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 (readers interested in brushing up on the effects of
whey on cancer, immunity, etc, can read previous articles by me
at the LEF's web site: www.lef.org and www.BrinkZone.com).
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.
Effects On Serotonin, Blood Sugar Regulation, And More!
Although the above would probably be the major mechanisms by
which whey could help the dieter, there are several secondary
effects of whey that may assist in weight loss. For example,
whey's effects on serotonin levels. Serotonin is probably the
most studied neurotransmitter since it has been found to be
involved in a wide range of psychological and biological
functions. Serotonin ( also called 5-hydroxytryptamine or
5-HT) is involved with mood, anxiety, and appetite.
Elevated levels of serotonin can cause relaxation and reduced
anxiety. Low serotonin levels are associated with low mood,
increased anxiety (hence the current popularity of the SSRI drugs
such as Prozac and others), and poor appetite control. This is an
extremely abbreviated description of all the functions serotonin
performs in the human body - many of which have yet to be fully
elucidated - but a full explanation is beyond the scope of this
article.
Needless to say, Increased brain serotonin levels are associated
with an improved ability of people to cope with stress, whereas a
decline in serotonin activity is associated with depression and
anxiety. Elevated levels of serotonin in the body often result in
the relief of depression, as well as substantial reduction in
pain sensitivity, anxiety and stress. It has also been theorized
that a diet-induced increase in tryptophan will increase brain
serotonin levels, while a diet designed for weight loss (e.g., a
diet that reduces calories) may lead to a reduction of brain
serotonin levels due to reduced substrate for production and a
reduction in carbohydrates.
Many people on a reduced calorie intake in an attempt to lose
weight find they are often ill tempered and more anxious.
Reductions in serotonin may be partially to blame here. One
recent study (The bovine protein alpha-lactalbumin increases
the plasma ratio of tryptophan to the other large neutral amino
acids, and in vulnerable subjects raises brain serotonin
activity, reduces cortisol concentration, and improves mood under
stress. Am J Clin Nutr 2000 Jun;71(6):1536-1544) examined whether
alpha-lactalbumin - a major sub fraction found in whey which has
an especially high tryptophan content - would increase plasma
Tryptophan levels as well reduce depression and cortisol
concentrations in subjects under acute stress considered to be
vulnerable to stress.
The researchers examined twenty-nine "highly stress-vulnerable
subjects" and 29 "relatively stress-invulnerable" subjects using
a double blind, placebo-controlled study design. The study
participants were exposed to experimental stress after eating a
diet enriched with either alpha-lactalbumin (found in whey) or
sodium-caseinate, another milk based protein. They researchers
looked at:
* Diet-induced changes in the plasma Tryptophan and its ratio
to other large neutral amino acids.
* Prolactin levels.
* Changes in mood and pulse rate.
* Cortisol levels (which were assessed before and after the
stressor).
Amazingly, the ratio of plasma Tryptophan to the other amino
acids tested was 48% higher after the alpha-lactalbumin diet than
after the casein diet! This was accompanied by a decrease in
cortisol levels and higher prolactin concentration. Perhaps most
important and relevant to the average person reading this
article, they found "reduced depressive feelings" when test
subjects were put under stress.
They concluded that the "Consumption of a dietary protein
enriched in tryptophan increased the plasma Trp-LNAA ratio and,
in stress-vulnerable subjects, improved coping ability, probably
through alterations in brain serotonin." This effect was not seen
in the sodium-caseinate group. If other studies can confirm these
findings, whey may turn out to be yet another safe and effective
supplement in the battle against depression and stress, as well
as reduced serotonin levels due to dieting.
Although there is a long list of hormones involved in appetite
regulation, some of which have been mentioned above, serotonin
appears to be a key player in the game. In general, experiments
find increased serotonin availability or activity = reduced food
consumption and decreased serotonin = increase food consumption.
If whey can selectively increase serotonin levels above that of
other proteins, it could be very helpful to the dieter.
Other possible advantages whey may confer to the dieter is
improved blood sugar regulation (Frid AH, Nilsson M, Holst JJ,
Bjorck IM. Effect of whey on blood glucose and insulin responses
to composite breakfast and lunch meals in type 2 diabetic
subjects. Am J Clin Nutr. 2005 Jul;82(1):69-75.) which is yet
another key area in controlling appetite and metabolism.
Finally, calcium from dairy products has been found to be
associated with a reduction in bodyweight and fat mass. Calcium
is thought to influence energy metabolism as intracellular
calcium regulates fat cell (adipocyte) lipid metabolism as well
as triglyceride storage. It's been demonstrated in several
studies the superiority of dairy versus non-dairy sources of
calcium for improving body composition, and the whey fraction
of dairy maybe the key.
The mechanism responsible for increased fat loss found with
dairy-based calcium versus nondairy calcium has not is not fully
understood but researchers looking at the issue theorized "...
dairy sources of calcium markedly attenuate weight and fat gain
and accelerate fat loss to a greater degree than do supplemental
sources of calcium. This augmented effect of dairy products
relative to supplemental calcium is likely due to additional
bioactive compounds, including the angiotensin-converting enzyme
inhibitors and the rich concentration of branched-chain amino
acids in whey, which act synergistically with calcium to
attenuate adiposity."
It appears components in whey - some of which have been mentioned
above - are thought to act synergistically with calcium to
improve body composition (Zemel MB. Role of calcium and dairy
products in energy partitioning and weight management. Am J Clin
Nutr. 2004 May;79(5):907S-912S.).
Conclusion
Taken in isolation, none of these studies are so compelling that
people should run out and use whey as some form of weight loss
nirvana. However, taken as a total picture, the bulk of the
research seems to conclude that whey may in fact have some unique
effects for weight loss and should be of great use to the dieter.
More studies are clearly needed however.
So what is the practical application of all this information and
how does the dieter put it to good use? Being the appetite
suppressing effects of whey appear to last approximately 2-3
hours, it would seem best to stagger the intake throughout the
day. For example, breakfast might be 1-2 scoops of whey and a
bowl of oatmeal, and perhaps a few scoops of whey taken between
lunch and dinner.
If whey does what the data suggests it does in the above, that
should be the most effective method for maximizing the effects of
whey on food (calorie) intake on subsequent meals as well as the
other metabolic effects covered. If working out, the schedule may
be different however and people should follow the pre and post
nutrition recommendations made in my ebook "Muscle Building
Nutrition" or advice easily found on the 'net via the many sports
nutrition and bodybuilding related web sites.
* Ebook can be found at: http://www.musclebuildingnutrition.com
Additional References Of Interest:
==================================
Curzon G.Serotonin and appetite.Ann N Y Acad Sci. 1990;600:521-
30; discussion 530-1.
Pierson ME, Comstock JM, Simmons RD, Kaiser F, Julien R, Zongrone
J, Rosamond JD. Synthesis and biological evaluation of potent,
selective, hexapeptide CCK-A agonist anorectic agents. J Med Chem
1997 Dec 19;40(26):4302-7
Blundell JE, King NA. Overconsumption as a cause of weight gain:
behavioural-physiological interactions in the control of food
intake (appetite). Ciba Found Symp 1996;201:138-54; discussion
154-8, 188-93
Zittel TT, von Elm B, Teichmann RK, Rabould HE, Becker HD.
Cholecystokinin is partly responsible for reduced food intake and
body weight loss after total gastrectomy in rats. Am J Surg 1995
Feb;169(2):265-70
Smith GP, Gibbs J. Are gut peptides a new class of anorectic
agents? Am J Clin Nutr 1992 Jan;55(1 Suppl):283S-285S
Strader AD, Woods SC. Gastrointestinal hormones and food intake.
Gastroenterology. 2005 Jan;128(1):175-91.
|
