In female cynomolgus macaques eating a Western diet, lower levels of the bacterium Prevotella copri are linked to greater diversity in gut microbes and higher levels of Eubacterium siraeum, which in...

We analyzed one assertion and found that in female cynomolgus macaques eating a Western diet, lower levels of the bacterium Prevotella copri are linked to greater diversity in gut microbes and higher levels of a different bacterium called Eubacterium siraeum, which in turn are associated with higher levels of HDL cholesterol in the blood [1]. HDL cholesterol is often called “good” cholesterol because it helps carry fat away from arteries. What we’ve found so far leans toward a connection between reduced Prevotella copri and higher HDL in this specific group of animals on this type of diet. There were no studies in our review that contradicted this pattern. However, this is based on a single assertion, and we have not reviewed enough studies to say whether this link holds in males, other primate species, or under different diets. The mechanism — how changes in one gut bacterium might influence another and then affect blood cholesterol — is not fully explained in the evidence we’ve seen. We also don’t know if this relationship would look the same in humans. Our current analysis shows a possible association in this narrow context, but more research would be needed to understand how consistent or meaningful this link is. For now, if you’re interested in gut health and cholesterol, this suggests that the balance of gut bacteria may play a role — but it’s just one piece of a much larger puzzle.