Nuts are a popular snack among the growing number of consumers seeking natural, nutrition-packed and convenient options. While nuts already have a wealth of research to support their various health benefits, two recent studies suggest nuts can improve cognitive function, when combined with the Mediterranean diet, and decrease risk of colorectal cancer in women.
A recent article online by JAMA Internal Medicine found supplementing the plant-based Mediterranean diet with antioxidant-rich extra virgin olive oil or mixed nuts was associated with improved cognitive function in a study of older adults in Spain.
The randomized clinical trial included 447 cognitively healthy volunteers (223 were women; average age was nearly 67 years) who were at high cardiovascular risk and were enrolled in the “Prevencion con Dieta Mediterranea" nutrition intervention.
Of the participants, 155 individuals were assigned to supplement a Mediterranean diet with one liter of extra virgin olive oil per week; 147 were assigned to supplement a Mediterranean diet with 30 g/d of a mix of walnuts, hazelnuts and almonds; and 145 individuals were assigned to follow a low-fat control diet.
The authors measured cognitive change over time with a battery of neuropsychological tests and also constructed three cognitive composites for memory, frontal (attention and executive function) and global cognition. After a median of four years of the intervention, follow-up tests were available on 334 participants.
At the end of the follow-up, there were 37 cases of mild cognitive impairment: 17 (13.4 percent) in the Mediterranean diet plus olive oil group; eight (7.1 percent) in the Mediterranean diet plus nuts group; and 12 (12.6 percent) in the low-fat control group. No dementia cases were documented in patients who completed study follow-up.
In addition, individuals assigned to the low-fat control diet had a significant decrease from baseline in all composites of cognitive function. Compared with the control group, the memory composite improved significantly in the Mediterranean diet plus nuts, while the frontal and global cognition composites improved in the Mediterranean diet plus olive oil group.
A different study, published online this month in the European Journal of Clinical Nutrition, found women who consumed a 1-oz serving of nuts, including tree nuts (such as almonds, Brazil nuts, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts), two or more times per week had a 13 percent lower risk of colorectal cancer (RR, 0.87; 95% CI, 0.72-1.05; P=0.06) compared to those who rarely consumed nuts.
The study evaluated 75,680 women in the Nurses’ Health Study, with no previous history of cancer.
Previous research has shown that women in this same cohort, who consumed a 1-oz serving of nuts two or more times per week, had a significantly reduced risk of pancreatic cancer (RR, 0.65; 95% CI, 0.47-0.92; P=0.007) compared to those who largely abstained from nuts.
“These findings are very encouraging," said Maureen Ternus, M.S., R.D., executive director of the International Tree Nut Council Nutrition Research & Education Foundation (INC NREF). “While we’ve known for years that 1.5 oz (or 1/3 c) of nuts per day can help reduce the risk of heart disease, more and more research is showing the potential beneficial effect of nut consumption on other chronic diseases such as diabetes and cancer."