In my 2022 blog, I express strong concerns about the unnecessary use of artificial ingredients, particularly coloring, in our food, pharmaceuticals, and personal care items. The FDA confirmed in 2022 that 28.1 million pounds of color additives were certified in batches, many for food purposes.

Artificial food coloring differs from natural food coloring as it is chemically modified from a compound (usually from petroleum) by the process of synthesis versus being directly extracted from nature and purified. Artificial coloring also has major differences in its molecular structure from the molecules derived from nature for the purpose of color.

Three major problems come up with the utilization of artificial coloring in food and personal care items. First, there have been many health concern that have been underscored since the 1980's.1 2  Second, there is a significant use of resources, mainly petroleum-based, in their production despite being non-essential. Lastly, when these artificial colors enter our waters (such as in a shampoo or soap), they become part of our environment and animal digestive system.

One of the most popular forms of artificial coloring used in our food is called azo dyes. Approximately 0.7 million tons of azo dyes are synthesized each year. When you take a close look at the ingredient listed on our food, you can recognize some of these names such as: Tartrazine (Yellow 5), Sunset Yellow FCF (Yellow 6), and Allura Red AC (Red 40). With the grass root movement of bringing awareness and new policies to stop Kellogg’s cereal and other companies for use of artificial dyes in America, it made me curious to see how these azo dyes are metabolized by our gut.

The gut microbiome has many essential roles in our body such as controlling our gut permeability, metabolism, production of vitamins (B’s and K) and immune responses. We have a symbiotic relationship with our gut bacteria and any interruption of this relationship causes inflammatory responses by our body which could lead to variable diseases such as IBS, Crohn’s disease and mental health issues.

For example, one of the most important molecules that our gut bacteria makes in the process of digesting our food is butyrate 3. This compound helps fuel our energy and help reduce inflammation in our body.  It is the bi-product of digestion of polysaccharides (complex sugars) from plants and animals.

So what do azo dyes produce in our intestines?

As a chemist when I look at a structure of azo dyes (Figure 1) I can see they all have some common features: the water-soluble sulfonate groups, the azo bond (N=N) and the benzene rings. Azo dyes can go through reduction to some extent by enzymes in our gut and rectum to be bio transformed into colorless aromatic amines, some of these may become less toxic than the original dye, but others, such as aryl amines and free radicals, are potentially carcinogenic. 

A recent paper 4 concluded that Sunset Yellow FCF and as well as its degradation products may induce significant adverse hematological, biochemical, and histological effects in rats. Furthermore, hyperactivity was also observed in groups administered with such synthetic food colorants. There is definitely not enough research done to find all the long term adverse affect of artificial food coloring on our health, but what is known is that these type of molecules are not a source of energy for our body and do not help in producing essential vitamins or nutrients.

For example, sulphanilic acid (an aromatic primary amine), is one of the common metabolites of both Yellow 5 & 6. This molecule which belongs to the family of aromatic primary amines has been found in colorectal cancer tissues. 5

Primary amines are reactive molecules in a way that they are readily available to form new bonds in the process of acylation/acetylation. In fact, the acetylated product of sulphanilic acid has been detected in urine of animal subjects who had ingested Yellow color 6.  In our body, the process of acylation is essential for building proteins from amino acids.

I wonder when there is an increase in the concentration of azo dyes in our body, is there a competition for useless azo dyes metabolites to get acylated versus the essential acylation of amino acids to make proteins? 

Another common metabolite of sunset yellow is 1-amino-2-naphthol-6-sulphonic acid which has been found to have carcinogenic properties.7

As long as you are regularly eating food that contains these artificial coloring, you are depriving your intestines and colon of a healthy environment that can produce anti-inflammatory agents. 

Next time when you are at a grocery store make sure to read the labels and choose food free of artificial ingredients. Unfortunately, most restaurant and fast food places use artificial coloring in their food as they have been declared safe by FDA and they are included in so many products such as beer, bread, condiments, cheese, deserts, candy, soda and cocktails.

At this point, it is our responsibility to demand companies to make their products free of artificial coloring or we stop buying from them. 

Also consumers need to be open to the changes companies have to go through to reformulate their products free of artificial ingredients.