I know there are smoothie fans here and we’ve discussed it a few different ways. I just read some very interesting research findings regarding using bananas in smoothies. It was significant enough I thought I would share it. I DID read the relevant parts of the base study from UC Davis and I’ll summarize that and link it below.
Bottom line first: Adding a banana to your smoothie will almost completely destroy most of the antioxidant flavonol content you would be getting from the berries, greens, etc.
Why?: The maceration (grinding/mixing together) exposes the flanonols to the PPO (polyphenol oxidase) of the banana - the chemical that turns them, and avocados, etc., brown. The PPO oxidizes the flavonols and functionally destroys them. It is very effective at this.
Take away: If you use banana in your smoothie, consume it immediately upon mixing and don’t store it. The nutritional degradation starts right away but is pretty complete in 20 to 30 minutes. Consider removing it from the smoothie recipe, or eating it separately, which reduces the effect.
They used a standard, tested dose of flavonols from cocoa in a banana smoothie vs a berry-only smoothie and tested the levels of serum flavonols at hourly increments. They used relatively healthy, fit, young men and this was a real human test, not simply a lab one with an uncertain in-body result.
The bananas and berries were all frozen before mixing, so the result was not highly temperature dependent as I was hoping. Personally, I’ll keep doing what I’m doing (1/4 to 1/3 of a frozen banana - much less than the study usage of a whole banana), but I will stop making a double batch and saving 1/2 for hours later.
Here are the results of the flavonol content of control and banana/non-banana smoothies (from study linked below):
The oxidative damage starts right away and is very complete in 20 to 30 minutes (from study linked below):
Here is the original article I ran across:
https://www.health.com/common-smoothie-mistake-7970159
Here is the study from UC Davis:
https://pubs.rsc.org/en/content/articlelanding/2023/FO/D3FO01599H
Bottom line first: Adding a banana to your smoothie will almost completely destroy most of the antioxidant flavonol content you would be getting from the berries, greens, etc.
Why?: The maceration (grinding/mixing together) exposes the flanonols to the PPO (polyphenol oxidase) of the banana - the chemical that turns them, and avocados, etc., brown. The PPO oxidizes the flavonols and functionally destroys them. It is very effective at this.
Take away: If you use banana in your smoothie, consume it immediately upon mixing and don’t store it. The nutritional degradation starts right away but is pretty complete in 20 to 30 minutes. Consider removing it from the smoothie recipe, or eating it separately, which reduces the effect.
They used a standard, tested dose of flavonols from cocoa in a banana smoothie vs a berry-only smoothie and tested the levels of serum flavonols at hourly increments. They used relatively healthy, fit, young men and this was a real human test, not simply a lab one with an uncertain in-body result.
The bananas and berries were all frozen before mixing, so the result was not highly temperature dependent as I was hoping. Personally, I’ll keep doing what I’m doing (1/4 to 1/3 of a frozen banana - much less than the study usage of a whole banana), but I will stop making a double batch and saving 1/2 for hours later.
Here are the results of the flavonol content of control and banana/non-banana smoothies (from study linked below):
The oxidative damage starts right away and is very complete in 20 to 30 minutes (from study linked below):
Here is the original article I ran across:
https://www.health.com/common-smoothie-mistake-7970159
Here is the study from UC Davis:
https://pubs.rsc.org/en/content/articlelanding/2023/FO/D3FO01599H