Why are nuts associated with decreased mortality, but not peanut butter?
According to the largest study of risk factors for death in human history, a poor diet causes more deaths than anything. Cigarettes only kill about 8 million people a year, whereas humanity’s diet kills millions more, as you can see below and at 0:20 in my video Do the Health Benefits of Peanut Butter Include Longevity?.
What are the worst aspects of our diet? Processed meat? Twinkies? Soda? No, the five deadliest things about our diet are: not enough fruit, not enough whole grains, not enough vegetables, too much salt, and not enough nuts and seeds, as shown here and at 0:42 in my video.
Nuts should come as no surprise since interventional trials have shown that eating nuts improves artery function, and arterial diseases like heart disease are among our leading killers. But that’s not all nuts can do. They may also improve blood sugar control, lower cholesterol, suppress inflammation, reduce oxidative stress, and feed our friendly gut flora. Do all nuts do that, or just tree nuts?
What about peanuts and peanut butter? About half of peanut consumption in the United States is from peanut butter, but the link between peanut butter consumption and mortality has not been evaluated thoroughly. To get that specific, we can call on the National Institutes of Health-AARP study, the largest prospective health and diet study in history that followed more than half a million people since the 1990s.
Researchers found that nut consumption in general appeared to protect against all-cause mortality, meaning nut-eaters live—on average—longer lives. Specifically, they are less likely to die from cancer, cardiovascular disease, liver disease, respiratory disease, kidney disease, and infectious causes (so, maybe nuts help immunity as well). However, no such associations were found for peanut butter. So, when it comes to living longer, peanut butter doesn’t seem to count. Why?
Well, we know peanut butter consumers tend to eat more meat, smoke cigarettes, and are less likely to exercise, but the researchers controlled for all those factors, as well as their alcohol consumption, fruit and veggie intake, education, and more. So, it’s not like the peanut butter eaters were just eating more white bread sandwiches or something. (The researchers didn’t control for sugar, though, so it’s possible they could have been eating more sugary jelly.)
Another explanation: It could be the processing that goes into making peanut butter—the added trans fat, oil, salt, and sugar. But regular nuts are also often eaten with added oil, sugar, and salt.
Could it just be the peanuts themselves? Technically, they aren’t nuts, so maybe they don’t have the same benefits. But no, a meta-analysis of all such studies found the same nut-like benefits for whole peanuts, but not peanut butter.
Well, one thing missing from even no-salt, oil-free, sugar-free nut and seed butters is intact cellular structure. As I noted in How Not to Diet, no matter how well we chew whole or chopped nuts, some of the nutrients remain trapped in tiny particles that deliver a bounty of prebiotic goodness to our friendly gut flora. That makes me wonder if there would have been any difference between chunky and smooth peanut butter.
Meanwhile, there is “compelling evidence” to recommend eating nuts (preferably raw nuts over salted or toasted, and whole or chopped nuts rather than nut butters) at least three times a week to maximize our chance of living a longer and healthier life.
Doctor’s Note
The healthiest nut may be walnuts. See Walnuts and Artery Function.
Won’t nuts make you fat, though? See Nuts and Obesity: The Weight of Evidence.
I mentioned my book, How Not to Diet, which you can read more about here. (All proceeds from my books are donated to charity.)
