If you see someone walking down the street with a coffee cup in hand that smells more like a bowl of chicken noodle soup than a pumpkin spice latté, don’t be alarmed. It’s just part of the newest food craze: drinking bone broth.

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Bone broth has been called everything from the new coffee to the next kale. The meaty broth is even credited with helping Kobe Bryant quickly bounce back after a major injury. It’s sold for upwards of $4 a pop in New York, and trendy L.A. restaurants are even serving bone broth cocktails. This is all to say that we’ve reached a peak bone broth moment—thanks in large part to the drink being Paleo-friendly (unlike coffee) and the rise in popularity of the nose-to-tail movement. But what's really in bone broth? And is there any scientific evidence to back up the elixir-like claims?

What Is Bone Broth?

The bone broth that’s in vogue today is basically the same as the chicken or beef broth that lines grocery store shelves—and the simple soup starter that home cooks have whipped up—for years. Throw bones (usually chicken, cow, pig, or sheep) in a stock pot along with water, veggies (like carrots, onions, and celery), and a dash of salt. Let the contents simmer for 24 to 48 hours (store-bought brands might cook for as few as 12 hours) and voilà, you’ve got bone broth.

In the simmering process, the bones break down, releasing collagen, which is thought to help with joint health, and gelatin, believed to help with digestion, in addition to calcium and vitamins C, D, and E.

The Scientific Evidence

There isn't much scientific evidence to back up the claims made by bone broth supporters, but there have been few studies on the topic. One from 1934 found that “bone and vegetable broths are not of great nutritional valueBone and vegetable broth. R. A. McCance, W. Sheldon, and E. M. Widdowson. Archives of Disease in Childhood. Aug 1934; 9(52): 251–258. . But it's worth noting that there have been tons of scientific advancements in the last 80 years, so the results could be different today. A slightly more recent study—we’re talking late ‘70s—found that eating chicken soup helped with inflammation and digestion in patients with a cold or the flu Effects of drinking hot water, cold water, and chicken soup on nasal mucus velocity and nasal airflow resistance. Saketkhoo K, Januszkiewicz A, Sackner MA. Chest. 1978 Oct;74(4):408-10. . And in 2013, researchers found that bone broth diets contain a higher amount of lead than a typical diet, but not levels that cause doctors any concern The risk of lead contamination in bone broth diets. Monro JA, Leon R, Puri BK. Medical Hypotheses. 2013 Apr;80(4):389-90. .

For now, most nutritionists are cautious about making recommendations about bone broth. Justin Robinson, a dietician and strength and conditioning coach who has worked with the Los Angeles Dodgers, likens the popularity of bone broth to kale, where people began to eat kale by the pound and ignored other green leafy vegetables like chard and spinach. “Should we eat soups made with bone broth?” Robinson asks. “Absolutely! But we shouldn’t have it for breakfast, lunch, and dinner at the expense of other foods.”

Jessica Redmond, another registered dietician and a Ph.D. student in the department of exercise science at Syracuse University, finds the scientific evidence to be lacking, but she also says we shouldn’t completely ignore the anecdotal evidence of health impacts from people who have been drinking bone broth for years. After all, bone broth is a central ingredient in Asian long-life soup and the soup known as Jewish penicillin. “Without more research, it’s hard to say what bone broth does and doesn’t do,” Redmond says. “It’s likely just one of the many health-promoting behaviors these bone-broth supporters have done for so long.”

So go ahead and make your favorite soup (preferably with homemade broth). Just don’t expect to wake up free of joint pain and stomach woes.

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