Dear Dr. Roach: I have seen numerous articles extolling the advantages of eating nuts because they are a good fat. I often have wondered if it matters whether the nuts are raw or roasted. Would you please explain the difference and the impact on ones health? D.O.
Answer: Scientists believe that nuts are healthy for us based on three different types of evidence. One is called epidemiological: People who eat nuts live longer and have less heart disease than people who dont eat nuts. This suggests nuts are good for you, but its not definitive. People who eat nuts may do other healthy things, which could be the real reason they live longer (this is called confounding).
A second line of evidence comes from watching what happens to factors that we believe are related to disease. People who add a reasonable amount of nuts to their diet often have improvements in their cholesterol levels. They also help some people lose a few pounds, possibly because the fat and protein in nuts makes them more filling than the (often processed) starches many people eat. This is also not definitive, because there are treatments that lower cholesterol but dont make people live longer or improve health.
The third is evidence from a large, interventional study on diet. A group of people were randomly assigned to either add more nuts to their diet, or to make no change (or some other change) in their diet. At least one study showed that when people changed their diet to include more nuts and seeds (but also more fruits and vegetables, more healthy oils, like olive oil, and less meat), they had less heart attacks than the group that did not change their diet. This evidence is strong, but its not clear whether its one change in the diet (just nuts) or all the changes in the diet that are responsible for the observed benefit.
In none of these kinds of studies were raw nuts compared against roasted. However, the composition of the fats does not change in nuts and seeds when roasted, and most experts believe it does not make a difference. So, I recommend partaking in nuts however you like them best.
Just one serving a day (30 grams or an ounce) makes a difference. They are quite high in calories, so its wise not to overdo it. If you dont like nuts (and obviously for those allergic), not eating them is not a major risk for developing heart disease.
