A team of researchers in the Netherlands said that the health benefits worked for those who ate around 10g of nuts or peanuts per day, but that the salt and vegetable oils found in peanut spread could cancel out the positive effects.
The effects were equal in men and women, they said.
Peanut butter contains salt and trans fatty acids which could inhibit the protective effects
Tree nuts and peanuts contain vitamins, fibres and antioxidants that may contribute to lower death rates – particularly in those suffering from respiratory diseases like asthma and emphysema, diabetes and neurodegenerative diseases, such as dementia.
They could also reduce the risk of cancer and cardiovascular diseases, such as heart attacks and strokes.
Epidemiologist Professor Piet van den Brandt, who led the study of more than 120,000 Dutch people between the ages of 55 and 69 at Maastricht University, said the findings were “remarkable”, particularly due to the small amount that needed to be eaten daily to make a difference.
“A higher intake was not associated with further reduction in mortality risk,” he said.
“This was also supported by a meta-analysis of previously published studies together with the Netherlands Cohort Study, in which cancer and respiratory mortality showed this same dose-response pattern.”
The study, which is published in the International Journal of Epidemiology, used data from the Netherlands Cohort Study, which has been running since 1986.
It also found that those who ate nuts regularly tended to be younger, more educated, drank more alcohol, ate healthier foods and were more likely to take supplements.
Women who ate nuts were leaner, less likely to smoke or suffer from diabetes.
