat.
- Researchers believe that how effective a specific diet is on lowering Alzheimer’s risk may operate through a combination of biological mediators and moderators.
Over the last few years, researchers have been examining different ways in which people may be able to lower their risk for a type of dementia called Alzheimer’s disease.
Some of these ways involve following
Previous research has linked specific dietary patterns, such as the Mediterranean, DASH (Dietary Approaches to Stop Hypertension),
“Alzheimer’s is the most common form of dementia and globally the population is rising with it,” Kuldeep Kumar, PhD, professor of statistics at the Center for Data Analytics at Bond University in Australia, told Medical News Today.
“However, it is genetically associated and the risk factors are modifiable,” said Kumar. “Diet is the most common modifiable risk factor and influences cognitive health in several biological ways.”
Kumar is the corresponding author of a new review published in the journal Frontiers in Nutrition, which found that following an Alzheimer’s-preventive diet involves more than just the foods you eat.
The review authors discussed that how effective a specific diet is in lowering Alzheimer’s risk may be due to a combination of biological mediators, like neuroinflammation and oxidative stress, and moderators such as a person’s genetics, sex, and age.
What influences a diet’s effect on Alzheimer’s risk?
For this review, researchers analyzed current evidence on how different dietary patterns impact a number of key biological mediators, or substances or networks that impact how different parts of the body communicate, including:
blood-brain barrier dysfunction- gut-brain axis dysregulation
hyperhomocysteinaemia (unusually high levels of the amino acid homocysteine in the blood)- insulin resistance
- neuroinflammation
- oxidative stress.
Scientists also examined how different modifiers might impact these biological mediators, such as:
- age
- APOE4 genotype
- biological sex
- disease stage
- physical activity
- socioeconomic status.
No ‘one size fits all’ for diet and Alzheimer’s risk
Based on their findings, the review authors suggest the need for a moderator-mediator framework to help figure out which type of dietary pattern is best for lowering Alzheimer’s disease risk for each person.
For example, researchers said that because genetic factors can impact dietary effects on cognitive outcomes, those carrying the APOE4 gene, which predisposes a person to Alzheimer’s may respond differently to certain diets than those not carrying the gene.
Kumar said that the review findings are significant because they show there is no “one size that fits all” when it comes to diet, and the process of finding which diet works best for each person is unlikely to be a simple one.
“With the current evidence the studies do not support any one particular diet pattern that would fit all,” he continued.
“Diet has the potential to affect Alzheimer’s disease and its progression. It should be critically understood and more personalized approaches should be developed to prevent it.”
– Kuldeep Kumar, PhD
Alzheimer’s risk reduction: Bespoke approach to diet may be best
MNT had the opportunity to speak with Dung Trinh, MD, an internist at the MemorialCare Medical Group and chief medical officer of the Healthy Brain Clinic in Irvine, CA.
Trinh, who was not involved in the research, said that the findings outline a very useful way to think about diet and Alzheimer’s disease, one that moves us beyond the oversimplified idea that there is one “best food” or one “best diet” for everyone.
“At the same time, I would caution patients that this is a review of existing evidence, not a new randomized clinical trial proving that a particular diet prevents Alzheimer’s disease,” Trinh continued.
“The encouraging message is that diet is a modifiable risk factor and may be one important component of a broader prevention strategy, but it should be considered together with exercise, blood pressure, diabetes control, sleep, and other lifestyle factors,” he cautioned.
MNT also spoke with Meridan Zerner, MS, RDN, CSSD, LD, CHWC, founder of Meridan Zerner Nutrition in Dallas, TX, who was also not involved in this review.
Zerner said the review validates, again, that there are many factors that play an important role in cognitive health through various, interrelated pathways.
“We know that certain dietary patterns found in the Mediterranean, MIND or DASH diets can improve vascular health, reduce inflammation, and help manage insulin resistance,” she explained.
“That, in turn, can participate in reducing the risk of Alzheimer’s disease and cognitive decline. But it isn’t a singular switch that can be turned on or off with predictable outcomes. I’ve had patients following a picture-perfect MeditDiet who still experience cognitive decline, and patients who eat a more conventional diet who do better than expected. There have to be individual variations.”
–Meridan Zerner, MS, RDN, CSSD, LD, CHWC
Tips for finding the right Alzheimer’s-preventive diet
Keeping all these different mediators and moderators in mind, the experts offered their top tips on how people can figure out which type of healthy diet pattern is best for them in potentially helping to lower their Alzheimer’s disease risk.
For most people, Trinh advised not getting too focused on choosing the “perfect” label between Mediterranean, MIND, or DASH, because these diets overlap substantially.
“They all generally emphasize vegetables, fruits, whole grains, legumes, nuts, and healthier fats while limiting highly processed foods, excess saturated fat, and refined carbohydrates,” he explained.
While there may not be a single “best” pattern someone could pick off a shelf, Zerner said there are ways to narrow down the next, best step — as a trial — based on what is going on with each individual.
“For example, if someone has hypertension, the DASH diet’s sodium/potassium management will target that vascular pathway directly,” she detailed. “If insulin resistance or metabolic syndrome is part of the diagnosis, then the higher fiber, anti-inflammatory focus of the Mediterranean diet may make more sense.”
“For each person, it is important to factor in what is sustainable,” Zerner continued. “The ‘best’ diet is the one a person can actually follow for years, since these effects would be cumulative.”
”This is the case for meeting with an RDN who can help each client implement the underlying principles — increasing plants and healthy fats, minimizing ultra-processed foods — and then adapt them to culturally familiar foods rather than a rigid template,” she advised.
