The Impact of Red 40 on the Gut-Brain Axis
What is Red 40?
The bright colors of candies, the vivid tint of mouthwash, and the bold shades of sports drinks all owe their eye-catching appeal to food dyes. While these additives don’t offer any nutritional benefits, they’ve long been used to enhance the appearance of foods, beverages, and medications, making them more visually enticing.
Recently, Aryelle Siclait, a reporter from TODAY Digital, dived in on the use of food dyes in the U.S. She covered how Robert F Kennedy said that the US has been feeding its own people with “petroleum-based chemicals without their knowledge or consent.” She included evidence on how research studies linked ultra-processed foods with artificial food coloring (azo food dyes), and further linked those artificial dyes with hyperactivity in children.
Another source demonstrates that it leads to several gastrointestinal problems, like inflammation and the elimination of beneficial bacteria.
“These dyes can kill beneficial bacteria, making it harder for our body to digest our food properly.” Inflamed gut means lots of gas, “bloating, pain, or even symptoms similar to irritable bowel syndrome” (diarrhea, constipation, cramping).
As such, based on the research mentioned, a clear link can be established between the use of azo food dyes and the gut-brain axis, giving the potential for side effects to arise.
Breakdown of Azo Food Dyes
Most food items sold in the United States contain some type of food dye. A good example of a commonly consumed U.S. food with food dye is Takis. The ingredient list of Takis is as follows: corn masa flour (processed with lime), soybean and/or palm and/or canola Oil, iodized salt, sugar, natural and artificial flavor, citric acid, soy protein, yeast, monosodium glutamate, maltodextrin, sodium diacetate, partially hydrogenated soybean oil, artificial colors (Red 40 Lake, Yellow 6 Lake)...” Let’s explore how these azo food dyes are broken down in the body.
The biological breakdown of azo food dyes is not significantly impacted by the normal bodily function of digestion. Azo food dyes relatively through the stomach with relatively small amounts of absorption within the small intestine, due to the lining allowing some to reach the bloodstream.
However, most breakdown of these food dyes happens in the large intestine.10 Within the large intestine, there are billions of residing bacteria, which cleave azo bonds and convert the dyes into aromatic amines. These aromatic amines are water-soluble and have been found to be toxic in high concentrations.
Areas of Impact from Substrates
The gut-brain axis is a communication system between the gut (and its microbacteria) and the central nervous system (CNS). For proper digestion, both must properly communicate with one another and send along proper messages. However, metabolites like aromatic amines from Red 40 are highly capable of disrupting this communication and causing improper signals to be sent in the gut-brain axis.
“Azo dyes can be reduced to aromatic amines by the intestinal microflora.” Once the microbacteria break apart the azo food dyes, the metabolites are sent to many places throughout the body. Through a key two-step process of metabolism, these metabolites increase their water solubility, so excretion becomes easier.
Unfortunately, not all metabolites are the same; some can more easily reach separate parts of the body, one being the brain.
There are many different areas of the brain associated with hyperactivity. Among these are the prefrontal cortex, basal ganglia, amygdala, and cerebellum, all of which may have their signals disrupted. This can result in various symptoms that are more broadly referred to as hyperactivity.
Red 40 can have further harmful effects on the gut-brain axis. By also damaging epithelial cells in the gut, symptoms of “leaky gut” are likely to occur. While there are many negative effects of the condition, the most relevant to this paper are the toxic metabolites entering the bloodstream and resulting in neuroinflammation.
In addition, the vagus nerve, part of the CNS, is one of the major communication pathways for the gut-brain axis. With an inflamed gut, the signals being sent by the vagus nerve can increase amygdala activity and further interfere with the prefrontal cortex, possibly increasing hyperactivity.
Exploring Side Effects of Impact
Many studies highlight the connection between common azo food dyes, behavioral issues, and cancer risks, especially in children. Here in the United States, they are reported to be safe according to the FDA. The European Union has banned certain food dyes, like those derived from coal and petroleum, and requires warning labels on others.
According to a review done by the California Office of Environmental Health Hazard Assessment (OEHHA), they conducted research on children and the effect of synthetic food dyes on their neurobehavioral outcomes (Figure 1). 27 trials were conducted, 25 of which were challenge studies. “[S]ixteen (64%) out of 25 challenge studies identified some positive association, and in 13 (52%) the association was statistically significant.” It is observed that there is a relationship between the adverse effects of synthetic food dyes and hyperactivity in children (Figure 1). Additionally, the FDA implements these regulations on synthetic food dyes based on older studies, which were not designed to assess children. Our consumption of these food dyes has been proven to affect our brain and gut connection.
“Attention deficit hyperactivity disorder (ADHD) is one of the most common behavioral disorders in children.” The symptoms include hyperactivity, low frustration tolerance, impulsivity, and inattention.
Another study conducted in the “early 1970s by Dr. Benjamin Feingold found that when hyperactive children were given a diet free of synthetic food dyes, symptoms of hyperactivity decreased.” By cutting out foods with these azo food dyes, children who are diagnosed with ADHD had their symptoms tamed. The food dyes are not a “major cause of ADHD per se, but seem to affect children regardless of whether or not they have ADHD.”
Conclusion
After observing the digestive process of azo food dyes and the harmful effects of their ingestion, we see that the consequences may in fact outweigh the benefits. We learn that the aromatic amines (a byproduct of azo food dyes) can significantly impact the gut-brain axis, possibly leading to a myriad of malfunctioning signals and bodily disarray.
“Artificial food colors (AFCs) have not been established as the main cause of attention-deficit hyperactivity disorder (ADHD), but accumulated evidence suggests that a subgroup shows significant symptom improvement when consuming an AFC-free diet”.
“Although the evidence suggested that some unknown proportion of children did respond to synthetic food colors, the U.S. Food and Drug Administration (FDA) interpreted the evidence as inconclusive”. Some believe that children in a classroom climate who consume more azo food dyes will suffer a negligible effect on their behavior. The weight of the evidence suggests that minimizing azo food dyes is a key method to keep your gut-brain axis functioning properly.
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