Cashews for cholesterol

When people ask us about snacking - and they do at almost every lecture we give - we tell them to eat nuts. Avoid the ones with the sweet coatings, like honey roasted, and stick with plain, raw or dry roasted. Best to be unsalted, but lightly salted is OK.

Because my goal is to get people to improve their diets and not to pressure people into following some "perfect" diet, we tell people to not worry too much about which nut to choose: "Which nuts? The ones you like." The Dietary Guidelines for Americans of 2010 specifically recommends that people consume more nuts as part of a healthy diet. The Food and Drug Administration allows manufacturers to state that "Scientific evidence suggests but does not prove that eating 1.5 ounces per day of most nuts, [such as name of specific nut,] as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease." The guidelines regarding this health claim specifically exclude making this claim about cashews, macadamia nuts, and Brazil nuts because of their higher levels of saturated fats.

Kraft Heinz Co. funded a piece of research carried out by an independent lab that looks at the impact of cashews on LDL cholesterol (the "bad" cholesterol) (Am J Clin Nutr doi:10.3945/ajcn.116.150037). Fifty-one adult men and women whose Body Mass Index was over 18 and less than 32 (clinically normal to moderately obese) and did not have heart disease, diabetes, or uncontrolled high blood pressure. For two four-week periods the participants received all of their meals from the researchers, eating breakfast each day in the lab and then taking home the day's lunches and dinners along with meals for the weekends. The authors worked with dietitians to create meal plans for each person that were designed to maintain their starting weight and provided about 49% of calories from carbohydrate, 16% of calories from protein, and 33% of calories from fat.

The individualized diets "were designed to reflect typical intakes of US adults," - that is, to represent a more or less "typical American diet." For one four-week period the participants received a daily snack of baked potato chips, which was accounted for in their weight-maintaining diet. For the other four weeks the participants were given a daily snack of cashews that represented the same number of calories.

At the start and end of each diet period the authors assessed the participants' cholesterol scores, comparing the scores at the beginning and end of each diet. Even though the participants were following a "typical American diet," after consuming between 1 and 2 1/4 ounces cashews for daily snacks for four weeks, the participants lowered their LDL cholesterol by an average of almost 5% and their total cholesterol by nearly 4% without affecting their HDL (good) cholesterol or their triglycerides.

What this means for you

As always, research that has been funded by someone who stands to gain from the outcome should be regarded with suspicion. That said, this appears to be a well-designed study, although we would love to know exactly which foods and in what amounts were considered a "typical American diet" and how that compared with the participants' usual diets. What we take from this is that if you like cashews better than other nuts, by all means, eat them: as with all nuts, bear in mind that they do contain calories and fat and take that into account in your daily consumption.

First posted: April 5, 2017