Health Claims

Eating walnuts or using vegetable oils instead of foods high in saturated fats can lower a type of 'lighter' bad cholesterol that's less likely to cause heart problems — but it doesn't seem to change the 'denser', more harmful type of bad cholesterol in people at risk for heart disease.

Swapping saturated fats like butter for unsaturated fats like olive oil doesn’t seem to help your body remove cholesterol better or change a key protein linked to cholesterol levels — so those things probably aren’t why this diet change helps lower bad cholesterol.

If you're at risk for heart disease, swapping out saturated fats for healthier fats from walnuts or vegetable oils won't raise a specific blood marker (called Lp(a)) that's linked to heart problems.

Replacing butter with oils like those in walnuts helps lower cholesterol because of the type of fat, not something special in the whole nut.

Eating walnuts or using vegetable oils instead of foods with saturated fats can lower bad cholesterol in people at risk for heart disease—by about 5 to 7%.

Eating a lot of macadamia nuts doesn’t really change your blood triglyceride levels — so if it helps your cholesterol, it’s probably not because it’s fixing your whole fat profile.

Eating lots of macadamia nuts might help improve your cholesterol levels and lower your risk of heart problems if you have slightly high cholesterol.

Eating about a handful of macadamia nuts every day might help lower bad cholesterol and improve heart health in people with slightly high cholesterol.

If people who are overweight or obese swap about 15% of their daily food calories with macadamia nuts for 8 weeks, it doesn’t seem to change their blood sugar or insulin levels in any noticeable way.

Eating macadamia nuts boosts a special healthy fat in your body by about a quarter, but even though it shows up in your blood, it doesn’t seem to improve metabolism in people who are overweight or obese.

Eating macadamia nuts might help lower cholesterol more in people who are overweight but not obese, especially if they have less body fat, compared to those with more body fat or obesity.

Eating macadamia nuts every day for two months might slightly lower bad cholesterol in people who are overweight or obese — but the change is pretty small and might not make a big difference.

Eating macadamia nuts every day — even if it adds about 97 extra calories — doesn’t make you gain weight or body fat if you're overweight and have belly fat, so they can be part of your regular diet without messing up your body composition.

Eating macadamia nuts every day might slightly improve blood clotting balance in men with high cholesterol, but the evidence isn't strong enough to be sure.

Eating a small handful of macadamia nuts every day for a month might help lower inflammation in men with high cholesterol, which could mean a lower risk of heart disease.

If men with high cholesterol eat a small handful of macadamia nuts every day for a month, it might help reduce harmful stress in their bodies that can lead to heart disease.

Eating nuts doesn't seem to make Mediterranean adults more likely to become overweight or obese over about two years.

People in Mediterranean countries who hardly ever eat nuts tend to gain about half a kilo more over two years than those who eat nuts a lot.

If you're an adult in the Mediterranean region and eat nuts at least twice a week, you're less likely to gain 5 kilograms or more over about two years compared to people who hardly ever eat nuts—even when accounting for things like how active you are or whether you smoke.

Eating a handful of walnuts every day for two months doesn’t seem to change key health numbers like good cholesterol, blood sugar, or inflammation in healthy white adults over 50 — so the heart benefits of walnuts might only show up in certain types of fats in the blood.

Eating a small handful of walnuts every day for two months might help lower bad cholesterol and a blood protein linked to heart disease in healthy older white adults.

Eating walnuts probably doesn't change certain blood proteins linked to heart health for most adults, but big servings might lower one of them — Apo-B — so more research is needed to be sure.

Eating walnuts probably won't raise your 'good' cholesterol (HDL) enough to make a real difference, even if you eat less than a small handful a day.

Eating walnuts might help lower unhealthy fat levels in your blood, especially if you start with high levels, have obesity, or only eat them for a short time.