This mechanism could be why fermented foods benefit immune health
How do fermented foods, such as yogurt and sauerkraut, benefit health, and the immune system in particular? A new study has uncovered a cell mechanism unique to humans and great apes that could offer an explanation.
The mechanism involves a cell receptor called HCA3. A cell receptor is a protein that allows specific signals to enter cells when a matching molecule binds to it.
While scientists have known about HCA3 for several years, it was not clear what role it played. Only humans and great apes have the HCA3 receptor. Other mammals, such as mice, do not.
Now a team from the University of Leipzig in Germany, together with other colleagues, have discovered that HCA3 is receptive to a particular metabolite, or byproduct, of lactic acid bacteria activity.
The metabolite has the name D-phenyllactic acid (D-PLA). When it binds to HCA3, it triggers a signal that alerts the immune system to the presence of the bacteria.
The researchers describe their findings in a recent PLOS Genetics study paper.
"We are convinced," says senior study author Claudia Stäubert, who works in the Medical Faculty at the University of Leipzig, "that this receptor very likely mediates some beneficial and anti-inflammatory effects of lactic acid bacteria in humans."
Lactic acid bacteria and fermented foods
Lactic acid bacteria are microbes that can ferment certain foods. For example, they can produce yogurt from milk and sauerkraut from cabbage. They are also present in the gut of most mammals.
The bacteria belong to a large group of "functional microorganisms" that ferment foods from plant and animal sources. These microbes alter food in many ways that humans make use of and are beneficial to health.
Not only can fermentation microbes alter the texture, flavor, and aroma of food, they also extend storage life through preservation, increase absorption of nutrients, break down toxins, stimulate probiotic activity, and produce antioxidants.
Research has shown that consuming fermented foods brings health benefits that are relevant to cancer, heart disease, allergies, diabetes, and gastrointestinal disorders.
However, while many studies have linked lactic acid bacteria to various health benefits, there is little understanding of the underlying biology.
Stäubert and her colleagues investigated this question by exploring the role of hydroxycarboxylic acid (HCA) receptors. These receptors, note the authors, "are regulators of immune functions and energy homeostasis under changing metabolic and dietary conditions."
