Why I would rather use sugar in my tea than an artificial sweetener, says professor Tim Spector

If you’ve recently enjoyed a low-fat yogurt, diet drink, cookie, or even a dollop of reduced-sugar ketchup on your chips, chances are you’ve consumed aspartame—the artificial (and virtually calorie-free) sweetener that has been a popular sugar substitute since the 1980s.

The same is true if you’ve used almost every popular brand of toothpaste, sucked on a sugar-free cough drop, or taken the antibiotic amoxicillin.

This man-made chemical food is so ubiquitous that it is now a basic ingredient in thousands of products found on UK supermarket shelves, often accompanied by labels suggesting that the lack of calories plays a valuable role in maintaining a healthy diet. healthy lifestyle.

But does it really do us good – or does it seriously damage our health?

It was reported last week that the International Agency for Research on Cancer (IARC) — a subsidiary of the World Health Organization (WHO) — will soon classify aspartame as “possibly carcinogenic,” or carcinogenic.

The IARC reviews the evidence on things that may be related to cancer, and over the years has looked at everything from eating red meat to night work and cell phone use.

It groups risk factors into four categories: carcinogenic (meaning the evidence is quite compelling), probably carcinogenic, possibly carcinogenic, and unclassifiable (insufficient evidence to fully assess risk).

Aspartame could now sit in the “possibly carcinogenic” category alongside a large and varied mix of suspected triggers, including diesel fuel, progesterone-only birth control pills, mothballs made with a chemical called naphthalene, and pickled vegetables consumed in large quantities in countries such as China and Korea.

This comes just weeks after the more conservative WHO said, although the evidence is inconclusive, it was concerned that long-term use of sweeteners such as aspartame could increase the risk of ‘type 2 diabetes, heart disease and mortality’. This was the first time an official body had raised concerns about sweeteners.

Last month I appeared on a Panorama program highlighting how a 2013 study reporting cancer in rats given humane equivalent doses of aspartame was criticized and effectively silenced by scientists funded by the food and beverage industry . I am not a big fan of rat studies to tell me if food is safe or not, as they are difficult to extrapolate to humans, and although esteemed charities such as Cancer Research UK and the European Food Safety Authority (EFSA) continue to do so. insisting – based on such studies – that aspartame is safe, it is unclear what data they have to actually prove it.

And are they looking in the right place? These tests usually feed the rodents large amounts of aspartame (or another chemical) and look for signs of cancer activity in major organs such as the liver. So far everything seems safe, says EFSA.

Yet we know from human studies published in renowned journals such as Cell that all common sweeteners can disrupt our gut microbiome, the intestinal cocktail of trillions of microbes that plays a crucial role in regulating our immune system, among other things. This is important because, although you may not realize it, your immune system is constantly putting out small cancer fires and destroying rogue cells before they have a chance to multiply – although in some rare cases, the cancer wins out.

Interference with that microbial mixture could potentially reduce the immune system’s ability to keep cancer at bay.

Unfortunately, many of the aspartame safety studies are based on old-fashioned testing methods — such as liver toxicity — developed long before science became aware of the significance of the gut microbiome; we now know that it is as important an organ as the liver.

In my opinion, this new knowledge about how essential gut microbes are to our health really changes things. For the past 30 years, we’ve been told that aspartame is perfectly safe, but we’re still using 1960s methods to test it.

Man-made sweeteners do not occur in nature, most of them come from the petrochemical industry and they are not inert, harmless substances. As a result, our microbiome has not evolved to produce the enzymes necessary to break down those chemicals and so it behaves abnormally and produces harmful signals to our immune cells.

Major studies have recently linked aspartame to cancer and increased mortality. Previous small studies have linked it to depression, insomnia, anxiety and learning difficulties, possibly involving similar mechanisms via the gut microbes (although more research is needed). But aspartame is only part of the problem.

People in Britain now consume almost 60 percent of their calories from ultra-processed foods (UPFs), which we now know cause people to overeat by 20 percent.

We’re not exactly sure why they do this, but they’re often flavored with aspartame and other chemical sweeteners like acesulfame K, saccharin, xanthan, sorbitol, and sucralose.

Some of these are hundreds of times sweeter than sugar, but are often used in products such as children’s drinks, infant formula, smoothies and yogurt. The net result is that they raise children’s sweetness thresholds so they crave even sweeter treats – just as a smoker craves a stronger nicotine hit from smoking more cigarettes. We know from scans that these flavorings act on the brain’s reward centers to produce an almost addictive craving for higher levels of sweetness.

We should be concerned about this because whether it’s a child or an adult, there’s some evidence that some sweeteners cause a similar spike in blood glucose levels as sugar, creating a mismatch between the brain signals and the actual calories and reward. We think this leads to overeating and seeking more sugary substances.

Earlier this year, the WHO published new guidelines stating that artificial sweeteners should not be used for weight management because they do not work.

Indeed, the evidence suggests that a drink marketed as “zero calorie” may actually cause you to gain weight, not lose weight.

A major factor behind our rising consumption of artificial sweeteners is the sugar tax, which was introduced in 2018 to reduce sugar intake and combat obesity. Most food and beverage companies have since reformulated popular treats to contain less sugar — by using much higher levels of sweeteners.

But while it’s been good for tooth decay, there’s no good evidence that the burden has reduced obesity. Why? Because while you may feel like you’re doing yourself some good by drinking a sugar-free fizzy drink, you’re preparing your brain to increase your appetite and have more sweet treats to satisfy your needs.

As things stand, I’d rather have a tiny bit of sugar in my tea or coffee than an artificial sweetener. At least I have a better understanding of what it’s going to do to my body, and I can see how much I’m adding.

Banning man-made sweeteners isn’t the short-term solution — they’re too ingrained in our food culture and part of the larger problem of UPFs. But whether or not they cause cancer, they help make us more obese and sick, and there are steps we can take to limit our exposure.

While it’s virtually impossible to completely cut out UPFs and drinks, try cutting back on regular items that almost always contain sweeteners, such as low-fat or low-calorie yogurt or smoothies, cookies, convenience foods, snack bars, and flavored drinks. At least treat yourself to the occasional diet soda or artificially sweetened drink, but stick to tea, coffee, or water most of the time.

The government should ensure that new chemicals are properly tested and instruct food and drink suppliers to put warning labels on ultra-processed products stating (as science is now telling us) that they contain sweeteners that can cause illness and lead to overeating.

We are already known as one of the sickest countries in Europe, with some of the highest levels of obesity and preventable deaths.

Do we really want that reputation to get even worse?

Professor Tim Spector is an expert in epidemiology and gut health at King’s College London and author of Food For Life: The New Science Of Eating Well (Jonathan Cape).