Health Science Group
What does it mean, SCIENTIFICALLY, for something to be "good for the body"?
In the Health Science Group, we take the question of what it really means for something to be "good for the body" as our keyword, working to clarify, at both the whole-body and molecular levels, how naturally derived bioactive compounds affect a range of health problems and diseases. In particular, we focus on chronic inflammation, held to lie at the root of nearly all chronic diseases, and use animal models and cultured cells to comprehensively study how the things we eat each day act on the body's internal systems and what results from that in the body as a whole.
The two faces of endocannabinoids in obesity-driven systemic inflammation
Overeating and obesity trigger inflammation throughout the body, and this is known to underlie a range of disorders, from diabetes to chronic pain. We focus on the endocannabinoid system, particularly the CB2 receptor expressed on immune cells, which is known as one of the regulatory systems for systemic inflammation.
In nerve injury, the CB2 receptor suppresses inflammation and pain. In inflammation associated with diet-induced obesity, however, we found the opposite: it drives inflammation and pain in peripheral nerves (Hosoki et al., Life Sciences, 2024). We have further found that this switch between "suppressing" and "promoting" is closely tied to age: even on the same diet, the way inflammation-driving immune cells accumulate changes markedly at a relatively early stage, corresponding roughly to the teens through thirties in humans. We are now working to uncover, at the molecular level, why the CB2 receptor shows such two faces, and how the immune cells behind them are generated and recruited.
Approaching sex differences in metabolism through an edible-insect factor that fattens only males
Even when we eat the same thing, the body responds differently from person to person, and between the sexes. Metabolism in particular shows marked sex differences: it is men who tend to accumulate visceral fat and to suffer the more serious consequences of obesity. Yet why men are especially prone to weight gain remains almost entirely unexplained at the level of the body's mechanisms.
We found that when a certain edible insect powder is mixed in small amounts into a standard diet, male mice alone gain weight markedly, even though food intake and caloric intake are unchanged. Females do not gain weight at all, and this difference cannot be explained by levels of sex hormones alone. It points to a male-specific metabolic mechanism that does not rely on sex hormones. We are now working to identify the active component derived from this insect, and to pin down where in the body it acts to fatten only males, closing in on the metabolic core that gives rise to this sex difference.
How everyday components of the diet relate to inflammation and the body
What we examine in asking "what is good for the body" is not only the special compounds. We also pursue how familiar, everyday components of the diet affect the body. For example, we have reported that dietary fiber, generally regarded as "good for you," can in fact have adverse effects unless the type is chosen with care (Ito et al., ACS Pharmacology and Translational Science, 2024). Beyond this: how excess salt alters the course of obesity-driven inflammation and pain; how components of spices engage in the regulation of inflammation; and how, as in food allergy, the immune response to what we eat ripples through the body. We take up these diverse questions through a single lens: the relationship between what we eat each day and how the body responds.