Oxford
University Press (OUP)
A paper published in the International Journal of Epidemiology confirms a link between peanut and nut intake and lower mortality rates, but finds no protective effect for peanut butter. Men and women who eat at least 10 grams of nuts or peanuts per day have a lower risk of dying from several major causes of death than people who don't consume nuts or peanuts.
The reduction in
mortality was strongest for respiratory disease, neurodegenerative disease, and
diabetes, followed by cancer and cardiovascular diseases. The effects are equal
in men and women. Peanuts show at least as strong reductions in mortality as
tree nuts, but peanut butter is not associated with lower mortality,
researchers from Maastricht University found.
This study was carried out within the Netherlands Cohort Study, which has been running since 1986 among over 120,000 Dutch 55-69 year old men and women.
Nut consumption was
assessed by asking about portion size and frequency of intake of peanuts, other
nuts (tree nuts), and peanut butter. The researchers from Maastricht University
analyzed the relationship with overall and cause-specific mortality since 1986.
The associations
between nuts and peanut intake and cardiovascular death confirm earlier results
from American and Asian studies that were often focused on cardiovascular
diseases.
However, in this new study, it was found that mortality due to
cancer, diabetes, respiratory, and neurodegenerative diseases was also lowered
among users of peanuts and nuts.
Project leader and epidemiologist Professor
Piet van den Brandt commented: "It was remarkable that substantially lower
mortality was already observed at consumption levels of 15 grams of nuts or
peanuts on average per day (half a handful). A higher intake was not associated
with further reduction in mortality risk. 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."
Peanuts and tree
nuts both contain various compounds such as monounsaturated and polyunsaturated
fatty acids, various vitamins, fiber, antioxidants, and other bioactive
compounds, that possibly contribute to the lower death rates. In contrast to
peanuts, no association was found between peanut butter intake and mortality
risk.
However, besides peanuts, peanut butter contains also added components
like salt and vegetable oils.
In the past, it has been shown that peanut butter
contains trans fatty acids and therefore the composition of peanut butter is
different from peanuts. The adverse health effects of salt and trans fatty
acids could inhibit the protective effects of peanuts.