Some nuts, especially walnuts, have high levels of healthy fats like Omega-3. New research reported in Circulation has shown that eating about half a cup of walnuts a day can reduce the levels of low-density lipoprotein (LDL) cholesterol slightly in healthy order people. There are different sized LDL particles, and the smallest have been linked to plaque buildup in the arteries.
“Prior studies have shown that nuts in general, and walnuts in particular, are associated with lower rates of heart disease and stroke. One of the reasons is that they lower LDL cholesterol levels, and now we have another reason: they improve the quality of LDL particles,” said study co-author Emilio Ros, M.D., Ph.D. of the Hospital Clínic of Barcelona. “Our study goes beyond LDL cholesterol levels to get a complete picture of all of the lipoproteins and the impact of eating walnuts daily on their potential to improve cardiovascular risk.”
The study was two years long and completed by 638 volunteers; one group ate half a cup of walnuts (about 113 grams) daily and the other group did not. The research determined that the people that consumed half a cup of walnuts daily reduced their total LDL particles by 4.3 percent and small LDL particles by 6.1 percent compared to people that did not eat walnuts. The levels of Intermediate Density Lipoprotein (IDL), a known LDL precursor, were also reduced in the walnut-eating group. Men experienced a greater reduction in LDL levels (7.9 percent) after walnut consumption compared to women (2.6 percent).
“Eating a handful of walnuts every day is a simple way to promote cardiovascular health. Many people are worried about unwanted weight gain when they include nuts in their diet,” Ros said. “Our study found that the healthy fats in walnuts did not cause participants to gain weight.”
In an unrelated study reported in the Journal of Nutrition, scientists found that pecans could have a similar effect.
One group of volunteers ate about one-third of a cup, or 68 grams of pecans equal to about 470 calories in addition to their regular diet, another group substituted the pecans for another food in their daily diet, and another group did not eat pecans.
After eight weeks of this regimen, the participants ate a meal high in fat, and the researchers monitored the changes in their blood sugar. The people that had eaten pecans, either in addition to or as a substitute for some of their regular food, had lower triglyceride levels after their meal compared to the group that had not eaten pecans. The lowest post-meal blood glucose was in those who'd substituted other foods with the pecans.
On average, the total cholesterol level in the study participants that ate pecans was reduced by five percent, while LDL went down between six and nine percent compared to those who had not eaten pecans.
“This dietary intervention, when put in the context of different intervention studies, was extremely successful,” said study co-author Professor Jamie Cooper of the University of Georgia. “We had some people who actually went from having high cholesterol at the start of the study to no longer being in that category after the intervention.”
This study shows that choosing healthy snacks and foods can have real benefits.