By Nicole Cain, ND, MA
The Burden of Alzheimer’s disease
Source: Pill Burrows/Dreamstime
Alzhiemer’s disease (AD), a neurodegenerative condition characterized by cognitive and behavioral impairment, is estimated to be at the foundation of as many as 80% of dementia cases.1 Projections indicate that more than 140 million individuals across the globe will be suffering from the condition by 2050.2 In the United States alone, reported deaths from Alzheimer’s disease increased nearly 150% between 2000 and 2018, for an annual total of more than 120,000.3
Although research is ongoing, the cause of and contributing factors to AD development and progression are still unclear. One of the most common hypotheses cites excessive buildup of beta amyloid (Aβ) plaques in the brain.4 The plaques cause damage to brain cells (neuron) and, ultimately, death. Current thinking focuses on inadequate Aβ clearance, rather than overproduction, as a causative factor.5 Additional work indicates that neuronal damage and related cognitive changes may be detected prior to excessive buildup of beta amyloid.6
Another hypothesis posits that the disease is closely related to abnormalities in the structure and function of the brain’s tau protein, a substance that helps to stabilize the internal skeleton of nutrient-delivering microtubules in the nerve cells (neurons) in the brain.7,8,9 When abnormal chemical changes occur, tau proteins detach from the microtubules and cling together forming neurofibrillary tangles.10
Research also suggests that the gut-brain axis plays a role in the development of neurodegenerative diseases, including Alzheimer’s.
The Gut Microbiome’s Role in AD
Animal and human models have revealed that the gut microbiome plays an essential role in healthy neurological activity. For example, the gut regulates metabolism of short-chain fatty acid (SCFA), brain-derived neurotrophic factor (BDNF), and production of other neuroactive molecules and neurotransmitters.6
Microbes in the gut also influence the brain through neurological, hormonal, metabolic, and immune system interaction. In fact, a 2022 review describes a distinct microbial “signature” that can reliably differentiate high-level Aβ Alzhiemer’s disease patients from normal controls. Preclinical studies have even shown that changes in the microbiome may offer predictive value into disease progression in high-risk AD patients prior to Aβ buildup.6
Often the foundational dysfunction in the gut-brain axis is linked to intestinal permeability, commonly known as “leaky gut.” The condition occurs, in part, as a result of inflammation in the gastrointestinal system related to a dysbiotic gut microbiome. Damage to intestinal cells increases the likelihood that undesirable microbes and toxins (e.g. lipopolysaccharides, or LPS) will escape the intestinal lumen and set off a body-wide inflammatory response.
The systemic inflammation can lead to erosion of the blood brain barrier (BBB) that normally shields the brain from circulating toxins and other undesirable substances—esulting in pathogens and toxins “leaking” into the brain. Further, research reveals that LPS in the brain contributes to the development of plaques, as do amyloids produced by gut bacteria, when the BBB is compromised.6
Fortunately, there are very simple lifestyle interventions that may help prevent the onset and progression of Alzheimer’s and similar diseases.
3 Simple Lifestyle Hacks to Protect the Brain
1. Feed the Good Bugs in the Gut
A gut-friendly diet of whole foods high in fiber has consistently proven to be an effective approach to supporting microbiome balance and brain health; it fosters production of cognition-supporting substances.11 The standard American diet, high in red meat and highly processed foods, is typically bereft of such capabilities. Eating plenty of colorful, plant-based dishes feeds the good bugs of the microbiome and provides needed micronutrients. Including a quality prebiotic for extra microbiome support is a great approach. If dysbiosis is suspected, a regimen of quality nutritional supplements including omega-3 fatty acids, glutathione, zinc, and collagen has been clinically shown to help seal and heal the gut.12
2. Balance the Gut Microbiome Population
Many studies have evaluated the benefits of quality probiotic supplementation to support gut microbiome diversity and the gut-brain axis. A 2019 clinical trial looked at inflammation and cognitive function in two groups of AD patients: The first group received probiotic strains of L. acidophilus, B. bifidum, and B. longum along with selenium over a period of three months, with the placebo group serving as a control. Those taking the probiotics and selenium demonstrated reduced inflammation and increased cognitive function.13 Other recent studies14,15 add evidence that quality probiotic and prebiotic supplementation may offer an effective strategy for supporting the gut-brain axis and preventing the pathological changes associated with neurodegenerative diseases like AD.
Brain Supportive Gut Microbes
“The latest research results…clearly show that oral administration of probiotic bacteria such as bifidobacteria and lactic acid bacteria in AD disease reduces cognitive deficits by reducing inflammation or the amount of Aβ accumulated in the brain structures.” Wiatrek, et al. 20229
Selection of a reliably effective probiotic formulation however, can be challenging. Multistrain probiotics offer the benefit of inter-strain synergies and additive beneficial effects,16 which may provide comprehensive support. But not all probiotic strains work well together. The best approach to selecting a brain health-optimized product is to ensure that the final formulation is supported by independent human clinical evidence of efficacy. Probiotic companies with this level of performance evidence make the research readily available for review.17
3. Stay Active
The myriad benefits of regular physical exercise are incontrovertible, including its healthful influence on both the mind and the microbiome. Regular movement and exercise such as running on a treadmill or daily walking can produce positive results for seniors including those suffering from the cognitive symptoms of AD.20,21 Making activity a lifestyle pays off in physical strength, energy, and long-term cognitive clarity.
Although many neurodegenerative diseases, including and especially Alzheimer’s disease, is on the increase,3 small shifts toward better gut-microbiome health can play a strong preventative role.