That is the opinion of the Center For Science in the Public Interest, joining a consensus of opinions from all of my most trusted sources.
It's not that juice is isn't healthy! It just shouldn't be so expensive, and it isn't going to perform miracles all by itself.
Lately, many have asked me about these exotic juices that are supposed to cure cancer, diabetes, fill in the blank...
It seems to me that what they all have in common is that they are all absurdly expensive, and were all once consumed ages ago by mysterious races of exotic people who are now all dead. These juices include acai, noni, mangosteen, and pomegranate, and there are probably others that I'm forgetting here.
OK, I hate always being such a downer! I hate telling people to not get excited over highly marketed health products! I am no fun at all! I wish I could be more fun.
If I wanted to be really popular and make lots of money like the convicted con artist Kevin Trudeau, I would just act like him, and tell everyone that every plant-derived product is wonderful, and that there is a conspiracy of doctors (who mysteriously never get cancer and their families never get sick?) withholding all this fantastic information from you. You'd be surprised how many people like hearing that, based on his book sales. Then I would be more popular and sell lots of books and make lots of money. Isn't that ironic? That's what I get for not being fun.
But I value truth more than I value being popular, and I am doing just fine, money-wise, anyway. I have this idealistic notion that, even for data that we don't like, data that conflicts with what we want, it may be that the real truth is more interesting and beautiful than our previous conceptions might allow. So we have to give up what we want, a lot, in science, and re-evaluate. That is why I think we need to take a hard look at unpromising products and deal with the data honestly. We just might learn something even more wonderful than we could have imagined in the first place.
Well, I have to say that juice isn't bad, it can even be very healthful! But it doesn't have to be exotic, and it certainly should not be expensive. Why not buy whatever locally made, inexpensive juice turns you on the most? If you really like it, chances are higher that you will actually drink it.
If it is really sweet, watch out for calories and sugar, that will not help with diabetes, now, and the natural sugars in the juice will turn into triglycerides (fat), which will make you fat! I had to laugh, when researching grape products for my book, over how many old references recommended the use of grape juice to "fatten up" a thin person. That advice is now sadly antiquated, but I am sure it was advice that worked. So keep it in moderation!
But I will say that many juices, especially some of the darker colored ones with those interesting plant pigments in them, certainly are healthy--in moderation. These reddish-purple anthocyanidins and their polymers (oligomeric proanthocyanidins, or "PCO"'s, "OPC"'s and an inordininate number of other synonyms) in particular may benefit our vasculature.
I know everyone is going on and on in the news lately about resveratrol from fermented red grape skins these days, and it is exciting stuff--in a test tube. But not in people, sad to say! That's too bad, because when resveratrol is dumped upon yeast, worms, and fruit flies, it turns on a life prolonging gene called SIR2, associated with the life prolonging effects of caloric restriction. Whether or not it can do the same for a calorically unrestrained person remains to be seen.
Another problem with resveratrol is that what little resveratrol that does get through the intestinal lining is quickly metabolized into other molecules. That sucker just does not get absorbed very easily. I have optimistically speculated in my book about how trace resveratrol metabolites might, having a similar structure, have similar activities to resveratrol in the exciting test tube studies, but again, that is a big if, and it hasn't been tested. Those metabolites are pretty short lived, so they are hard to do studies on.
But a recent Nature article suggests that it may not be the resveratrol from wine, but these OPCs, that are contributing to the heart benefits of moderate red wine drinking.
If so, that's good news for people who drink other red juices, that often contain either OPCs, or similar molecules, and their chemical precursors, the anthocyanidins.
What is perplexing is that these PCOs are pretty large molecules, and they also stick to proteins in our gut, so you might think we have trouble absorbing them. I think we do have trouble absorbing them. But some of the smaller ones may slip through the intestinal lining into the blood (simulated gut lining tests suggest this is so). What is nice about them in our blood stream is that they seem to have a relaxing effect on blood vessels and blood pressure, according to several studies. They may also stick to bacteria and prevent the bacteria from doing us some harm, perhaps. That last OPC trick relates to the famous use of cranberry juice to prevent urinary tract infections, and recent data suggest cranberry could assist in preventing attacks of bugs that cause foodborne illness. (Of course, I wouldn't substitute it for washing everything thoroughly!)
When I am living in Wisconsin (I move around a lot) I like the local cherry juice, which is abundant there. But it's cheap and easy to get when I live there. Instead of trying for pricey, grass-is always-greener juices from distant exotic places, why not look around you and support your local farmers?
Yes, juices can be very healthy! But are they cures for all sorts of diseases? What do you think?
Even my dad (an engineer) just wrote me, this morning, from Florida:
Hi Holly,
Just got back from our class at the Unity church. I picked up a flier that talks about the berry acai berry that has destroyed cultured human cancer cells in a recent Univ. of Florida study, one of the first to investigate the fruit's puported benefits. Published Jan 12th in the Journal of Agricultural and Food Chemistry, the study showed extracts from acai berries triggered a self-destruct response in up to 86% of leukemia cells tested.
I can mail the one page to you or fax it. Our fax is the same as the house phone.
Love dad, gotta go do eng'g work...ugh
And this is what I wrote back:
Hi dad!
Don't believe the expensive exotic berry juice stuff. I have read a lot about that, lately, and these are examples of popular marketing schemes (also with mangosteen juice and noni juice, and others) that have made millions but have very little good data to support them.
For example, you put berry juice, or spit, or coffee, or tea, or dirt or (fill in the blank!) in any bunch of cells in culture (like cancer cells) and-oh my god-they die. No kidding. When I worked in the lab my cultured liver cells would just die if I sneezed on the dish they were growing in. What a pain. Cells are easy to kill, in a dish, even cancer cells.
It isn't a cure for cancer. Show me some tests with actual people who have cancer, and I am talking double blind placebo controlled tests, not testimonials. Then I will be interested.
Love, H
