The connection between your brain and gut just got more interesting. Our gut bacteria (AKA microbiome) drive much of our immunity and new research out of Oregon Health and Science University (OSHU) has discovered that alterations in these bacteria may be associated with Alzheimer’s Disease.
The study done in wild type mice was featured in the Journal of Scientific Reports. Scientists discovered a link between the composition of the gut microbiome and behavioral and cognitive performance of mice with genetic predisposition for Alzheimer’s disease.
The researchers note the “Epigenetic mechanisms occurring in the brain, as well as alterations in the gut microbiome composition, might contribute to Alzheimer’s disease (AD), Human amyloid precursor protein knock-in (KI) mice contain the Swedish and Iberian mutations (AppNL-F) or those two and also the Arctic mutation (AppNL-G-F). In this study, we assessed whether behavioral and cognitive performance in 6-month-old AppNL-F, AppNL-G-F, and C57BL/6J wild-type (WT) mice was associated with the gut microbiome, and whether the genotype modulates this association.”
Senior author Jacob Raber, PhD, a professor of behavioral neuroscience in the OHSU School of Medicine jokes that the expression “you are what you eat” is very fitting here. Although the mice were fed the same chow, the gut microbiome is affected in a genotype-dependent fashion, which may consequently impact the brain.
The research is the first to identify a direct link between the gut microbiome and behavioral and cognitive changes in an animal model of Alzheimer’s disease.
The researchers evaluated DNA methylation in the hippocampus of the brains of female mice and studied whether changes in the hippocampal DNA methylation were linked with gut microbiome. They discovered regions in the brain where genes overlapped and were more methylated in the hippocampus, with more susceptibility to Alzheimer’s.
This is an initial study to show a relationship between changes in the gut microbiome and epigenetic changes in neural tissue in the hippocampus, the area of the brain impacted in Alzheimer’s. Other studies have found that altered neurogenesis in the adult hippocampus suggests an early critical time in the development of AD.
“Microbes may elicit an impact on behavioral and cognitive measures relevant to Alzheimer’s disease via epigenetic changes in the hippocampus,” Raber said. “Or, alternatively, it might be that the epigenetic changes in the hippocampus affect changes in the gut microbiome.”
While more research is needed, these results have given scientists more data to connect the dots in understanding the gut microbiome’s role in neurological disorders and diseases. The OSHU investigators are trying to find out whether it’s possible to lessen the likelihood of Alzheimer’s-like symptoms in mice that are genetically predisposed by changing their diets.
Concerned about Alzheimer’s Disease? Consider the MIND diet
The MIND diet is a combo platter of the Mediterranean diet and DASH diet. It basically comes down to controlling your blood pressure (DASH) and eating a more plant-based diet to improve your gut microbiome. Below are a few quick tips:
- Include mostly whole grains for fiber. Choose 100% whole grain bread and cereal, brown rice, rolled oats, bulgur, and quinoa regularly.
- Add leafy greens to your daily diet.
- Include foods containing omega-3 fatty acids such as salmon, ground flaxseed, and walnuts.
- Limit your intake of red meat, processed meat, and fried foods.
- Include a ½ cup of some type of beans daily (black beans, lentils, kidney beans, etc).
- Choose high-potassium fruits like citrus fruit, kiwi, bananas, or melon.
- Include low-fat dairy products in your diet for calcium and vitamin D. Think yogurt, skim or 1% milk, or low-fat cheese.
- Add berries to your diet a few times per week.
- Avoid heavily-processed fast food, snack crackers, high-fat desserts and frozen meals high in sodium and fat.
By Lisa Andrews, MEd, RD, LD
Stephanie Ronco has been editing for Food and Health Communications since 2011. She graduated from Colorado College magna cum laude with distinction in Comparative Literature. She was elected a member of Phi Beta Kappa in 2008.