Gut Bacteria and Alzheimer’s: Is There a Dietary Connection?

Alzheimer’s Disease is a devastating illness. It not only steals the memory, cognition, self-reliance and eventually the life of the victim, it has profound, painful and lasting affects on the victims friends and family. Nobody in the orbit of this disease escapes unscathed.

Researchers and medical professionals have been searching for ways to predict, prevent and possibly cure this terrible disease for decades. But what if the answer to reducing the risk of Alzheimer’s wasn’t “out there” but “in here?”

What if the microbiome of your gut could be the key, or a significant part of the key, to preventing Alzheimer’s disease?

Researchers at Wake Forest Baptist Medical Center think they may have found at least the beginning of the answer. They believe that it’s possible a specific kind of diet may affect gut bacteria in ways that decrease the risk of Alzheimer’s Disease.

While the size of the study was small at just 17 participants, there are some real positives here. The study was randomized and double-blind and involved a single site of application and data-gathering. The findings appear in the current issue of EBioMedicine, a Lancet journal publication.

This small pilot study involved 17 people, 11 of whom had previously been diagnosed with mild cognitive impairment (MCI.) Among the first things noted by researchers were several distinct gut microbiome signatures in the participants with MCI that weren’t in the people without MCI. A gut microbiome signature is the profile of chemicals produced by the bacteria in the gut. The researchers discovered that the signatures of the participants with MCI matched up with higher levels of markers of Alzheimer’s in the cerebrospinal fluid of the participants with MCI.


Participants were assigned to two groups. Each group followed either a low-carbohydrate, modified Mediterranean-ketogenic diet or a low-fat, higher carbohydrate diet for six weeks. After the initial six week period, each group went through a “washout” period of six weeks, then switched to the other diet plan. During each period, researchers measured the markers of Alzheimer’s, which included amyloid and tau proteins, in the cerebrospinal fluid. They also measured gut microbiome and fecal short-chain fatty acids.

In both study groups, the results were the same. The modified Mediterranean-ketogenic diet produced positive changes in gut microbiome and the associated metabolites. These changes correlated with reduced levels of Alzheimer’s markers in the cerebrospinal fluid of both groups.

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“The relationship of the gut microbiome and diet to neurodegenerative diseases has recently received considerable attention, and this study suggests that Alzheimer’s disease is associated with specific changes in gut bacteria and that a type of ketogenic Mediterranean diet can affect the microbiome in ways that could impact the development od dementia,” said Hariom Yadav, Ph.D., assistant professor of molecular medicine at Wake Forest School of Medicine, who co-authored the study with Suzanne Craft, Ph.D., professor gerontology and geriatric medicine at the medical school and director of Wake Forest Baptist Health’s Alzheimer’s Disease Research Center.

“Our findings provide important information that future interventional and clinical studies can be based on,” Yadav said. “Determining the specific role these gut microbiome signatures have in the progression of Alzheimer’s disease could lead to novel nutritional and therapeutic approaches that would be effective against the disease.”

While the study was small and lacked diversity relative to ethnicity, age and gender, the results were remarkably consistent throughout the sample group. I think it’s clear that there is more to the “gut-brain connection” than meets the eye and certainly there may be more ways for us to improve resistance to neurodegenerative diseases (ND’s) using dietary interventions than we may have previously believed.

For victims of Alzheimer’s and other ND’s, as well as the people who care about them, this is very good news and may offer one more weapon in the battle against Alzheimer’s and other neurodegenerative diseases.

Keep the faith and keep after it!


Journal Reference – Ravinder Nagpal, Bryan J. Neth, Shaohua Wang, Suzanne Craft, Hariom Yadav. Modified Mediterranean-ketogenic diet modulates gut microbiome and short-chain fatty acids in association with Alzheimer’s disease markers in subjects with mild cognitive impairment. EBioMedicine, 2019

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