For ‘responders’, the LDL cholesterol improvements were correlated with increases in levels of Parasutterella bacteria in the gut. Parasutterella is a member of phylum Proteobacteria, which are generally considered to be undesirable or even pathogenic members of the gut microbiome.
“While the effect of RPS [resistant potato starch] on LDL cholesterol was modest (mean change - 0.33 mmol/L in Responders) compared to cholesterol lowering medications, RPS supplementation may help reduce LDL levels in combination with other therapies,” wrote the researchers in the journal BMC Nutrition.
“The evaluation of Parasutterella levels in the gut microbiome to predict a person’s response to RPS is consistent with a personalized approach to medicine and speaks to growing appreciation for the role that differences in gut microbiome composition play in shaping human health,” they added.
The study used the commercially available MSPrebiotic product by Canada-based MSP Starch Products. The company also offers the resistant potato starch as an ingredient under the brand name Solnul. The product has previously been shown to significantly increases the abundance of Bifidobacterium. As reported by NutraIngredients-USA, a recent low dose clinical study supported the efficacy of a 3.5 grams dose.
The study was performed by Dr Jason Bush, Solnul’s CSO, and Dr Michelle Alfa from the University of Manitoba.
Commenting on the new study, Dr Bush told NutraIngredients-USA: “We continue to dig deeper into our understanding of how Solnul resistant potato starch influences individual’s health via the gut microbiome, leading to novel discoveries like this one that can be used in the context of personalized nutrition.”
Drs Bush and Alfa analyzed data from a randomized, placebo-controlled clinical trial that evaluated the effects of resistant potato starch (30 grams per day) or placebo (30 grams per day of digestible corn starch) in 75 people.
The results showed that, after 12 weeks, the abundance of Parasutterella tended to increase in the gut microbiome of people in the RPS group, and those were correlated with reductions in LDL levels.
Digging into the data some more, Drs Bush and Alfa found that the LDL cholesterol reductions were not observed in everyone, and the “responders” had significantly higher levels of Parasutterella at the start of the study and again after 12 weeks of RPS supplementation.
Teasing apart the details
Jason Leibert, Solnul’s Chief Growth Officer, told us: “Quality inputs and consistency in production make it possible for us to tease apart these details to better understand how Solnul is functioning in the microbiome as a prebiotic. Through our commitment to clinical research, we’re able to gather next level insights of the gut microbiome.”
Intriguingly, Parasutterella does not utilize resistant starch as a fermentation substrate, and the two amino acids known to support the growth of the genus are not present in resistant potato starch.
“Thus, it is unclear from our data how RPS supports the growth of Parasutterella,” wrote Drs Bush and Alfa. “… resistant starch may generally support the growth of Parasutterella, through cross-feeding or some other indirect mechanism(s). Indirect growth via complex ecological interactions could explain why RPS consumption stimulated growth of Parasutterella in some people and not others.”
The study also asks questions around the existing definition of prebiotics: “A substrate that is selectively utilized by host microorganisms conferring a health benefit”, because this study indicates that certain health benefits may be attributed not directly to the bacteria selectively utilizing the prebiotic, but to ecological consequences of prebiotic consumption.
The researchers concluded: “Further research is required to identify these factors [including prebiotic consumption, the baseline level of this organism and the co-abundance response of the host’s gut microbiome.] and the mechanisms by which they interact to influence cholesterol homeostasis.”
Source: BMC Nutrition
Volume 6, Article number: 72, doi: 10.1186/s40795-020-00398-9
“Increasing levels of Parasutterella in the gut microbiome correlate with improving low-density lipoprotein levels in healthy adults consuming resistant potato starch during a randomised trial”
Authors: J.R. Bush, M.J. Alfa