Everyday ‘super-ingredient’ that can boost cancer treatment

From cleaning to baking to a home remedy for heartburn, bicarbonate of soda has a wide range of uses in the home.

But it has also become a staple among an unliklely group of users – Olympic athletes.

At last year’s Paris Games, sports scientists working with elite teams from the UK and the US estimated that more than 80 per cent of middle-distance runners competing in the games used some form of ‘bicarb loading’.

The idea is that its alkaline properties counteract lactic acid build-up in the muscles to reduce fatigue, helping them run faster for longer.

However, such anti-acidic properties may mean the kitchen staple has an even wider range of benefits – it’s now being trialled in childbirth to restart stalled labours, and has even been studied experimentally in cancer and kidney disease because of its ability to neutralise acid in body tissues.

When it comes to running its secret is helping muscles to keep working to their maximum capacity, says Professor Andy Jones, a sports physiologist at the University of Exeter who has worked with elite runners including Sir Mo Farah.

When you train or race at high intensity, lactic acid is quickly produced, which makes it harder for the muscles to contract properly, leading to fatigue.

‘Sodium bicarbonate is an alkaline that helps neutralise acid produced during exercise,’ explains Professor Jones. ‘We already have some bicarbonate in our blood. However, by ingesting sodium bicarbonate we can increase our blood bicarbonate store and therefore our ability to neutralise this acid, allowing the muscles to keep working for longer.’

In a study published in the European Journal of Sport Science in 2021, taking a small dose of 0.3 grams of sodium bicarbonate per kilogram of body weight – about 20g for a 70kg runner – mixed with water and about 90 minutes before intense exercise helps muscles keep contracting when they would normally tire.

He says the benefit is small but significant – typically a one-to-two-second improvement over 800 metres. ‘Not massive but potentially very important at the elite level,’ he says. Enough potentially to get a medal. He adds: ‘Almost all elite middle-distance runners use it.’

And because it’s a natural dietary compound, it’s permitted by all anti-doping agencies. It is little surprise that amateur runners are now harnessing its benefits.

Bicarbonate of soda – or sodium bicarbonate – is a naturally occurring mineral salt, though today it’s mostly made in factories using a 19th-century process that combines common salt and limestone to form the same simple compound found in mineral springs.

First mass-produced in the 1840s for baking and cleaning, it wasn’t until the 1970s that scientists confirmed its surprising ability to boost athletic performance.

A 2021 study in the International Journal of Sport Nutrition and Exercise Metabolism reviewed more than 150 trials and found that taking sodium bicarbonate consistently improved performance by 1 to 3 per cent in events lasting from 30 seconds to ten minutes. The researchers concluded it works best for sports where bursts of effort are followed by short rests, such as interval running, cycling or swimming.

Other studies from the University of Exeter have shown that blood bicarbonate levels peak around 90 minutes after ingestion, so timing is key.

The effect is greatest in middle-distance events such as the 400m, 800m and 1,500m, which rely heavily on high-intensity energy that produces a lot of lactic acid. For 100m or 200m sprints or longer races, the impact is smaller.

Hayley Hemmings, national endurance manager at England Athletics, agrees the benefits are real but individual. ‘It can help in middle-distance to 5k races by letting athletes push harder for longer,’ she says. ‘But like those carbon “super shoes” [carbon-plated running shoes that helped break records at recent marathons by improving running efficiency] some people respond and some don’t. You need to test it in training, not on race day.’

She adds that for recreational runners, it may help those who train hard, but for most Parkrun joggers, for instance, it’s unnecessary and could cause bloating or discomfort.

And she warns: ‘Check with your GP if you have any medical conditions, as it’s high in sodium.’

But while for lesser beings ordinary kitchen bicarb may be the answer, for elite athletes it’s not that simple. For Emily Simpson, 25, from Sheffield, a middle-distance runner, bicarbonate has become part of her race-day routine. She began experimenting with it two years ago after hearing about it from her coach. Since then, she says she has shaved about two to three seconds off her 1,500m times and feels stronger in the final stages of races. This season she placed inside the top ten nationally for the first time, finishing eighth in the UK rankings.

Like many runners, Emily struggled at first with stomach upset when she mixed ordinary baking soda with water. She recalls feeling bloated and crampy and says there were days she had to miss training because of it. Bicarbonate causes problems because it reacts with acid in the stomach, producing carbon-dioxide gas that leads to bloating and nausea.

That drawback has limited its use for decades, as the side-effects made it impractical for most athletes.

Then in 2023 Maurten, the Swedish sports-nutrition company, launched Bicarb System – a hydrogel formula that’s made bicarbonate easier to tolerate. It’s taken in two stages: the bicarbonate powder in tablet form is mixed with a thick gel that coats the pills. The gel prevents the bicarbonate reacting with stomach acid, meaning fewer cramps.

Each ‘dose’ (a sachet) costs £15, yet the active ingredient is the same baking soda sold in supermarkets for 59p.

Professor Jones, who is not involved with the company, describes it as ‘a game changer’ because it largely removes the gut discomfort that once limited its appeal.

There is also growing interest in how bicarbonate interacts with other performance aids. A joint study by researchers at Exeter and Bath Universities, published in Sports Medicine Open in 2023, found that combining bicarbonate with natural nitrates such as those in beetroot juice gave athletes a small extra edge – roughly a 2–3 per cent boost in stamina compared with bicarbonate on its own – by helping muscles use oxygen more efficiently and delay fatigue.

The same kitchen compound has also shown promise in a far more surprising setting – the maternity ward.

Susan Wray, a professor of physiology at the University of Liverpool, has spent years studying why some labours slow down or stop progressing – a problem that often leads to interventions such as a caesarean.

‘About 10 per cent of first-time mothers experience slow or dysfunctional labour,’ she told the Daily Mail. ‘We found that the uterus muscle can become acidic, rather like an athlete’s tired muscles. Bicarbonate neutralises that acid and restores contractions.’

In a trial at Liverpool Women’s Hospital between 2015 and 2017, involving 200 women whose labours had slowed or stopped, those who drank a bicarbonate solution of one level teaspoon (about 4g-5g) of bicarbonate dissolved in 200ml of water about an hour before receiving the usual oxytocin drip – used to restart contractions – were around 17 per cent more likely to give birth naturally than those given oxytocin alone.

Professor Wray says the findings are promising but need confirmation in larger studies. ‘Oxytocin is the only drug we have to help women whose labours have stalled, and it’s not very good,’ she says. ‘In seventy years of use there’s no solid evidence it cuts the number of emergency C-sections, and it carries small but known risks such as uterine rupture and stillbirths.’

‘Bicarbonate is cheap, safe and widely available,’ she adds. ‘It could be transformative – especially in poorer countries where obstetric care is limited.’

A larger international trial in Denmark is now being set up to test the approach.

Meanwhile, Professor Wray warns: ‘This is not something women should try at home. The bicarbonate solution was given in hospital under medical supervision and carefully timed with oxytocin.’

The same ability to counter acidity that helps muscles and the womb may also boost the body’s capacity to neutralise acid in conditions where excess acidity harms cells. When tissues become too acidic, the chemical balance inside them breaks down, enzymes stop working properly and blood flow is reduced.

For example, excess acid can speed up damage from chronic kidney disease, while in cancer, an acidic environment allows tumours to invade healthy tissue and resist the immune system’s attacks.

So far the results have been mixed. Professor Miles Witham, a geriatrician at the University of Newcastle, led a trial in 2021, the BiCARB trial, which tested bicarbonate tablets in older people with kidney disease – after two years, it showed no improvement in kidney function or muscle strength, and those on bicarbonate reported more stomach upset than those on dummy pills.

‘We hoped it would improve muscle strength and quality of life,’ he says. ‘But it didn’t. People on bicarbonate had more side-effects such as bloating and nausea.’

But he adds that bicarbonate therapy still has a role for patients with advanced kidney disease who have very acidic blood, as it can help correct that imbalance and protect bone and muscle.

Professor Robert Gatenby, an oncologist at the Moffitt Cancer Center in Florida, has shown in animal experiments that oral sodium bicarbonate can slow tumour growth by reducing acidity around cancer cells. ‘The problem,’ he told the Mail, ‘is that the oral dose needed to achieve this in humans causes severe gastrointestinal toxicity.’ His team is now exploring targeted treatments that deliver bicarbonate directly to tumours or slow intravenous infusions that bypass the stomach and avoid side-effects.

Of course better known is using bicarbonate of soda as a home remedy for indigestion and heartburn – half a teaspoon in water fizzes up and quickly neutralises stomach acid. But doctors say that while it can bring temporary relief, it’s not something that should be used regularly. As Professor Laurence Lovat, a consultant gastroenterologist and director of the London Gastroenterology Centre, explains it is high in sodium and the risk is using it can masks more serious digestive problems such as gastro-oesophageal reflux disease.