Too much protein..really? (part 1)
It is often reported (and with very good reason!) that
everything should be taken in moderation. This is nowhere more true than with
factors that affect your precious self! So, needless to say that media reports
suggest an effect a deleterious effect of overconsumption of the overtly masculinised,
required macro-nutrient, protein.
You’ve probably heard that too much protein is not good. Reported
by media outlets and your mother or father (I know mine do!) too much protein
puts stress upon your renal system and causes bone calcium excretion. This isn’t
just a housewives tale however, but has credence in that this evidence was drawn
from good quality published articles.
BUT ladies and gentleman, it is my feeling that this
knowledge requires an update and until that time no conclusion can be made as
to protein and its negative effects upon the renal system and bone calcium
So let’s break down my reasoning by looking at the studies
cited as the evidence for not consuming more protein than the RDA..
Protein and Renal
This is a classic case of media outlets causing a hubbub while
taking information out of context. The main point of debate is that an excess
intake of protein above the RDA causes chronic renal disease through increased
glomerular pressure and hyperfiltration. The data for this is sound enough,
with the frontier study that caused the media excitement being that of Barry M,
et al, 1982.
This article is methodologically well put together and is
deserved of its title as a frontier study (that which leads the way, as being
the first study, for further research in its field). However, picking it apart
(unfortunately it’s behind a paywall: http://1.usa.gov/1aLkB0j)
I came to realise the incorrectness of its use as a study to back up protein
moderation in a healthy individual.
- The majority of the evidence used is cited from
- Another group of evidence collection is that of
patients with co-existing renal disease.
- No healthy individuals are used as an evidence
Therefore, I conclude that this study is not suitable to be
used in order to draw association between increased protein intake and renal
Don’t want to take my
word for it?
Why would you? But there are published article’s out there
without the media spotlight upon them that back up what I’m saying:Martin W, et al (2005):
Concluded that –
“Although excessive protein intake remains a
health concern in individuals with pre-existing renal disease, the literature
lacks significant research demonstrating a link between protein intake and the
initiation or progression of renal disease in healthy individuals.”Further, Martin went on to say –“there is not
sufficient proof to warrant public health directives aimed at restricting
dietary protein intake in healthy adults for the purpose of preserving renal
function.”Knight E, et al (2003) designed
a prospective cohort study (which is a study using a group of individuals and
following them from the outset to the end of the study, measuring predetermined
outcomes overtime. These usually include both a control and treatment group).
It was concluded that high protein intake was not associated with renal
function decline in women with normally (healthy) operating kidneys.Blum M, et al (1989), in a
study using both vegetarians (a group which is demonstrated to have lower
protein intake) and non-vegetarians, both displayed similar deterioration in
renal health with age. It concluded no difference in age, sex, weight and
kidney function between groups.Kidney health and the bodybuilder’s diet?
You may be reading this and wondering whether any studies
have been conducted regarding us (a very broadly termed “us”). Us athletes and our high protein diets to aid weight loss, or high
protein diets and resistance training or endurance.
Well, to the best of my knowledge, no credible studies
have focused in on these topics. However, what can be taken away from this to
begin with is that at the current time,
no authority should be warranted towards decreasing protein intake in order to
maintain renal function.In my opinion, it would appear that protein intake over the
RDA, even so far as 1.4-2g/kg (a range commonly stated as that required for
exercising individuals) of bodyweight show no risk factors for decreased kidney
function, in healthy, exercising individuals. It should still be prudent to
mention that those individuals with mild renal insufficiency should monitor
their intakes more closely, as evidence shows that protein intake may be
closely related to the progression of renal disease.
Well, that went on for a bit longer than I thought it might
today! I’ll be bringing you part 2 as soon as I can, debunking protein intake linked to decrease bone health. In the meantime, if you
have any thoughts or could highlight any studies relevant to increased protein
intake (over 100g per day) regarding kidney health, I’d more than appreciate taking a