Adding half a cup of walnuts to your daily diet can lower cholesterol levels by about 8.5% and reduce your risk of heart disease, according to one study.
Researchers at the Hospital Clínic de Barcelona recruited 628 adults and made half of them on a diet that included the daily consumption of walnuts.
After two years, the team found that nut eaters also had modest reductions in cholesterol levels called low-density lipoprotein (LDL).
High levels of LDL, sometimes called “bad cholesterol,” are associated with an increased risk of heart disease and stroke.
Study participants who ate nuts daily saw a reduction in both the total number of LDL particles in the blood and, in particular, the number of small LDL particles.
According to the American Heart Association, walnuts have a high content of omega 3 fatty acids, the heart-healthy fat that is famously found in fatty fish.
One study found that adding half a cup of walnuts (pictured) to your daily diet can lower cholesterol levels by about 8.5% and reduce your risk of heart disease.
“Previous studies have shown that walnuts in general, and walnuts in particular, are associated with lower rates of heart disease and stroke,” said Emilio Ros, author of the paper and a nutrition expert at Hospital Clínic de Madrid. Barcelona, in Spain.
One reason is that they lower LDL cholesterol levels and now we have another reason: they improve the quality of LDL particles.
LDL particles come in various sizes. Research has shown that small, dense LDL particles are more often associated with atherosclerosis, plaque, or fatty deposits that build up in the arteries.
“Our study goes beyond LDL cholesterol levels to get a complete picture of all lipoproteins and the impact of eating new foods daily on their potential to improve cardiovascular risk.”
In their research, Dr. Ros and colleagues analyzed data on 628 healthy adults (each aged 63 to 79) living in Barcelona, Spain, or Loma Linda, California.
Participants were divided into two groups, and the first added half a cup of walnuts to their daily diet, while the other refrained from eating any nuts.
After two years, the team tested each participant’s cholesterol levels, in addition to analyzing the concentrations and sizes of their lipoproteins to look for known characteristics that are associated with an increased risk of cardiovascular disease.
The researchers found that participants in the nut-eating group ended up with lower LDL cholesterol levels at the end of the study period, averaging 4.3 mg / dL.
At the same time, their total cholesterol was reduced by an average of 8.5 mg / dL.
Regular consumption of walnuts was found to be associated with a 4.3% reduction in the total number of LDL particles and small LDL particles by 6.1%, both changes related to a lower risk of cardiovascular disease.
In addition, the team found that the medium-density lipoprotein or ‘IDL’ cholesterol, which is a precursor to LDL, was also decreased in the walnut group.
(In the last decade, medical experts have noted that IDL cholesterol is a relevant lipid cardiovascular risk factor independent of LDL cholesterol).
The researchers noted that for reasons that are not yet clear, changes in LDL cholesterol in the walnut group differ by sex.
In men, the average reduction was 7.9%, while it was 2.6% in women.
“While this does not lead to a tremendous decrease in LDL cholesterol, it is important to note that at the beginning of the study all of our participants were fairly healthy, free of major noncommunicable diseases,” Dr. Ros said.
However, as expected in an elderly population, about 50% of participants were being treated for both high blood pressure and hypercholesterolemia.
Thanks in part to statin treatment at 32%, the average cholesterol levels of all the people in our study were normal.
“For people with high blood cholesterol levels, the reduction of LDL cholesterol after a diet enriched with nuts can be much greater.
“Eating a handful of nuts every day is an easy way to promote cardiovascular health,” the researcher continued.
The researchers noted that their study was limited by the fact that both they and the participants knew who among the latter ate nuts.
However, they added, the study involved two different cohorts with different diets.
“The results were similar in both groups, so we can safely apply the results of this study to other populations,” said Dr. Ros, who noted that more research will be needed to clarify differences in the results of LDL between men and women.
The full findings of the study, which was funded by the California Walnut Commission, were published in the journal Circulation.