Debunking myths about diet and dementia with enhanced clinical trials

The Nutrition for Dementia Prevention Working Group has recommended that clinical trials surrounding diet and dementia are vital.
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The Nutrition for Dementia Prevention Working Group has recommended that clinical trials surrounding diet and dementia are vital.

Is there a link between diet and dementia? Is there such thing as dementia preventing or aggravating foods? Despite what the internet says, there is no solid clinical evidence. Considering this, the Nutrition for Dementia Prevention Working Group has recommended that clinical trials need to improve diet and dementia research to provide clear scientific evidence.

“Many trials have not found that making people eat healthily or exercise is translating into benefits in the ways that are expected from the epidemiological research,” said Hussein Yassine, MD, associate professor of medicine and neurology at the Keck School of Medicine of USC and the Kenneth and Bette Volk Chair of Neurology of USC. “That means either there is no causal connection or that these studies have not been properly designed.”

The researchers surveyed existing literature on diet and dementia risk and published their analysis in The Lancet Healthy Longevity.

Diet and dementia: are your food choices increasing your risk?

It is challenging to locate a causational link between diet and dementia due to the sheer number of external factors, from where you live to access to healthcare.

It is unknown how long it takes for a diet to affect cognition and brain health, posing a challenge for diet and dementia clinical trials. It creates difficulty in determining the length of a study that will lead to meaningful data.

“If it takes five to 10 years, then studies that lasted for two years or less are not accurately reflecting the effect of the diet on cognition,” commented Yassine.

The researchers stated that future research should address the effects of specific nutrients on brain health.

Enhancing clinical trials with medical technology

Using biomarkers instead of cognitive tests could lead to more meaningful results, revolutionising future clinical trials and their outcomes.

Medical technology could play a key role in tracking brain changes over time. Additionally, blood and stool testing indicate how nutrients are absorbed, which provides useful insight into the link between diet and dementia.

Genetic testing can also be an effective tool, according to Yassine, who studies apolipoprotein E4, or APOE4, which is the strongest genetic risk factor for late-onset Alzheimer’s disease. He noted that people with this genetic variant respond differently to diet than non-carriers. Here, genetic testing can improve the quality of research with more personalised interventions.

An emerging trend is utilising the microbiome for research purposes. Yassine noted that people benefit from food differently based on variations in the microbiome. “You cannot fully study how the diet is working without studying the microbiome,” said Yassine. Another evolving research topic is the relationship between gut microbiota and cognition in large populations of diverse individuals.

Creating the optimal nutrition clinical trial

The researchers concluded that future clinical trials should employ a wider variety of study designs and participant selection requires more scrutiny.

They noted that one strategy is small, personalised trials that focus on genetic risk, quality of diet and an analysis of their microbiome while using biomarkers to understand brain function. Another workable approach is designing a large, pragmatic electronic health trial using mobile devices or tablets for data collection aimed at individuals with dementia risk factors.

Furthermore, encouraging more research on middle-aged populations can highlight how the brain changes over time. Moreover, the dietary preference of underrepresented groups affected by dementia, should be considered.

“This is an important document for anyone researching diet and how it relates to dementia,” said Lon Schneider, MD, Professor of Psychiatry and the Behavioural Sciences at the Keck School of Medicine and Della Martin Chair in Psychiatry and Neuroscience. Dr Schneider also serves on The Lancet Commission on dementia prevention, intervention, and care. “It is important that future trials yield accurate results that can be translated into better clinical care for patients.”

“We are pleased to contribute to this working group, and to help turn these recommendations into reality,” said Heather M. Snyder, PhD, Alzheimer’s Association vice president of medical and scientific relations.


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