Richard, annonas have been eaten by humans for thousands of years without any ill effects. How long has imidacloprid been around? You can count the years on your hands. Look at the track record of pesticides considered by scientist to be "safe" in the past. So many believed safe and then removed from the market. Why is that?
Oscar,
This is exactly my point. In the case of annonas, they have been consumed for thousands of years and when someone developed a Parkinsonian syndrome people simply said "that's life." Until some one studied it there was no thought that it could be due to consuming soursop products. Pesticides (and other man made compounds) are found to have negative attributes because they have been studied. We live in a world of natural toxins and our bodies have evolved to deal with them (do you know how much methanol is in your body right now?). After all, the most toxic substances known to man are all natural products.
Let me restate, I firmly believe that we all need to minimize our use of pesticides and herbicides, both natural and man made. They are not good for either the enviornment or us. Ideally, we need to keep our plants well fed and healthy and allow them to defend themselves naturally. Unfortunately sometimes, especially when young, they may need a little help. But to hear people make blanket statements that natural is good and man made is bad is just foolish (I am not attempting to imply that this is your opinion).
Richard
Richard, did you actually read this study? It never established a causal relationship between eating annonas and Parkinson's disease. The study was an experiment on mice. They were injected with high doses of synthesized annonacins. Not by being fed fruits. They were given very high doses of annonacin created in the lab, hundreds of times of the equivalent amount you would find naturally in a fruit. This study really had nothing to do with eating annonas, or even with soursops. It was a very flawed study and was not even accepted by the scientific community. The conclusions people drew from it after not reading the study were even more flawed. Also there is no proof at all that cultures that eat a lot of annonas have higher incidence of Parkingson's disease (or any other disease). For example, the same areas that ate cherimoyas in the past, high Andes, continue to do so to this day. But there is no Parkinson's there. If you look at incidence of Parkinson's disease the highest is in agricultural communities were a whole lot of pesticides, herbidicies, fungicides are used. It's very prevalent in small midwest towns in farmers that spray their crops regularly with chemicals. "The world's highest prevalence of Parkinson's Disease of any region is in Nebraska, U.S.A. with 329.3 people per 100,000 population.":
An interesting article about what communites have high prevalence of
Parkinsons:
http://viartis.net/parkinsons.disease/prevalence.htm
Substances known to cause Parkinson's:
http://www.viartis.net/parkinsons.disease/toxic.causes.htm
That's not accurate.
1) What's being discussed isn't just Parkinson's in general, but
a very specific atypical form of Parkinson's which is rare outside areas where annonas are consumed. It's this form that is linked to annonacin.
2) There has not been just one study; there've been a number, and they all track different lines of evidence. There's now a direct chemical basis for why the chemical should induce aptosis in dopamine-producing brain cells (
the same method it does in certain cancer cells), direct laboratory evidence of applying annonacin to cultures of such cells
causes them to die, direct evidence in lab animals that the sort of blood levels of annonacin found if you consume one soursop a day (known from the earlier anti-cancer studies)
causes the disease, and statistical human population studies that
correlate the disease to annona consumption levels, to an astonishing degere (while only 60% of islanders conumed the fruit and 43% the tea, 97% of those with the condition consumed the fruit and 83% the tea). What more do you need?
3)
Annonacin is not just in the tea in dangerous levels, and it's not just in guanabana.
These "downer" results weren't reached on purpose by people looking to damn annonas, by the way. The earlier research on annonacin was its potential use as an anti-cancer drug. The neurotoxicity was discovered as a side effect, and hence more research was called for. Basically, it works "too well". It doesn't only cause cancerous cells to die, but also some types of cells that you really *don't* want to die.
And again, I'll reiterate, I still eat annonas (even though Parkinsons' runs in my family!) - just in moderation. It's the dose that makes the poison**. And I'm not going to pretend that something I enjoy doesn't carry risks simply because I enjoy it. And my hope is that some day people will find ways to effectively breed it out of our favorite varieties or at least get the level down to irrelevant quantities. I know at the very least this is already being done with pawpaw, and there are low-annonacin cultivars out there like "sunflower".
** - Now, some poisons are such that any amount consumed is damage that doesn't go away, and if you accumulate enough, you have big irreversible problems. Annonacin doesn't seem to be this way. The lab studies show that neuron cells stop dying and can recover whenever there's not annonacin in the body for a length of time, and the population studies show that young people with the atypical parkinsons whos top consuming the fruit can have their symptoms decline or go away completely.