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.