The Bountiful Benefits of Bone Broth: a Comprehensive Guide Vol.3

Posted: 15/03/2017 in Diet, Paleo Diet, Science and stuff
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By Chris Kesser (web)

Bone broth and your health

At this point, I hope you have a solid understanding of the components of bone broth. Now let’s get on to the health benefits!

Skin health
Skin is composed of two layers, the epidermis and the dermis. The epidermis, or upper layer, is composed of keratinocytes and is largely responsible for skin barrier function. Underneath is the dermis, a dense matrix of collagen, along with some GAGs, that provides structural and nutritive support (22). Keratin, collagen, and GAGs are abundant in bone broth, particularly if the skin from the animal is included in the cooking process.

In a 2014 randomized and controlled trial, collagen consumption significantly improved skin elasticity and tended to improve skin moisture content (23). Collagen scaffolds are widely used in medical applications to promote tissue regeneration and heal wounds (24). One study in mice found that supplementing the diet with gelatin was able to protect against UV-induced skin damage (25). GAGs offer additional skin benefits. The GAG hyaluronic acid has been shown to promote skin cell proliferation and increase the presence of retinoic acid, which improves the skin’s hydration (26), and dermatan sulfate has been shown to aid in cell turnover and wound repair (27).

Metabolic and cardiovascular health
Remember glycine, an amino acid that is particularly abundant in bone broth? Glycine plays a role in blood sugar regulation by controlling gluconeogenesis, the production of glucose in the liver (28), and has even been suggested to counteract some of the negative effects of dietary fructose consumption (29). Glycine has also been shown to reduce the size of heart attacks (30).

Furthermore, glycine balances out methionine intake. Muscle meats and eggs are high in methionine, an amino acid that raises homocysteine levels in the blood. High homocysteine is a significant risk factor for serious diseases like heart disease, stroke, mental illness, and fractures and increases our need for homocysteine-neutralizing nutrients like vitamins B6, B12, folate, and choline (31). Those eating lots of animal protein need adequate glycine to balance out the methionine from meat, and you’ll get that from bone broth. For more information, check out Denise Minger’s awesome presentation in which she discusses this very issue.

Muscle and performance
Glycine is also important for the synthesis of hemoglobin and myoglobin, which transport oxygen throughout the blood and muscle tissue, respectively (32). Glycine also increases creatine levels, which leads to an increase in anaerobic (high-intensity) exercise capacity, and stimulates the secretion of human growth hormone (HGH), which may enhance muscle repair (33, 34, 35). Recent evidence suggests that proline may play a role in regulating the mTOR cellular signaling pathway, which integrates signals from nutrients, growth factors, stress factors, and cellular energy status to affect cell function and growth. Proline, together with other amino acids, activates mTOR, resulting in enhanced muscle protein synthesis (36).

Adenosine triphosphate (ATP) is the chemical form of energy in the body that can be used to perform work. Phosphorus is required for the formation of this compound, and ATP cannot be biologically active unless bound to a magnesium ion. Phosphorus deficiency has been shown to reduce muscle performance (37, 38). Both phosphorus and magnesium are present in bone broth in modest amounts.

Bones and joints
It should be pretty obvious that the best way to get the nutrients necessary to build bone is from bone itself! Drinking bone broth provides all of the raw material for building healthy bones: calcium, phosphorus, amino acids, and more. A deficiency of the raw materials for building bone can result in a number of different conditions. For example, osteoporosis is associated with reduced levels of collagen and calcium in the bones (39, 40). Of course, you’ll also need the nutrients required to support the building process, like vitamins D, K2, and C. (To learn more about building healthy bones and where to get these nutrients on a Paleo diet, check out this article.)

As for joint health, lubrication by GAGs is the key to a full range of motion, whereby part of one bone can slide smoothly and painlessly over part of another. Sure, you could buy expensive supplements containing glucosamine and chondroitin sulfate to keep your joints healthy, but why, when these and a host of other beneficial nutrients can easily be obtained from bone broth? After all, GAGs are not the only component of broth that improves joint health. Collagen supplementation has been shown to reduce joint pain in athletes (41).

Gut health
A healthy colon contains a single tight layer of epithelial cells, a thick mucus layer, and a diverse collection of microbes. Microbial dysbiosis and a thinning of this mucus layer can quickly compromise the integrity of the epithelial barrier. Microbes and dietary proteins can then “leak” into the bloodstream and invoke an inflammatory response by the immune system. Lipopolysaccharide (LPS), a component of bacterial cell walls, stimulates a particularly robust immune response (42).

Bone broth is a staple of gut-healing diets, and rightfully so! Gelatin absorbs water and helps maintain the layer of mucus that keeps gut microbes away from the intestinal barrier. In a mouse model, gelatin supplementation reduced the severity of colitis by strengthening the mucus layer and altering gut microbiota composition (43). Gelatin and glycine have also been shown to reduce the inflammation caused by LPS (44, 45). Glycine has been shown to protect against gastric ulcers as well (46). Glutamine also helps maintain the integrity of the gut mucosa and intestinal barrier (47).

Digestion
Bone broth has so many benefits to gut health that I had to make digestion its own section! Drinking broth with meals is an excellent way to aid digestion. Glycine stimulates the production of stomach acid, which is essential for the proper digestion of food (48). Low stomach acid (hypochlorhydria) is surprisingly common in developed countries and can lead to a number of health issues.

Glycine is also an important component of bile acid, which is released to aid in the digestion of fats in the small intestine (49). Bile acid is important for maintaining normal blood cholesterol levels. The presence of gelatin in the gut also draws fluid into the intestine, improving gut motility and supporting healthy bowel movements. Low blood levels of collagen have been associated with inflammatory bowel disease (50).

Detoxification, liver, and kidney health
Recently, there has been some concern regarding the lead toxicity of bone broth. However, the vitamins and minerals that are abundant in bone broth, and in Paleo diets in general, can protect against the harmful effects of toxins like lead. Glycine also stimulates production of glutathione, the body’s master antioxidant (51). In animal models, glycine has been shown to speed recovery from alcohol-induced fatty liver disease (52), protect liver cells against hypoxia (53), and improve survival after liver transplantation (54). In humans, glycine reduces oxidative stress in patients with metabolic syndrome (55).

Proline plays a role in apoptosis, the process by which the body breaks down old cells, clears up waste products, and recycles raw materials for use in healthy cells (56). Proline can scavenge free radicals, effectively acting as an antioxidant (57). Glutamine, on the other hand, acts as a nontoxic nitrogen transporter, carrying amine groups safely through the bloodstream to the kidney. In the kidney, the conversion of glutamine to glutamate regulates acid–base balance by producing ammonium (58).

Eye health
Yes, bone broth may improve eye health. The cornea consists of three primary layers: an outer epithelial layer, a middle layer, and an inner endothelial layer. Hyaluronic acid stimulates proliferation of the epithelial cells that line the cornea (59) and is commonly used during eye surgery to help replace lost fluids (60). The middle, or stromal, layer is largely made of collagen, keratan sulfates, and chondroitin sulfates. Keratan sulfates have been shown to be essential to the transparency of the cornea (61), while chondroitin sulfate has been shown to influence the development of neural pathways in the retina (62). The amino acid glycine has also been shown to delay the progression of cataracts in a rat model of diabetes (63).

Brain health
Numerous components of bone broth influence the nervous system. The healthy fats in bone broth, particularly if made with marrow bones, provide a source of fuel and raw material for the brain. After all, more than 60 percent of the human brain is composed of fat (64). Glycine has been shown to protect against neuronal death after ischemic stroke (65) and likely plays a pertinent role in the development of the brain in the womb and during the first few months after birth (66). Calcium is essential for nerve conduction. When a nerve cell is stimulated, the influx of calcium triggers neurotransmitter release, allowing the signal to be passed on to the next nerve cell. Calcium deficiency affects this transmission and can result in symptoms of depression, insomnia, and hyperactivity. Lastly, chondroitin sulfate plays an important role in regeneration and plasticity in the central nervous system (67), meaning it is essential for learning and memory.

Mood and sleep
Bone broth can also improve both mood and sleep. Glycine is an inhibitory neurotransmitter, meaning it can decrease anxiety, promote mental calmness, and help with sleep (68). One study found that three grams of glycine given to subjects before bedtime produced measurable improvements in sleep quality (69).

Unlike methionine, glycine does not compete with tryptophan for transport across the blood–brain barrier (70). Tryptophan is the precursor (raw material) for serotonin, a neurotransmitter that contributes to feelings of well-being. Serotonin, in turn, is a precursor to melatonin, a hormone that regulates sleep–wake cycles. This is why a diet that includes bone broth and fattier cuts of meat can help prevent the depression and insomnia that some people may experience when eating a diet high in methionine-rich lean meat and eggs.

Immune function
While ancient folk wisdom suggests that bone broth can cure the common cold, modern science has confirmed that the components of bone broth do indeed influence the immune system. For example, glycine receptors have been identified on the outer surface of several different types of immune cells (71, 72). The effect is a dampening of the immune response, resulting in reduced inflammatory signaling molecules and oxidative stress that may reduce damage to lungs and other tissues (73). The GAG heparin sulfate has been shown to influence B cell function, T cell function, and macrophage activity (74).

Where to source bone broth

To summarize, bone broth has an incredible number of potential health benefits and is rooted in a long history of human use. It makes an excellent addition to any diet and can be used in a multitude of dishes. Bone broth can be made at home or it can be bought pre-made.

Homemade bone broth is simple to make. Ask your local farmers if they have soup bones, or roast a whole pastured chicken and save the bones for making broth. Chicken feet, chicken necks, calves’ feet, and marrow bones are particularly valuable additions to broth. You can find a good basic recipe over at the Weston A. Price Foundation website.

Pre-made bone broth is also a good option. Be sure to:

  • Buy broth that is organic and made from pasture-raised animals or wild-caught fish (this minimizes the toxins and maximizes the nutrients you get from the bone broth).
  • Avoid cans and other containers that contain bisphenol A (BPA), a potent endocrine disruptor, or other BPA substitutes.
  • Check out my favorite brand of broth: Kettle and Fire uses bones of organic, pasture-raised animals along with organic vegetables, sea salt, and herbs, all slow-simmered for 24 hours.

However you choose to get your hands on this liquid gold, be sure to make bone broth a staple in your diet!

 

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