Cocktails of food additives and diabetes risk: New study

Before the food industry uses a new food additive, it must be checked for safety. Companies need to provide evidence that it doesn’t damage DNA and increase the risk of cancer.

Of course, this is important, but it doesn’t go far enough.

Food manufacturers don’t have to show that the mixture of additives they use is safe, or that continuous use over long periods of time — chronic consumption — is safe.

Because they’re not legally obliged and because funding is hard to come by, studies looking at the effects of combinations of additives are rare.

A new study in PLOS Medicine dives into this question. It shows that two common mixtures of additives are associated with an increased incidence of type 2 diabetes. 

What do we know about additives and health?

Additives have a wide range of uses in the food industry, including colorants, flavorings, antioxidants, preservatives, emulsifiers, and more. 

As we mentioned, individually, the additives used in foods don’t increase the risk of cancer significantly. 

However, there are many other aspects of health that aren’t checked before adding these compounds to food. For instance, manufacturers don’t have to investigate an additive’s influence on gut health, inflammation, or metabolic health.

And when we remember that many products contain a number of additives, the picture grows even more complex — some of these compounds may interact with each other, potentially increasing the health risks.

For instance, laboratory studies in cell samples suggest that some additives are more toxic in combination than their individual toxicity combined.

Although these lab studies provide hints at the effects of mixtures of additives, there has been very little human research.

Cocktails of additives

In the new study, the researchers used data from 108,643 adults involved in the NutriNet-Santé study — a long-term nutrition study conducted in France.

These individuals provided detailed information about their diets, and the scientists followed them for an average of 7.7 years. 

In their analysis, the scientists focused on the 75 most common additives.

Each of the 75 were consumed by at least 5% of the participants. They next used an algorithm to identify five broad mixtures of additives that people tended to consume.

Which mixtures did what?

As part of their analysis, the scientists controlled for variables that might influence the results. For instance, they accounted for diet quality and intake of sugar, saturated fat, energy, and alcohol.

This helped them tease out the effects of the additives rather than the effects of the overall diet.

After crunching the numbers, they found that two of the five common mixtures of additives — called Mixtures 2 and 5 — were significantly associated with an increased incidence of type 2 diabetes.

FYI: In studies, “incidence” means the rate at which something occurs during the study follow-up. In this case, participants were followed for an average of 7.7 years.

So, those who consumed Mixtures 2 and 5 were more likely to develop type 2 diabetes during this time frame.

What was in Mixtures 2 and 5?

It also contained the preservative potassium sorbate and the colorant curcumin.

These additives often appear in industrially processed foods, like broths, dairy desserts, and sauces.

Mixture 5

This mix mostly contained additives found in soda and other sugary drinks, including:

What does it all mean?

According to the authors, their results suggest that the increased incidence of diabetes associated with Mixtures 2 and 5 wasn’t driven by any individual additives. 

Although the researchers didn’t investigate precisely how these interactions affected diabetes risk, they suggest it might be due to their influence on the gut microbiome:

This is because evidence is mounting that the gut microbiome is linked to metabolic conditions like type 2 diabetes. 

Although research into additives and the gut microbiome is limited, some animal studies suggest an effect.

For instance, studies show that guar gum, an emulsifier in Mixtures 2 and 5, alters the gut microbiome, increases inflammation, and affects metabolism in mice.

Limitations and the future

This new study provides a fascinating glimpse into the potential effects of consuming cocktails of additives. But we have to remember that this is the first study of its kind.

Also, because of the nature of the study, it can’t prove causation — just correlation. And there’s always the chance that the scientists didn’t control for all of the important variables.

With this in mind, the authors call for more research: Both longer studies and shorter, more tightly controlled studies to help pick apart this incredibly complex topic. 

They also suggest that the safety of food additives should be reassessed and include investigations into how they interact.

If you’d like to learn more about these compounds and their impact on health, we have a handy guide covering more than 100 additives.