Findings
support recommendations to increase consumption of plant proteins
BMJ
Diets
high in protein, particularly plant protein, are associated with a lower risk
of death from any cause, finds an analysis of the latest evidence published
by The BMJ.
The
researchers say these findings "support current dietary recommendations to
increase consumption of plant proteins in the general population."
Diets
high in protein, particularly protein from plants such as legumes (peas, beans
and lentils), whole grains and nuts, have been linked to lower risks of
developing diabetes, heart disease and stroke, while regular consumption of red
meat and high intake of animal proteins have been linked to several health
problems.
But
data on the association between different types of proteins and death are
conflicting.
So
researchers based in Iran and the USA set out to measure the potential
dose-response relation between intake of total, animal, and plant protein and
the risk of death from all causes, cardiovascular disease, and cancer.
They reviewed the results of 32 studies that reported risk estimates for all cause, cardiovascular, and cancer mortality in adults aged 19 or older.
All
studies were thoroughly assessed for bias (problems in study design that can
influence results).
Mathematical
models were then used to compare the effects of the highest versus lowest
categories of protein intake, and analyses were done to evaluate the
dose-response relations between protein intake and mortality.
During
a follow-up period of up to 32 years, 113,039 deaths (16,429 from
cardiovascular disease and 22,303 from cancer) occurred among 715,128
participants.
The
results show that high intake of total protein was associated with a lower risk
of all cause mortality compared with low intake.
Intake
of plant protein was associated with an 8% lower risk of all cause mortality
and a 12% lower risk of cardiovascular disease mortality. Intake of animal protein
was not significantly associated with risk of cardiovascular disease and cancer
mortality.
A
dose-response analysis of data from 31 studies also showed that an additional
3% of energy from plant proteins a day was associated with a 5% lower risk of
death from all causes.
Possible
reasons for the beneficial effects of plant proteins include their association
with favourable changes in blood pressure, cholesterol and blood sugar levels,
which might help to lower the risk of conditions such as heart disease and type
2 diabetes, say the researchers.
They
point to some limitations, such as differences in the way studies assessed diet
and the possibility that some effects may have been due to unmeasured
(confounding) factors. What's more, as most of the included studies were from
Western nations, the findings may not be applicable to other countries.
However, strengths include the large number of participants and deaths, providing a detailed insight into the association between intake of dietary protein and risk of mortality based on the current evidence, they write.
"These
findings have important public health implications as intake of plant protein
can be increased relatively easily by replacing animal protein and could have a
large effect on longevity," say the researchers.
While
further studies are required, these findings "strongly support the
existing dietary recommendations to increase consumption of plant proteins in
the general population," they conclude.
