Bone broth is a liquid broth made from the bones of various animals. It boasts many benefits including:
•    It contains trace vitamins and minerals extracted from the meat and bones used to make the broth
•    It can inspire a sick or picky animal to eat by adding flavor and moisture
•    It can add extra moisture to the diet especially useful for cats, those in kidney failure or those that suffer from other urinary tract issues like UTI's
•    It can help underweight companions gain or maintain a proper weight
•    Aid those with hip and joint problems from the glucosamine and chondroitin extracted from specific bones like poultry feet and bone marrow
•    Support a healthy immune system
•    Reduce inflammation
•    Anti-Tumor
•    Cell protecting 
•    Lower blood sugar and regulate insulin
•    Normalize stomach acid
•    Detoxification
•    Heart healthy

Unfortunately, despite these amazing benefits, bone broth isn't all it's cracked up to be.

First off it is a cooked product. As we understand from raw feeding anything where heat is applied can easily become denatured in nutrients, fats and enzymes can be destroyed and proteins alter in shape reducing their digestibility and nutrient content (1, 2, 3, 4, 5). Many claims of bone broth don't come from studies performed on bone broth, rather stems from the assumption that if bone contains these nutrients the bone broth will too. Furthermore, there is no set bone broth recipe, so studies can us different bones, from different animals, with or without veggies ....

 

In most bone broth recipes, you are supposed to use an acidifying agent like lemon juice or more commonly apple cider vinegar to help release nutrients from the bone. Instead most of the nutrients are left to settle at the bottom of the broth as bone sentiment (6). While you can include this when feeding bone broth, you will have better luck of supplying trace vitamins and minerals by serving whole raw bone.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The USDA does provide an analysis of a beef broth (7) but it contains only 19, 17 and 64 milligrams of calcium, magnesium and phosphorus respectively as well as 444 mg of potassium and 457 mg of sodium. Given that there is no ingredient list these figures could have been a result of added veggies or sodium. However British nutritional science Robert McCance and Elsie Widdowson did conduct a study. They found that vinegar made no difference in the extraction of potassium and that only 10 mg of calcium and 2 mg of magnesium was extracted from each 100 grams of bone. Even with 4 tablespoons of vinegar being added, calcium extraction did not increase. Again, this broth contained veggies which a prey model raw broth would not. Eventually the scientists did make two broths with just bone. Located below is the analysis. As you can see the mineral content is still very low (8)

Although studies that directly relate to a PMR based bone broth is limited, studies for its spectacular nutrient content is also lacking from what is available.

This would imply that bone broth is also not supportive for ill animals. Although it can help with dehydration, due to its lack of nutrients there is little nutritious support for your companion. 

NOTE: Do not feed bone broth to an animal prone to epilepsy/seizures, autoimmune disease or leaky gut syndrome (which is connected with several conditions). While bone broth cooks, glutamic acid is produced. The longer it is cooked the higher the content. High amounts of glutamic acid and glutamate can trigger seizures as well as behavior changes and tics (9, 10, 11).
What is true or at least semi true about bone broth is that it contains a good source of protein in the form of collagen. To simply state that collagen in bone broth directly translates to collagen in the body is an understatement however. The body uses the collagen but must digest it first to utilize it. Collagen is in the bones as well as connective tissues and muscle (12) that is then found in the gelatin (jelly layer) found at the top of the bone broth. While bone broth does provide protein, it provides protein from non-essential proteins versus essential proteins that are required to be supplied by the food in order to nourish the body (13). So, while the claim that it aids in hip and joint health (14) is partially true it's important to remember that the joint health portion of bone broth is NOT found in the liquid but rather the gelatin (15).

Detoxification in a dog, cat or ferret with a malfunctioning liver is a more serious condition that bone broth would not fix and is best looked at by a doctor. While it may seem that bone broth is detoxing the body, the basic fact that liquids go through the liver as part of the digestion process and thus is detoxed out the body is a basic function of the body that would occur regardless of the bone broth being present. Therefore, if the liver is functioning and doing its job, bone broth isn't going to help with detoxification as that's already the livers job in the first place. 

Keep in mind that most studies that one comes across will not be performed using bone broth. They may be using hydrolyzed collagen or other more concentrated supplements which ARE easier to digest and utilize by the body. Thus, these results can be misleading to those wanting to use bone broth as an addition for their companion’s food.

That all being said in most cases there are little risks to feeding bone broth and:
-It can help get ill animals to consume liquids replacing lost electrolytes
-Those with joint issues if the gelatin is used
-Providing extra moisture for cats or those in kidney failure (16)
-Aid with rehydration replenishing lost sodium and moisture 
-Possibly aid in boosting immune system (17)
-Helping to maintain a healthy weight if the fat is not skimmed off

If you feel that bone broth is for you, it's actually quite simply to make in your very own home
1. Gather an assortment of raw meaty bones together. 
-You can use just about any bone from any animal. Chicken, turkey and duck feet as well as beef marrow bones will contain more components that will aid with joint health. These bones as well as others provide other trace vitamins and minerals

2. Put the bones in a slow cooker/crock pot and cover with water

3. Add 3-4 tablespoons of apple cider vinegar. This acidifying agent helps to extract valuable vitamins and minerals. 

4. Cook on high for 1 hour

5. Cook on low for about 24-48 hours
-You will know when the broth is done when many of the bones are soft and can be smoothed between the fingers or break apart when stirring. Some bones like the marrow bones may not do this but some ribs, whole prey, feet etc. may.

 
6. Turn off the slower cooker or crock pot and let the broth cool

7. Sift out all meat and bones
-Cooked meat has little nutrient values (it's also now in the broth which you will be feeding) and bones become unsafe to feed. They become brittle and splinter which can cause obstruction, chocking and/or proliferation.

-Depending on the purpose of the broth you can also skim off the extra fat 

8. Once cooled and skimmed, you can poor into freezer safe containers such as Tupperware, mason jars or even make broth cubes. These are great for individual portions. After frozen break, apart and store in a container or freezer bag. When ready to use take on out and let defrost.

9. Serve
-Bone broth can be fed on its own in liquid form or freezer cubes as a summer time treat. It can also be served with a full meal of meat, organs and bone.

Note: Bone broth is NOT a substitute for bone. You must still include raw meaty bones or other source of calcium to the raw diet.

 

REFERENCES:

1.    Kimura, M, and Y Itokawa. “Cooking Losses of Minerals in Foods and Its Nutritional Significance.” Journal of Nutritional Science and Vitaminology., U.S. National Library of Medicine, 1990, www.ncbi.nlm.nih.gov/pubmed/2081985.
2.    Peterson, Michelle E. et al. “The Dependence of Enzyme Activity on Temperature: Determination and Validation of Parameters.” Biochemical Journal 402.Pt 2 (2007): 331–337. PMC. Web. 3 Mar. 2018.
3.    Nishiura, James. “Effect of Temperature on Enzyme Activity.” Effect of Temperature on Enzyme Activity, Brooklyn College City University of New York , academic.brooklyn.cuny.edu/biology/bio4fv/page/enz_act.htm.
4.    M. Koizumi, H. Hirai, T. Onai, K. Inoue and M. Hirai, Collapse of the hydration shell of a protein prior to thermal unfolding, J. Appl. Cryst. 40 (2007) s175-s178.
5.    Warner, K. “Impact of High-Temperature Food Processing on Fats and Oils.” Advances in Pediatrics., U.S. National Library of Medicine, 1999, www.ncbi.nlm.nih.gov/pubmed/10335369.
6.    CrashCourse. “Precipitation Reactions: Crash Course Chemistry #9.” YouTube, YouTube, 15 Apr. 2013, www.youtube.com/watch?v=IIu16dy3ThI&list=PL8dPuuaLjXtPHzzYuWy6fYEaX9mQQ8oGr&index=9.
7.    USDA. “Food Composition Databases Show Foods -- Soup, Stock, Beef, Home-Prepared.” Food Composition Databases Show Foods -- Oil, Soybean, Salad or Cooking, United States Department of Agriculture , ndb.nal.usda.gov/ndb/foods/show/06170?fgcd=&manu=&format=&count=&max=25&offset=&sort=default&order=asc&qlookup=Soup%2C%2Bstock%2C%2Bbeef%2C%2Bhome-prepared&ds=&qt=&qp=&qa=&qn=&q=&ing=.
8.    McCance R A and Widdowson E M (1934) Bone and vegetable broth. Archives of disease in childhood. 9(52): 251–258. 
9.    BLAYLOCK, RUSSELL. “FOOD ADDITIVES: WHAT YOU EAT CAN KILL YOU.” THE BLAYLOCK WELLNESS REPORT 4 (OCT. 2007): 3-4. PRINT.
10.    Hawkins, Richard A. “The Blood-Brain Barrier and Glutamate.” The American Journal of Clinical Nutrition 90.3 (2009): 867S–874S. PMC. Web. 11 Sept. 2018.
11.    U.S. Food and Drug Administration “FDA and Monosodium Glutamate (MSG)” August 31, 1995
12.    Lodish H, Berk A, Zipursky SL, et al. Molecular Cell Biology. 4th edition. New York: W. H. Freeman; 2000. Section 22.3, Collagen: The Fibrous Proteins of the Matrix. Available from: https://www.ncbi.nlm.nih.gov/books/NBK21582/
13.    Bello, A E, and S Oesser. “Collagen Hydrolysate for the Treatment of Osteoarthritis and Other Joint Disorders: a Review of the Literature.” Advances in Pediatrics., U.S. National Library of Medicine, Nov. 2006, www.ncbi.nlm.nih.gov/pubmed/17076983.
14.    Eastoe, J. E. “The Amino Acid Composition of Mammalian Collagen and Gelatin.” Biochemical Journal 61.4 (1955): 589–600. Print.
15.    Van B. Robertson, William. “Metabolism of Collagen in Mammalian Tissues.” Biophysical Journal 4.1 Pt 2 (1964): 93–106. Print.
16.    Clark, William F. et al. “The Chronic Kidney Disease Water Intake Trial: Protocol of a Randomized Controlled Trial.” Canadian Journal of Kidney Health and Disease 4 (2017): 2054358117725106. PMC. Web. 11 Sept. 2018.
17.    Fallon, Sally, et al. Nourishing Broth: an Old-Fashioned Remedy for the Modern World. Grand Central Life & Style, 2014.