If you’re looking to improve your heart health, it may be worth adding almonds to your snack mix, according to a recent study in the American Journal of Clinical Nutrition.
Researchers found that replacing typical snacks like chips and cookies with almonds lowered LDL (bad) cholesterol levels and improved endothelial function (which involves the membrane inside the heart and blood vessels that’s responsible for clotting, relaxation, and contraction).
Looking at a four-day food diary from 6,802 adults, researchers found that those who ate almonds—the median amount of almonds eaten was five grams, or about four almonds, daily—had fewer markers for cardiovascular disease risk and a healthier diet overall, including higher intakes of protein, vitamin C, and fiber, according to lead study author Wendy Hall, Ph.D., head of the Nutrition Metabolic Research Unit at King’s College London.
“The takeaway is that this is a very simple dietary strategy, involving replacing typical snacks—other than fruit—with whole almonds,” she told Runner’s World. “It improves that capacity of arteries to relax in response to increased blood flow, an independent predictor of cardiovascular disease.”
In terms of why, she added that there isn’t one sole reason, but likely a combination of two major effects. One is that replacing those other snack foods would lower your consumption of salt, sugar, and saturated fat, she said. The other is that almonds are nutritionally dense foods that are high in fiber, good-for-you plant compounds (like polyphenols, which are packed with antioxidants), and full of micronutrients like magnesium, vitamin E, and riboflavin, which have all been shown to improve vascular function, Hall said.
A caveat here is that the trial was funded by the Almond Board of California—which doesn't automatically throw the findings into question, but as a 2018 research review in the American Journal of Public Health suggests, corporate interests and industry involvement are important to highlight.
That said, the study does seem to rigorously avoid the “correlation doesn’t equal causation” trap. Observational nutritional studies can be notoriously tricky in this regard because it’s challenging to prove causation when so many other factors are at play. For example, if a group of runners all get faster eating a certain food during training, that doesn’t necessarily mean that specific food causes an increase in speed; it may be that being timed and observed is what motivates them to run faster, and what they eat is simply correlated with those performance improvements.
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But this study’s use of a randomized, controlled trial does demonstrate causation, Hall said, because almond intake was tracked over the four-day period, as well as nutrient levels and cardiovascular disease risk indicators. When it came to body fat, though, there was some correlation involved there.
“Those who consumed the whole almonds during the four-day period were more likely to have lower body fat,” Hall said. “This does not show that almonds caused lower body fat, but instead, that health-conscious individuals are more likely to eat whole almonds.”
It should be noted, though, that consuming more than 42.5 grams of almonds, or about 35 almonds, is not effective for weight loss, per a 2018 meta-analysis.
Previous research on the impact of almonds on heart health has yielded similar results. For instance, a 2014 study published in Free Radical Research found that eating almonds can reduce the risk of heart disease by keeping your blood vessels in top shape. (The antioxidants in almonds help reduce blood pressure and improve blood flow.)
That association, along with this recent 2020 study, suggests that consuming almonds, particularly when they’re bumping less-healthy options from your diet, can be part of other healthy strategies—like exercise—to reduce the risk of heart disease.
