Longevity Briefs: Making Permanent Toxins In The Blood Less Permanent

Posted on 9 May 2022

Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

Why is this research important: Humans may be exposed to a variety of toxic substances on a daily basis, such as alcohol and ammonium. Most toxins are very efficiently degraded and removed from the body by the liver and kidneys, but unfortunately, a few of them are very persistent. Perfluoroalkyl and polyfluoroalkyl substances (PFAS), which come from plastic, have been nicknamed ‘forever chemicals’ because of how resistant they are to being degraded. Research has found that PFAS can accumulate in the human bloodstream, and are associated with low foetal weight, impaired immunity, obesity and altered liver function. No matter what detox practitioners may tell you, no amount of fasting, salty lemon juice or laxatives will get rid of them. Once PFAS reach the blood, they are very slow to clear.

What did the researchers do: This study enrolled 285 Australian firefighters who had elevated blood levels of a PFAS called perfluorooctane sulfonate. Firefighters tend to be exposed to particularly high levels of PFAS because they are present at high levels in firefighting foams. Since PFAS cannot be removed from the blood by the body’s organs, researchers wanted to see if simply removing the blood itself would reduces PFAS levels. Firefighters were randomised to either donate plasma (blood without the blood cells) every 6 weeks for 12 months, donate blood every 12 weeks for 12 months, or be observed only.

Mean (average) changes in perfluorooctane sulfonate (PFOS, left) and perfluorohexane sulfonic acid (PFHxS, right) between the start and end of the study period.
Effect of Plasma and Blood Donations on Levels of Perfluoroalkyl and Polyfluoroalkyl Substances in Firefighters in Australia

Key takeaway(s) from this research: At the end of the 12 month period, plasma donors experienced a significant reduction in blood levels of both perfluorooctane sulfonate and perfluorohexane sulfonic acid, while the blood donors experienced a lower but significant reduction in perfluorohexane sulfonic acid only, and the observation group showed no changes in blood PFAS levels.

This research is the first to show that PFAS can be effectively removed from the blood. But why was removal of plasma, which is just the liquid component of the blood without the cells, more effective than removing whole blood? The likely explanation is that plasma donors donated more frequently (though not as frequently as was planned) than blood donors, and each plasma donation was 800mL compared with 470mL for whole blood. Furthermore, more PFAS are bound to molecules in the plasma than to blood cells, and so a given volume of plasma contains more PFAS than the same volume of whole blood, making plasma removal more efficient. More studies will be needed to refine the process of removing PFAS, such as by figuring out the optimal interval between blood [plasma]donations.


Effect of Plasma and Blood Donations on Levels of Perfluoroalkyl and Polyfluoroalkyl Substances in Firefighters in Australia: http://jamanetwork.com/article.aspx?doi=10.1001/jamanetworkopen.2022.6257

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