If you're 50 or older and eat a small handful of raw walnuts every day for six weeks, it might help your body build up healthy fats in your blood cells — a sign that walnuts are getting into your cells and doing their job.

What we've found so far is that eating 42 grams of raw walnuts daily for 6 weeks may increase levels of omega-6 fatty acids in the red blood cells of healthy adults over 50. Our analysis of the available research leans in this direction, based on the evidence we’ve reviewed. We looked at one key assertion from the data, which suggests that when adults aged 50 or older eat a small handful of raw walnuts each day for six weeks, it could help raise levels of healthy fats—specifically omega-6 fatty acids—in their red blood cells [1]. This change might mean that the nutrients from walnuts are being absorbed and incorporated into cells, which is a sign they’re having a biological effect [1]. The evidence we’ve reviewed shows 64.0 supporting points for this idea and no studies or assertions that contradict it [1]. However, we want to be clear: this is a narrow look at one specific outcome. Omega-6 fatty acids are a type of polyunsaturated fat that the body needs for brain function and cell growth. While they are often discussed in the context of balance with omega-3 fats, our current analysis does not address overall health effects, disease risk, or how this change in fatty acid levels impacts the body long-term. Our current analysis shows the evidence leans toward an increase in omega-6 fatty acid levels in red blood cells with daily walnut intake over six weeks. But we don’t yet know how meaningful this change is for health, or whether it applies equally to everyone over 50. Practical takeaway: If you're over 50, adding a handful of raw walnuts to your daily diet might change the fat profile in your blood cells. We’re still learning what that means for your overall health.