A meta-analysis published in the recent issue of the American Journal of Clinical Nutrition evaluates how the plant-based omega-3 fatty acid alpha-linolenic acid (ALA) offers protective effects on cardiovascular diseases (CVD). The study found ALA to be associated with a lower risk of CVD, particularly coronary heart disease (CHD) death. These findings support the potential heart health benefits of ALA and suggest consumers should obtain adequate amounts of ALA in their diets. Walnuts are a key source of ALA and the only nut that provides a meaningful amount of the essential plant-based omega-3 fatty acid offering 2.5 grams of ALA in a mere handful.
This systematic review incorporated 27 original studies and included 251,049 individuals and found that overall ALA exposure was associated with lower risk of CVD. In fact, in the pooled dietary analysis, each 1 gram per day increment of ALA intake was associated with a 10 percent lower risk of CHD death. Previously, the majority of research funding of omega-3 fatty acids have been directed towards marine sources, however recently increased attention has been given to its plant-based counterpart ALA, and has been suggesting that ALA consumption also offers cardiovascular benefits. The researchers believe that there may be a direct or indirect antiarrythmic effect of ALA that could partially explain why ALA appeared protective against CHD. Previous studies have found ALA consumption may lower cholesterol levels, positively affect thrombosis, improve endothelial function and decrease inflammation.
The type of omega-3s found in walnuts and other plant sources are different from the type of omega-3s found in fish. According to Penny Kris-Etherton, Ph.D., Distinguished Professor of Nutrition at The Pennsylvania State University, consumers need to understand the nutritional benefits of plant-based omega-3 fatty acids. She notes that "research is showing that the effects of ALA may have unique and independent benefits important to our wellbeing."
Cardiologist Dr. James Beckerman finds this study extremely noteworthy and suggests people include more ALA rich food sources into their diet to promote heart health and potentially lower the risk of fatal cardiac events. "Given that plant sources of ALA are cheaper and more accessible to many people as compared to omega-3 fatty acids from fish, this study expands our arsenal to fight heart disease with safe and well tolerated dietary interventions that are easy for people to incorporate into their lifestyles," notes Dr. Beckerman.
The Institute of Medicine (IOM), which establishes nutrient requirements, recommends that people should consume 1.1 to 1.6 grams a day of ALA which can easily be attained. "Eating a handful of walnuts, for example, is a great way to boost your ALA intake. In just a handful, or ounce of walnuts you get well over the amount of ALA recommended by the IOM, not to mention a whole host of additional nutrients," states Dr. Kris-Etherton. In addition to ALA, walnuts have high antioxidant content, along with numerous micronutrients that Dr. Kris-Etherton thinks may work together synergistically.