The study, published in International Journal of Epidemiology, noted that previous research has associated nut intake with lower mortality, but few studies have investigated causes of death other than cardiovascular disease – or questioned whether there is a dose-response relationship.
Led by Professor Piet van den Brandt from Maastricht University, the research team found a 23% lower chance of death during the 10-year study in people eating at least 10g (0.3oz) of nuts or peanuts a day. There was no benefit for peanut butter, which is high in salt and trans fats.
“Total nut intake was related to lower overall and cause-specific mortality (cancer, diabetes, cardiovascular, respiratory, neurodegenerative diseases, other causes) in men and women,” wrote the authors.
“Peanuts and tree nuts were inversely related to mortality, whereas peanut butter was not.”
van den Brandt told the BBC had taken into account the mitigating factor that nut consumers ate more fruit and vegetables and that women who ate nuts were often leaner, and adjusted the results accordingly.
"It was remarkable that substantially lower mortality was already observed at consumption levels of 15g of nuts or peanuts on average per day,” he added.
Researchers used data from the Netherlands Cohort Study, which has been running since 1986 among more than 120,000 Dutch men and women, aged 55 to 69.
They assessed how often people ate peanuts, other nuts, and peanut butter, and how much of these foods they consumed. Mortality rates and causes of mortality were then assessed ten years after the initial assessment took place.
The team then analysed the relationship between nut consumption and overall mortality from any cause, and death from a specific cause – revealing a link between tree nut and peanut consumption and cardiovascular deaths that backs up earlier results from American and Asian studies.
However, the new study also found that mortality due to cancer, diabetes, respiratory, and neurodegenerative diseases was also lowered among people who eat peanuts and tree nuts.
There was an average 23% lower risk of 10-year mortality across all diseases, with a decrease of:
- 45% for neurodegenerative disease
- 39% for respiratory disease
- 30% for diabetes
There was no benefit for peanut butter, which the team noted are high in salt and trans fats, and therefore may have negative impacts.
Source: International Journal of Epidemiology
Published online ahead of print, doi: 10.1093/ije/dyv039
“Relationship of tree nut, peanut and peanut butter intake with total and cause-specific mortality: a cohort study and meta-analysis”
Authors: Piet A van den Brandt, Leo J Schouten