Exposure to certain toxic compounds including beta-N-methylamino-L-alanine (BMAA), formaldehyde, and heavy metals like manganese, mercury, and zinc increases the likelihood of developing amyotrophic lateral sclerosis (ALS), according to a review paper.
The authors claim that BMAA is a toxic compound made from algae and that it causes ALS.
The report,“Systematic and state-of the science review of the role of environmental factors in Amyotrophic Lateral Sclerosis (ALS) or Lou Gehrig’s Disease,” was published inScience of The Total Environment.
It is not known what causes ALS. However, the only risk factors for the disease are age, male sex, family history, and gender. There is a lot of research that has examined whether environmental factors can affect ALS development.
A trio from Arizona State University analyzed published scientific literature on ALS. Their review included 258 studies, many of which used rodent models. They also evaluated more than 80 environmental toxicants.
“Narrowing possible risk factors to a likely subset will hasten the work needed to determine whether these factors are merely associated or actually causal to ALS,” Melanie Newell, a doctoral student at Arizona State and the paper’s lead author, said in a Press release.
Researchers found that BMAAis the most well-studied environmental factor related to ALS. Based on the amount of data supporting a connection between the two, they asserted that “causal criteria have been met” in other words, their analysis suggests enough data exist to conclude that BMAA can cause ALS.
Other risk factors that are highly rated include formaldehyde, a preservative that is toxic to nerve cells and heavy metals like manganese, mercury and zinc.
Analyses of 62 studies which examined the statistical relationships between different toxins and ALS risk found that higher levels of BMAA, formaldehyde and heavy metals were associated with a greater risk. For example, ALS risk is still high in areas where BMAA contamination via diets such as eating fish from contaminated rivers is more common.
“BMAA, formaldehyde, manganese, mercury, and zinc emerged as the five highest ranked environmental factors … These are the environmental toxins most recommended for the most immediate research,” the scientists concluded.
“It is important to note that still other environmental factors not yet identified may also play a role in ALS,” they added, stressing a need for further research.
They also used available data to estimate the incidence of ALS. In the United States, there were 16,707 cases of ALS in 2015. This number is expected to rise to 22,654 in 2040. If U.S. trends are maintained, there will be more that 200,000 cases by 2240.
“Meanwhile, funding available through the National Institutes of Health (NIH) has been relatively stable for ALS and Parkinson’s disease research, while Alzheimer’s disease research has been increased significantly since 2015,” the researchers wrote.
“Many disease trends in industrialized nations are increasing to an extent and within a rather short time scale which simply cannot be explained by inherently slow genetic changes. To improve U.S. and global health outcomes, studying environment factors is key,” Newell said.
