If anyone has been watching or reading the news recently they will have seen “Protein as bad as smoking” as a headline.
What they may however not know is the following.
The study was epidemiological. That is to say that the study by it’s very nature, is looking at data after it has happened and creating an hypothesis, not a conclusion.
It was also done on those 50 and above, and in the group 65+, it showed a positive correlation with protein, with lower mortality.
There was no control group involved and as a result, one cannot conclude anything and regard it as proof, or movements in that said direction.
Mice in the second study, were injected cancer cells into, higher protein was two fold increase, not the 19 fold increase of smoking. Even at this point, it is mice being studied, which are similar in many ways yet not the same as human studies, due to the simple fact we are (clearly!) two different species.
One also must consider, that the cancer cells were injected, not a natural mutation in the cellular activity of the animal.
One day could long into the future, they will perhaps tell the truth rather than go for publicity and so extra funding… However that doesn’t create a good story, does it?
What is more, the study does not indicate the level of activity, nor general life style of said participants. Comparing the needs of an avid trainer, to a complete couch potato could not be more be more different.
Things you should consider according to the NHS:
The human data used was not specifically collected for the purpose of the current study. This meant that the researchers had to rely on the completeness of, for example, national data on deaths and causes of death. This may mean that deaths of some participants may have been missed.
Information on food intake was only collected for one 24-hour period, and this may not be representative of what people ate over time. Most people (93%) reported that it was typical of their diet at the time, but this may have changed over the 18 years of follow up.
The researchers took into account some factors that could affect results, but not others, such as physical activity.
Although the study was reasonably large, numbers in some comparisons were relatively low, for example, there were not many diabetes-related deaths and only 437 people overall ate a low protein diet. The broad confidence intervals for some of the results reflect this.
Many news sources have suggested that a high protein diet is “as bad for you” as smoking. This is not a comparison that is made in the research paper, therefore its basis is unclear. While we do need some protein in our diets, we don’t need to smoke, so this is not a helpful comparison.
While the authors suggested that people eat a low protein diet in middle age and switch to a high protein diet once they get older, it is not possible to say from the study whether this is what the older participants actually did, as their diets were only assessed once.
Ideally the findings need to be confirmed in other studies set up to specifically address the effects of higher protein diets, particularly the strikingly different results for different age groups.
