Research & Your Health is a series of articles written in accessible, everyday language, focused on the latest scientific research of natural health products.
On November 30, 2015
Background: Tree nuts (almonds, Brazil nuts, cashews, filberts, macadamias, pecans, pine nuts, pistachios, and walnuts) contain healthy fats, vegetable protein, fibre, a variety of vitamins and minerals, and other bioactive compounds. Despite the fact that nuts have a strong nutritional profile, research has produced inconsistent results. Some studies have found that nuts are inversely associated with all-cause mortality, cardiac mortality, cholesterol levels, oxidative stress, inflammation, insulin resistance, hyperglycemia, triglycerides and other metabolic markers. However, other studies found no association with body weight, hypertension, Type 2 diabetes and other metabolic-related markers. This study looked at metabolic markers and tree nut consumption from participants of the National Health and Nutrition Examination Survey (NHANES).
Objective: The purpose of this study was to examine associations between tree nut consumption, and metabolic and cardiovascular markers among participants of the NHANES from 2005 to 2010.
Methods: Data from participants aged 19 and over in NHANES 2005, 2007 and 2009 were combined to give a sample size of 14,386. Two 24-hour dietary recalls were used to assess tree nut consumption. Anthropometric data (height, weight, waist circumference, body mass index) were assessed in addition to blood pressure, cholesterol, triglycerides and blood glucose levels. Insulin resistance was calculated using the Homeostatic Model of Assessment-Insulin Resistance via fasting serum insulin and fasting plasma glucose. Metabolic
syndrome was assessed from abdominal obesity, hypertension, high density lipoprotein cholesterol, triglycerides, fasting glucose and relevant medications or insulin.
Results: Approximately 6.8 per cent of the population consumed tree nuts. Body mass index (3 per cent), waist circumference (2 per cent) and systolic blood pressure (2 per cent) were lower in those who consumed tree nuts. Obesity (25 per cent) and elevated waist circumference (21 per cent) were less prevalent among tree nut consumers. Triglycerides, glucose, and insulin levels were not significantly different among the two groups.
Conclusion: Tree nut consumption has the potential to improve metabolic measures, reduce systolic blood pressure, and lower the risk of obesity.
Findings in Perspective: Tree nuts contain a strong nutrient profile and a myriad of bioactive compounds. This study found that those who consume tree nuts have improved metabolic and cardiovascular markers. This study is “population-based” and cannot determine if tree nut consumption causes improved health benefits. However, the associations
found support that tree nut consumption may be beneficial for metabolic and cardiovascular health.