Commonly used sweetener has ‘unexpected effect on immune system’, say scientists

An artificial sweetener commonly used in hot drinks and found in diet soft drinks could suppress the immune response to disease in mice, new research suggests.

Scientists at the Francis Crick Institute found that consuming a high amount of sucralose lowers activation of T cells – a type of white blood cell – in the animals.

If it is found to have similar effects in humans and could in the future be used to treat people with autoimmune disorders, including conditions like type 1 diabetes, they added.

Researchers said their findings should not sound alarm bells for those wanting to ensure they have a healthy immune system or recover from disease.

Humans consuming normal or moderately elevated amounts of sucralose would not be exposed to the levels achieved in this study.

The doses tested were within recommended consumption limits, but would be the equivalent of drinking about 30 cups of sweetened coffee in a day, or 10 cans of a diet fizzy drink.

Sucralose is an artificial sweetener, about 600 times sweeter than sugar, that is commonly used in drinks and food, but the effects it has on the body are not yet fully understood.

Karen Vousden, senior author and principal group leader at the Crick, said: “We’re hoping to piece together a bigger picture of the effects of diet on health and disease, so that one day we can advise on diets that are best suited to individual patients, or find elements of our diet that doctors can exploit for treatment.

“More research and studies are needed to see whether these effects of sucralose in mice can be reproduced in humans.

“If these initial findings hold up in people, they could one day offer a way to limit some of the harmful effects of autoimmune conditions.”

Fabio Zani, co-first author and postdoctoral training fellow at the Crick, added: “We do not want people to take away the message that sucralose is harmful if consumed in the course of a normal balanced diet, as the doses we used in mice would be very hard to achieve without medical intervention.

“The impact on the immune system we observed seems reversible and we believe it may be worth studying if sucralose could be used to ameliorate conditions such as autoimmunity, especially in combinational therapies.”

Mice in the study were fed sucralose at levels equivalent to the acceptable daily intake recommended by the European and American food safety authorities.

While these doses are achievable, they would not normally be reached by people simply consuming food or drinks containing sweeteners as part of a normal diet.

The mice fed diets containing high doses of sucralose were less able to activate T cells in response to cancer or infection. No effect was seen on other types of immune cells.

The researchers hope the findings could lead to a new way of using much higher therapeutic doses of sucralose in patients.

Julianna Blagih, co-first author and former postdoctoral training fellow at the Crick, said: “We’ve shown that a commonly used sweetener, sucralose, is not a completely inert molecule and we have uncovered an unexpected effect on the immune system.

“We are keen to explore whether there are other cell types or processes that are similarly affected by this sweetener.”

Karis Betts, senior health information manager at Cancer Research UK, said: “This study begins to explore how high doses of sucralose could potentially be used in new treatment options for patients, but it’s still early days.

“The results of this study don’t show harmful effects of sucralose for humans so you don’t need to think about changing your diet to avoid it.”

The findings are published in the Nature journal.