In the last several decades, many diseases have become less deadly. Prostate cancer as a cause of death has decreased by seven percent, heart disease by eleven percent, and stroke by sixteen. The fatality of Alzheimer’s disease (AD), on the other hand, has increased by 123 percent. Affecting nearly six million individuals and amassing nearly $300 billion in healthcare costs per year, AD is now the sixth leading cause of death in the United States, causing symptoms such as impaired memory and cognitive decline (1). And, as of today, there is no cure.
The neurological basis of AD has been researched for decades, but what if the solution to this public health crisis lies not in the brain, but in the gut?
Dr. Laura Bonfili at The University of Camerino in Italy has discovered that the progression of AD in mice can be reversed solely by treating them with a specific probiotic formulation called SLAB51 (2). Probiotics are supplements used to treat digestive issues by introducing beneficial bacteria to the gut, and they could be the key to saving millions of lives.
In this new study, Bonfili and her team orally administered SLAB51 dissolved in water to mice with AD and healthy mice, using plain water as a control for both groups. Over time, the researchers performed behavioral tests on the mice and found that the treated mice had higher cognitive function than those of the control group. Moreover, the brains of the mice were analyzed to uncover the physical effects of the treatment. Whereas the brain weights of untreated AD mice significantly declined over several months (thus indicating disease progression), the brain weights of SLAB51-treated mice stayed consistent with that of healthy mice. Perhaps most notable is that mice treated with SLAB51 were found to have lower concentrations of amyloid-beta, a peptide linked to AD development, in the brain (2).
All of these results indicate that the researchers’ formulation not only ameliorated the symptoms of AD, but significantly reduced the development of the disease. Moreover, researchers from Kashan University in Iran analyzed the effects of a similar probiotic formulation on humans diagnosed with AD, and found the same mitigating effects (3).
Do these findings insinuate that an imbalanced gut microbiome is the cause of AD? Not necessarily, but there is evidence that microbes may be playing a critical role in the development of the disease. In an attempt to assess physicians’ occupational hazards, researchers at Dartmouth Medical School have compared the incidence of certain diseases in neurosurgeons to that of the general public. Many different diseases were examined, but only AD had significantly higher rates of incidence in neurosurgeons than expected for the average person (4). A separate study demonstrated that individuals were six times more likely to develop dementia (which is primarily caused by AD) if their spouse also suffered from dementia. These results offer convincing evidence that AD may be contagious—caused not by genetics, but by a germ.
The prospect of pathogenic AD may be frightening, but it also widens the range of research opportunities and treatment options for those diagnosed with the disease. Best of all, if microbes are truly to blame for AD, potential treatments wouldn’t require any invasive surgeries or complicated procedures. Instead, all it would take is a supplement or antibiotic similar to those already sold on pharmacy shelves around the world.
Now that’s a no-brainer.
Edited by: Julia Bulova
Illustrated by: Eugenia Yoh