A Calcium-Rich Multi-Mineral Intervention to Modulate Colonic Microbial Communities and Metabolomic Profiles in Humans: Results from A 90-Day Trial
MN Aslam, CM Bassis, IL Bergin, K Knuver, SM Zick, A Sen, DK Turgeon & J Varani
Background:
Epidemiological studies have shown an inverse relationship between calcium intake and colon cancer incidence. In two long-term (15-18 month) studies in mice, Aquamin more effectively suppressed colon polyp formation than calcium alone. The goal of this latest study was to determine if this beneficial activity was mediated indirectly through effects on the gut microbial population and/or changes in gut microbial metabolic activity by measuring the effects of Aquamin on colonic microbial community and metabolomic profile.
Thirty healthy human participants (10/group) were enrolled in a 90-day trial in which Aquamin (800mg Ca/day) was compared to calcium alone or placebo. Before and after the intervention, colonic biopsies and stool specimens were obtained and analysed.
Results:
Compared to pretreatment values, intervention with Aquamin led to a reduction in total bacterial DNA (p=0.0001) and a shift in the microbial community (p=0.0087). Treatment with calcium also produced a decline in total bacteria, but much smaller than seen with Aquamin, while no reduction was observed with placebo in the colon. In parallel with microbial changes, a reduction in total bile acid levels (p= 0.0375) and a slight increase in the level of the short-chain fatty acid (SCFA) acetate in stool specimens (p<0.0001) from Aquamin-treated participants was noted. No change in bile acids or SCFAs was observed with calcium or placebo.
What this means:
For the first time we have demonstrated in a trial that the microbiome does change with Aquamin compared to placebo or calcium alone. This is important.
We see a decrease in bacteria with Aquamin. While we do not understand this fully yet, we do know from previous research that Aquamin has positive effects on the gut. The decrease in bacteria is at phyla (family) level – this needs to be at species and strain level. This is in hand. Finally, we show a decrease in bile acids and an increase in fatty acids – both known to be positive events in the gut.
Figure below: ThetaYC (qYC) distances for comparison of pre- vs post-supplementation values in gut bacterial community composition for colon (A) and stool (B) samples. Higher values reflect greater differences. ** reflects significance at p=0.0087 relative to calcium. The insets show that the majority of the Aquamin (colon and stool) samples were above the median value for all samples. The majority of placebo and calcium samples were at or below the combined median value.
Figure Above: Alterations in the relative abundance of major gut phyla with Aquamin supplementation. The change in the relative abundances pooled by phyla and assessed by pre- post-intervention analysis among three interventions in colon and stool specimens. ** reflects significance at p<0.01, *** reflects significance at p<0.001 and **** reflects significance at p<0.0001.