Two sensational pieces of research in the media have
suggested that high protein diets are bad for us, so I thought I take a closer
look at their research.
The first group of researchers said that diets high in
protein are life shortening. I think it’s important to point out that these
researchers studied mice not people, and gave them diets with protein levels
ranging from 5%-60%. Mice (such as house mice) naturally eat plants (low in
protein), so if you think about it giving them a high protein diet would kill
them faster than a low protein diet. All this research seems to show is that
mice live longer on a diet similar to their natural diet – no surprises there!
The second group of researchers analysed the diet of 6,831
middle-aged and older American adults and concluded that “Those who derived
more than 20 per cent of their calories from protein were four times more
likely to die of cancer or diabetes than other people” and that "a
high-protein diet, particularly if the proteins are derived from animals, is
nearly as bad as smoking". Firstly, this research is based on the analysis
of one 24hr food recall per person, and one blood test result (from only 35% of
participants), with the cause of death followed up 18 years after the survey.
Media statements have been deceptive as the researchers’
initial findings, which were not reported, showed that a higher percentage of
low protein eaters died of cardiovascular disease and cancer than those on high
protein diets.
After having another look at age groups and blood test results the researchers concluded that low protein eaters aged 50-65yrs had a lower risk for cancer, but once they were over 66yrs this was not true and low protein levels were harmful while high and moderate levels of protein were protective.
Use this link to view the data
http://download.cell.com/cell-metabolism/mmcs/journals/1550-4131/PIIS155041311400062X.mmc1.pdf
More interesting information from this research:
- The average BMI was around 27% for all participants, which is an overweight classification.
- More than 80% of the high protein group already had diabetes at the time of the survey – nearly 30% had changed their diet recently for health reasons.
- Less than 7% of the participants were in the low protein group.
- There was no discussion on fruit and vegetable intake as they were included in the “Carbs” category.
- Meal size was not noted, so the servings for the “low” protein group could have been very large while still only delivering less than 10% of its calories from protein.
The Ministry of Health guidelines (2003) recommend that we
get 11-15% of our energy from protein, but the 2008/2009 nutrition survey
showed that adult New Zealanders get 16.5% of their energy from protein, with
the top source of protein being, wait for it, bread.
What do I recommend? The protein needs for each individual will depend on their age, health
history and health goals. Typically ¼ -⅓ of your meals and snacks should be
from a variety of great protein sources, this would be a moderate protein
intake of around 15-20%. If you are interested in more specific advice give me
a call.
