HEART HEALTH BENEFITS OF WALNUTS MAY START WITH THE GUT, SAYS NEW STUDY

A new clinical trial reveals there may be a connection between heart and gut health aided by consumption of walnuts. Findings from this new study, published in the Journal of Nutrition, show that consuming walnuts enriches certain gut bacteria in the digestive system associated with improvements in blood pressure and cholesterol. Researchers believe this could be due to the unique combination of bioactive compounds, fatty acids and dietary fiber found in walnuts. 1

More and more, consumers seek foods that help manage risk factors and provide health benefits, with digestive and heart health being among the top sought after benefits. This is with good reason considering that cardiovascular mortality in the MENA has been estimated to triple from 1990 to 2020. While the survival rate from a heart attack in the Western hemisphere (countries such as Copenhagen) is on average 60-64%, Middle Eastern countries fall drastically short of this average, especially in light of the statistics that show this rate goes no higher than a mean 5-10% in Dubai. With that said, another health problem threatening the UAE increasingly is gastro-intestinal diseases.

Doctors state that 2 out of 10 people in the UAE suffer from poor gut health, which makes them equally grave as heart diseases, and that poor eating habits might have an effect on the aggravation of the problem. 2

In this new trial conducted at The Pennsylvania State University and Juniata College, study participants included 42 overweight or obese (BMI: 25.0 – 39.9 kg/m 2 ) individuals aged 30-65 and at risk for heart disease. Participants first followed an average American diet (48% carbohydrate, 17% protein, 35% fat, 7% saturated fat) for two weeks to be sure that everyone started at the same baseline. They were then randomly assigned to a diet that replaced some saturated fat with either walnuts, a vegetable oil blend that included the same fatty acids as walnuts (including omega-3 ALA, a type of polyunsaturated fat), or a vegetable oil blend that was higher in omega-9 oleic acid (a type of monounsatured fat). These diets were designed to understand if the good, unsaturated fats in walnuts are responsible for benefits or if other nutrients found in whole walnuts, such as bioactive compounds and fiber, may be playing an additional role. All participants followed each diet for six weeks with a break (average of 22.8 days) in between each intervention. Standard markers of heart health, such as blood pressure and cholesterol, as well as the microorganisms living in the digestive tracts of theparticipants were assessed beforeand after each of the diets.

Individuals who consumedwalnuts and the vegetable oilwith the same fatty acid profileas walnuts showed positiveshifts in gut bacteria comparedto the average American diet,suggesting a positive impact ofomega-3 ALA. Those followingthe walnut diet only, had a uniqueenrichment of a particular speciesof bacteria – one that plays animportant role in metabolizingellagitannins, a bioactivecomponent of walnuts that maybe associated with cardiovascularbenefits. The types of fatty acidsin walnuts and vegetable oil maypositively impact gut health, butthis study also suggests there arebenefits in consuming a wholewalnut.

As with any scientific research,some study limitations should beconsidered. The study did notevaluate secondary metabolites,which can be used to assess thefunctional capacity of gut bacteria,nor did it assess the conversionof ALA to EPA, which couldimpact the gut microbiota aswell. Additionally, fecal samplesmay not be representative of theentire gut environment, which ishighly variable among individualsdepending on diet, medications,lifestyle and other factors. Forthese reasons, larger and longertermstudies are needed toclarify these effects in a broaderpopulation.

1. One ounce of walnuts provides 18g of total fat, 2.5g of monounsaturated fat, 13g of polyunsaturated fat, including 2.5g of alpha– linolenic acid (the plant-based omega–3), and 2g dietary fiber.

2. See the article on Gulf News here: https://gulfnews.com/uae/health/gutdiseases-on-the-rise-in-the-uae-doctorssay-1.1314131