Artificial sweeteners are low-calorie or calorie-free chemical substances used instead of sugar to sweeten foods and drinks.

They're found in thousands of products, from drinks, desserts and ready meals, to cakes, chewing gum and toothpaste.

Sweeteners approved for use in the UK include:

• acesulfame K
• aspartame
• saccharin
• sorbitol
• sucralose
• stevia
• xylitol

Both Cancer Research UK and the US National Cancer Institute have said sweeteners do not cause cancer.

"Large studies looking at people have now provided strong evidence that artificial sweeteners are safe for humans," states Cancer Research UK.

All sweeteners in the EU undergo a rigorous safety assessment by the European Food Safety Authority (EFSA) before they can be used in food and drink.

As part of the evaluation process, the EFSA sets an acceptable daily intake (ADI), which is the maximum amount considered safe to consume each day over the course of your lifetime.

You do not need to keep track of how much sweetener you consume each day, as our eating habits are factored in when specifying where sweeteners can be used.

Are sweeteners healthy?

Sweeteners may be safe, but are they healthy? Food manufacturers claim sweeteners help prevent tooth decay, control blood sugar levels and reduce our calorie intake.

EFSA has approved the health claims made about xylitol, sorbitol and sucralose, among others, in relation to oral health and controlling blood sugar levels.

Dietitian Emma Carder states: "Research into sweeteners shows they're perfectly safe to eat or drink on a daily basis as part of a healthy diet."

She also says they're a really useful alternative for people with diabetes who need to watch their blood sugar levels while still enjoying their favourite foods.

"Like sugar, sweeteners provide a sweet taste, but what sets them apart is that, after consumption, they do not increase blood sugar levels," she says.

It's been suggested that the use of artificial sweeteners may have a stimulating effect on appetite and, therefore, may play a role in weight gain and obesity.

But research into sweeteners and appetite stimulation is inconsistent. Also, there's little evidence from longer term studies to show that sweeteners cause weight gain.