The interesting link between gum health and metabolic syndrome
Periodontal or gum disease is a significant risk factor for metabolic syndrome, considered to be a group of conditions that increase the risk of heart disease and diabetes. In a new study, researchers at Tokyo Medical and Dental University (TMDU) found that infection with Porphyromonas gingivalis, the bacterium that causes periodontal disease, causes metabolic dysfunction of skeletal muscle – the precursor of metabolic syndrome – by altering the composition of the intestinal microbiome.
Periodontal bacteria have long been known to cause inflammation in the oral cavity, but inflammatory mediators also increase systemically. As a result, sustained infection with periodontal bacteria can lead to increased body weight and increased insulin resistance, a hallmark of type 2 diabetes. The function of insulin is to help transfer blood glucose to the tissues and – most importantly – to the skeletal muscle, where a quarter of the total glucose is stored.
Surprisingly, insulin resistance plays a key role in the development of metabolic syndrome, a group of conditions that include obesity, altered lipid metabolism, high blood pressure, high blood glucose levels and systemic inflammation. Although the skeletal muscle plays a key role in lowering blood glucose levels, a direct link between periodontal bacterial infection and metabolic function of skeletal muscle has not yet been established.
“Metabolic syndrome has become a widespread health problem in the developed world,” says the study’s lead author, Kazuki Watanabe. “The purpose of our study was to investigate how periodontal bacterial infection could lead to metabolic changes in skeletal muscle and thus the development of metabolic syndrome.”
To achieve their goal, the researchers first investigated antibody titers against Porphyromonas gingivalis in the blood of patients with metabolic syndrome and found a positive correlation between antibody titers and increased insulin resistance. These results showed that patients with metabolic syndrome were susceptible to Porphyromonas gingivalis infection and thus had an immune response, producing antibodies against germs.
To understand the mechanism behind the clinical observation, the researchers then used an animal model. When Porphyromonas gingivalis was given to mice through a high-fat diet (a prerequisite for the development of metabolic syndrome), the mice developed increased insulin resistance, fat infiltration, and lower muscle glucose uptake in the skeletal muscle, compared to those who did not receive the bacteria.
But how was this bacterium capable of causing systemic inflammation and metabolic syndrome? To answer this question, the researchers focused on the intestinal microbiome, the network of bacteria present in the intestine, with which the body coexists symbiotically. Curiously, the researchers found that in mice given Porphyromonas gingivalis, the gut microbiome was significantly altered, which could lower insulin sensitivity.
“These are striking results that provide a mechanism for the relationship between the Porphyromonas gingivalis periodontal bacterial infection and the development of metabolic syndrome and metabolic dysfunction in skeletal muscle,” says the study’s author, Professor Sayaka Katagiri.
Because the gums have very important roles, from fixing the teeth and protecting the alveolar bone, to aesthetic aspects, we need to pay close attention to their care in two ways: good hygiene and creating an inexhaustible source of nutrients to support the gums’ health. The Dahna app can be an extremely useful tool for a healthy and nutritionally balanced diet, which we kindly invite you to download and test.