Jeanette Brooks: Welcome to Medicine With a Fork, a podcast from the nonprofit Gaples Institute. We are an educational nonprofit working to advance the role of nutrition and lifestyle in medicine.
I'm Jeanette Brooks, the Director of E-Learning Experience at the Gaples Institute. And today our topic is “Health in a Nutshell.” We're covering important evidence that clinicians will want to know about nuts.
And to help us unpack that is the Gaples Institute's Executive Director, Dr Stephen Devries. He's a preventive cardiologist, and he's spent more than 30 years working to help patients and clinicians understand the health impact of diet and lifestyle. Steve, great to have you here!
Dr Stephen Devries: Nice to be with you Jeanette, thank you.
Brooks: So let's go ahead and jump right in. I know for a long time, nuts were kind of shunned by people who were concerned about their weight—but now they seem to be making quite a comeback; they're kind of having a moment. And they're being recognized, in fact, as a much healthier choice than a lot of other snacks. Can you tell us why that is? What's the magic about nuts, and what sort of health benefits do they bring to the table?
Devries: Nuts are associated with a really wide range of some very impressive health benefits. Consider these, for example: one ounce of nuts, which is equivalent to about a medium handful, eaten five days a week, has been linked to a 20% reduction in the risk of heart disease. And for individuals with diabetes, the reduction is 34%. So it's huge! And nuts are also linked to a lower risk of diabetes, nuts have been shown to reduce inflammation and specifically to be associated with reduced markers of CRP and interleukin six, and as surprising as it may seem, several large studies show that nut intake is associated with improved longevity. So a lot of information about the benefits of nuts.
Brooks: That really is impressive. A lot of good reasons there to make nuts part of the conversation when we talk to patients about healthy foods. How have you seen the research bear this out, though? Like, have nuts been a prominent part of any randomized clinical trials?
Devries: Yes, they have. One, a very well-known one, is PREDIMED. PREDIMED is a primary prevention study of a Mediterranean-style diet. It had over 7000 participants and it included an intervention arm that consisted of individuals assigned to take a Mediterranean-style diet enhanced with nuts, which was about one ounce of nuts per day.
And what they showed in PREDIMED was that those in the Mediterranean-style diet enhanced with nut group, that they had a 28% reduction in major cardiovascular events compared to controls.
Brooks: Wow. And that's just for one ounce. That's some fascinating evidence. So does it matter what kind of nuts we're talking about? Do these kinds of benefits apply to all nuts, or are there any kinds of nuts that maybe patients should avoid?
Devries: All nuts have been shown to have beneficial effects—even peanuts, which technically are legumes—but walnuts and almonds are the most studied. So if you're looking for the weight of the evidence, I would say walnuts and almonds.
Brooks: That's really interesting, and also good to know about peanuts, that their nutritional profile lines right up with the same benefits of other nuts. So Steve, do we know what it is about nuts and their chemical makeup that makes them so protective?
Devries: Nuts really are a package of many protective nutrients. First of all, nuts have healthier versions of fat and they vary depending on the particular nut. For example, walnuts are rich in Omega-3s. Almonds are rich in monounsaturated fat, the same kind of fat found in extra-virgin olive oil. Nuts also are loaded with fiber, and apart from grains, nuts are the type of food actually richest in fiber. And much of that fiber, in addition to other compounds found in nuts, serve as a prebiotic, which means they act as a fuel substrate for healthy diversity in our gut microbiome. So again, nuts have a role to play in this fascinating story that's unfolding about the health of our body relating to the health of our microbiome.
Nuts are also rich in plant sterols, and these are compounds that reduce the absorption of cholesterol from the digestive tract. Nuts have lots of vitamin E and we know from previous work that vitamin E in supplements has not generally been borne out to be a beneficial for health, but vitamin E found naturally in food has been shown to be helpful.
Nuts also are very high in magnesium, a cardioprotective compound that we know, in addition to many other factors, is associated with reduction in blood pressure. All of these factors are above and beyond the fact that nuts are a very healthy source of plant-based protein. So we've got all of these actions working together to make the package that is in nuts.
Brooks: It sounds like a lot of facets coming together to make this really a superstar food. What about preparation? I know some people prefer to eat certain kinds of nuts raw. Like, I like raw cashews, but I also like roasted almonds. Is there a difference in their nutritional profile if they're roasted or not?
Devries: Well, what's important to know is that many of the health-promoting polyphenols that are found in the skin of nuts are actually lost during the roasting process. So overall, it's probably a bit better to recommend unroasted nuts, but it's good to know that both unroasted and roasted have been shown to be beneficial.
Brooks: You mentioned earlier that nuts have one of the healthiest forms of fat. But one concern that I'm sure patients might find hard to shake is the idea that nuts are pretty high in fat and in calories, right? So how does that factor in? How should clinicians answer patients' concerns about fat and calories and weight gain when they have this conversation about nuts?
Devries: Well, you're absolutely right, nuts are truly calorie-dense, but here's the interesting part. When nuts are consumed in moderation, they are not associated with weight gain. In fact, in a large prospective study that included over 120 000 individuals, daily nut consumption was associated with actual weight loss over a four-year period.
Here are some reasons why: It's surprising to some, to realize that our bodies don't absorb all of the calories from nuts. In fact, from whole nuts, studies show that typically people will absorb only 75% to 85% of the caloric content. And what happens to the rest? It just passes through the digestive tract unchanged.
So that's one mechanism why nuts don't lead to weight gain. The other effect is that nuts are highly satiating. And so people who eat nuts tend to eat less of other presumably less healthful products after they consume nuts.
Brooks: You talked about moderation. It sounds like it's not okay to just go wild and eat and unlimited quantity, right? Tell us a little bit about what is a healthy boundary.
Devries: Well, you're right. Obviously eating big bags of nuts is not a good plan at all. A healthful portion is about an ounce, which would be equivalent to a medium-sized handful, as often as once a day. And best of all is if those nuts are eaten in place of other less-healthy snacks, instead of in addition to them.
So that would be good advice to recommend to your patients: to not only add nuts, but to subtract the unhealthy snacks that they might be eating and replace them with healthful portions of nuts.
Brooks: That makes total sense. Steve, what other practical tips can you leave us with regarding nuts? Both for the clinician who's trying to help their patient add nuts to their diet and also for clinicians themselves as part of their own self-care and healthy choices?
Devries: Well, nuts are a low-maintenance snack, no refrigeration required, and they can stay fresh for a long time. So those are great attributes off the bat. For patients, I would say specifically to recommend perhaps that your patients carry a small bag of nuts with them, and keep them in their briefcase or purse or in the car. And that way, when they're hungry, they may not be as tempted to walk into a donut shop. Instead they can reach for the bag of nuts they already have with them.
And for clinicians, in terms of self-care, you might want to consider, as I have done, keeping a small bag of nuts in your coat or close by, so that they're available for a quick snack you might grab when you have just a few minutes in between patients.
Brooks: That's great advice, especially because of the satiety factor that you mentioned earlier, to quickly meet that need when you're really hungry.
Steve, thanks so much for sharing all this. It helps a lot to know the science behind why nuts are such a good choice.
Devries: Great to be with you. Thank you.
Brooks: And for our listeners, the nonprofit Gaples Institute offers a toolkit of really effective resources to help you build not only your nutrition knowledge about nuts and a whole host of other nutrition topics, but also your patient-counseling skills. We've created a unique and self-paced interactive online course for health professionals with patient education materials included, and it's four hours of continuing medical education.
If you're an AMA member, you do receive a discount and you can find out more at NutritionForDocs.org
On behalf of the Gaples Institute, thanks for joining us today on Medicine With a Fork—we look forward to seeing you next time.
©Copyright 2021 - Gaples Institute
Disclosure Statement: Dr. Devries is the salaried executive director and Jeanette Brooks is the salaried director of e-learning for the Gaples Institute, an educational nonprofit that offers accredited continuing medical education courses for sale to health professionals. Courses are developed entirely through philanthropy to the Gaples Institute, a nonprofit that does not seek or receive corporate support. Neither Dr. Devries nor Jeanette Brooks receive royalties or personal consideration of any kind from the sale of these courses.
Financial Support Disclosure Statement: This podcast was developed with no corporate support.
et al. Nut Consumption in Relation to Cardiovascular Disease Incidence and Mortality Among Patients With Diabetes Mellitus. Circulation Research
. 2019;124(6):920–929.Google Scholar
et al. Nut Consumption and Risk of Cardiovascular Disease. J Am Coll Cardiol
. 2017;70(20):2519–2532.Google Scholar
FB. Changes in diet and lifestyle and long-term weight gain in women and men. N Engl J Med
. 2011;364(25):2392–2404.Google Scholar
JA. Metabolizable Energy from Cashew Nuts is Less than that Predicted by Atwater Factors. Nutrients
. 2018;11(1).Google Scholar
et al. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts. New England Journal of Medicine
. 2018;378(25):e34.Google Scholar