CHAPTER 7

Proteoglycans: Sweet on Collagen, Cartilage, and Bones

In the 1930s, Dr. Francis Pottenger concluded that the healing power of broth came from its hydrophilic, water-loving nature. Every pot of properly made broth is full of huge, water-trapping molecules known as proteoglycans, a word that derives from proteo, meaning “of protein,” and glykos, meaning “sweet.” Proteoglycans wind over, under, and around the collagenous fiber networks that appear in skin, cartilage, and bones. Their principal job is to get and hold water. They are very, very thirsty.

The Goo Molecule for Lubrication and Shock Absorption

Hyaluronic acid (HA) is a type of proteoglycan known as the “goo molecule.” It’s comprised of thousands of the protein sugars known as GAGs and found just about everywhere in the human body. HA goo is the key to broth that gels.

HA lubricates and cushions joints, muscles, bones, and other movable parts, and is a major component of synovial fluid. Elbows, knees, and other joints are surrounded by a capsule that secretes synovial fluid. A key function of this viscous fluid is shock absorption to prevent wear and tear on the joint. Because healthy cartilage has no blood vessels, synovial fluid carries nutrients to the cartilage and removes waste from the joint capsule.

Structured Like a Christmas Tree

Jiggly yet structured, proteoglycan molecules are a primary component of the matrix or filler substance that exists between cells. Proteoglycans resemble freshly cut Christmas trees with a central trunk and bushy branches. Hyaluronic acid forms the trunk, and the sulfur-containing molecules chondroitin sulfate and keratan sulfate make up the branches. All are a type of mucosaccharide known as glycosaminoglycans (GAGs). Mucopolysaccharides are long chains of sugar molecules tricked out with some amino acids. In electrical terms, the chondroitin sulfate and keratan sulfate molecules carry negative charges and repel each other. By keeping their distance from one another, they keep cartilage plump and create space for the water they need to attract and hold.

HA abounds in the gristle known as hyaline cartilage. Indeed, hyaline is short for hyaluronic acid. Hyaline cartilage covers the ends of the long bones where articulation occurs and provides a cushioning effect for the bones. Hyaline cartilage also supports the tip of the nose, connects the ribs to the sternum, and forms most of the larynx and supporting cartilage of the trachea and bronchial tubes in the lungs.

Every cell in the body contains some HA, but it’s concentrated in skin tissue. It is found in the deep underlying dermal areas as well as the visible epidermal top layers. That means it is also concentrated in the “skin” tissue that lines the intestinal tract. The HA provides continuous moisture by binding up to a thousand times its weight in water. With age and ill health, the ability of the skin to produce HA decreases. The general public knows HA best for its use in cosmetics, particularly in creams for “intense hydration” and “lip plumping.”

Because HA lives three days or less in most of the body and less than a day in the skin, the body needs to make a lot of it—and often. Giving the body the raw materials it needs to make HA by including a lot of broth in the diet is clearly a good policy and a recipe for radiant skin.

For use in medicine, HA was once extracted from rooster combs but now tends to be manufactured in labs using a strain of Bacillus subtilis genetically modified to yield maximum hyaluronan content. It’s often incorporated into skin lotions for eczema, psoriasis, and other itchy, dry skin conditions; incorporated into scaffolding applied to wounds postoperatively to speed healing; and injected right into the joints of arthritis patients. Without HA, there would be fewer successful cataract operations, corneal transplants, detached retina repairs, and other eye surgeries.

Astonishingly, modern medicine may soon promote HA to improve our sex lives. In the May 2013 issue of the International Journal of Impotence Research, we learn that 110 “Italian stallions” underwent injections of HA into the penis to increase volume and circumference, prevent premature ejaculation, and improve overall sexual satisfaction. According to their doctors at the Centro di Medicina Sessuale in Milan, both the men and their partners concluded the procedure was worth it and that size really does matter.

Glucosamine Creates and Renews Cartilage

Glucosamine is a natural constituent of GAGs, made up from glucose (the principal sugar the body uses for fuel) and glutamine (a conditionally essential amino acid found abundantly in broth). The body uses up glucosamine when it creates and renews cartilage, intervertebral discs, and synovial fluid. Glucosamine is best known as a supplement that helps repair cartilage, decrease inflammation, alleviate joint pain, and increase range of motion, but it has many other uses as well.

In the gut, glucosamine helps repair the defensive barrier in the mucosa called the glycosaminoglycan layer, or GAG layer. Defects in the GAG layer of the intestines contribute to autism, Crohn’s disease, rheumatoid arthritis, and other autoimmune disorders. In the bladder, defects in the GAG layer contribute to interstitial cystitis. All of these conditions seem to improve with the help of GAG-rich bone broth.

“ Recovery from Raw Food Veganism

I am from Romania, and am currently studying in the United States to become a health coach and spread the word about traditional food. For me, bone broth has played a big part in my full recovery from a year on a high raw vegan diet. I realized what a big mistake the raw food diet was when I saw my twenty-two-month-old baby daughter start to get brown stains on her front teeth. Shortly after introducing the broth and other traditional foods, her tooth decay stopped. She still has the stains, but the rest of her teeth are perfect.

I am convinced that the bone broth keeps us away from colds, even when all the children around are on antibiotics and coughing. While we were on the raw foods diet, my daughter would get colds easily. She also now prefers to be very lightly dressed, even during winter. For me there is no more pain in the joints of my toes, which surely occurred from the lack of bones and cartilage in my raw foods diet. I have also gotten rid of a very upsetting eczema on both my palms, which had also developed under the raw foods diet.

Best of all, I am seven months pregnant with my second child, who was conceived on our very first try. My daughter, who is now three years old, was conceived with difficulty after several years of trying. At that time I was eating pretty much a traditional diet, though always careful not to eat much fat. My pregnancy is going really well and my body is stronger than ever. Bone broth is one of the foods that we have on our table every single day, especially as a soup made with vegetables, meat, and eggs, and soured with borscht (a fermented liquid made mainly from grains). We make chicken, pork, duck, and veal bone broth on a regular basis. We also enjoy chicken and pork meat jelly.

—Simona D., Bucharest, Romania ”

Galactosamine for Immunity

Galactosamine, the other sugar found in GAGs, is less well known but promoted as able to slow down tumor growth and enhance cellular communication. Changes in glycosylation involving galactosamine are associated with the immune complex formation found in autoimmune disorders such as rheumatoid arthritis. Low levels of it have been associated with heart disease.

Glucosamine and galactosamine together would appear to help the immune system to normalize, whether it needs calming because it is overactive or needs boosting because it is underactive. Amply present in collagen, cartilage, and broth itself, these saccharides offer help to people suffering from osteoarthritis, autoimmune disorders, infectious diseases, and even cancer.

Chondroitin Sulfate Cushions and Protects Cartilage

Chondroitin is a large, gel-forming molecule that cushions cartilage and protects it from compression. It is a key proteoglycan found in cartilage and widely sold along with glucosamine as an osteoarthritis remedy. Critics contend that chondroitin is too large to be absorbed, yet it seems to be absorbed sufficiently to make a difference for those seeking arthritis cures. As a supplement, chondroitin derives from the cartilage of cows, pigs, poultry, or fish, although some manufacturers are pulling it from algae. In the diet, we get chondroitin sulfate every time we chew the gristle on a drumstick or partake of cartilage-rich bone broth.

The Body’s Many Sugars

Glucosamine and galactosamine are metabolic derivatives of N-acetylglucosamine and N-acetylgalactosamine, two of eight sugars that a few scientists and many multilevel marketers consider essential. The others are glucose, mannose, galactose, xylose, fucose, and N-acetylneuraminic acid. The body needs these sugars to form glycoproteins (sugars with protein, including proteoglycans, a glycoprotein with extra sugars) and glycolipids (sugars with fats).

Figure 5: Glyconutrients: Glycoproteins (sugars with protein) and glycolipids (sugars with fat) are little antennae that stick out from the surface of every one of fifty trillion or so cells in the body. They perform many functions including the sending, receiving, and coding of information.

Hunter-gatherers ate plenty of the insects, leaves, roots, mushrooms, and seaweeds that contain these essential sugars, but such foods tend to be scarce in the modern diet. In theory the body can produce needed saccharides from glucose, but in practice production can slow down or even fail if the body is inadequately nourished, sick, or stressed.

In their search for good health, many people today have chosen to supplement with beta glucans, maitake D-fraction, mannose, larch bark extract, aloe vera, inulin, and other saccharide-rich products. Foodwise, good sources are reishi, maitake, shiitake, and cordyceps mushrooms, garlic and onions, coconut meat, oatmeal, the pectins in fruits such as apples and grapefruit, chitin from the shells of insects and crustaceans, and breast milk. Glucosamine and galactosamine are present in good old-fashioned bone broth.

Proteoglycans are valued for their mucopolysaccharide content, but sulfur—as in glucosamine sulfate and chondroitin sulfate—deserves credit as well. People suffering from osteoarthritis and other chronic diseases rapidly turn over sulfur supplies in the body. Sulfur deficiency then inhibits GAG production, and a vicious cycle begins. Sulfur deficiency is widespread today because of foods grown on depleted soil and plant-based diet fads.

Clearly, science supports glucosamine, GAGs, and goo for health, healing, and anti-aging. But why settle for fractions that have been pilled, patented, and packaged for profit when nourishing bone broth offers proteoglycans and much, much more? “Just a spoonful of sugar makes the medicine go down” sang Julie Andrews in Mary Poppins. In broth, the complex sugars known as proteoglycans are part of the medicine.