In a study published in the Journal of the American College of Nutrition[i], researchers compared risk factors for heart disease, type 2 diabetes and metabolic syndrome of nut consumers versus those who did not consume nuts. Tree nut (almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts) consumption specifically, was associated with higher levels of high-density lipoprotein-cholesterol (good cholesterol) and lower levels of C-reactive protein, a marker for inflammation which can lead to a variety of chronic diseases including heart disease.
"One of the more interesting findings was the fact that tree nut consumers had lower body weight, as well as lower body mass index (BMI) and waist circumference compared to nonconsumers. The mean weight, BMI, and waist circumference were 4.19 pounds, 0.9kg/m2 and 0.83 inches lower in consumers than non-consumers, respectively," stated Carol O'Neil, PhD, MPH, RD, lead author on the paper and Professor at Louisiana State University Agricultural Center.
The study looked at 13,292 men and women (19+ years) participating in the 1999-2004 National Health and Nutrition Examination Surveys (NHANES). Intake was from 24-hour recall data and tree nut consumers were defined as those who consumed ≥ ¼ ounce/day.
Tree nut consumption was associated with a five percent lower prevalence of metabolic syndrome, a name for a group of risk factors that occur together and increase the risk for coronary artery disease, stroke and type 2 diabetes. In addition, tree nut consumers had a lower prevalence of four risk factors for metabolic syndrome: abdominal obesity, high blood pressure, high fasting glucose (blood sugar) levels and low high-density lipoprotein-cholesterol levels.
Moreover, previous research by the same authors[ii], showed that although tree nut consumption in the U.S. population is relatively low (mean intake of 1.19 ounces/day for nut consumers) nutrient intakes and diet quality were significantly improved when tree nuts were consumed. The latter appear to be associated with a greater intake of whole grains, fruits, and less saturated fatty acid, sodium and calories from solid fats, alcohol and added sugars. As a result, Dr. O'Neil recommends, "Tree nuts should be an integral part of a healthy diet and encouraged by health professionals--especially registered dietitians."
Maureen Ternus, M.S., R.D., Executive Director of the International Tree Nut Council Nutrition Research & Education Foundation (INC NREF), adds, "In light of these new data and the fact that the FDA has issued a qualified health claim for nuts and heart disease with a recommended intake of 1.5 ounces of nuts per day, we need to educate people about the importance of including tree nuts in the diet."