Farm Progress

In the last twenty years, 91 studies and counting have linked numerous potential health benefits from walnuts in the areas of heart health, diabetes, weight management and cognitive function.

May 16, 2013

4 Min Read

In 1993, the New England Journal of Medicine (NEJM) published landmark research from Loma Linda University showing the heart protective quality of walnuts.  In the two decades since, 91 studies and counting, worldwide, have linked numerous potential health benefits from walnuts in the areas of heart health, diabetes, weight management and cognitive function.  Additional research has been investigating the potential benefits of walnuts on various types of cancer in animal models (the results are indicators that are used as background and to formulate hypotheses for other studies); this includes eight studies co-funded by the American Institute for Cancer Research, resulting in $488,000 in grants supporting walnuts health research.

Such research has contributed to the shift in perception from walnuts being a food to avoid because of fat, to being named a "SuperFood"1 with "good fat." In fact, the health benefits are now the top reason that consumers are purchasing more walnuts.

Other milestones have included:

• In 2004, the U.S. Food and Drug Administration (FDA) affirmed a qualified health claim for walnuts, one of the first for a whole food.  "Supportive but not conclusive research shows that eating 1.5 ounces of walnuts per day, as part of a low saturated fat and low cholesterol diet and not resulting in increased caloric intake may reduce the risk of coronary heart disease.  See nutrition information for fat content."2

• In 2011, the American Heart Association certified walnuts as a heart-healthy food with its Heart-Check mark, an icon that consumers trust.

• In 2012, walnuts were the only nut to receive health claims from the European Union. Walnuts received four: one specific to walnuts and blood flow, and three generic health claims.

Joan Sabate, M.D., Dr.PH., Chair of the Nutrition Department at Loma Linda University, served as principal investigator of the 1993 study3that directly linked the benefit of walnut consumption to serum cholesterol in a small group of healthy men. "Twenty years ago we released the first study showing the health benefits of walnuts.  Subsequent years of research have shown benefits in other populations. Now, the results of a trial from Spain4, recently announced at Loma Linda, further demonstrate that a plant-based diet, infused with nutritious unrefined plant fats, can have long-lasting effects for heart health," said Dr. Sabate in reference to the landmark Spanish PREDIMED (PREvencion con DIeta MEDiterranea) trial results. This newly published study found a Mediterranean diet including nuts, primarily walnuts, reduced the risk of cardiovascular diseases (myocardial infarction, stroke or cardiovascular death) by 30% and specifically reduced the risk of stroke by 49% when compared to a reference diet consisting of advice on a low-fat diet (American Heart Association guidelines). Please note, because the study participants were at high cardiovascular risk, whether the results can be generalized to persons at lower risk or to other settings requires further research.

Increasing demand

"The PREDIMED study is very important to the field of nutrition in that it looked at clinical outcomes, not just risk factors, which sets a tone for future research – that you can study what we eat in its natural form and come out at the end with reduced disease events," said David R. Jacobs, Jr., Ph.D., Professor of Epidemiology, School of Public Health, University of Minnesota, who also commented that this research should be of interest to the 2015 Dietary Guidelines for Americans advisory committee. It is particularly important to scientists because the clinical trial design meets a very high standard for validity of the results.

Researchers, including Dr. Sabate, believe it is the synergy of nutrients in the whole walnut that yields the benefits, but note that walnuts are unique among nuts as the only one with a significant amount of alpha-linolenic acid (ALA), the plant-based essential omega-3 fatty acid.

The California walnut industry has been at the forefront and a leader in research focused on whole foods. "The industry is proud to grow a whole food that tastes great, is very versatile, and has proven health benefits. Consumers have responded overwhelmingly to the health message," said Dennis A. Balint, chief executive officer of the California Walnut Commission (CWC). "In 1987, health was not at all associated with walnut purchases. Now, after twenty years of health research and ninety-one publications, 86% of consumers believe walnuts are a nutritious food."

Commenting on what this all means to the California walnut growers, Carl Cilker, a grower and the chair of the CWC's market development committee says, "Walnut growers have always believed in the healthy value of their crop and results from years of research have shown health benefits beyond what we imagined. Future research will increase our knowledge of walnuts' benefits and will underscore the importance of providing a stable supply for the increasing number of consumers who purchase them."

The latest research:

•   Landmark Clinical Study Reports Mediterranean Diet Supplemented with Walnuts Significantly Reduces Risk of Stroke and Cardiovascular Diseases

•   New Harvard study reports walnut consumption to be linked to lower risk of type 2 diabetes in women

For more industry information, health research and recipe ideas, visit

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