The Biochemical Magic of Raw Milk and Other Raw Foods: Glutathione

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One of the many benefits of raw milk may be its ability to promote the production of a wonderful little compound called “glutathione” — this tiny compound consists of just three amino acids, but it is the master antioxidant and detoxifier of the cell.

Looking at this little molecule for a few moments may be reductionist, but understanding how a food provides its benefits not only helps us better understand how to produce, prepare, and use that food, but also helps us identify other foods that may offer similar benefits.  As I will describe below, for example, large amounts of raw fruits and vegetables may provide some glutathione-boosting power for people who cannot tolerate smaller amounts of raw milk.  Heck, even — shudder — raw egg whites may give a glutathione boost in some people comparable to that given by raw milk!

Glutathione — The Master Antioxidant and Detoxifier

Glutathione maintains vitamins C and E in their reduced, active forms.  It tightly regulates the production of hydrogen peroxide, which is a valuable signaling compound in small amounts but which promotes oxidative destruction of the cellular machinery in larger amounts.  It quickly neutralizes lipid peroxides — nasty, dangerous breakdown products of the delicate and precious polyunsaturated fatty acids found in our cell membranes.  On top of all these antioxidant functions, our cells use glutathione to make drugs and toxic chemicals more water-soluble so they can be excreted.  Without glutathione, the antioxidant system breaks down, and toxic chemicals hang around to wreak havoc in our cells and tissues.

Protein — It’s Great, But It’s Not Enough

Our bodies synthesize glutathione from protein.  The most important amino acid needed for glutathione synthesis is cysteine.  Cysteine is a sulfur-containing amino acid that is found in the diet, especially in animal proteins, and that our livers also make from methionine, another sulfur amino acid.  These are the same dreaded sulfur amino acids that vegetarians claim leach calcium from our bones.  As I pointed out in a blog post a few months ago, they don’t.

Studies in both rats and humans show that deficient intakes of these supposedly bone-eroding sulfur amino acids lead to a deficient synthesis of glutathione.  The more extensive rat studies show that glutathione increases as dietary protein increases, and that related antioxidant and detoxification enzymes increase in tandem.

In fact, this is true even when the protein is the supposedly cancer-causing milk protein, casein.

There is just one problem, however.  Once we meet our requirement for protein and sulfur amino acids, eating extra protein or sulfur amino acids fails to boost glutathione any further.  Rats need to consume about 15 percent of calories from protein in order to maximize levels of glutathione and its associated antioxidant and detoxification enzymes.  Preliminary evidence in humans suggests that the glutathione-boosting power of protein maxes out at one gram of protein per kilogram of body weight per day and 24 milligrams of sulfur amino acids per day.  For someone who weighs 110 pounds, this is 50 grams of protein per day; for someone who weighs 150 pounds, it’s about 70 grams of protein per day, and for someone who weigh 180 pounds, it’s about 80 grams of protein per day.  Consuming this amount of protein from virtually any mix of whole foods will satisfy the requirement for sulfur amino acids.

Excess cysteine, in fact, when consumed as a free amino acid, can actually deplete glutathione levels.  Why?  As it turns out, cysteine can be toxic because of its vulnerability to oxidation.  Except in acidic environments like the digestive tract, cysteine rapidly oxidizes and generates free radicals that can wreak havoc on the delicate structures of our cells and tissues.  Consequently, our bodies don’t let free cysteine hang around, and when we eat lots of it, we convert the excess to taurine and sulfate and get rid of it.

Never fear!  There is more to the story than regular ol’ animal protein.  The valiant, cape-wearing, free radical-wrestling, toxicant-thwarting Raw Milk and his courageous army of raw food volunteers is here to rack up our glutathione points even higher.

The Undenatured Whey Proteins Save the Day

In the late 1980s, a group of researchers from the Montreal General Hospital Research Institute and McGill University compared the ability of different proteins to stimulate immune function in mice.  They kept the level of protein constant at 20 percent, but varied the type of protein, testing casein, soy, wheat, corn, egg white, fish, beef, spirulina, another alga called scenedesmus, and, finally, whey.  The whey protein promoted better immune function than all of the other proteins, and it achieved this marvelous feat by increasing the amount of glutathione available to the spleen, allowing the rapid multplication of immune-enhancing white blood cells.

In 1991, however, these researchers stumbled upon a critical discovery: whey proteins only boost glutathione status in their raw, undenatured state.

They made this discovery by complete accident when a shipment of whey protein from Denmark mysteriously lacked the glutathione-promoting activity of the preparation they had been using before.  So they put a number of whey proteins to the test by feeding them to mice and measuring the concentrations of glutathione in their livers and hearts.  Only their original preparation boosted glutathione status.  What turned out to be the difference?  Most of the products had undergone much more extensive heat treatment, causing two very delicate proteins, beta-lactoglobulin and serum albumin, to head for the highway.  These two proteins contain unique glutamyl-cysteine bonds that resist digestion and enter the blood stream in tact.  The glutamyl-cysteine bond is two-thirds of a glutathione molecule, and thus much more easily turned into glutathione itself.

Raw Egg White — The Trusty Sidekick?

The researchers searched over thirty publications identifying the sequences of edible plant and animal proteins and concluded that the only two types of protein in the food supply containing these unique bonds are whey proteins and egg white proteins.  They noted the following:

It may also be noteworthy that from time immemorial, whey from raw milk and/or undenatured raw egg white have been administered to children and to the sick as prophylactic or therapeutic measures in folk medicine.

I have heard of a number of cases of people benefiting from including raw egg whites in their diet.  It should be noted, however, that raw egg whites contain substances that inhibit digestion and decrease the availability of biotin.  Some people may benefit from their apparent glutathione-boosting ability, and this may be especially important for people who cannot tolerate milk, but in others the risk of biotin deficiency or digestive troubles might outweigh this benefit.  Intestinal flora produce biotin and egg yolks are loaded with it.  Maintaining proper intestinal flora and eating plenty of egg yolks may allow some people to reap the benefits of raw egg whites if they do not have trouble digesting them.

Attack Of the Ultra-High Temperatures

As milk is heated, the delicate whey proteins denature and start to associate with the casein fraction.  Even the small amount of heat involved in pasteurization decreases the whey protein concentration of milk, but ultra-high temperature (UHT) pasteurization and sterilization cause the worst declines.  I made the graph below from a study that purchased milk from several sources, each prepared in a different way.  It shows the percentage of total protein in the milk represented by whey proteins.  Since the different milks were from different sources, the difference could reflect both the heat treatment and the fact that the milk came from different cows that may have otherwise been treated differently.  In any case, it suggests the pasteurized milk we could buy at the store has much less whey protein than the raw milk we could get from the farm.

Since pasteurization decreases the total protein content of the milk, the concentration of whey proteins in the total milk fairs even worse:

High-temperature short-time (HTST) pasteurized milk had 30 percent less whey protein than raw milk, while UHT milk had a whopping 80 percent less and sterilized milk had a ginormous 87 percent less!

To make matters worse, heating milk also reduces the proportion of total whey protein represented by those magical yet delicate glutathione-boosting proteins.  This next study did things the right way and purchased raw milk from one source and subjected the milk to different heat treatments.  So we can without hesitation chalk these differences up completely to heat:

Whey protein from HTST milk has 22 percent less beta-lactoglobulin than raw milk.  If HTST also destroys 3o percent of the whey protein, then a glass of pasteurized milk has 45 percent less undenatured beta-lactoglobulin than a glass of raw milk.

While I had trouble finding a study that quantified the effect of HTST (about 72 C for 15 seconds) on serum albumin, a second rigorous study showed that heating milk at only 65 C for 15 seconds slashed away 40 percent of the serum albumin while heating the milk at 85 C for 30 seconds destroyed 77 percent of it:

If we give HTST the benefit of the doubt and assume its destructive effects are more similar to the effects seen with 65 C than those seen with 85 C, then we can conclude that it destroys roughly 45 percent of the glutathione-boosting properties of milk.  The undenatured whey protein that proved useful for boosting glutathione and immune function in mice was produced with a single round of “classical” pasteurization at 63 C for 30 minutes, which led to an even greater destruction of serum albumin, resulting in a total loss of 52 percent of the whey’s glutathione-boosting power.  The other whey proteins suffered even more heat damage during processing and failed to boost glutathione at all.

How Much Extra Glutathione Does Raw Milk Give Us?

What follows should be regarded as a very rough calculation that relies on several unproven assumptions, including the following: a) that the researchers’ hypothesis that the glutamyl-cysteine bonds are in fact responsible for the glutathione-boosting power of whey protein is true, b) that the total body increase in glutathione was similar to the increase seen in the tissues the researchers measured, and c) that raw, undenatured whey protein produces a similar response in people as it produces in mice.  Whey protein has in fact been shown to increase glutathione status in people, but for obvious reasons no one has ever dissected a human into bits to analyze the total amount of glutathione produced.

Relying on these imperfect assumptions, then, we can calculate that each glass of raw milk provides about 9.3 milligrams of glutathione while pasteurized milk provides only 4.5 milligrams:

Humans appear to make about 185 milligrams of glutathione per day when they meet the requirement for protein and sulfur amino acids.  A “milk fast” on 1500 calories of raw milk per day would provide the requirement for protein and sulfur amino acids and supply an extra 100 milligrams of glutathione-boosting power.  This should theoretically boost glutathione levels over 50 percent.  It should not be surprising, then, that such “milk fasts” have proved useful in the past for boosting immune function, recovering from illness, and regenerating vibrant health.

Raw egg whites contain a similar concentration of the unique glutathione-boosting glutamyl-cysteine bonds.  If indeed these bonds are responsible for raw milk’s glutathione-boosting power, raw egg whites might have similar power.  As noted above, many people may have have trouble with raw egg whites because of the biotin-binding factors and digestive enzyme inhibitors, but many other people, especially those who do not tolerate raw milk, may derive a big glutathione boost from them.  Raw milk and raw eggs should both be handled carefully to preserve these delicate bonds, and blending them into smoothies may cancel out some of the benefit.

Glutathione In Raw Fruits, Vegetables, and Other Foods

While raw milk and possibly raw egg whites contain unique glutathione-boosting proteins, most foods also contain small amounts of glutathione itself.  Studies in animals and humans have shown that dietary glutathione increases blood levels of glutathione, but one study in mice suggested that under ordinary conditions, dietary glutathione cannot boost its own concentration in other tissues except in the lung, where large amounts of glutathione are needed to maintain the fluidity of mucus.  When the researchers fed the mice a drug that inhibits glutathione synthesis, however, dietary glutathione did in fact boost tissue glutathione levels, which shows that cells do have the capacity to absorb it.

Thus, dietary glutathione should protect our intestines, blood, and lungs from oxidative assault, but huge amounts may be needed in order to give the same boost to our other tissues as we would get from raw milk. Once again, however, the heavy hand of heat takes a strike against our little hero.  The following data are taken from this paper.  Consider the effect of heat on spinach glutathione:

Or on the amount of glutathione in peaches:

Juicing is a particularly noxious way to treat fruits.  This is at least true when using commercial methods.  Each fruit in the following chart has two bars, one on the left for the whole fruit and one on the right for the corresponding fruit juice:

Asparagus, avocado, okra, spinach, squash, tomatoes, and potatoes rank among the richest plant foods measured.  Whole grains, legumes, vegetarian meat substitutes, and refined foods that have been measured contain little to no glutathione.

Meats contain lots of glutathione, but fats such as butter and lard contain zero.  Zip.  Zilch.  Nada.  Loading up on lean meat is a bad idea unless you want to suffer from rabbit starvation.  Usually the digestive tract releases cysteine into our bloodstream slowly so that it never has much of a chance to accumulate and oxidize, but overdosing on lean meat might even provide enough cysteine to begin depleting glutathione levels.  While a raw “milk fast” may give us a huge glutathione boost, a lean “meat fast” is more likely to make us sick.

The best foods for boosting glutathione status appear to be raw milk or raw egg whites.  Many people who cannot tolerate pasteurized milk report that they can tolerate raw milk.  Many others report that they cannot.  Raw egg whites contain their own risks from anti-nutrients, but people who digest them well and get plenty of biotin from their intestinal flora or from additional egg yolks may be able to reap their glutathione-boosting benefits in the absence of milk.

Besides these two unique sets of proteins, meeting our daily needs for protein with moderate amounts of meat, fish, eggs, legumes, or other plant and animal protein foods, and loading up on raw fruits and veggies appear to be the best ways to give us a good glutathione boost.  A diet rich in the full spectrum of nutrients will also provide many other vitamins and minerals important to boosting glutathione status in less direct ways.

Glutathione is not the only benefit of raw foods, nor is loss of glutathione the only drawback to excessive heating and processing.  So we clearly should not base our diet merely on these data.  Some people, moreover, have intolerances to fruits and vegetables, just as others may not tolerate dairy or egg whites.  These facts emphasize the importance of considering each individual’s unique biochemistry rather than making a one-size-fits-all diet for everyone.

However, to the extent that glutathione is responsible for some of the miraculous recoveries people experience with raw milk, many of us may be able to enhance these recoveries even further by loading up on raw fruits and veggies, and people who cannot tolerate raw milk may benefit from consuming these foods in addition to raw, whole eggs if they do not have a problem with whites.

“Reducing” one of our favorite foods to a new favorite molecule may thus help us come up with better holistic solutions to promote vibrant health.  Here’s to yours!  And may the world obtain the same.

Read more about the author, Chris Masterjohn, PhD, here.

© 2015 The Weston A. Price Foundation for Wise Traditions in Food, Farming, and the Healing Arts.