Regular readers of my work have come to expect articles about
the power of whey proteins to potentaily fight cancer and
improve immunity among its many benefits. The ability of whey to
fight cancer, improve glutathione levels and immunity, is well
documented.
Additional research suggests possible medical uses for whey that
are quite unexpected and different from whey’s traditional role
as an immune booster and anti cancer functional food. For
example, whey may be able to reduce stress and lower cortisol
and increase brain serotonin levels, improve liver function in
those suffering from certain forms of hepatitis, reduce blood
pressure, as well as other amazing recent discoveries, such as
whey’s possible effects on weight loss, which is the focus of
this article.
What is whey?
When we talk about whey we are actually referring to a complex
milk-based ingredient made up of protein, lactose, fat and
minerals. Protein is the best-known component of whey and is
made up of many smaller protein subfractions such as:
Beta-lactoglobulin, alpha-lactalbumin, immunoglobulins (IgGs),
glycomacropeptides, bovine serum albumin (BSA) and minor
peptides such as lactoperoxidases, lysozyme and lactoferrin.
Each of the subfractions found in whey has its own unique
biological properties. Modern filtering technology has improved
dramatically in the past decade, allowing companies to separate
some of the highly bioactive peptides - such as lactoferrin and
lactoperoxidase - from whey.
Some of these subfractions are only found in very minute amounts
in cow’s milk, normally at less than one percent (e.g.,
lactoferrin, lactoperoxidase, etc.)
The medicinal properties of whey have been known for centuries.
For example, an expression from Florence, Italy. Circa 1650, was
"Chi vuol viver sano e lesto beve scotta e cena presto" which
translates into English as "If you want to live a healthy and
active life, drink whey and dine early."
Another expression from Italy regarding the benefits of whey
(circa 1777) was "Allevato con la scotta il dottore e in
bancarotta." Which translates into English "If everyone were
raised on whey, doctors would be bankrupt."
Is whey a weight loss functional food?
A few years ago, I might have said no. Now I am not so sure.
Although there was a smattering of studies suggesting whey had
certain properties that might assist with weight loss, a number
of recent studies appear to further support the use of whey as a
possible weight loss supplement. Most interesting - at least to
nerds like me - the effect appears to be not by a single
mechanism, but several. This article will briefly explore a few
possible pathways by which whey may assist the dieter.
"I’m hungry!"
Human hunger and appetite are regulated by a phenomenally
complicated set of overlapping feedback networks, involving a
long list of hormones, psychological factors as well as
physiological factors, all of which are still being elucidated.
It’s a very intensive area of research right now, with various
pharmaceutical companies looking for that "magic bullet" weight
loss breakthrough they can bring to market.
One hormone getting attention by researchers looking for
possible solutions to obesity is cholecystokinin (CCK). Several
decades ago, researchers found CCK largely responsible for the
feeling of fullness or satiety experienced after a meal and
partially controls appetite, at least in the short term.
Cholecystokinin (CCK) is a small peptide with multiple functions
in both the central nervous system and the periphery (via CCK-B
and CCK-A receptors respectively). Along with other hormones,
such as pancreatic glucagon, bombesin, glucagon-like peptide-1,
amide (GLP-1), oxyntomodulin, peptide YY (PYY) and pancreatic
polypeptide (PP)., CCK is released by ingested food from the
gastrointestinal tract and mediates satiety after meals.
Such a list would not be complete without at least making
mention of what many researchers consider the "master hormones"
in this milieu, which is insulin and leptin. If that’s not
confusing enough, release of these hormones depends on the
concentration and composition of the nutrients ingested.
That is, the type of nutrients (i.e., fat, protein, and
carbohydrates) eaten, the amount of each eaten, and composition
of the meal, all effect which hormones are released and in what
amounts... Needless to say, it’s a topic that gets real
complicated real fast and the exact roles of all the variables
is far from fully understood at this time, though huge strides
have been made recently.
Whey’s effects on food intake.
This (finally!) brings us to whey protein. Whey may have some
unique effects on food intake via its effects on CCK and other
pathways. Many studies have shown that protein is the most
satiating macro-nutrient. However, it also appears all proteins
may not be created equal in this respect.
For example, two studies using human volunteers compared whey
vs. casein (another milk based protein) on appetite, CCK, and
other hormones (Hall WL, Millward DJ, Long SJ, Morgan LM.Casein
and whey exert different effects on plasma amino acid profiles,
gastrointestinal hormone secretion and appetite. Br J Nutr. 2003
Feb;89(2):239-48).
The first study found that energy intake from a buffet meal ad
libitum was significantly less 90 minutes after a liquid meal
containing whey, compared with an equivalent amount of casein
given 90 minutes before the volunteers were allowed to eat all
they wanted (ad libitum) at the buffet. In the second study, the
same whey preload led to a plasma CCK increase of 60 % ( in
addition to large increases in glucagon-like peptide [GLP]-1 and
glucose-dependent insulinotropic polypeptide) following the whey
preload compared with the casein.
Translated, taking whey before people were allowed to eat all
they wanted (ad libitum) at a buffet showed a decrease in the
amount of calories they ate as well as substantial increases in
CCK compared to casein. Subjectively, it was found there was
greater satiety followed the whey meal also.
The researchers concluded "These results implicate
post-absorptive increases in plasma amino acids together with
both CCK and GLP-1 as potential mediators of the increased
satiety response to whey and emphasize the importance of
considering the impact of protein type on the appetite response
to a mixed meal." Several animal studies also find whey appears
to have a pronounced effect on CCK and or satiety over other
protein sources.
It should be noted however that not all studies have found the
effect of whey vs. other protein sources on food intake (Bowen
J, Noakes M, Clifton P, Jenkins A, Batterham M.Acute effect of
dietary proteins on appetite, energy intake and glycemic
response in overweight men. Asia Pac J Clin Nutr.
2004;13(Suppl):S64.).
It should also be noted that although studies find protein to be
the most satiating of the macro-nutrients, certain protein
sources (e.g. egg whites) may actually increase appetite
(Anderson GH, Tecimer SN, Shah D, Zafar TA. Protein source,
quantity, and time of consumption determine the effect of
proteins on short-term food intake in young men. J Nutr. 2004
Nov;134(11):3011-5.), so protein sources appear worth
considering when looking to maximize weight loss and suppress
appetite.
How whey achieves this effect is not fully understood, but
research suggests it’s due to whey’s high glycomacropeptide and
alpha-lactalbumin content, as well as its high solubility
compared to other proteins, and perhaps it’s high percentage of
branch chain amino acids (BCAA’s).
Whey’s effects on bodyfat, insulin sensitivity, and fat
burning... .
So we have some studies suggesting whey may have some unique
effects on hormones involved in satiety and or may reduce energy
(calorie) intake of subsequent meals, but do we have studies
showing direct effects of whey vs. other proteins on weight
loss? In animals at least, whey has looked like a promising
supplement for weight loss.
Although higher protein diets have been found to improve insulin
sensitivity, and may be superior for weight loss (with some
debate!) then higher carbohydrate lower protein diets, it’s
unclear if all proteins have the same effects.
One study compared whey to beef (Damien P. Belobrajdic,, Graeme
H. McIntosh, and Julie A. Owens. A High-Whey-Protein Diet
Reduces Body Weight Gain and Alters Insulin Sensitivity Relative
to Red Meat in Wistar Rats. J. Nutr. 134:1454-1458, June 2004)
and found whey reduced body weight and tissue lipid levels and
increased insulin sensitivity compared to red meat.
Rats were fed a high-fat diet for nine weeks, then switched to a
diet containing either whey or beef for an additional six weeks.
As has generally been found in other studies, the move to a high
dietary protein reduced energy intake (due to the known
satiating effects of protein compared to carbs or fat), as well
as reductions in visceral and subcutaneous bodyfat.
However, the rats getting the whey, there was a 40% reduction in
plasma insulin concentrations and increased insulin sensitivity
compared to the red meat. Not surprisingly, the researchers
concluded "These findings support the conclusions that a
high-protein diet reduces energy intake and adiposity and that
whey protein is more effective than red meat in reducing body
weight gain and increasing insulin sensitivity."
Other studies suggest taking whey before a workout is superior
for preserving/gaining lean body mass (LBM) and maintaining fat
burning (beta oxidation) during exercise over other foods taken
prior to a workout. The study called "A preexercise
lactalbumin-enriched whey protein meal preserves lipid oxidation
and decreases adiposity in rats" (Am J Physiol Endocrinol Metab
283: E565-E572, 2002.) came to some very interesting conclusions.
One thing we have known a long time is the composition of the
pre-exercise meal will affect substrate utilization during
exercise and thus might affect long-term changes in body weight
and composition. That is, depending on what you eat before you
workout can dictate what you use for energy (i.e. carbs, fats,
and or proteins) which alters what you burn (oxidize) for energy.
The researchers took groups of rats and made the poor buggers
exercise two hours daily for over five weeks (talk about over
training!), either in the fasted state or one hour after they
ingested a meal enriched with a simple sugar (glucose), whole
milk protein or whey protein.
The results were quite telling. Compared with fasting (no food),
the glucose meal increased glucose oxidation and decreased lipid
oxidation during and after exercise. Translated, they burned
sugar over body fat for their energy source. In contrast, the
whole milk protein and whey meals preserved lipid oxidation and
increased protein oxidation. Translated, fat burning was
maintained and they also used protein as a fuel source.
Not surprisingly, the whey meal increased protein oxidation more
than the whole milk protein meal, most likely due to the fact
that whey is considered a "fast" protein that is absorbed
rapidly due to it’s high solubility.
As one would expect, by the end of the five weeks, body weight
was greater in the glucose, whole milk protein and whey fed rats
than in the fasted ones. No shock there. Here is where it gets
interesting: In the group getting the glucose or the whole milk
protein, the increase in weight was from bodyfat, but in the
whey fed group, the increase in weight was from an increase in
muscle mass and a decrease in bodyfat!
Only the rats getting the whey before their workout increased
muscle mass and decreased their bodyfat. The researchers
theorized this was due to whey’s ability to rapidly deliver
amino acids during exercise. Is this the next big find in sports
nutrition or those simply looking to preserve muscle mass loss
due to aging?
Hard to say at this time being it was done in rats, but if it
turns out to be true in humans (and there is no reason people
can’t try it now) it would indeed be a breakthrough in the quest
to add muscle and lose fat.
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