A new study, published in the online journal PLOS ONE, looks at the association between tree nuts (almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts), metabolic syndrome (MetS) and obesity in a population with a wide range of nut intake ranging from never to daily.
Researchers at Loma Linda University studied 803 Seventh-day Adventist adults using a validated food frequency questionnaire and assessed both tree nut and peanut intake together and separately. Mean tree nut intake was 16 grams/day among the high tree nut consumers and 5 grams/day among low tree nut consumers. "Our results showed that one serving (28g or 1 ounce) of tree nuts per week was significantly associated with 7% less MetS," stated lead researcher Karen Jaceldo-Siegl, DrPH, "Doubling this consumption could potentially reduce MetS risk by 14%." She added, "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."
MetS is a cluster of risk factors shown to be associated with death, a twofold increased risk for cardiovascular disease, and a fivefold increased risk for type 2 diabetes. While the diagnostic criteria can vary, presence of any three of the five following conditions results in a diagnosis of MetS: abdominal obesity, elevated triglycerides, low HDL cholesterol (the good cholesterol), high blood pressure, and hyperglycemia (high blood sugar levels). Based on NHANES data from 2003-2006, an estimated 34.3% of the U.S. population has MetS.
In addition to the effect of nuts on MetS, the researchers also looked at the effect on obesity. "We found that high tree nut consumers had significantly lower prevalence of obesity compared to the low tree nut consumers," stated Dr. Jaceldo-Siegl. "And, high consumers of tree nuts had the lowest prevalence of obesity when compared to the low peanut/tree nut groups."
This latest study comes on the heels of the nuts and all-cause mortality study published in the New England Journal of Medicine last month. "All of this new research supports the growing body of evidence showing that consuming nuts can improve your health," states Maureen Ternus, M.S., R.D., Executive Director of the International Tree Nut Council Nutrition Research & Education Foundation (INC NREF). "In 2003, FDA (in its qualified health claim for nuts and heart disease) recommended that people eat 1.5 ounces of nuts per day - well above current consumption levels - so we need to encourage people to get their handful of nuts every day."