- Bone broth has gained the reputation as a nutritional powerhouse with claims that it relieves joint pain, enhances gut health, slows aging, and improves skin health.
- While broth has a long tradition of healing properties, there are few studies on bone broth (or broth or stews) itself.
- Even though it lacks evidence, it has been used traditionally and provides nutrients that are backed by science, such as collagen, gelatin, essential and conditionally essential amino acids, and minerals.
- Buy bone broth tested for heavy metal content.
The Deeper Dive:
In the past few years, bone broth has become one of those nutritional powerhouses that many experts promote as an essential component of a healthy diet. However, does bone broth live up to this reputation?
Let’s take a look at the proposed benefits and what the science has to say about it.
If you read blogs and books promoting bone broth, you will see that it has the potential to help with many health concerns. The most commonly listed include:
- Joint pain relief
- Gut health due to:
- Gelatin content
- Ability to restore gut lining
- Detox support due to:
- Digestive support
- Skin health
However, the literature is light on studies looking at bone broth or even broth and soups in general. This lack of data makes it hard to confirm or argue against these proposed benefits since there are limited studies confirming the benefits or proving the hypotheses wrong.
One study compared enriched chicken bone broth and homemade bone broth to see if it had anti-inflammatory properties on an animal model of temporomandibular disorder (TMD). They found the enriched chicken bone broth significantly reduced the expression of PKA, a pro-inflammatory protein, as well as attenuated nociception (the response to harmful stimulus). However, the homemade bone broth did not have the same effect.
In 2000, a study found that chicken soup significantly inhibited the migration of neutrophils in a concentration-dependent manner, demonstrating that chicken soup may have a mild anti-inflammatory effect supporting its long use as the go-to meal when you are ill.
That’s about all I could find in terms of studies on bone broth, soups, or broths, except for one more study referenced below. So, how did bone broth get its reputation if there are limited studies promoting its efficacy? Well, some of it comes from traditional diets that use bone broth as a base for soups and stews, which often have a reputation for healing. This is similar to the way you or someone you know may pick up some chicken soup when you feel ill because that is what your parents did when you were a child, and their parents did before them.
However, a lot of the reputation comes from looking at the different components of bone broth, which have been shown to have some beneficial properties.
Breaking It Down
The major health-promoting properties include:
- Essential and conditionally essential amino acids
Bone is made up of collagen, which can be broken down into specific amino acids and minerals such as calcium and magnesium. When you make a broth from the soup, at least some of those components remain. How much depends on the recipe, length of time you cook it, and other factors.
Let’s take a look at the breakdown of components to see what the literature has to say about their proposed benefits.
One of the main reasons for the respectable reputation bone broth holds is that it is a good dietary source of collagen. Collagen contains 19 amino acids, although the composition and percentage of certain amino acids, especially hydroxyproline, may differ based on the source of the collagen.
Collagen wins the prize for the protein that is most abundant in the body, and you can find it in the skin, bones, muscles, and tendons. There are sixteen types of collagen, although the most common are type I, II, III, and IV, and each has a different function. The body can synthesize collagen, but there is a need for a lot of it, so it is important to have the right components to synthesize sufficient quantities.
Lack of collagen, including low serum levels of collagen, has been linked to Inflammatory bowel diseases, including ulcerative colitis and Crohn’s disease.
Collagen supplementation, including the use of collagen peptides, has been found to:
- Reduce joint pain in athletes and improve joint health in those with knee osteoarthritis
- Postpone and reduce the progress of sarcopenia (the loss of muscle with age) in older men in tandem with resistance training
- Improve skin health, especially in relation to aging (increase hydration and collagen density in the dermis, increase skin firmness, induce production of both collagen and hyaluronic acid, increase skin elasticity, and reduce wrinkles and other effects of photoaging)
- Improve the appearance of cellulite, including reducing the cellulite degree and waviness on the skin and improving dermal density
- Improved markers for type-2 diabetes, including reduced HbA1c, triglycerides, total cholesterol, LDL, and diastolic blood pressure
- Prevention of atherosclerosis
Can the collagen in bone broth do what these studies promise? The jury is still out since there are not too many studies on bone broth itself. There was one study published in 2018 that compared the collagen from bone broth to that of supplemental sources. The study found lower levels for certain amino acids, including hydroxyproline, glycine, proline, hydroxylysine, leucine, and lysine, compared to 20 g of a collagen supplement. They also found the amino acid content varied depending on the recipe and preparation.
The researchers determined that bone broth was not a reliable source of these amino acids from collagen. One thing to note about this study is that it was comparing food sources to standardized supplementation. It is similar to saying that an orange has less vitamin C and in variable amounts compared to a supplement dose.
As will be seen, bone broth also contains other elements that combined and, acting in synergy, could grant some of its promoted efficacy.
Gelatin is a natural protein that contains between 84 and 90% collagen as well as some mineral salts and water. There are 18 amino acids in gelatin, including glycine, alanine, valine, leucine, proline, hydroxyproline, and glutamic acid. You make gelatin through boiling animal bones and cartilage to extract collagen and then process it.
Based on one rat study, there was a relative bioavailability of gelatin of 74.12% and absolute bioavailability of 85.97%. About half of the gelatin absorbed in the intestine was in the form of collagen peptides. Since gelatin contains collagen, some of the above benefits may also be imparted through gelatin.
Gelatin specifically has been shown to:
- Reduce inflammation in intestinal cells, including that caused by LPS
- Increased collagen synthesis, especially when combined with vitamin C and an exercise program
- Decreased severity of colitis, including re-establishing the gut barrier function and modulating the microbiota
- Manage chronic diarrhea, including protecting against coli-induced membrane integrity reduction when combined with probiotics
- Enhance wound healing, including in diabetics
Several of the above studies on gelatin are animal models and cell studies, so some of the efficacy may not apply in real-world scenarios with humans.
As discussed, collagen and gelatin, and thus bone broth, contain a significant number of essential, nonessential, and conditional amino acids. Conditional amino acids are those the body can synthesize, but in times of stress and illness, the body may not be able to synthesize them. They include proline, glutamine, cysteine, arginine, serine, and others, many of which are in collagen.
Some of the 18 amino acids found in collagen that have helped it earn its reputation include:
- Proline—an important but not essential amino acid (our bodies can synthesize it using arginine and glutamine) that makes up a third of the collagen amino acids. The requirement for this amino acid is higher than many of the others.
- Hydroxyproline—once considered not significant, we now know it plays a role as a substrate to synthesize glycine, pyruvate, and glucose. It can also regulate redox states through scavenging oxidants. Hydroxyproline exists only in collagen, making sources of collagen such as bone broth a unique dietary resource for this protein.
- Glycine—protects against oxidative stress and is an important precursor (along with cysteine and glutamate) of glutathione, one of the major antioxidants in the body. Studies have found that supplementing with glycine and cysteine can restore glutathione synthesis and reduce oxidative stress.
- Glutamic acid—the amino acid that is an important building block of glutamine, another one of the major proteins in the body (including acting as fuel for enterocytes, maintaining the integrity of the intestinal mucosa, and working as a precursor for glutathione) and glutamate, which is the main excitatory neurotransmitter.
Bone broth can be a source of these important amino acids, some of which can be hard to find in other food sources.
Essential and Nonessential Minerals
Another reason many tout bone broth comes from the essential minerals and other nutrients found in the bone, including the following:
As the name suggests, essential minerals are essential to health. Deficiency and insufficiency are linked to many diseases.
In addition to these minerals, bone broth also contains glucosamine and chondroitin. Glucosamine and chondroitin, especially when taken in combination, have been linked to:
- Joint health, including in appeasing symptoms of osteoarthritis, such as reducing pain, stiffness, and joint swelling
- Improvement in mobility and walking speed in those with osteoarthritis
- Reduced systemic inflammation (using hsCRP as a marker) and oxidative stress
- A reduction in colorectal cancer risk
- Reduced total mortality and a reduction of risk of death from cancer and respiratory diseases
One study looked at the essential metals in bone broth, as well as the quantity of toxic metals. The researchers used bones from domestic pigs and cows purchased locally in Taiwan. They also tested commercially available bone broth foods to determine the levels of essential and toxic metals. They found doses of several essential minerals, including calcium, magnesium, iron, zinc, and copper. However, the mean ratios were typically less than 5% of the DRI. There were higher levels of chromium. They did find levels for lead and cadmium but determined they were safe unless one was to consume a significant amount of bone broth.
The researchers also found that increased cooking time leads to greater extraction of metals, especially calcium and magnesium. Adding an acid to the broth increased the extraction of all metals except zinc and iron, with the greatest increases occurring with calcium and magnesium. They also found that the bones from different areas of the body could have different levels of minerals.
Thus, bone broth may be a source of several essential minerals, but it will most likely not have high levels, requiring you to find additional sources.
As with many foods and items on the market, even those with potential health benefits, there are concerns to be aware of.
For one, there is a potential for bone broth to be contaminated, especially with heavy metals. Bone is known to contain heavy metals. One study looked at whether lead leached from the bones into the bone broth during cooking. They looked at three different organic chicken broths and found a significant increase in lead compared to the water in which it was cooked.
Another potential concern is that if you do not make the bone broth from scratch, then you may end up eating a highly processed version if you do not do some smart shopping. As with many foods, the more processing that occurs, the higher the potential for lower quantities of nutrients as well as the addition of unhealthy additives, including excess sodium, sugar, and MSG.
So, is bone broth all it is cracked up to be? It does contain many essential nutrients beneficial to health. The literature does not have sufficient research on bone broth itself, but the components of bone broth have been shown to be beneficial. It is also possible that when they exist in one source, they work synergistically for even better results.
Should you make bone broth your number one staple? Possibly not. That is something to discuss with your doctor, nutritionist, or another health practitioner. However, as part of a balanced, plant-based, colorful diet, it may just impart some helpful benefits. Play with it as a foundation for hearty soups and stews as we move into the fall and winter months and see how you feel, unless contraindicated for some reason.