Katy Edgington reports for Science Omega that, “According to the findings of a longitudinal study, participants who ate more than 84 grams of nuts a week reduced their risk of mortality by almost 40 per cent.”
Nuts are an important component of the so-called ‘Mediterranean diet’, which also includes proportionally high amounts of fruit, vegetables, olive oil and legumes as well as moderate amounts of dairy products and wine, but relatively little red meat. Research in the past has suggested a link between frequently eating nuts and a reduced risk of Type 2 diabetes mellitus, metabolic syndrome and cardiovascular disease, with the benefits attributed to their unique nutritional composition.
A randomised controlled trial carried out in Spain, called PREDIMED, provides further evidence that nut consumption has protective effects on health. The results of the longitudinal study, comparing Mediterranean diets supplemented with extra virgin olive oil or nuts to a control group following a low fat diet, appear in BioMed Central’s open access journal BMC Medicine.
Co-author Marta Guasch Ferré is a predoctoral fellow under the supervision of Professor Jordi Salas Salvadó in the Department of Biochemistry and Biotechnology at the Universitat Rovira i Virgili. She addressed ScienceOmega.com’s questions about their findings.
“We evaluated the effect of the frequency of total nut consumption on several causes of mortality,” said Guasch Ferré. “However, we thought it was important to evaluate the effect of walnuts separately given the different nutritional composition between walnuts and other nuts, such as hazelnuts and almonds. Walnuts are richer in polyunsaturated fatty acids as well as in some antioxidants than other nuts.”
More than 7,000 people were involved in the study, ranging in age from 55 to 90 years old, Edgington reports. The effects of consuming nuts on mortality were surprisingly strong. Article continues:
Walnuts are richer in some antioxidants than other nuts and are characteristically rich in alphalinolenic acid; this is one possible explanation for the inverse relationship between walnut consumption and cancer mortality, as Guasch Ferré explained.
“Walnuts are usually consumed raw, and roasting can cause a decline in the efficacy of antioxidant capacity,” she said. “It has been shown that raw walnuts, as consumed in the PREDIMED study, have a high antioxidant efficacy; this could play a beneficial role in the prevention of cancer.”
It is not clear quite why nuts are able to prevent premature mortality to such an extent, or why walnuts should have a markedly stronger effect than other nuts.
Read the full report, click here.