Eating walnuts doesn't seem to change levels of a protein in the blood called ICAM-1, which is linked to inflammation, at least based on studies in adults.

What we've found so far is that eating walnuts does not appear to change levels of ICAM-1 in adults [1]. ICAM-1 is a protein in the blood that is associated with inflammation, and some foods may influence its levels. However, based on the evidence we’ve reviewed, walnuts don’t seem to have a noticeable effect on this particular marker. Our analysis of the available research shows that all 45.0 supporting assertions point to no meaningful change in ICAM-1 levels after consuming walnuts [1]. There were no studies or assertions that reported a decrease or increase in ICAM-1. This means that, at least in the studies we examined, adding walnuts to the diet didn’t shift this specific inflammation marker up or down. We want to be clear that this doesn’t mean walnuts have no effect on health — only that, based on what we’ve seen so far, they don’t seem to influence ICAM-1 levels in adults. There may be other markers of inflammation or health that are affected, but for ICAM-1 specifically, the evidence we’ve reviewed leans toward no change [1]. It’s also important to note that our current analysis is based on a limited type of evidence — just one set of assertions, all pointing in the same direction. We don’t yet have a full picture of how walnuts might affect different people or whether longer-term intake could make a difference. As more data becomes available, our understanding may evolve. Practical takeaway: If you're eating walnuts hoping to lower ICAM-1 levels, the evidence we’ve reviewed so far doesn’t support that effect — but walnuts may still offer other benefits unrelated to this specific protein.