Bone Broth: Spanish Study on Ham Bones Shows Heart Health Benefits

It seems like restaurants everywhere are serving bone broth, which has recently gained a reputation as a superfood with health benefits ranging from better sleep to stronger joints. Actual scientific research on these benefits has been sparse, but a new study published Wednesday in the Journal of Agricultural and Food Chemistry suggests there’s truth to at least some of those claims.

Even a broth novice knows that bones are the key to a good soup, but the new study shows that bones release not only flavor but also an array of useful biological components that — if they survive the cooking process — could have a big impact on heart health.

It’s not hard to find ham bones in Spain, which is where Leticia Mora-Soler, Ph.D., the study’s lead author, conducts research for Valencia’s Institute of Agrochemistry and Food Technology. The harder task, which she and her team set out to accomplish, is to figure out what happens to those ham bones when you add them to soup, eat it, and then digest it.

They found that the dry-cured ham bones they studied contain a series of peptides (chains of amino acids) that could improve heart health. But more importantly, some of those peptides were tough enough to withstand the traditional broth-making treatment as well as human digestion, which she simulated in her lab.

The ham bones contained four different types of peptides: ACE-I, ECE inhibitors (used in drug form to treat high blood pressure), PAF-AH inhibitors, and DPP-IV inhibitory peptides. Though they work on different systems in the body, all of them have demonstrated potentially useful biological effects, from helping to alleviate high blood pressure and blood clots to managing symptoms of type 2 diabetes.

“The ACE-I, ECE, DPP-IV, and PAF-AH inhibitory activity of these peptides is directly related with antihypertensive, antidiabetic, and antithrombotic activities, all of them affecting the cardiovascular system,” Mora-Soler tells Inverse.

It’s wasn’t exactly a surprise that these peptides were found in the bones. The authors explain in the paper that there’s already been some interest in using “food byproducts” (like bones) as a source of useful peptides since they contain collagen (the tissue found in nails or hair), as many bone broth proponents will also tell you.

But the fact the peptides are present in the bones doesn’t guarantee that they’ll actually make it through the cooking or digestion process. This, Mora-Soler explains, can be both good and bad, depending on how long the peptide is. On one hand, it can make them more active — and hopefully beneficial — but it can also render them useless.

“Heat and indeed simulated digestion can break down the peptides to smaller peptides, sometimes rendering them inactive, and sometimes it can break down longer peptides to more active ones,” she explains. “In this study, the ACE-I and DPP-IV inhibitory activity remained stable against heating as well as after simulated in vitro gastrointestinal digestion.”

To test how well the peptides fared when cooked, the team heated 50 grams of ground-up, dry-cured Spanish ham bones with 100 milliliters of water. She heated her broths to boiling in one round for only 20 minutes and the other for an hour. A quick disclaimer: This isn’t supposed to be a recipe, but she admits that “this procedure can be easily recognized as a part of a traditional broth/soup recipe made at home.”

Mora-Soler found that when she made broths from the bones and put them through simulated human digestion, ACE-I and DPP-IV inhibitory peptides seemed to thrive after both processes. PAH-AH inhibitors fared especially well, increasing their activity after digestion. ECE inhibitors didn’t fare so well, as their activity decreased after digestion. At the end of the day, she says, it’s really the ACE-I DPP-IV inhibitors that were robust enough to make the jump from broth to stomach, where they can hopefully lead to improved heart health.

Their results, the team writes, “suggest that dry-cured ham bones habitually used in the traditional household cooking of stews and broths could have a positive impact on cardiovascular health and a possible reduction of high blood pressure for consumers.”

Unfortunately, Mora-Soler didn’t have any specific dry-cured ham bone broth recipes to share. But she suggests this broth is a good base to start another recipe, if both taste and peptide content is the goal.

“To this,” she adds, “any other ingredient could be added to prepare a healthy and nutritive broth.”