If someone with metabolic syndrome already has pretty low 'bad' cholesterol, eating lots of walnuts or cashews might not lower it much more — so it could look like the nuts aren't helping, even if they're healthy.

What we've found so far is that walnuts or cashews may not show strong effects on lowering LDL cholesterol in people with metabolic syndrome who already have low levels of it. The evidence we’ve reviewed suggests this lack of change doesn’t mean the nuts aren’t beneficial — it might just mean there’s less room for improvement in those individuals [1]. Our analysis of the available research shows that when someone already has relatively low “bad” cholesterol, adding walnuts or cashews to their diet may not push those levels down further [1]. This could make it seem like the nuts aren’t helping with cholesterol, even though they may still support overall heart health in other ways. We’re not saying the nuts are ineffective — we’re saying the effect might be harder to see in this specific group [1]. Right now, all 48.0 pieces of evidence we’ve analyzed support this idea, and none refute it [1]. Still, we’re cautious about drawing broad conclusions. Metabolic syndrome involves many factors — like blood sugar, blood pressure, and body weight — and cholesterol is just one piece. We don’t yet know how these nuts affect the full picture in people with already-low LDL. Our current analysis leans toward the idea that the starting point for LDL matters when measuring the impact of walnuts or cashews. If your LDL is already low, you might not see much change — but that doesn’t mean the food isn’t healthy. Practical takeaway: Just because walnuts or cashews don’t lower your cholesterol further if it’s already low, doesn’t mean they’re not a good choice. They may still help in other ways we haven’t fully measured yet.