Pistachio Nut Consumption and Serum Lipid Levels

Abstract

Objective: Clinical and epidemiological studies have reported the beneficial effects of tree nuts and peanuts on serum lipid levels. We studied the effects of consuming 15% of the daily caloric intake in the form of pistachio nuts on the lipid profiles of free-living human subjects with primary, moderate hypercholesterolemia (serum cholesterol greater than 210 mg/dL).

Methods: Design: Randomized crossover trial. Setting: Outpatient dietary counseling and blood analysis. Subjects: 15 subjects with moderate hypercholesterolemia. Intervention: Fours weeks of dietary modification with 15% caloric intake from pistachio nuts. Measures of Outcome: Endpoints were serum lipid levels of total cholesterol, HDL-C, LDL-C, VLDL-C, triglycerides and apolipoproteins A-1 and B-100. BMI, blood pressure, and nutrient intake (total energy, fat, protein, and fiber) were also measured at baseline, during, and after dietary intervention.

Results: No statistically significant differences were observed for total energy or percent of energy from protein, carbohydrate or fat. On the pistachio nut diet, a statistically significant decrease was seen for percent energy from saturated fat (mean difference, −2.7%; 95% CI, −5.4% to −0.08%; p = 0.04). On the pistachio nut diet, statistically significant increases were seen for percent energy from polyunsaturated fat (mean difference, 6.5%; 95% CI, 4.2% to 8.9%; p<.0001) and fiber intake (mean difference, 15g; 95% CI, 8.4g to 22g; p = 0.0003). On the pistachio diet, statistically significant reductions were seen in TC/HDL-C (mean difference, −0.38; 95% CI, −0.57 to −0.19; p = 0.001), LDL-C/HDL-C (mean difference, −0.40; 95% CI, −0.66 to −0.15; p = 0.004), B-100/A-1 (mean difference, −0.11; 95% CI, −0.19 to −0.03; p = 0.009) and a statistically significant increase was seen in HDL-C (mean difference, 2.3; 95% CI, 0.48 to 4.0; p = 0.02). No statistically significant differences were seen for total cholesterol, triglycerides, LDL-C, VLDL-C, apolipoprotein A-1 or apolipoprotein B-100. No changes were observed in BMI or blood pressure.

Conclusion: A diet consisting of 15% of calories as pistachio nuts (about 2–3 ounces per day) over a four week period can favorably improve some lipid profiles in subjects with moderate hypercholesterolemia and may reduce risk of coronary disease.

• pistachio nuts
• cholesterol
• lipoprotein
• diet
• coronary heart disease

Supported by an unrestricted small grant from the California Pistachio Commission.

We are indebted to our subjects for their dedicated participation in the study, to Kathy Bough, RD and Eileen Brown, RN for their assistance in carrying out the study, and to Kathleen McMahon, PhD, RD for technical review of the manuscript.