What’s wrong with artificial sweeteners?

As sugar substitute erythritol is linked to a higher risk of heart attack, we put sweeteners under the microscope.

Artificial sweeteners are considered helpful in combating the obesity epidemic. Picture: istock

Varying in taste from 200 to 20,000 times as sweet as table sugar, artificial sweeteners are considered helpful in combating the obesity epidemic. Yet periodically some have been found to have health risks themselves.

The latest to fall under the spotlight, in a new study published in the journal Nature Medicine, is the sugar substitute erythritol. Marketed as a zero-calorie sweetener, it is a type of sugar alcohol that is found in some fruits, albeit in tinier concentrations than in processed foods and fizzy drinks. In the newly published findings, blood samples of 1,157 patients being monitored for the risk of cardiovascular disease revealed that those with the highest blood concentration of erythritol were more likely to have a heart attack or stroke over three years.

Previous studies have suggested that artificial sweeteners can have a negative effect on metabolic health, blood sugar control and appetite. According to the dietician Dr Linia Patel, who has studied intakes of sweeteners on health, they are deemed safe for human consumption but concerns are being raised about their increasingly widespread use. “Over the last decade manufacturers have gone crazy about adding sweeteners to so many products,” Patel says. “You can now find them in more or less everything, from salad dressings and soups to yoghurt and toothpaste, and my concern is what this will mean for public health ten or 15 years down the line.”

But so far what do we know about sweeteners?

Are sweeteners bad for the gut?

In recent years scientists have looked at whether some sweeteners harm the balance of gut bacteria. When rats were fed an artificial sweetener containing sucralose for three months, levels of beneficial gut bacteria dwindled significantly. Meanwhile, a study at the Weizmann Institute of Science in Israel last year concluded that commonly used sweeteners were potentially damaging to metabolic health. Why this happens is not clear.

“Although it’s too early to confirm, some sweeteners appear to have unexpected effects on the microbiome,” Patel says. “Overconsuming them is probably not a good idea for optimal gut health.”

Previous studies have suggested that artificial sweeteners can have a negative effect on metabolic health, blood sugar control and appetite. Picture: istock

Do sweeteners help with blood sugar control?

In a 2019 review published in the British Medical Journal, researchers said that small, short-term studies found artificial sweeteners improved fasting blood glucose levels, but some trials have shown that certain sweeteners disrupt the body’s ability to control blood sugar, eventually triggering metabolic changes that raise the risk of type 2 diabetes.

Drinks sweetened with sucralose, for example, have been shown to hamper blood sugar regulation, and in the Israeli study two other sweeteners (saccharin and stevia) had a similarly negative effect. Not every participant’s ability to regulate blood sugar was affected in the same way, suggesting individual variations in the ways people respond to sugar alternatives.

Do fake sugars cause hunger pangs?

While animal studies have suggested that sweeteners can stimulate appetite in the brain, a large review of available studies found that artificial sweeteners don’t adversely affect calorie intake. Patel says she was surprised to find results of her own study in the journal Nutrients showed that consumption of artificially sweetened drinks led to lower sugar intake overall. “It was not what I expected to see,” she says.Should we all avoid sweeteners? In a Cochrane review in the BMJ researchers who looked at 35 observational studies and 21 controlled trials of sweetener consumption found that while they probably offer no health benefits, they likely do no harm either.

“Studies linking sweetener consumption to disease usually involve much higher intakes than you would achieve with a regular diet,” Patel says. “However, given that they are now added to so many different products, my advice would be to cut down where you can.”

A large review of available studies found that artificial sweeteners don’t adversely affect calorie intake. Picture: istock

PROS AND CONS OF THE SWEETENERS

Erythritol

Pros: Some studies have shown it to be a favourable replacement for sugar, although much of the research has been performed on animals.

Cons: Can cause diarrhoea and gastric issues in some people. The latest study has associated a high consumption with increased risk of cardiovascular disease.

Aspartame

Pros: According to the NHS and Cancer Research UK, sweeteners do not cause cancer, while the US Food and Drug Administration states that more than 100 studies have confirmed aspartame is safe.

Cons: Last year French researchers suggested that people “consuming larger quantities of artificial sweeteners, particularly aspartame and acesulfame-K, had higher risk of overall cancer compared to non-consumers”, but the researchers accepted that there were limitations including selection bias.

Another review highlighted bias of results with sweetener industry-sponsored studies more likely to confirm aspartame is safe. However, regulators worldwide continue to regard aspartame as safe.

Sorbitol

Pros: An analysis of studies by researchers at King’s College London reported that regularly chewing sugar-free gum containing sorbitol (or xylitol) can reduce the risk of tooth decay by up to 28 per cent.

Cons: It can have laxative effects in sensitive people, and a study suggested that they could experience chronic diarrhoea and abdominal pain after consuming substantial amounts of it.

Saccharin

Pros: The oldest and among the most widely used of artificial sweeteners. Added to jams, sweets, medicines and toothpastes. High doses of saccharin were shown not to raise the risk of healthy adults developing type 2 diabetes in research from 2021, and a two-week study showed it didn’t change the gut microbiome status of humans or mice.

Cons: Long-term consumption has been linked to kidney damage.

The Times