This French prospective cohort study identified small associations between certain mixtures of food additives and the risk of developing type 2 diabetes.

The mixtures of additives were identified using computer algorithms. Study participants were predominantly female (79.2%), relatively young (average age 41 years), well-educated, and within the healthy weight range (average BMI 23.6 kg/m2). Ethnic background was not reported (ethical reasons cited).

Australia’s food supply is different from France’s, and it is not known how common the additive mixtures identified would be consumed in this country, and by whom.

In Australia, type 2 diabetes occurs most commonly after the age of 45 years, in overweight or obese (BMI > 25 kg/m2) people (more frequently men than women), from lower socio-economic backgrounds, and incidence (new cases) has been decreasing over the past decade.

The observed associations are both less than 20%, so residual confounding is likely a significant problem within this study.

While novel, the generalisability of this French observational study to people at risk of type 2 diabetes living in Australia is unknown. 

Our food supply is regulated by Food Standards Australia New Zealand and the types and amounts of additives permitted to be added to foods and drinks is carefully assessed and reviewed on a regular basis.

Studies which monitor health outcomes of our changing dietary complexity are few and  crucial. The use of additives has in general increased food availability, improved shelf life and reduced food insecurity, but at a price. We are bound increasingly to apply a benefit, risk cost analysis to food choice regarding health and sustainability, understanding how socioecologically dependent we are.

This French study looks at how additive complexity might operate with regard to diabetes risk and finds that some profiles can be adverse, notwithstanding that they include components heretofore considered protective like modified starches, suggesting nutritional trade-offs.

Much could be debated in the findings, but, together with other evidence, my take would at least be that non-nutritive sweeteners should no longer be used.

I can see this paper leading to more scary headlines about food additives, but although the work is based on a large dataset, we need to be careful about what conclusions are drawn from it.

As the authors themselves clearly state, the study does not prove that food additives cause diabetes. All that is reported are slight associations between certain mixtures of some additives and the likelihood of type 2 diabetes, and there are some large caveats to this.

Firstly, an association between two factors does not mean one caused the other; it just means there appears to be an association between them.

Secondly, the authors didn’t measure food additive intake directly. They relied on self-reporting of food intake from study participants and then estimated the additive intake from this. This is a reasonable approach, but self-reported data is often inaccurate. This means great care must be taken in interpreting the results.

It is also not clear from the main paper how the authors classified someone as having diabetes. Diagnosis does not seem to have been done by a medical professional but rather estimated by self-reported health data and medication use from a linked database. This is far from conclusive. 

So, whilst this is an interesting theoretical study, people should not worry. In the end, all that can really be said is that, based on self-reported data and estimations of possible food additive consumption and health conditions, there is a possible, small association between two specific mixtures of additives and the likelihood of type 2 diabetes, and the error bars are pretty big on even this conclusion.

Type 2 diabetes arises when various parts of the body becoming resistant to the normal action of insulin, which is to pack sugar away in cells. 

The result is elevated blood sugar levels that can cause damage to the eyes and to organs like the liver. The chance of developing type 2 diabetes increases with age, and it is associated with increased body weight, obesity and lack of physical activity, all of which track with age, too.

Exposure to chemical substances is not believed to be a cause of type 2 diabetes. The French researchers whose work is reported in this paper set out to find such a cause. They were testing not a single substance but instead they surveyed the effects of mixtures of additives that are commonly included in processed food, such as starch, pectin, vegetable gums, and citric acid which is also naturally present in some foods). 

They identified two mixtures - of 8 and 15 constituents, respectively - that did correlate with slight effects. Only one of the mixtures included the kind of 'chemical suspects' that one expects to find in such studies, the two synthetic sweeteners, aspartame and sucralose. The associations between the mixtures and the condition were very weak, and similar mixtures that included many of the same constituents showed no association. Of course, association does not equal causation. The researchers mention this, but you have to read a long way into the paper to find it. It's not mentioned in the abstract and the title of the paper includes only the merest hint of association, let alone causation.

Testing a single substance for toxicity or the ability to damage our bodies in other ways is difficult enough. Only in a very few cases have pairs of substances or small groups of substances that are chemically closely related ever been tested. The results have been ambiguous, to say the least. Testing mixtures of 8 or 15 substances is just not good science. The authors themselves suggest that 'the potential synergies and antagonisms may be of interest in future mechanistic investigations' but that's really just an admission that their own approach was overly optimistic in its search for a definite cause of type 2 diabetes.

Although it has involved a lot of work - not just by the 23 authors of this paper, but by the 100,000 people who were surveyed - the results are weak. I wondered why this was ever published. The answer may have something to do with 'publish-or-perish' or the journals' approach to 'put the work out there' and let the scientific community decide on its validity. This can lead to sensationalism, but I don't think it will in this case because it's not sensational enough.

I find these results surprising because both mixtures contain substances that occur naturally in food and are recognised forms of dietary fibre (xanthan gums, guar gums and carrageenan). This means they provide fuel for our large bowel microbiome. Guar gum is a highly viscous fibre known to slow down the rate of digestion and absorption of carbohydrates, more so than any other fibre. Citric acid is found in citrus fruits, and also slows down digestion and reduces glycaemia.  

Both mechanisms would therefore be expected to REDUCE the risk of type 2 diabetes, not increase it. I suspect these findings are simply chance findings because the researchers were ‘fishing’ and looked at so many food additives. 

At present, there is a bias towards finding fault with food additives and processed foods.  In Australia, all food additives other than flavours are highly regulated with substantial data to back up their safety in the amounts used in food.

The authors here looked at whether diabetes risks were impacted by different mixtures of food additives. They found a very small increased risk of diabetes associated with two mixtures of additives, and no increase for the other three mixtures that they tested – these mixtures included a wide range of additives such as aspartame, guar gum, curcumin, and more.
 
The study is reasonably strong, but suffers from weaknesses in the underlying cohort. These results are entirely based on self-report, which is to say that the only information that the authors had on how many food additives people ate was how much they said they were eating. This form of self-report is notoriously unreliable and impossible to correct for in large epidemiological studies of this nature.
 
It's also unclear what meaning these results have. The biggest risk increase in the study was seen for Mixture 5, which contained 14 different food additives including citric acid and paprika extract. But due to the complex methodology the authors used to create these mixtures, it’s not clear how you could implement these findings in your daily life. The closest the authors come is saying that it might be a good idea to reduce your soft drink intake, but we didn’t really need this study to know that. It’s an interesting piece of research, but it’s hard to see how the results could be used outside of a strictly research setting.

This study has looked at the impact of commonly used additives in ultra-processed foods in our food system and their association with Type 2 diabetes. This study was conducted on a large group of over 108,000 adults in France over a 7 ½ year time period. Dietary data was collected from dietary records every 6 months, and from this the intake of additives was calculated.

The researchers found that there were two groups of food additives that were linked with an increased risk of type 2 diabetes. In the statistical analyses the researchers took into account the participants' weight, sociodemographic factors, lifestyle practice and their diet.

The first group of food additives included modified starches, pectin, guar gum, carrageenan, polyphosphates, potassium sorbates, curcumin, and xanthan gum. The other group included citric acid, sodium citrates, phosphoric acid, sulphite ammonia caramel, acesulfame-K, aspartame, sucralose, arabic gum, malic acid, carnauba wax, paprika extract, anthocyanins, guar gum, and pectin.

However, it must be remembered that this is an observational study and not an experimental study, and hence a cause-and-effect relationship cannot be drawn from it. Additionally, the intake of food additives in the diet of the participants could not be verified by any blood or urine tests.

There is a growing evidence base of the impact of UPF [ultra-processed foods] on both physical, cognitive and mental health. As well as containing low levels of nutrients, high levels of saturated and trans fats, sugar and salt, UPF also contain food additives to improve taste and shelf life of foods. This study adds to this evidence base of the health risks associated with a high intake of UPFs.