Regularly drinking protein shakes could raise the risk of deadly colon cancer, a top cancer doctor has warned.
Over the last 30 years, young diagnoses of the disease have shot up by 80 per cent across the globe, research suggests.
Scientists have suggested a host of factors are likely behind the phenomenon—from increasing pollution to rising obesity and even invisible particles of plastic in drinking water.
But now an ‘unhealthy’ obsession with protein powders has also been linked to an increased risk of bowel cancer.
Dr James Kinross, a colorectal surgeon at Imperial College London, told LadBible that those who use the popular supplements may be increasing their risk of cancer-causing inflammation.
‘These protein powders are bad news and really bad for your gut,’ he said.
‘When [your body] breaks down and metabolises proteins, one of the by products is toxins which drive inflammation and cause bowel cancer.’
He added that protein powders—popular with gym bunnies—’profoundly change the gut microbiome’—the community of ‘friendly’ bacteria that live in the gut, causing inflammation and releasing toxins.
Doctors are sounding the alarm over the dangerous ‘obsession’ with having lots of protein and the modern approach to supplementation
These harmful compounds raise the risk of damage to DNA in cells, which in turn increases the chance that they could turn cancerous, experts have warned.
Research has long shown that diets high in ultraprocessed foods, including protein powders, can also disrupt the natural balance of bacteria in the gut, triggering inflammation that can trigger a host of health complications, including bowel cancer.
For this reason, Dr Kinross—who has treated cancer patients for more than 20 years—advised ditching the protein powder and aiming for plant-based proteins, such as pulses and over animal proteins.
‘Just completely avoid powdered fibres…they’re terrible for your gut,’ he warned.
Other ultraprocessed foods that Dr Kinross warned against include processed red meat, like bacon and ham, which have also been linked to bowel cancer.
‘If you’re going to have red meat, you want to have high-quality red meat’, the oncologist explained.
‘And it should be a once-a-week thing. It’s a treat.’
Research has so far linked three meat-related chemicals to bowel cancer risk, including heme iron, nitrates and amines.
Bowel cancer can cause you to have blood in your poo, a change in bowel habit, a lump inside your bowel which can cause an obstructions. Some people also suffer with weight loss a s a result of these symptoms
While nitrates themselves are not carcinogenic, Dr Kinross said they can interact with digestive chemicals in the body to create cancer-causing compounds.
‘If you can just replace one portion of red meat with some white fish or chicken, you will significantly reduce your risk of bowel cancer,’ he said.
‘You don’t need to be vegan to have a healthy gut. That’s definitely not true, but what you shouldn’t be doing is having meat with every single meal’.
Dr Kinross also blamed companies that ‘egregiously market’ ultraprocessed foods, like cakes, crisps and ready meals, to young people for surging bowel cancer diagnoses.
His alert comes amid a growing body of research that has uncovered how emulsifiers, typically found in protein shakes and ultraprocessed foods, could be an overlooked contributor to bowel cancer.
Studies have found that these additives can weak havoc on the gut microbiome, causing bloating, bowel changes and inflammation linked to cancer.
Dr Maria Abreu, president of the American Gastroenterological Association, previously told DailyMail.com: ‘Chronic inflammation leads to colon cancer, and I suspect that’s transformative in this new rise of young people developing colon cancer,’ she told this publication previously.
US specialists have said frequently consuming a high ‘inflammatory diet’ is being ‘overlooked’. Foods that fall under the category include red and processed meats, sugary drinks, refined grains like white pasta or bread and even tomatoes
The Nova system, developed by scientists in Brazil more than a decade ago, splits food into four groups based on the amount of processing it has gone through. Unprocessed foods include fruit, vegetables, nuts, eggs and meat. Processed culinary ingredients — which are usually not eaten alone — include oils, butter, sugar and salt
‘One of the things that has changed very dramatically in our food supply is the addition of emulsifiers.’
A 2024 review published in the journal Nutrients found that the emulsifier carrageenan, often found in pre-made protein shakes, is broken down in the stomach, and turned into a toxic substance.
This degraded emulsifier can trigger intestinal ulceration and inflammation, reducing bacteria diversity and increasing the risk of bowel cancer.
It comes as research presented at the American Society of Clinical Oncology (ASCO) conference in Chicago earlier this month found that colon cancer patients who stuck to an anti-inflammatory diet reduced the risk of the disease spreading by 38 per cent.
Colon cancer, long considered a disease of old age, is increasingly striking people in their 20s, 30s and 40s in a phenomenon that has baffled doctors around the world.
Over the last 30 years, young diagnoses of the disease have shot up by 80 per cent across the globe.
Around 32,000 cases of colon cancer are diagnosed every year in the UK and 142,000 in the US.
In addition to raising the risk of colon cancer, scientists have found that ready-to-drink protein shakes could lead you to an earlier grave.
A recent study determined the shakes could be just as bad for health as a Kinder Joy chocolate egg, even though one is billed as healthy and the other junk food.
Researchers from Brazil said both have around 160 calories and are considered ultra-processed foods.
Lead author Dr Eduardo Nilson of Brazil’s Oswaldo Cruz Foundation said: ‘High consumption of ultra-processed foods leads to an increased risk of several noncommunicable diseases and all-cause mortality.’
One study published in the American Journal of Preventive Medicine found that for every 10 per cent increase in calories from ultra-processed foods, to an early grave. per day, the risk of dying early from any cause increased by 2.7 per cent.
It suggests that a single 11-ounce Muscle Milk protein shake with about 160 calories could raise your mortality risk in the same way as a piece of candy, solely because of how it is processed. On average, an 11-ounce drink takes only 11 sips to drink.
The team found that in the US, ultra-processed foods account for more than half of daily calorie intake. These products were associated with roughly 13.7 percent of all premature deaths, an estimated 124,000 early deaths each year. Similar patterns were seen in the UK.
