New research reveals that our blood is full of caffeine (and often Xanax)

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Imagine you’re a researcher and you order up well over a dozen batches of ostensibly pure blood from a blood bank to use in your work. Upon testing it, however, every single sample comes back positive for caffeine – and many come back positive for the anti-anxiety drug Xanax, as well.

In conducting a mass spectrometry research at Oregon State University, Richard van Breeman and Luying Chen needed to purchase 18 batched of ostensibly pure human blood serum collected from multiple donors. They bought the blood from biomedical suppliers, who get their blood from blood banks, who give them inventory that’s near its expiration date.

To their surprise, all 18 batches tested positive for caffeine. More eye-openers: many of the samples contained residue of a cough suppressant, tolbutamide, a medication used to treat Type 2 diabetes, and Xanax, an anti-anxiety drug. Not only was it a relief that this particular blood didn’t get transfused into someone who needed it, but it raised the question about the purity of blood in blood banks.

And it showed how much people really, really loved their caffeine. And also, if you happen to receive a blood transfusion, your chance of receiving that and the other medications listed are fairly high.

“From a ‘contamination’ standpoint, caffeine is not a big worry for patients, though it may be a commentary on current society,” said Chen, a Ph.D. student, in a release. “But the other drugs being in there could be an issue for patients, as well as posing a problem for those of us doing this type of research because it’s hard to get clean blood samples.”

The study was published in the Journal of Pharmaceutical and Biomedical Analysis.

Coffee blood

The reason Chen and van Breemen were doing the study in the first place was to test a new method for assessing the probability of interactions between botanical dietary supplements and drug metabolism. There are often major negative reactions if someone who is taking medication takes the wrong herbal supplements.

“Botanicals basically contain natural products with drug-like activities,” van Breemen said. “Just as a drug may alter the drug-metabolizing enzymes, so can natural products. It can become a real problem when someone takes a botanical supplement and is also on prescription drugs – how do those two interact? It’s not straightforward or necessarily predictable, thus the need for methods to look for these interactions. The odd thing, in this case, was finding all the tainted blood.”

The scientists had to recruit two individual donors who managed to agree to abstain from caffeinated foods and beverages so that the research could be completed with a control group.

There is a bit of a paradox of both caffeine and Xanax being found in American’s blood. While moderate doses of caffeine have mainly positive effects on most people, it also increases the production of cortisol, which is a 2005 report published in Psychosomatic Medicine, leads to negative outcomes like weight gain, heart disease, and… anxiety. Which may explain the presence of the Xanax.

The National Institutes of Health’s Office of Dietary Supplements and the NIH’s National Center for Complementary and Integrative Health supported this research.