First, I would like to thank Dr. David A. Morton for his very courteous and considerate critique of my article "Beyond the mangosteen- a future full of color." I have been attacked many times online and found his approach very thoughtful and measured. My thanks, this was much appreciated.
Observations about your comments regarding my article:
I must initially mention that:
1) I did not realize the article I wrote for a talk in Anaheim would actually lead to a response and
2) was pleased to see that the 'other' fruits and nuts that I am interested in got some exposure. This latter issue was the more important one, not the comments about the hyperbole surrounding the mangosteen.
3) It was not my intention to be drawn into a debate over this wonderful and delicious fruit.
That said, I recognize the need to respond to the comments made by Dr. Morton and expand on some differences between us as to both opinion and science, as follows.
The issues raised by Dr. Morton where he indicated that I may have been "possibly inaccurate" are when I stated that;
1) there are limited medicinal qualities in the use of the mangosteen
2) that much of those benefits related to dysentery and may be attributable to tannin, not xanthone and therefore,
3) I must be saying there are no other biologically active components in the mangosteen
4) I am choosing to downplay xanthones, the root name of the product Morton mentioned, and instead am giving the impression that all of the current xanthone research is misplaced
My primary reason for being invited to the gathering in Anaheim for Nutracon was as a speaker on exotic fruits and nuts with great future potential. This was followed by my being an attendee at the Natural Products Expo West, a "commercial nutritional product companies" show. My talk for Nutracon was to emphasize the potential commercial and nutritional benefits and opportunities presented by some of the newer fruits on the market. I was not there to beat my drum about the mangosteen (I grow and sell the fresh fruit and am sold out indefinitely) but rather to highlight the rationale behind my being selected as a speaker. I am a firm believer in the direction that I hope the market is taking, where the consumer learns more and makes informed choices based on good science, not folklore. While at this huge event I tried some extraordinary new products, juices, yogurts, condiments, teas of every imaginable type, healthy oils, saw some things I thought were years off and learned a lot. This is a wonderful event, takes days to see in its entirety. I spent 16 hours on my feet over two days just to take it all in.
Mangosteen- from folklore to today
I would like to focus a bit on Dr. Morton's remark that I stated that there are “limited medicinal qualities” in the mangosteen fruit. This is not quite what I said. I clearly referred to the past, not the present and all of my remarks were focused on historical claims, not present claims. I deal with the present below.
Let's first look at his list of disorders that are the basis for folkloric i.e. past claims of medicinal benefits, each group from a different country:
Diarrhea, dysentery, skin infections and eczema
Chronic dysentery, diarrhea, other gastrointestinal problems, gout, fevers and urinary infections
Fevers, thrush, diarrhea, dysentery and urinary disorders
Treat stomach ache and diarrhea
Treat bowel complaints
On both my web site www.mangosteen.com and in the article referred to above, I repeatedly make the observation that mangosteens in the past have had a place in medicinal applications. But I stand by my comment that uses were limited and possibly can all be explained by the presence of tannins. I want to emphasize again that I clearly make the distinction between the past folklore and the present ongoing research.
And let's not misconstrue folkloric claims as proof of any actual benefits. For example, in the last century several consumer products incorporated radium as a tonic, for facial creams, in suppositories, added to chocolates... and you can guess how that went. Anecdotal or folkloric information should not be taken as the gospel. In some cases, doing so can make you quite ill or even kill you. Also, if you have any of the above disorders, is your next stop the health food store? I would hope not.
Less extreme and more recent, look at safrole in sassafras tea; banned as a possible carcinogen after close to a century of consumption here in the US. Or the occasionally lethal outcome associated with herbals containing ephedra, now banned in the US. Ephedra has a very large folkloric database, possibly much larger than the mangosteen. My point is that you can only go so far with folklore. You have to be informed, selective and discriminating, because it is not always a good thing when history repeats itself!
Before anyone goes ballistic, I would like to add the obvious: In many cases, folkloric knowledge has led the way to very important findings and medications. Ephedra, mentioned above, plays a significant role in several FDA- approved pharmaceuticals and in OTC medications, as well. Folkloric knowledge has led to discovery of many compounds that were subsequently studied, quantified, tested in lab animals, then in clinical trials with humans and finally introduced legitimately into the marketplace as FDA-approved pharmaceuticals. Possibly, someday, this will be the case with the mangosteen - but that is many years from now, if ever.
I see recurring themes in Dr. Morton's list of past uses; dysentery and diarrhea, the two things we agree upon which comprise the bulk of the historical applications. No argument there. But if you take out the disorders that affect the GI tract, what's left? All that remains are fevers, gout, eczema and thrush.
As far as I know, none of these are treated with any mangosteen-based formulations today by any licensed M.D. hoping to remain licensed. Much better alternatives came along. All are either treated by or can be cured by pharmaceuticals. The same applies to diarrhea and dysentery. In summary, not one of these disorders listed above is currently being treated with any mangosteen product, processed or otherwise, by a scientist or practicing physician who is willing to publish results in a peer-reviewed journal, and blogs don't count. As for FDA-approved mangosteen-based pharmaceuticals, I don't think there are any today.
Let's not forget, all of the references above highlight the distant past, from the last century and back; the extracts used then were crude, variable and indiscriminate as to individual chemicals in the rind and edible aril. I would contend that there is no present need for any processed mangosteen beverage based on issues of the past that are so completely addressed by modern medicine. Past folkloric usage of the mangosteen for a limited list of disorders is interesting but irrelevant today. Okay, so maybe folks today are drinking processed mangosteen products because why not, they like the flavor or maybe there is something nutritious in them. Vitamin C, perhaps, like in orange juice. Certainly past folklore would not be a reason.
In summary, considering the staggering number of diseases out there, this list above is, to my way of thinking, a very short list. I would like to emphasize again that folkloric claims are not a proof of any actual benefits. What would constitute a long list of medical claims? The list above is minuscule when compared to all of the ridiculous claims still online attached to the processed mangosteen products of some (but not all) companies.
Let me now address the leap from the past uses of mangosteen fruits (people also just ate them as food, they are delicious!) to current claims of benefits for a wide spectrum of ailments and the elevation of one particular chemical in this fruit – xanthone; the root word for the product Dr. Morton mentions.
The past use of mangosteen for treating diarrhea, dysentery, gout, fevers, thrush and so on, is already documented. But if the past uses are not a good justification for consumption of these mangosteen-based drinks today, what is? Is Dr. Morton saying the current research and the papers on xanthone are based on past lore? Not really. His list of citations indicates contemporary lines of research that are largely different from the past and have nothing to do with tannins, either (see below). So let's forget the past and move forward to the present.
Tannins versus xanthones
I put forward the distinct possibility that the primary use of mangosteen preparations for dysentery was due to the high concentration of tannins, not the xanthones so highly touted by sellers of mangosteen products. I am not a physician or biochemist but this just seemed like common sense based on high school biology. I put it forward as theory or conjecture. Dr. Morton, in response, said the following:
"However, if tannins are the only biologically active mangosteen constituent, why are scientists focused on studying xanthones and their effects on disease instead of tannins?"
Why indeed! But I never said "only". What I said was;
"The rind possesses a great diversity of complex organic chemicals, amongst which are tannic acid and xanthones."
I left the door open to there being any number of other bioactive compounds, including xanthones. I was simply trying to make the point that tannins and not xanthones might account for the most important benefit resulting from the folkloric treatment of diarrhea and dysentery with mangosteen preparations.
Dr. Morton goes on to say that there are no papers published on tannins in the mangosteen, but there are:
Nakasone, H. Y. and Paull, R. E. (1998). Mangosteen. In: H. Y. Nakasone and
R. E. Paull (eds.). Tropical Fruits, CAB International: 359-369.
MacMillan, H. F. (1956) Tropical Planting and Gardening with Special
Reference to Ceylon. 5th Edition. MacMillan and Co. London
Coronel, R. E. (1983) Mangosteen. In: Promising Fruits of the Philippines.
College of Agriculture. UPLB, Los Banos, Philippines: 307-322.
Yapwattanaphum, C., Subhadrabandhu, S., Sugiura, A., Yonemori, K. and
Utsunomiya, N. (2002) Utilisation of some Garcinia species in
Thailand. Acta Horticulturae, 575(2): 563-570.
Further, it is pointed out by Dr. Morton that scientists are more focused on the medicinal benefits of xanthones than tannins. Researchers from three countries are mentioned and a tally of over 100 papers are put forward to substantiate this assertion. Impressive. And of course the one study (after how many years of selling this product?) commissioned by XanGo is highlighted even though it has not yet appeared in any scientific peer-reviewed journal. Okay, so let's say there are over 101 articles on xanthones. But now, in my defense, as I originally asserted years ago, let's take a look at tannins in general and tannin for dysentery in specific.
Go to www.scirus.com and do a search for tannins+dysentery and you’ll find over 1000 hits. Tannins+diarrhea results in over 3000 hits. Let's separate the chaff from the grain. Is there more research being done on xanthones and health or on tannins and diarrhea and dysentery? Answer: tannins and their beneficial effect on diarrhea and dysentery. A small sample can be seen below.
Treatment of chronic diarrhea in Crohn disease. A pilot study of the clinical effect of tannin albuminate and ethacridine lactate. Fortschr Med. 1993 Mar 10;111(7):114-8.
Nonantimicrobial agents in the prevention and treatment of traveler's diarrhea. Clin Infect Dis. 2005 Dec 1;41 Suppl 8:S557-63.
Tyler VE. Herbs of Choice: The Therapeutic Use of Phytomedicinals. New York: Pharmaceutical Products Press, 1994, 51-4.
Weiss RF. Herbal Medicine. Gothenburg, Sweden: Ab Arcanum and Beaconsfield, UK: Beaconsfield Publishers Ltd, 1988, 101-2.
Tannin-rich carob pod for the treatment of acute-onset diarrhea. J Pediatr Gastroenterol Nutr. 1989 May;8(4):480-5.
Interestingly, there are numerous papers showing that tannins may have many benefits that go way beyond treating dysentery so who knows, maybe we should be looking next at "TannGo"! But I digress. The papers above regarding tannin comprise in vitro and in vivo studies, and in vivo with people, no less. In fact, there are thousands of papers on tannins with respect to anti-cancer benefits, anti-inflammation, antibacterial activity, antifungal activity, eczema and so on. Maybe the xanthone researchers should be looking at tannins!
Recommending that people benefit from daily consumption of any beverage by singling out words from scientific papers written by researchers who used test tubes, agar dishes, rats and rabbits but never humans is tenuous at best. What precisely in these products matches in both purity and quantity what the scientists used? And how does drinking it and sending it through the harsh environment of the human digestive tract compare with use in test tubes, agar dishes and so on?
Drawing a straight line from the lab and the test tube to your stomach by promoting a beverage that is a whole fruit mangosteen cocktail combined with several other fruit juices and unknown amounts of everything seems like quite a leap of faith. How do you know which component (or components) is doing what? Or which fruit? No one knows, yet.
Dr. Morton's citations of active and ongoing research involves xanthones and cancer, inflammation, eczema, arthritis, antibiotic and antifungal effects. Are we to conclude that they are telling people that these are the reasons one should drink processed mangosteen beverages, in lieu of consultation with medical practitioners?
Choosing to consume these drinks is, in my opinion, a recreational choice and nothing more. If scientists isolated an anti-cancer compound in a ground cover in your front yard and published this in a respected journal, would you put this plant in a blender and start drinking it every morning? I hope you answered "no." It should also be noted that on occasion, long term administration of some anti-cancer compounds can sometimes later cause cancer, liver and kidney damage and reduction in the efficacy of the immune system. All I am saying is; everything in moderation.
I am not saying that going forward there is no merit to further research into xanthones. I am all for it. The earliest data are promising for many fruits that contain xanthones (and tannins!) and "proanthocyanidins, anthocyanins, catechins, and polysaccharides." But the product mentioned above is not called ProGo or AnthoGo or CateGo, it's named after xanthone. And if you look at the scientific papers on proanthocyanidins, anthocyanins, catechins and polysaccharides in the mangosteen, it appears that all of the data was collected years after the product mentioned was already on the market.
I personally gain by the broader acceptance of the mangosteen as a grower of the fresh fruit. So, why is there the same or greater buzz associated with the pomegranate, cranberry, assai, sour cherry, goji or even the humble blood orange? In some cases, it is because the much more advanced ongoing research both in vitro and in vivo has also already generated exciting results in countless thousands of scientific peer-reviewed papers. Much of it is from human studies.
I, too, welcome the debate and am grateful for the opportunity presented to me to defend my comments and observations. I try to always make sure everything I say or write is verifiable, backed by science that has survived the scrutiny of peer review or I identify it as opinion. Who knows, maybe someday a substance in the mangosteen will be identified that stands up to the scrutiny of peer review, verification by repeated testing and shows documented benefits in people's health. But as of today, I see only anecdotal or testimonial evidence without the needed science to back it up and chemicals in test tubes that may not even survive the journey through your stomach. And it has been this way for years.