Broths made with many parts of plants and animals are a long-standing feature of cuisines throughout the world. Yet, surprisingly little research has been done on their method of preparation or health benefits.

Stocks and Broths

You're going to find a good bit of confusion in the popular press about bone broths since some kitchen experts describe broths as focusing on vegetables and meat rather than bones (even though some bone may be included). By contrast, they describe "stocks" as relying more on bone, even though some meat may be attached to the bone and some vegetables may be added. From a practical standpoint, we would expect greater flavor to be released during the simmering process from meat and vegetables than from bone, and while we think of broths as being consumable on their own, we think of stocks as typically being added as a base ingredient in recipes. While these distinctions may fall away in the practice of everyday cooking (for example, in the likelihood that there will still be some meat attached to most bone), we would not expect a bone-focused broth (with very little meat and no vegetables) to achieve the same rich flavoring as a broth that contained these other ingredients.

Fish Bone

The chemistry of all bone is very interesting from a nutrient standpoint, and there are some particulars about fish bone that have also received special attention in food research. First, like most bone, fish bone contains a large amount of collagen protein. This protein forms about 90% of the organic matrix in the bone. Some of this protein gets released into broth made with animal or fish bone. As you will see in our chart below, the total amounts ends up being about 5 grams of protein per cup of broth. Like all bone, fish bone is also mineralized and contains hydroxyapatite (also called "durapatite" and "hydroxylapatite"). This mineral compound is rich in both calcium and phosphorus. There are also smaller amounts of many additional minerals in bone, including silicon, magnesium, zinc, copper, selenium, potassium, boron, and vanadium.

In comparison to other vertebrate bones, the bones of fish are less mineralized, and this lesser degree of mineralization makes them less dense. This lower density makes it somewhat easier for both minerals and collagen proteins to be released from the bone in lab studies using acids (like acetic acid) or enzymes (like pepsin) to extract collagen proteins from fish bone. As there is similar collagen in the fish skins as well, collagen proteins are also extracted from fish skins (like salmon skin) in this way. However, we have yet to see studies on kitchen preparation of bone broths that show the practical impact on this fish bone chemistry on the bone broth itself. When comparing fish bone broths to animal bone broths, it is possible that these two features of fish bone—lesser mineral density and somewhat easier protein and mineral extraction—might partially balance each other out, leaving you with a bone broth from fish bone that is roughly comparable to a broth made with animal bone.

Fish Versus Animal Broth Nutrients

Leaving aside the nutrient specifics of bone broths, we looked at protein and mineral comparisons in fish broths, chicken broths, and beef broths as documented in the U.S. Department of Agriculture (USDA) National Nutrient Database (SR 25 edition), developed by the USDA Nutrient Data Laboratory at the Beltsville Human Nutrition Resource Center in Beltsville, MD. Unfortunately, we do not know the exact food components used to produce the three broths below, including the presence or absence of bone. But the results here are still indicative of the information that we have reviewed for both bone-containing and non-bone-containing broths, and can be helpful in putting broth questions into perspective.

USDA Nutrient Database Profiles for Fish, Chicken, and Beef Broth

As you can see in the chart above, fish broth is higher in some nutrients than chicken or beef broth, yet lower in other nutrients. From a bird's eye perspective, what strikes us most in this chart is the relatively small amount of daily recommended nutrient levels provided by all three broths. One cup of any broth provides 10% or less of each nutrient listed, and in some cases, far less. Yet we do not see these results as negative in any way! All three broths are using up very few calories from your daily calorie budget (only 1-2%) while they are providing small amounts of many important nutrients. In summary, broths seem like a great way to bring delicious flavor and additional nutrients into your meal plan, even though it seems difficult to rely on them to meet a large percentage of your nutrient needs. And although we suspect that this same summary holds true for meat broths, vegetable broths, and bone broths (including fish bone broths), we do not have enough research evidence here to provide you with any conclusions about nutritional differences based on broth constituents.

A Final Note About Bone, Meat, and Vegetable Quality

Regardless of the broth type that you might decide to incorporate into your meal plan, the quality of your broth components is of primary importance. We've seen studies, for example, showing migration of lead into broth from lead-containing chicken bone at a concentration of about 16 micrograms per cup of broth. That level is equivalent to 70 parts per billion (ppb), and is actually above the 15 ppb action level for lead in drinking water set by the U.S. Environmental Protection Agency (EPA). The health of an animal's bones—or the bones of a fish, or the leaf of a plant—depends on the same set of factors as our overall human health, and those factors include diet and environmental circumstances. At WHFoods, we believe that consumption of certified organic foods can go a long way in protecting your food quality, together with careful selection, storage, and cooking of the foods. In the case of animal foods, we believe that grass feeding and pasture raising can also increase food quality. In each of our individual food profiles, we provide you with detailed information for selecting the highest quality versions of all WHFoods, including animal foods, seafood, and vegetables. If you decide to bring broth into your diet, we encourage you to make quality a top priority, regardless of the broth type that you choose.

Please note that on page 87 of George Mateljan's new World's Healthiest Foods book, you can find a great recipe for "Rich Vegetable Broth" and on page 607 there is an excellent recipe for fish soup/broth.

References

• Bello AE and Oesser S. Collagen hydrolysate for the treatment of osteoarthritis and other joint disorders: a review of the literature. Curr Med Res Opin. 2006 Nov;22(11):2221-32. Review.
• Lin B, Zhang F, Yu Y, et al. Marine collagen peptides protect against early alcoholic liver injury in rats. The British Journal of Nutrition107.8 (Apr 28, 2012): 1160-6.
• Liu L, Wang Y, Peng C, et al. Optimization of the Preparation of Fish Protein Anti-Obesity Hydrolysates Using Response Surface Methodology. International Journal of Molecular Sciences14.2 (2013): 3124-3139.
• Monro JA, Leon R, and Puri BK. The risk of lead contamination in bone broth diets Medical Hypotheses, Volume 80, Issue 4, April 2013, Pages 389-390.
• Ragle RL and Sawitzke AD. Nutraceuticals in the management of osteoarthritis : a critical review. Drugs Aging. 2012 Sep;29(9):717-31.
• Szpak, P. Fish Bone Chemistry and Ultrastructure: Implications for Taphonomy and Stable Isotope Analysis, Journal of Archaeological Science (2011), doi: 10.1016/
• j.jas.2011.07.022.
• Thompson RL and Buckley JD. Protein hydrolysates and tissue repair. Nutrition Research Reviews24.2 (Dec 2011): 191-7.
• Toppe J, Albrektsen S, Hope B, et al. Chemical composition, mineral content and amino acid and lipid profiles in bones from various fish species. Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, Volume 146, Issue 3, March 2007, Pages 395-401.

Visit the Hot Topics Archive