The 10 ‘danger’ ingredients to avoid in supplements with links to gut inflammation, diarrhoea and even cancer

WHETHER we’re aiming for better sleep or clearer skin, there’s a supplement for just about everything these days.

But do we really know what we’re putting into our bodies?

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Many of us take supplements every day – but are we checking the ingredients carefully enough?[/caption]

It turns out many seemingly healthy pills and potions are packed full of potentially nasty ingredients.

Some can have minor side effects, like stomach aches, bloating and diarrhoea.

But others contain fillers, oils and flavourings linked to hyperactivity, high cholesterol and even cancer.

Dr Amos Ogunkoya, a GP and sports and exercise medicine specialist, says: “I see first-hand the risks of unregulated supplements.

“Many people take products without knowing exactly what’s in them or how they might impact their health.

“Whether you’re an athlete, a regular gym-goer, or you’re simply looking to improve your health, transparency, safety and informed choices are vital.”

There are 11 ingredients he would be particularly wary of…

1. Magnesium stearate

Magnesium stearate is a salt-like component used in medicines and cosmetics.

It’s generally considered safe to consume, but it carries some unpleasant side effects in larger doses.

“It’s used as a ‘filler’ agent, and can impact the body’s ability to absorb nutrients,” Dr Ogunkoya says.

It can also irritate the mucus lining on your bowels, causing spasms and diarrhoea.

“This is especially problematic for people with irritable bowel syndrome (IBS),” the GP adds.

“It’s not inherently harmful, but because it offers no health benefit, it should just be avoided.”

2. Silicon dioxide

Also look out for silicon dioxide, sometimes listed as silica – an anti-caking agent that prevents clumping.

It’s most commonly found in supplements claiming to improve bone, skin, hair and nail health, according to Health.

“The long-term effects of silicon dioxide aren’t fully understood, but a high-quality supplement doesn’t need this additive,” Dr Ogunkoya warns.

“Often, the big issues are with microplastics or nanoparticles if the production of it is poor, and these can accumulate in the body’s tissues.

“It’s unlikely to be massively dangerous but it’s obviously unnecessary to ‘dirty’ your body and it’s simply not needed in supplements.”

3. Guar gum

If you regularly suffer from bloating, steer clear of guar gum.

“It’s often used to thicken powders and capsules, but it’s linked to digestive discomfort, gut irritation and inflammation, which can cause bloating, constipation, and diarrhoea,” Dr Ogunkoya says.

“It’s not good for gut mobility, and some studies have shown it can slow down the movement of food through the body.”

It’s an authorised food additive in the EU, but it’s banned in weight loss products in the United States.

The Food and Drug Administration (FDA) found that in high doses, it caused “dangerous” problems, including obstruction of the food pipe and small bowel.

One person taking the guar gum-containing diet pill Cal-Ban 3000 died, though details surrounding the exact cause were not published in the American Journal of Gastroenterology.

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Lots of pills are ‘bulked out’ by cheap fillers, experts warn[/caption]

4. Brown rice flour

You might not think much of brown rice flour as a supplement ingredient – it’s natural after all.

But it’s simply used to “bulk up” products, with no nutritional value, Dr Ogunkoya says.

“It’s just a cheap filler – and it’s one of the worst offenders, used to pad out capsules,” he adds.

“Depending on its source, there can be contamination with other products.

“A 2016 study found brown rice flour contained traces of arsenic – a potentially toxic heavy metal.”

Some research has highlighted that the consumption of arsenic-containing rice and rice-based products (like cereals, cakes and crackers) can increase cancer risks, especially in young children.

5. Artificial colours and flavours

Taking a bright red tablet might be slightly more appealing than a beige or brown one.

And one that tastes of raspberry is a whole lot nicer than one that tastes of mud.

But many supplements use artificial colours and flavours to achieve these results.

“Artificial colourings like red 40 (also called allura red or E129) and yellow 5 (sometimes called tartrazine or E102) have been linked to hyperactivity, particularly in children,” Dr Ogunkoya says.

“Some studies have even linked ingredients like these to cancer.”

A 2004 analysis of 15 studies concluded that “widely distributed” artificial food dyes can increase hyperactivity in kids.

Further research by scientists at Virginia Commonwealth University found animals given high doses of blue 2 had significantly more brain tumours than the control groups, and a study published in Toxicology and Applied Pharmacology found male rats given red 3 had an increased risk of thyroid tumours.

These tests were done on animals, and further research is needed on the potential dangers for humans.

However, products containing the following artificial colours must carry a warning on the packaging in the UK:

• Sunset yellow FCF (E110)
• Quinoline yellow (E104)
• Carmoisine (E122)
• Allura red (E129)
• Tartrazine (E102)
• Ponceau 4R (E124)

This will say: “May have an adverse effect on activity and attention in children.”

Take extra care when ordering supplements online, as not all countries have the same restrictions.

6. Proprietary blends

One of the biggest red flags on a supplement label is the term “proprietary blend”, according to Dr Ogunkoya.

“This is a loophole that allows companies to list multiple ingredients without revealing exact amounts, making it impossible to know if you’re actually getting enough of the active ingredients to be effective,” he adds.

“It’s a common marketing trick – brands include small amounts of beneficial ingredients to make their product seem impressive while filling the rest with cheap, ineffective substances.

“If a supplement isn’t transparent about dosages, you have to question how effective it really is.

“It’s a major red flag.”

A product might say it contains a “proprietary blend of 11 superfoods or minerals” – but it may not specify exactly what these are or how much you’re getting.

It makes it tricky to know if you’re hitting the NHS‘ recommended intakes, like 550mg of phosphorus a day, for example.

7. Titanium dioxide

Titanium dioxide (TiO2 – E171) is banned in the EU after being deemed a possible carcinogen by the European Food Safety Authority (EFSA) and International Agency for Research on Cancer.

But products containing it are available in other countries, and any still within their use-by date are still permitted to be sold in Britain.

Professor Maged Younes, chair of EFSA’s expert Panel on Food Additives and Flavourings (FAF), says: “Taking into account all available scientific studies and data, the Panel concluded that titanium dioxide can no longer be considered safe as a food additive.

“A critical element in reaching this conclusion is that we could not exclude genotoxicity concerns after consumption of titanium dioxide particles.

“After oral ingestion, the absorption of titanium dioxide particles is low, however they can accumulate in the body.”

“It’s used as a whitening agent for tablets, but it can cause DNA damage and it is generally not safe to consume,” Dr Ogunkoya adds.

8. Hydrogenated oils

You may think you’ve given up hydrogenated oils by swerving margarine, cakes and ready-to-use dough.

But this type of trans fat, often used to keep foods fresher for longer, could be lurking in your daily capsules.

“This can have detrimental effects on your cholesterol levels, and can lead to an increased risk of heart attacks, stroke, and systemic inflammation,” Dr Ogunkoya says.

According to the NHS, adults should have no more than 5g of trans fats a day.

There will be nowhere near that amount in one pill, but if you’re also consuming other high-fat foods, it’s important to take note.

One study that followed almost 85,000 women over 16 years found those who consumed the highest amounts of trans fats had a significantly higher risk of type 2 diabetes.

Other research has suggested that hydrogenated vegetable oil could increase inflammation in the body – a known contributor to heart disease, diabetes and cancer.

And further investigations indicate that trans fats can increase levels of LDL (bad) cholesterol while decreasing HDL (good) cholesterol, both of which are risk factors for heart disease.

9. Carrageenan

Carrageenan is derived from red seaweed.

It’s commonly used to thicken foods, but it has no nutritional value, according to WebMD.

While generally recognised as safe for human consumption, there is growing evidence that it can have an adverse effect on gastrointestinal health.

Dr Ogunkoya says: “It has been found to cause gut inflammation and digestive distress.

“There have been some studies that have shown that it can worsen IBS and colitis.”

Healthline also points to research suggesting carrageenan could promote or cause inflammation, bloating, IBS, glucose intolerance, food allergies and bowel cancer.

“Increased inflammation can lead to a greater likelihood of other diseases, such as inflammatory bowel disease, arthritis, and tendonitis,” the site adds.

10. Artificial sweeteners

Artificial sweeteners aren’t just reserved for fizzy drinks.

Dr Ogunkoya says people must check for them in supplements too.

“We know that artificial sweeteners like aspartame (E951) and sucralose (E955), can disrupt the gut microbiome – and we know how important gut and brain function are for our overall health,” the GP says.

“They can also worsen insulin resistance and increase your risk of metabolic disease.”

The World Health Organization (WHO) labelled aspartame, found in Diet Coke, chewing gum, toothpaste and chewable vitamins, a potential cancer risk.

Dr Francesco Branca, director of the Department of Nutrition and Food Safety, says: “The assessments of aspartame have indicated that, while safety is not a major concern at the doses which are commonly used, potential effects have been described that need to be investigated by more and better studies.”

How to spot a ‘good’ supplement

So you know what you don’t want in your supplements. But how do you spot a good one?

“The best supplements are transparent, well-researched, and free from unnecessary additives,” Dr Ogunkoya says. Look for:

• Patented ingredients – such as KSM-66 Ashwagandha for stress and cognitive function or PureWay-C Vitamin C for better immune support
• Certificate of Analysis (COA) – an independent quality test to verify purity and ingredient accuracy
• Clear labelling – avoid proprietary blends that hide dosages
• Money-back guarantee – reputable brands stand behind their products and ensure accurate dosing

“By checking for these factors, you can avoid being misled by marketing hype and choose supplements that actually work,” he adds.

In the UK, regulated supplements must meet strict safety and labelling standards set by the Food Standards Agency (FSA) and Medicines and Healthcare products Regulatory Agency (MHRA).

This ensures they contain safe, accurately dosed ingredients and comply with Good Manufacturing Practices (GMP).

However, unregulated supplements, often bought online or imported, aren’t subject to these checks.

“This means they can contain incorrect dosages, banned substances, or harmful contaminants without consumers realising,” Dr Ogunkoya says.

“Many also use proprietary blends to hide ingredient amounts, making it difficult to know exactly what you’re taking.

“To stay safe, always buy from reputable brands, check for third-party testing, and use tools like the SafeSupp app to verify what’s really in your supplements.”

Steer clear of social media

Influencers are often trying to flog us make-up and handbags, but many also promote supplements.

“One of the biggest risks today is misinformation on social media,” Dr Ogunkoya says.

“A worrying 39 per cent of people in the UK – rising to 60 per cent among those aged 25 to 34 – turn to influencers and online sources for supplement advice, compared to just 26 per cent who seek guidance from qualified healthcare professionals.

“Social media is filled with misleading claims, unverified advice, and promotions that focus more on engagement than evidence.

“Many supplements pushed online lack clinical research, and some influencers promote unsafe or unregulated products for financial gain, often without declaring sponsorships.

“This is particularly dangerous when supplements are marketed as quick fixes or alternatives to proper medical treatment, or when people combine multiple products without understanding potential interactions.

“Without proper regulation, harmful or ineffective supplements can gain popularity, putting people at risk.”

Always speak to a doctor before taking supplements, especially those you’ve seen advertised online.

The SafeSupp app

As a nation, we consume a staggering 81million supplements every day in the UK.

But many of us are unaware of what we’re actually taking, according to a new report by Earth’s Secret.

The results showed 80 per cent of people who take supplements never read the ingredients label.

And only 20 per cent of those who take them claim they would know how to spot a ‘red flag’ ingredient.

To help educate Brits on safe supplement consumption, the brand has launched SafeSupp (available on the AppStore and Google Play) – a new app which identifies good products and problem ingredients.

It allows customers to scan ingredient labels to find out if they are safe, and whether they contain any potentially damaging ingredients.

For each, it will give them a score out of 10, and there is also a 24-hour chat feature so users can ask any specific questions.

Amy Peacock, founder of Earth’s Secret, says: “We know from our research that people are feeling confused and overwhelmed by the amount of information and products available when it comes to supplements.

“As a result, a staggering amount of people are consuming them ‘blind’, and not checking what they’re actually putting into their bodies.

“Supplements are an incredible way to improve both your short-term and long-term health, yet many mass produced supplements contain filler ingredients that can do more harm in the long run than good.

“With our new SafeSupp app and campaign, we want to help educate people on what to take – and any ingredients to watch out for like magnesium stearate, silicon dioxide, maltodextrin, guar gum, and brown rice flour.

“These ingredients offer no health benefits and can even hinder nutrient absorption.”