New research from the American Heart Association shows that healthy older adults who ate a handful of walnuts (about ½ cup) a day for two years reduced their LDL (“bad”) cholesterol levels as well as the number of LDL particles, a predictor of cardiovascular disease risk. The study explored the effects of a walnut-enriched diet on overall cholesterol in elderly individuals from diverse geographical locations and spanning two years.
Walnuts are a rich source of omega-3 fatty acids (alpha-linolenic acid), which have been shown in previous research to have a beneficial effect on cardiovascular health. "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, MD, PhD, director of the Lipid Clinic at the Endocrinology and Nutrition Service of the Hospital Clínic of Barcelona in Spain.
"LDL particles come in various sizes. Research has shown that small, dense LDL particles are more often associated with atherosclerosis. 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."
In a sub-study of the Walnuts and Healthy Aging study, a large, two-year randomized controlled trial examining whether walnuts contribute to healthy aging, researchers evaluated if regular walnut consumption, regardless of a person's diet or where they live, has beneficial effects on lipoproteins.
This study was conducted from May 2012 to May 2016 and involved 628 healthy participants between the ages of 63 and 79. Participants were randomly divided into two groups: active intervention and control. Those allocated to the intervention group added about a half cup of walnuts to their usual daily diet, while participants in the control group abstained from eating any walnuts. After two years, participants' cholesterol levels were tested, and the concentration and size of lipoproteins were analyzed.
Among key findings of all study participants:
- At 2 years, participants in the walnut group had lower LDL cholesterol levels -- by an average of 4.3 mg/dL, and total cholesterol was lowered by an average of 8.5 mg/dL.
- Daily consumption of walnuts reduced the number of total LDL particles by 4.3% and small LDL particles by 6.1%. These changes in LDL particle concentration and composition are associated with a lower risk of cardiovascular disease.
- Intermediate Density Lipoprotein (IDL) cholesterol also decreased. It is known that IDL cholesterol is a precursor to LDL and refers to a density between that of low-density and very-low-density lipoproteins. In the last decade, IDL cholesterol has emerged as a relevant lipid cardiovascular risk factor independent of LDL cholesterol.
- LDL cholesterol changes among the walnut group differed by sex; in men, LDL cholesterol fell by 7.9% and in women by 2.6%.
"While this is not a tremendous decrease in LDL cholesterol, it's important to note that at the start of the study all our participants were quite healthy, free of major non-communicable diseases. However, as expected in an elderly population, close to 50% of participants were being treated for both high blood pressure and hypercholesterolemia. Thanks in part to statin treatment in 32%, the average cholesterol levels of all the people in our study were normal," Ros said. "For individuals with high blood cholesterol levels, the LDL cholesterol reduction after a nut-enriched diet may be much greater."
At Herbsea, we are staunch proponents of Hippocrates’ famous missive: “Let your food by thy medicine.” Eating from Mother Nature’s diverse pantry is a sound, proven way to improve your health and well-being.
Rjaram S, et al. “Effects of Walnut Consumption for 2 Years on Lipoprotein Subclasses Among Healthy Elders: Findings From the WAHA Randomized Controlled Trial.” Circulation, 2021