Transcript: Higher Quality May Mean Higher Risk
Why is animal protein associated with increased levels of the cancer promoting growth hormone IGF-1, but not plant protein? Let’s go back to the tinkertoy analogy. Let's say you’re trying to build a really big pyramid, and instead of starting from scratch, a pile of little pyramids dropped in front of you.
Ooh, that makes things easier, and start stacking them together.
But what if you still want to build your big pyramid, but instead, a pile of cubes were dropped at your feet. You still have all the essential elements there, you could undo them all and rebuild them into little pyramids to build into your big pyramid, but you can imagine the cube pile might just not be as good a stimulus as the pyramid pile to instantly just want to start piling them together. Maybe you want see what’s on TV first or something.
It’s the same thing with our liver and insulin-like growth factor 1. With the exception of the animal protein gelatin, all proteins, plant and animal, contain all nine essential amino acids. So pretty much all proteins, in that sense, are complete proteins. Other than jello and marshmallows, there's basically no such thing as an incomplete protein. When you hear about high versus low quality proteins, what they’re talking about are the relative proportions of the different essential amino acids. The more closely the proportion matches our own proteins, the higher quality it’s considered.
So when our liver gets hit with a big load of incoming animal proteins, it’s like hey this is easy, let’s just send out IGF-1 to get cells dividing like crazy to use some of this up. It’s like the pile of pyramids. It’s meat; we’re meat, let’s just pile it on.
Whereas when you get plant protein cubes, all the essential elements are there. Your body can break them down into all the essential amino acids it needs, but it just doesn’t stimulate the same kind of real estate boon that animal protein does, so you don’t get as many new cancer condos poppin’ up in your body.
That’s my attempt at a lay explanation; for any biochem geeks out there, basically unlike the essentials, particularly arginine and the pyruvate precursors may be shunted into gluconeogenesis, oxidized into urea, and so, you know, tend to present less of a proteogenic stimulus, but back to me speaking English.
There’s only one truly "perfect protein." Without a doubt, the highest quality protein on the planet--for us-- is human flesh. Failing that though, any flesh will do. We don’t practice species cannibalism; instead we practice like kingdom cannibalism, right? Or if fellow mammals, class cannibalism. And by eating other animals we’re getting protein that more closer mirrors our own than a banana's, but now we know that doesn’t necessarily mean it’s a good thing.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by Kerry Skinner.
Please consider volunteering to help out on the site.