The health benefits of consumption of tree nuts (almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts) were explored by three new studies.
Researchers found that tree nut consumption was associated with a better nutrient profile and diet quality; lower body weight and lower prevalence of metabolic syndrome; and a decrease in several cardiovascular risk factors compared to those seen among non-consumers.
First, researchers at Loma Linda University studied 803 adults using a validated food frequency questionnaire and assessed both tree nut and peanut intake together and separately.
"Our results showed that one serving (28g or 1 ounce) of tree nuts per week was significantly associated with 7 percent less MetS," stated lead researcher Karen Jaceldo-Siegl, DrPH.
"Interestingly, while overall nut consumption was associated with lower prevalence of MetS, tree nuts specifically appear to provide beneficial effects on MetS, independent of demographic, lifestyle and other dietary factors," the researcher noted.
The second study looked at 14,386 adults participating in the 2005-2010 National Health and Nutrition Examination Surveys (NHANES). Intake was from 24-hour recall data and tree nut consumers were defined as those who consumed more than 1/4 ounce of tree nuts (average consumption was about an ounce/day).
As seen in previous research, tree nut consumers had higher daily intakes of calories and nutrients of concern, but lower intakes of added sugars, saturated fats, and sodium than non-consumers.
Tree nut consumers also had lower weight, BMI, and waist circumference than non-consumers.
In addition, those who consumed tree nuts had lower systolic blood pressure and higher HDL-cholesterol (the good kind).
On a population basis, these reduced risk factors could lead to better health.
Finally, a third study looked at several markers for cardiovascular disease risk. In 2011, researchers from the University of Toronto and St. Michael's Hospital in Toronto, Canada, published the largest study to date on nuts and diabetes, showing that approximately two ounces of nuts a day, as a replacement for carbohydrate foods, can improve glycemic control and blood lipids in those with type 2 diabetes.
The researchers looked at the effects of nuts on various cardiovascular markers.
"We found that nut consumption was associated with an increase in monounsaturated fatty acids (the good fats) in the blood, which was correlated with a decrease in total cholesterol, LDL cholesterol (the bad kind), blood pressure, 10-year coronary heart disease risk, HbA1c (a marker of blood sugar control over the previous three months) and fasting blood glucose," explained Cyril Kendall, Ph.D., of the University of Toronto.
"Nut consumption was also found to increase LDL particle size, which is less damaging when it comes to heart disease risk," Kendall added.
According to Dr. Kendall, this study found additional ways in which nut consumption may improve overall cardiovascular health.
The studies were presented this week at the Experimental Biology Meeting in Boston, MA.