Supplementing the diet with the omega-3 fatty acids they provide is linked to a significant effect on bad cholesterol.
Excess cholesterol remains one of the main cardiovascular risk factors both in Spain and in much of the Western world. Although it is true that heart health should be analyzed from the whole lifestyle perspective, particularly the LDL cholesterol, the “bad” cholesterol, remains a concern to be taken into account.
Thus, multiple studies have analyzed how to reduce this substance through dietary improvements, Beyond the various medications currently in existence.
Now, a new study published in Circulation the journal of the American Heart Association, by Emilio Ros, MD, Ph.D., and his colleagues from the Endocrinology and Nutrition Service of the Hospital Clinic of Barcelona, have found a new collaborator in this battle against cholesterol: the walnuts. Within the group of nuts and dried fruits, they stand out for being a source of omega-3 fatty acids, specifically alpha-linolenic acid. which has been linked to beneficial effects on cardiovascular health.
As Ros recalls, previous studies have suggested that nuts in general, and walnuts in particular, are associated with a lower level of heart disease and cerebrovascular disease, given their potential to reduce levels of “bad cholesterol”. But now, according to the new study carried out in Barcelona, there is something else: nuts are associated with lower levels of heart disease and stroke. walnuts may improve the quality of LDL particles.
LDL particles are known to possess various sizes. Small, dense LDL particles would be most significantly associated with atherosclerosis or fatty plaque that builds up in the arteries. And walnuts, the researchers say, may have the potential for improving the situation.
This new work would be a sub-study of the Nuts and Healthy Aging Study. a large two-year randomized controlled trial that looked at whether nut consumption would contribute to healthy aging. In the case of the substudy, it has looked at whether nut consumption would have an effect on cholesterol, regardless of a person’s diet or where they live.
In this case, data from 708 men and women (68% women) aged 63 to 79 years, living in Barcelona (Spain) and Loma Linda (California) have been analyzed. The study was conducted between May 2021 and May 2016. Participants were randomly divided into two groups: the control group, and the intervention group. This second group added half a cup of walnuts to their usual daily diet (about 50 grams). while the control group ate no nuts.
After the passage of two years, the cholesterol levels of the participants were analyzed including the concentration and size of cholesterol-carrying lipoproteins by nuclear magnetic resonance spectroscopy. This test allows for a more precise analysis of lipoprotein characteristics, as their size and density have been associated with variations in cardiovascular disease risk.
In total, 628 of the participants’ cholesterol could be fully analyzed, since about 10% did not continue the study. But some of the following could be extracted conclusions:
– Participants who consumed walnuts reduced their LDL cholesterol 4.3 mg/dL on average, and total cholesterol by 8.5 mg/dL on average.
– The Daily consumption of walnuts reduced the number of LDL particles by 4.3%, and small LDL particles by 6.1%. These changes in concentration and composition would be associated with a lower cardiovascular risk, according to the authors.
– Intermediate-density lipoprotein (IDL) cholesterol also decreased. IDL is a precursor of LDL, and lies between low and very low-intensity lipoproteins; it is an intermediate step.
– LDL cholesterol changes also differed by sex: in men, LDL cholesterol decreased by 7.9%, while in women it decreased by 2.6%.
Modest, but significant improvements
The authors are aware that the consumption of walnuts does not result in a large decrease in LDL cholesterol. However, the findings are significant and they did have a real impact on the participants: all were healthy, but 50% of them were taking treatments for hypertension and hypercholesterolemia preventively.
Thanks to such treatments, 32% of the participants maintained normal average cholesterol levels, and the authors suggest that adding a handful of walnuts on a daily basis would achieve a greater reduction. in these cholesterol levels. Furthermore, the healthy fats in the nuts did not contribute to weight gain in the participants: moderate consumption has actually been linked to weight loss as, despite being calorie-dense, they induce satiety.
Even so, the authors are also aware that. the study is not without limitations: both the participants and the researchers knew who was eating nuts and who was not, although the study did not involve populations with very different diets. But further research should be done, especially regarding the results on LDL variations between men and women.