Walnuts are an oft-cited complementary remedy for reducing cholesterol, but that’s not the reason why they improve your heart wellness. This is according to a new study, set to be published in the Journal of Nutrition, which claims that consumption of whole walnuts or their extracted oil can reduce your cardiovascular risk through a mechanism other than simply lowering cholesterol.
According to Penny Kris-Etherton, Distinguished Professor of Nutrition at Penn State, ‘We already know that eating walnuts in a heart-healthy diet can lower blood cholesterol levels, but, until now, we did not know what component of the walnut was providing this benefit. Now we understand additional ways in which whole walnuts and their oil components can improve heart health.’
For the study, which was a randomised-controlled trial, 15 participants with elevated blood cholesterol were given one of four treatments. Some participants consumed 85 grams of whole walnuts, some six grams of the skin, some 34 grams of defatted nutmeat, and the rest were given 51 grams of oil. Before the treatments were administered, the team evaluated biochemical and physiological responses in the participants, and then did so again 30 minutes, one hour, two hours, four hours and six hours after administering the treatments.
So what mysterious benefit did the study actually find in walnuts? The results of the study revealed that a one-time consumption of the oil component in walnuts favourably affected vascular health. However, in the participants who consumed whole walnuts, the nuts helped their HDL (good) cholesterol perform more effectively in transporting and removing excess cholesterol from their body.
Claire Berryman, a graduate student in nutritional sciences at Penn State, commented, ‘Our study showed that the oil found in walnuts can maintain blood vessel function after a meal, which is very important given that blood vessel integrity is often compromised in individuals with cardiovascular disease. The walnut oil was particularly good at preserving the function of endothelial cells, which play an important role in cardiovascular health.’ The researchers surmised that, as walnuts contain alpha-linolenic acid, gamma-tocopherol and phytosterols, this may explain the positive effects of the walnut oil treatment. Berryman added, ‘Implications of this finding could mean improved dietary strategies to fight heart disease.’
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