Bone broth: benefits, big claims and potential risks

When people insist you should "clean your plate", they rarely mean you ought to tackle the bones as well. Yet for some diners, bones - or more precisely what they can yield - are the most appealing part.

Bone broth has moved from an everyday kitchen standby to a modern wellness trend, repeatedly promoted as a superfood by celebrities and lifestyle influencers.

Well-known names including Salma Hayek and Gwyneth Paltrow are said to rely on it for both appearance and wellbeing, and the late basketball icon Kobe Bryant reportedly used it as a pre-game meal.

Despite the current buzz, bone broth is anything but novel. Versions of it can be traced back to prehistoric cookery, traditional Chinese medicine and folk remedies across many cultures.

So what is bone broth in practical terms - and do the health claims stand up?

Often referred to simply as stock, this nutrient-rich liquid is produced by gently simmering animal bones and connective tissues - such as cartilage and tendons - for 12 to 48 hours.

That long, slow simmer draws compounds including collagen, amino acids and minerals out into the cooking liquid, creating a deeply savoury broth that can be drunk as-is or used to underpin soups, sauces and stews.

Shop-bought bone broth is easy to pick up, but making it at home typically gives you far more control over what goes in and may result in a more nutritious final product. Common components include chicken, beef or fish bones, water, vinegar (used to help pull minerals from the bones), plus herbs and vegetables to add flavour.

Skin benefits

Much of bone broth’s reputation rests on collagen - the structural protein found throughout connective tissue, including skin, cartilage, tendons and bones. It’s often suggested that collagen supports joint mobility and helps minimise visible signs of skin ageing.

Research has reported that hydrolysed collagen (a form broken into smaller pieces to aid absorption) can improve skin elasticity and hydration, and may lessen wrinkles. Other studies indicate it could reduce joint pain and stiffness, particularly among people with osteoarthritis.

That said, much of the evidence comes from studies of collagen supplements. Even though bone broth is frequently marketed as a collagen-rich superfood, studies indicate most bone broths don’t provide collagen in amounts comparable to those used in supplement trials where benefits have been observed.

More consistently, collagen production is associated with an overall balanced diet that includes plenty of protein, vitamin C and healthy fats.

Big claims, little evidence

Bone broth provides amino acids such as glutamine, glycine and arginine, which are often discussed in relation to supporting the gut lining and helping immune function.

Glutamine, especially, is thought to assist in repairing the intestinal wall and may help prevent "leaky gut" - a proposed situation in which toxins and bacteria can cross a weakened gut barrier and potentially trigger inflammation.

Some researchers have even proposed connections between gut health and conditions including autism, ADHD, depression and schizophrenia, although this remains a disputed topic and is not well studied.

Nutritionally, bone broth tends to be low in calories while offering a meaningful amount of protein, which can help you feel full and may support weight management. It also contributes fluids and electrolytes - including sodium, potassium and magnesium - which can be helpful when you’re ill or recovering.

There is some support for the idea that bone-broth nutrients, amino acids in particular, can reduce inflammation and assist immune activity. Overall, however, direct human evidence on the benefits of drinking bone broth is limited. It’s also worth weighing potential risks before making it a regular part of your diet.

Heavy metal

Animal bones can accumulate heavy metals, including lead. Because bone broth is simmered for extended periods, those metals may leach into the liquid. Study findings are mixed, and any risk is likely influenced by where the bones come from and their quality.

If a broth contains elevated heavy metals, it may cause problems ranging from relatively minor symptoms such as headaches, vomiting and tiredness, through to more serious long-term consequences like organ damage.

The science on toxic metals in bone broth is not clear-cut. With recipes varying widely, it’s difficult to pin down the precise nutritional profile of any individual broth.

A further concern is salt: many commercially available bone broths are high in sodium, which can increase blood pressure and put extra strain on the heart and kidneys. Reading labels carefully - or preparing your own - helps you keep sodium levels in check.

Bone broth also contains glutamate, a naturally occurring amino acid. Some people report anxiety, restlessness or headaches after consuming glutamate, although the evidence here is largely anecdotal.

Food safety matters too. If bone broth is prepared or stored incorrectly, it can become contaminated with bacteria, leading to gastrointestinal infection with symptoms such as vomiting and diarrhoea. Chill or freeze broth quickly after cooking, and make sure it is reheated thoroughly before you drink or use it.

Bone broth can still be a wholesome and enjoyable addition, particularly when it’s home-made from high-quality ingredients. It provides fluid, delivers protein and brings plenty of flavour - but it isn’t a miracle cure, and its benefits are likely more modest than marketing suggests.

For those aiming to support collagen, the most reliable approach is a nutritious, balanced diet. Eating enough protein, whole grains, fruit and vegetables provides the building blocks your body needs to produce collagen naturally.

Beyond diet, everyday habits also make a difference. Aim for good-quality sleep (seven to nine hours per night), keep stress manageable, avoid smoking, and protect your skin by using sunscreen.

Although bone broth may have some advantages, strong scientific evidence for a major role in collagen production remains limited. It’s better viewed as a nourishing complement to healthy living rather than a cure-all.

Dipa Kamdar, Senior Lecturer in Pharmacy Practice, Kingston University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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