I’m a “PhD-Type”

An advocate of science not banana-induced hysteria

While I’m not a fan of Rhonda Patrick (FoundMyFitness), her messaging, her style, or her influencer persona. Her latest smoothie-bananas commentary seems to have triggered a new round of banana-induced hysteria. But responses have been far worse than the original claim.

The study in question was published three years ago by more than half a dozen UC Davis researchers:

Javier I. Ottaviani, Jodi L. Ensunsa, Reedmond Y. Fong, Jennifer Kimball, Valentina Medici, Gunter G. C. Kuhnle, Alan Crozier, Hagen Schroeter, Catherine Kwik-Uribe. “Impact of polyphenol oxidase on the bioavailability of flavan-3-ols in fruit smoothies: a controlled, single-blinded, cross-over study.” Food & Function, 2023, 14(18): 8217. DOI: 10.1039/D3FO01599H doi.org/10.1039/d3fo015…

It was a small, well-controlled cross-over trial showing that polyphenol oxidase (PPO) reduced the bioavailability of beneficial flavan-3-ols by roughly 84% when bananas were blended into the smoothie, compared with berries or capsules. The paper carried more than fifty supporting references. In one response (link), there was no intelligent critique, just “this is only one study,” “bananas have potassium and fiber,” “I like bananas in my smoothie,” followed by a slide into disparaging the “PhD-types.” One comment did call out how divisive the presentation was, it was then I put down my phone and sat with it a while.

This was a study conducted by "PhD-types" that confirmed something already well understood. Polyphenol oxidase (PPO, EC 1.10.3.1, catechol oxidase) has been known and characterized for more than half a century. It's abundant in bananas, avocados, apples, and mushrooms: a copper-containing enzyme that normally protects damaged plant tissue from pathogens and further injury.

One excuse floated was that gut microflora would break the flavan-3-ols down anyway, so the enzyme shouldn't matter. That misses a key distinction. PPO oxidizes flavan-3-ols into reactive o-quinones, which then polymerize into browning pigments and protein adducts, chemically altered and largely unavailable. Gut bacteria do something different: they metabolize flavan-3-ols into phenyl-γ-valerolactones, phenylvaleric acids, hydroxybenzoic acids, and hydroxyphenylpropionic acids, several of which retain measurable biological activity. Enzymatic oxidation and microbial metabolism are not the same process, and they don't produce the same outcome. Yes, this is just more "PhD-type stuff." And just saying: adding ignorance to arrogance is always a bad combination.

These reactions are worth responding to, because it more than just bananas

It's about what happens when expertise becomes an object of suspicion rather than a resource. It's when "PhD-type" gets used as an insult instead of a description.

I want to say something plainer here, without irony. Scientists, registered dietitians, nurses, and every other professional who spends years training to understand how the body and the world actually work have earned something. Respect for work done and thinking before reaction. Those that understand basic principles and where scientific literacy actually starts while being serious enough to engage with what it actually says.

This episode brought back a memory from medical school now decades ago. A bit of storytelling: Yes, we, as students, sat in the same lectures as the medical students alongside a tiny cohort specializing in toxicology. One day a visiting ER physician came to lecture and delivered a popular message. “I save lives!” he opened, with the kind of authority that doesn’t invite disagreement. Then he spent time disparaging the first two years of medical school as a waste of time. “These professors, these PhDs, are teaching you stuff you’ll never actually use, just wait until you get to the clinics!” I remember looking around and thinking that a hundred medical students were about to applaud. The message landed the same way then as it does now, on a smoothie thread decades later.

Physician don’t save lives in a vacuum. This ER physician’s fast, decisive competence exists only because someone else spent years working out the pharmacology, the pathophysiology, the toxicology underneath it. Those “worthless” two years that he was so quick to write off matter and save far more lives collectively (pharmaceuticals, biologics, vaccines, and more). That perspective is harder to see, but easy to mock.

To close, I’ll keep being a “PhD-type”

….and I won’t disparage the science minded individuals (with or without a degree) with a label. Don’t subscribe to those that do. I’ll support those that strive to make the world a better place. I’d rather be that than be the loudest person in the room who did not bother to read or understand a paper and just how obvious it’s conclusion might be. Was this just one study - hardly.

I'll update this article or supplement it over time, providing additional references and expanding into genetic techniques targeting PPO (e.g., Arctic Apples and, yes, more bananas).

Stay safe