Numerous studies have found that increased tree nut consumption is associated with lower risks of cardiovascular disease.
Nuts are nutritional powerhouses, boasting unsaturated fatty acids, proteins, fiber, phytochemicals, antioxidant compounds, and vitamins that offer cardiovascular and metabolic benefits.
Although nuts are an energy-dense food, regular nut consumption has been associated with lower risks of obesity—likely because they are rich in fiber, which can increase satiety.
When evaluating your diet, it’d be nuts not to consider heart health. But for most people, it doesn't take drastic measures to reduce risks of hypertension, cardiovascular disease, (CVD), and other health complications. Studies suggest heart health can be improved by eating more nuts—presuming you are not allergic to them.
Whether you're a healthcare practitioner looking to improve your own health, or want to advise your patients, here’s what research says about which nuts are best to eat, and how they could help keep heart failure and stroke at bay.
Nuts and heart health
Many studies have found that increased nut consumption is associated with lower risks of cardiovascular disease. This includes research published in the Journal of the American Heart Association in 2020, which involved three large cohorts.
For the study, researchers used data on more than 34,000 men from the Health Professionals Follow‐Up Study (1986-2012), 77,800 women from the Nurses’ Health Study (1986-2012), and more than 80,700 women from the NHS II (1991-2013) to examine the relationship between changes over 4 years in nut consumption and the risk of cardiovascular disease over the subsequent 4 years.
Their findings indicated that an increase of 0.5 servings of nuts daily—a full serving is 1 ounce—lowered the risk of cardiovascular disease, coronary heart disease, and stroke: CVD (relative risk [RR], 0.92; 95% CI, 0.86–0.98), coronary heart disease (RR, 0.94; 95% CI, 0.89–0.99), and stroke (RR, 0.89; 95% CI, 0.83–0.95).
This association was more significant for those who increased their nut consumption by more than 0.5 servings daily.
Researchers also found a link between a decrease in nut consumption and higher risks of deleterious cardiovascular outcomes over the subsequent 4 years: Individuals who cut nut consumption by ≥0.50 servings/day had a higher risk of developing CVD (RR, 1.14; 95% CI, 0.99–1.32), coronary heart disease (RR, 1.06; 95% CI, 0.88–1.28), and stroke (RR, 1.28; 95% CI, 1.02–1.60) when compared with those who maintained their nut consumption.
Another study published in Circulation Research in 2019, measured the impacts of eating nuts on cardiovascular disease in diabetes patients. Researchers analyzed data on more than 16,200 men and women with diabetes, collected between 1980-2014.
Researchers found that increased nut consumption was associated with a lower risk of incident cardiovascular disease and CVD mortality.
Compared with patients who didn’t change their nut eating habits after being diagnosed with diabetes, those who increased their nut consumption had an 11% lower risk of CVD, a 15% lower risk of coronary heart disease, a 25% lower risk of CVD mortality, and 27% all-cause mortality.
The authors concluded, “Our findings support the recommendation [that] including a variety of nuts as part of healthy dietary patterns is cardioprotective and provide[s] theoretical evidence that replacing animal‐based protein with plant‐based protein can be helpful in the prevention of CVD.”
The nutritional profile of nuts
Nuts boast a favorable nutritional profile, which offers cardiovascular and metabolic benefits. This includes unsaturated fatty acids, proteins, fiber, phytochemicals, and antioxidant compounds. Nuts also contain vitamins, like vitamin E and folate, and minerals, including calcium, potassium, and magnesium.
Researchers involved in the 2020 Journal of the American Heart Association study noted that these elements improve several cardioprotective factors, like blood lipid levels, endothelium function, systemic inflammation, oxidative stress, and insulin sensitivity.
Other studies have found that a daily serving of nuts can reduce total cholesterol concentration and low‐density lipoprotein cholesterol concentration, as well as triglyceride levels in certain participants.
Citing supportive evidence from other studies, the authors wrote: “In a pooled analysis of 25 controlled trials, daily nut consumption reduced total cholesterol concentration and low‐density lipoprotein cholesterol concentration by 10.9 and 10.2 mg/dL, respectively; nut consumption also reduced triglycerides in subjects with higher baseline levels (>150 mg/dL). A relatively large clinical trial (n=305) demonstrated a blood pressure-lowering effect of daily consumption of walnuts (30–60 g/d, depending on energy requirements) in elderly individuals, which may partially explain the lower risk of stroke associated with walnut consumption reported herein.”
Despite the fact that fat content makes nuts an energy-dense food, regular nut consumption has been associated with lower risks of obesity. This is likely because nuts are rich in fiber, which can increase satiety and hunger suppression, and delay gastric emptying.
Nuts may offer other benefits too. Some trials have indicated that nuts may improve metabolite circulation by reducing branch chain amino acid and acylcarnitines, and may help regulate the gut microbiome, but confirmation requires further research.
Which nuts are best?
The studies above focused on tree nuts and peanuts (which are technically legumes, not nuts). Tree nuts involved in the studies included: walnuts, almonds, Brazil nuts, cashews, pistachios, pecans, macadamias, hazelnuts, and pine nuts.
While the researchers didn’t analyze each nut individually, they concluded that tree nut consumption was generally associated with a lower risk of total cardiovascular disease. Interestingly, the findings of the 2019 Circulation study found that peanut consumption was only associated with lower all-cause mortality, rather than specific improvements to cardiovascular markers.
Other studies have shown that combinations of nuts may have different health effects. For example, a study cited in the Circulation article showed that regular consumption of a mix of walnuts, almonds, and hazelnuts induced a 28% reduced risk of experiencing major cardiovascular events compared with a control diet.
Another study also cited in that publication indicated that an increase in tree nuts, but not peanuts, is associated with a lower risk of cancer recurrence or mortality among patients with colon cancer.
While researchers hypothesize that this may be due to compositional differences (peanuts have a lower oil content, higher saturated fatty acid content and lower levels of some biological compounds) more research is required to confirm this.
What this means for you
Numerous studies have shown that tree nuts are associated with reduced risk of cardiovascular disease. And because of their high fiber content, nuts tend to make you stay fuller longer. However, keep in mind that nuts, because of their high fat content, are high in calories, so it's best to eat them in moderation.