To maintain good intestinal transit, fiber consumption is essential. But according to a French study, their benefits go beyond the digestive sphere and also concern our cardiovascular health.
Their benefits on intestinal transit are constantly praised. Fiber should be part of a balanced diet. But they would also possess other virtues.
Fibers, a key part in the prevention of cardiovascular diseases
Researchers from Inserm and Paris-Cité University were interested in the role of the intestinal microbiota in the development of atherosclerosis, which is the deposition of atherosclerotic plaques in the arteries, a prelude to the appearance of a cardiovascular pathology such as myocardial infarction.
Mice were therefore put on a diet low in fiber and high in fat, in order to observe the effects of this diet on the rodents’ bodies. Results: Mice fed a high-fat, low-fiber diet experienced “an increase in metabolic risk factors linked to cardiovascular diseases (significant weight gain, hyperglycemia, insulin resistance, increased liver weight and its triglyceride content, etc.)” note the researchers, unsurprisingly.
On the other hand, and more surprisingly, “un overall imbalance of the microbiota – in its composition and in its immune response –, resulting in particular in an alteration in the production of metabolic derivatives by the bacteria which compose it. In particular, short-chain fatty acids, resulting from the fermentation of fibers and recognized for their positive impact on health, are produced in lower quantities. say the scientists.
It is this imbalance itself which is associated with a worsening of the manifestations of atherosclerosis at the vascular level. “However, fiber supplementation helped counter these effects.” experts estimate.
The absence of fiber, more than the fat content, is harmful to cardiovascular health
“These results indicate that, in mice subjected to a fatty diet, a pathological intestinal microbiota accelerates the development of atherosclerosis. explains Soraya Taleb, Inserm research director at the Paris Cardiovascular Research Center (Inserm/Paris Cité University). “Our observations also show that more than its high fat content, it is the low quantity of fiber contained in this diet which is at the origin of the imbalance of the microbiota and therefore of the worsening of atherosclerosis. This further supports the idea of a primordial role of fiber in structuring a healthy microbiota and in the prevention of systemic inflammatory diseases such as cardiovascular diseases.“.
Trace the cells to understand the mechanism
How can intestinal transit promote atherosclerosis? To understand this, scientists used tracing techniques to follow the migration of immune cells.
This method made it possible to “cto confirm that these were indeed the cells coming from the mesenteric lymph nodes (fold of the peritoneum membrane which surrounds the intestine) which, after passing from the intestine into the blood circulation, accumulated in atherosclerotic plaques and thus contributed to the development of atherosclerosis..
According to Soraya Taleb, “the fact that we have been able to observe that immune cells are capable of migrating from the intestine to the periphery and thus generating systemic inflammation aggravating atherosclerotic plaques adds a new dimension to our understanding of the link between diet, intestine, microbiota and atherosclerosis”.
Before concluding : “Additional work will need to be carried out to identify which bacteria in the microbiota are involved in this mechanism, in order to be able to consider targeted therapeutic approaches and study these mechanisms in humans..