At least according to this study, acetogenin toxicity levels were unaffected after 12 minutes at 160 C (320 F), so it is unlikely that tea brewed at much lower temperatures for shorter times is reducing any acetogenin toxicity.
Which honestly isn’t that surprising, since most of the structure of these things is just a long saturated carbon-chain with some hydroxyl and ketone groups attached. It’s been a while since I’ve done much chemistry, but by and large those don’t looks like terribly unstable chemicals.
Sure, but it’s helpful to know the mechanism of action.
Seed oils high in PUFAs tend to increase the ratio of polyunsaturated fats to monounsaturated and saturated fats in cell membranes. This on its own is completely harmless. The issue arises during episodes of elevated oxidative stress, wherein the polyunsaturated fats get exposed to free radicals which break the unsaturated bonds and produce new free radicals, a chain reaction that only stops once the cell’s own antioxidants neutralize the free radical with an electron-transfer reaction, typically done by vitamin E, which then chains with other antioxidants like vitamin C and glutathione.* Those broken unsaturated bonds in the cell membrane aren’t a huge deal, since the membrane is mostly just physical support for the cell. But having too many PUFAs in the cell membrane then is just increasing the odds of that oxidative stress will propagate and migrate into the cell where it can cause more significant damage.
So seed oils increase the chances of increased harm from oxidative stress. It’s a kind of second-order, secondary effect. Add to that the fact that most Americans have too many lipids in their body anyway, and that second-order, secondary effect starts to pile up over the years.
But below a certain level, the PUFAs in your cell membranes are unlikely to chain react under oxidative stress, especially if your body’s own antioxidant system is in good order and your body isn’t filled with excess lipids. There is a reasonably safe amount of PUFAs. It’s probably lower than what most Americans are at, but it’s still fairly darn high.
Annonacin and other acetogenins are quite different. They kill cells directly and effectively are poisons. The chemicals inactivate a critical enzyme in the mitochondria, halting the formation of ATP and starving the cell of energy, which then results in cell death. For whatever pharmaceutical reason, the chemical is particularly adept at entering and poisoning neurons in the brain stem. That’s really not a good thing. At all. Sure, there’s a lower limit on toxicity, because the loss of a few neurons can be managed, but it’s not like with PUFAs were the body has a stasis point at which it can manage the harm indefinitely. Neurons generally don’t come back, and eventually, you lose enough of them for the brain to start failing.
And like, sure, if you take some cancer cells in a petri dish and dose them with acetogenins, the cancer cells die. But that’s true of just about any poison. “Anti-cancer” research is one of the most BS-ridden areas of research out there, partially because the bar is so low: does it kill cancer cells in a petri dish? Yes? Yay! You just got grant funding and a bunch of science journalists’ ears.
This XKCD comic explains it well:
The last point I think worth bringing up is that it should be pretty unsurprising these acetogenins are bad news. They’re structurally in the same group, the polyketides, as a lot of other rather potent things, including a bunch of insecticides and many, many antibiotics and fungicides, and even some famous carcinogens such as aflatoxin.
Should you never eat anything in the Annona family? I wouldn’t say so. The dose makes the poison, as they say, and many of the fruits are honestly not that high dose anyway. But the tea is. And unlike RoundUp, or red meat, or artificial sweeteners and food colorings, we actually have clinically-proven cases of acetogenins in tea made from Annona actually killing people directly, a lot of people. Eating the fruits a few times a year probably kills a few neurons, but it’d take hundreds of years to make a difference, at which point you’re already dead from something else. It could kill you, but it won’t be the thing that kills you first. But drinking the tea is known to kill you fast enough to actually kill you first.
I’d compare it to mangos. Mangos are great. They taste good, they’re good for you, and they’re abundant. But mangos actually contain a bit of urushiol. Not enough to generally matter or to cause any noticeable amounts of cell death, but enough that people who are allergic to urushiol often can’t eat mangos. Mango leaves, though, or better yet, poison ivy leaves, have a lot more urushiol. Even though urushiol is actually quite a powerful anti-cancer agent (it’s an anti-any-living-cell agent is the problem, same with annonacin), it’s not something you want in or on your body. And while I’d never say don’t eat mangos because of the urushiol, I’m pretty confidant in saying, please, please do not make tea from poison ivy leaves. Ditto Annonaceae. Eat the fruits in moderation, but perhaps leave off the tea. Camellia tea with a bit of bitter orange peal tastes better anyway and makes for great Star Trek references.
Just my $0.02 anyway.
*It is worth pointing out, no, none of these are plant-based polyphenol antioxidants. Your body does not use polyphenols or other plant pigments. In fact, because of how many antioxidants work as basically just carriers of free radicals, antioxidants themselves can cause oxidative stress if they are outside of the specific cellular pathways that handle that electron transport chain, which is exactly what eating antioxidants is. The benefit to eating those is because they cause somewhat mild oxidative stress themselves and so upregulate your body’s own antioxidant system. “Somewhat mild” being in comparison to say smoking or getting a major infection, but it’s still harmful to your body, just the sort of harm that tends to make your body strong if you are otherwise healthy and eating well. But, and this gets glossed over basically everywhere, if you are already under a lot of oxidative stress, adding more by eating a bunch of plant polyphenols is not likely going to help. And if you’re not getting adequate dietary vitamins A, C, and E, and precursors for glutathione and other animal antioxidants, then plant antioxidants are not going to help you at all.
