Eating walnuts every day for up to 6 months doesn’t really change your 'good' cholesterol levels — it stays about the same as if you didn’t eat them.

What we've found so far is that the evidence does not support the idea that eating walnuts increases HDL cholesterol levels in adults. Our analysis of the available research shows that walnut consumption, even daily intake for up to six months, does not appear to have a meaningful effect on 'good' cholesterol [1]. While walnuts have been linked to benefits for other aspects of cholesterol metabolism, the data consistently point to little to no change in HDL levels [2]. We reviewed two assertions from the scientific literature, with a total of 95.0 supporting instances and no refuting ones. However, it’s important to clarify: all supporting evidence actually aligns with the conclusion that walnuts do not raise HDL cholesterol. In one analysis, researchers observed that people who ate walnuts daily for up to six months showed no significant change in their HDL levels compared to those who didn’t [1]. Another assertion echoed this, noting that while walnuts may support heart health in other ways—such as improving LDL or triglyceride levels—they do not meaningfully increase HDL [2]. Our current analysis shows a consistent pattern across the evidence we’ve examined: walnuts are not linked to higher HDL cholesterol. That doesn’t mean they lack cardiovascular benefits—just that boosting 'good' cholesterol doesn’t appear to be one of them. We’re basing this on what we’ve reviewed so far, and our understanding could evolve as more data become available. Practical takeaway: If you're eating walnuts to improve heart health, they may still help in other ways—but don’t count on them to raise your good cholesterol.