August 1, 2014
Tree Nuts Can Provide Modest Decreases In Blood Fats And Sugars
April Flowers for redOrbit.com - Your Universe Online
The University of Toronto and St. Michael's Hospital led an international team of scientists in conducting two meta-analyses involving tree nuts. Examples of tree nuts include: almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts.
The first analysis, published online in the British Medical Journal Open examined the effects of tree nuts on metabolic syndrome (MetS) criteria. The findings revealed that the consumption of tree nuts resulted in a significant decrease in triglycerides and fasting blood glucose.
The researchers, including Dr. John Sievenpiper from the Clinical Nutrition and Risk Factor Modification Center at St. Michael's, say that two of the five risk factors for MetS are reduced by eating tree nuts. These factors raise the risk for heart disease and other health problems such as diabetes and stroke.
The research team screened 2,000 articles published in peer-reviewed journals to find 49 randomized control trials with 2,000 participants. The participants consumed approximately 50 grams, or 1.5 servings, per day. Most North Americans, according to Sievenpiper, consume less than one serving a day.
A person with MetS presents at least three of the following risk factors: low levels of "good" cholesterol; high triglycerides; high blood pressure; high blood sugar; and extra weight around the waist.
Tryglycerides and blood glucose are types of blood fats. Sievenpiper and his colleagues found the largest reduction in these fats when tree nuts replaced refined carbohydrates rather than saturated fats. Even though nuts are high in calories and have a high fat content (unsaturated), the team found no adverse impact on the other factors for MetS.
"We found that tree nut consumption of about two ounces per day was found to decrease triglycerides significantly by ~0.06 mmol/L and to decrease fasting blood glucose significantly by ~0.08 mmol/L over an average follow-up of eight weeks," stated Cyril Kendall, Ph.D., of the University of Toronto.
The second paper, published online in PLOS ONE, found that tree nut consumption also aids in lowering and stabilizing blood sugar levels in Type 2 diabetes sufferers when compared to those on a control diet.
The researchers examined 12 clinical trials with 450 participants. The data revealed that eating approximately two servings of tree nuts a day improved the two key markers of blood sugar: the HbA1c test, which measures blood sugar levels over three months, and the fasting glucose test, where patients are not allowed to eat or drink anything but water for eight hours before their blood glucose levels are tested.
Again, Sievenpiper said that the best results were observed when tree nuts replace refined carbohydrates rather than saturated fats.
In these trials, the participants consumed 56 grams, or two servings, of tree nuts a day. Again, no adverse effects were seen in the areas of weight gain. "Tree nuts are another way people can maintain healthy blood sugar levels in the context of a healthy dietary pattern," he said.
According to Dr. Kendall, "Both of our analyses indicate that daily tree nut consumption has an overall metabolic benefit and can improve risk factors for metabolic syndrome, and glycemic control in individuals with type 2 diabetes."
"With MetS and diabetes on the rise worldwide, this is yet another reason to include tree nuts in your diet every day," states Maureen Ternus, M.S., R.D., Executive Director of the International Tree Nut Council Nutrition Research & Education Foundation (INC NREF). INC NREF provided funding for the studies. "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. We need to encourage people—especially those at risk for MetS and those with diabetes—to get their handful of nuts every day."