Broths made from meat bones have been touted as foods that soothe arthritis, boost immune function, and smooth your skin. But the claims often exceed the evidence.
In the last couple of years, bone broths have become so popular they are being hailed as “the new coffee.” While bone-broth shops aren’t about to replace Starbucks outlets any time soon, some people are drinking mugs of the soup not just at noon, but also at break time throughout the day. Media coverage of the bone-broth phenomenon is filled with testimonials to the soups’ purported health benefits—as bone builders, immune boosters, and even wrinkle removers. However, there is scant scientific evidence to support those claims.
What are bone broths?
Bone broths are as old as the ages. Most cooks know them as chicken stock or beef stock—soup bases made by simmering bones in water with seasonings for as long as two days. Bone broths are a staple of the Paleolithic, or Paleo, diet—an eating plan based on the foods thought to have been consumed by hunter-gatherers who roamed the earth more than 10,000 years ago. The Paleo diet is heavy on meat, poultry, and fish, along with fruits and vegetables, but excludes grains, legumes, dairy products, alcohol, and coffee. Although it has many proponents, it doesn’t align with the proposed 2015 Dietary Guidelines for Americans, which promote whole grains and legumes and advise limiting consumption of red meat.
Caitlin VanDreason, a registered dietitian and clinical nutrition manager at Harvard-affiliated Cambridge Health Alliance, says bone broth has at least one thing going for it—it’s a fairly good source of protein, containing 6 to 12 grams a cup. However, the other claims are more questionable.
Claims with some support
Scientists have been curious about the health benefits of bone broths for more than 80 years. A 1934 nutritional analysis in The Archives of Disease in Childhood concluded that bone broths are not of “great nutritional value.” However, a few small studies have found some benefit for chicken broth, including the following:
Chicken soup helps clear nasal passages. A 1978 study of nine women and six men reported in the journal Chest found that sipping hot chicken soup increased the flow of mucus significantly better than sipping either hot or cold water.
Chicken soup may reduce inflammation. Laboratory tests of chicken soup reported in Chest in 2000 determined that chicken soup inhibits the activity of neutrophils—white blood cells that are the “first responders” of inflammation. However, this effect hasn’t been confirmed in controlled studies of adults.
Claims with no support
There is no scientific evidence, however, to support many of the claims for any type of bone broth. For example:
Bone broths don’t relieve joint pain. Arthritis is a result of the loss of collagen, which cushions joints. Although bone broth contains collagen, dietary collagen isn’t absorbed as is and sent straight into your joints. Like other proteins, collagen is broken down into amino acids, which become building blocks for body tissues. It won’t be transported directly to your knees, hips, or other joints.
Bone broths don’t make skin firmer and smoother. This claim is also based on collagen, which forms a layer of tissue that supports the skin. Just as dietary collagen isn’t transported directly to your joints, it isn’t taken into your skin, either.
Bone broths don’t improve digestion. Bone broths contain gelatin, which is claimed to be a digestive aid, although there is little evidence of its effectiveness.
Bone broths don’t strengthen bone. Just because a soup is derived from bone doesn’t mean it will build bone or prevent osteoporosis. Even when simmered for 48 hours, bones release very little calcium into the broth.
Building on bone broth
Bone broth—either store-bought or homemade—benefits from the addition of vegetables. If you’re heating up some broth or simmering a pot of bones, consider adding herbs, spices, and vegetables like carrots, tomatoes, cabbage, kale, green beans, and legumes to create a hearty, satisfying soup. There is ample evidence that people who begin a meal with a bowl of soup consume fewer calories over all. “Soup adds volume to what you’re eating so you get full faster. It’s a good way to have a really filling meal without a ton of calories,” VanDreason says. However, once you begin to add potatoes, flour, or cream, you’re also adding significant calories. Although creamed soups and chowders may be delicious, they should be enjoyed only occasionally, and then in small portions.