This article was first published in聽
A short video of Robert F. Kennedy Jr. squirting a blue liquid into a glass of water would hardly have raised an eyebrow were he not the U.S. secretary of health and human services. But given that he now sits atop the U.S. health pyramid, as incredible as that is, his actions reap interest.
Although Kennedy has not commented on the video, judging by the shape of the bottle and the stunning blue colour of the liquid, there is little doubt that it is methylene blue, a dye that has taken social media by storm. TikTokers proudly display their blue tongues and ramble on about better brain performance, immunity boosting, warding off cancer, and protecting themselves from Alzheimer鈥檚 disease. As far as evidence goes, the only thing they can count on is peeing blue.
To be sure, methylene blue is a fascinating chemical. Its origin takes us back to the second half of the 19th century, the heyday of the fledgling dye industry sparked by William Henry Perkin鈥檚 accidental discovery of mauve, the first synthetic dye. It wasn鈥檛 long before a number of other dyes flowed out of chemists鈥� flasks, including methylene blue, synthesized in 1876 by Heinrich Caro at the BASF company in Germany.
It was a useful textile dye, but also caught the attention of Dr. Paul Ehrlich, who had become interested in the ability of certain dyes to stain microbes, making them visible under the microscope. He found that not only did methylene blue selectively stain the parasite that was known to cause malaria, it also killed the organism. That was a fascinating discovery, but was shunted aside because quinine had already been proved to be an effective treatment for malaria. However, with the parasite now developing resistance to currently used drugs, methylene blue is seeing a revival.
During the 1930s, another use for methylene blue took the stage: It was able to detect the purity of milk, a growing concern at the time. Methylene blue can exist in either a blue 鈥渙xidized鈥� form as long as oxygen is available, or a 鈥渞educed鈥� colourless version in the absence of oxygen, known as leucomethylene blue. Milk always contains some dissolved oxygen, and given that bacteria in milk need oxygen to survive, a reduction in dissolved oxygen means bacteria are happily multiplying.
A few drops of methylene blue will turn a sample of milk blue, and the colour will persist as long as there is sufficient oxygen. The time it takes for the colour to disappear is therefore proportional to the extent to which bacteria are present. Properly pasteurized milk will show no colour change, while contaminated raw milk will see the colour slowly disappear. This test is still used by milk producers today.
There is one other major use of methylene blue, and that is in the treatment of methemoglobinemia, a condition in which the oxygen-carrying capacity of hemoglobin is impaired. Hemoglobin is a complex molecule found in red blood cells that has an ion of iron with a plus-two charge (ferrous iron) in the middle. It is to this ion that oxygen binds as blood travels through the lungs, and from which it is transferred to cells as needed. The ferrous ion can lose an electron, giving it a plus-three charge, and this 鈥渇erric鈥� ion does not have an affinity for oxygen. Hemoglobin with a ferric ion is referred to as 鈥渕ethemoglobin鈥� and cannot deliver oxygen to tissues, resulting in anemia and, in an extreme case, death.
Any chemical that can remove an electron from ferrous iron can cause methemoglobinemia. Conversely, a substance that can donate an electron to ferric iron can be used to treat the condition. Methylene blue happens to be such a substance. When administered intravenously at a dose of one to two milligrams per kilo of body weight, it is converted by an enzyme in the body to colourless leukomethylene blue. This is an effective electron donor and reduces ferric iron to ferrous, restoring the ability of red blood cells to transport oxygen.
What sort of chemical can trigger methemoglobinemia? Nitrites are the classic example. They are familiar as additives in processed meats, where they reduce the risk of contamination by clostridium botulinum, the bacteria that can cause potentially lethal botulism. Nitrites also enhance colour by binding to the muscle protein myoglobin to form red nitrosomyoglobin.
The amount of nitrite added to processed meat is nowhere near a dose that can cause methemoglobinemia, but a high dose of nitrate in drinking water can be an issue. Nitrates are commonly used as fertilizer, and runoff from fields can end up in drinking water. When ingested, nitrates can be reduced in the stomach to nitrites, particularly in infants who are then at risk for methemoglobinemia.
The greatest risk from nitrites, however, does not come from accidental ingestion, but from intentional ingestion by people attempting to self-harm. There are a number of reports in medical literature describing suicides as well as cases in which, luckily, the person was found in time to be saved by the administration of methylene blue.
Aside from treating methemoglobinemia, methylene blue is sometimes used during surgery to visualize tissues and fluids where the dye is preferentially taken up. But why methylene blue has emerged as a dietary supplement, with claims of marvellous effects, is a mystery given that there is a lack of supporting evidence.
Some laboratory studies using cell cultures have shown that the chemical can detangle the cluster of proteins that characterizes Alzheimer鈥檚 disease, but early expectations that it can therefore serve as a treatment for the disease have not been met. Neither are there clinical studies that demonstrate methylene blue having an effect on memory, cognition, longevity, sleep, skin aging or enhanced energy, as claimed by proponents. There are, however, risks 鈥� mostly minor, such as nausea or diarrhea 鈥� but there is one potentially major problem.
Methylene blue is an inhibitor of monoamine oxidase, an enzyme that degrades some naturally occurring biochemicals such as serotonin, a chemical that controls mood. Selective serotonin reuptake inhibitors (SSRIs) are widely used drugs to treat depression by increasing serotonin levels in the brain, but in the presence of methylene blue the therapeutic level can be exceeded and a condition known as 鈥渟erotonin syndrome鈥� can arise. This can cause agitation, rapid heartbeat, hallucinations and lack of muscle coordination. Anyone taking SSRIs should stay away from methylene blue. So should others until there is clinical evidence of benefit.
Just why Kennedy was taking methylene blue, if indeed he was, we do not know. If it was for improved cognition, it didn鈥檛 work.
