Another extremely helpful and well-meaning person offering me a haven from my gammy hips (which are pretty good at the moment, thanks for asking). The conversations follow a similar pattern - a recommendation from them, a cursory googling by me, a you-should-really-take-it follow up from them, a there's-no-evidence reply from me, and the obligatory blog post.
In the past, I've dealt with silicon gels, glucosamine, condroitin, rosehips and cod liver oil, and blogged them for posterity. When real medicine can't deliver, there are plenty of 'natural medicine' and quackery companies ready to pounce in with stories of cure and relief from these stubborn diseases.
So, how do you go about finding out if cherries are the wonderfruit we are being lead to believe it is? It's actually quite tough - googling "cherries, arthritis" brings up reams and reams of companies either promoting cherries as an arthritis cure, or publishing press releases on behalf of these companies - no balance, no evidence, no proof, no journalism, just unequivocal breathless fawning.
So I made a few assumptions - the most well-promoted cherry seller will probably have somewhere on their website the strongest possible claims backed up by the strongest possible evidence that cherries can cure arthritis. (Actually, thanks to the work of the MHRA, no self-respecting company would claim a cure, the strongest they can get away with is "alleviation of the pain of arthritis" or similar - this turns the potion from a cure into a painkiller at best). Given that they want to sell me their cherry produce, no doubt they will have done the hard work for me and compiled all the different studies from all over the world to convince me of it's efficacy and encourage me to buy.
Let me introduce to you CherryActive. I should say, that CherryActive aren't touting an arthritis pill per se, their magical cherries will help a whole range of ailments and in various situations, such as:
Improved Recovery from sport
What a panacea. However, I'll stick to the arthritis section. My cherry advocate kindly sent me "The Montmorency Cherry Nutrition Report", commissioned by the Cherry Marketing Institute (CMI), an organization funded by North American tart cherry growers and processors. A cynic might question the independence of such a brochure, but at least we can be sure it will be thorough, if perhaps over-egged.
(There is good reason to believe it may be over-egged, as the FDA last year announced a permanent injunction against some cherry-sellers for putting medicinal claims on their packaging that were not based in fact. In 2005, the FDA sent a warning letter to a list of cherry manufacturers warning them that their dubious claims could land them with a hefty fine. These are the same cherry growers and processors who fund the CMI).
Straight to page 5, for the heading "Arthritis & Gout".
[First of all, it's important to distinguish between arthritis and gout. Gout is the deposition of uric acid crystals on the cartilage of joints and tendons, which causes inflammation and pain. These crystals can continue to form Tophi, which can go on to cause "gouty arthritis". Arthritis is one of those catch-all words, which means 'joint inflammation' and covers a multitude of different conditions. Gout, however, although an inflammatory disease, is very different from rheumatoid or osteoarthritis.]
Gout seems to have some research in its favour - a paper in the Journal of American Nutrition (Jacob, 2003) indicates that a good dose of cherries of a day can lower the plasma urate level and may give credence to its anti-gout legend. The 10 candidates had to eat 45 cherries in 10 minutes after a overnight fast. The significant (p<0.05) decrease in plasma urate (μmol/l) went from 214±13 to 183±15 - this was compared with other fruit, however strawberries gave a reduction, and given the wonder-components associated with cherries are supposed to be the anthrocyanidins which give them their red colour, it's surprising they didn't compare more red fruit. In any case, they used sweet Bing cherries, not tart Montmorency cherries, and a study with 10 people and huge error bars doesn't carry much weight, but nonetheless, it's a maybe, for mild gout.
So what about arthritis, either osteo or rheumatoid? The brochure gives two papers that "suggest that consumption of cherries may be beneficial for the management and prevention of inflammatory diseases". (We all enjoy woolly modifying words like 'suggest' and 'may'). The first, van Acker (1995) is a research communication connecting flavenoids (such as anthrocyanidins) as scavengers of Nitric Oxide radical, however this molecule is ubiquitous in the body and very beneficial - it helps gentleman stand to attention when required. It has nothing to do with cherries and nothing directly to do with arthritis - to put this research in the category of "Cherries help with Arthritis" is really cloud cuckooland and another example of the nonsense surrounding 'antioxidants'.
The second is by Kelley et al, published in 2006 in Journal of Nutrition. It was a follow on from the Jacobs study above involving more people (18) and again involved the consumption of a daily amount of 45 sweet Bing cherries (not a pill nor a syrup but the cherries themselves). This study was longer term, looking at some inflammation markers after 0, 7, 14 and 28 days and 28 days after the discontinuation of the study. There was also a reading taken 8 days before the study began. The study found that C-Reactive protein, a protein found in the blood as a response to inflammation, decreased during the intervention period with the cherries. The researchers admit that it was a small study, with no placebo and that the difference seen could have been something other than the cherries, but it still warrants more research:
These should be confirmed in studies with larger number of subjects and also in subjects with preexisting inflammatory conditions such as CVD, arthritis, smokers, and older subjects.
There is a third paper (Tall 2004), but it involves heating rat's paws and measuring the inflammation - to be honest I want to know if a human with arthritis will benefit from eating cherries; this paper talks about anthrocyanins (present in many different fruit) in treating inflammatory pain in rats. Those two statements are very, very far apart.
And there you have it. That is the weighty mass of evidence that the Cherry Marketing Institute has helped fund, and my goodness it is unimpressive - to the point where I'm annoyed I won't get the three hours back again it has taken me to research it all.
To recap, a company called CherryActive, which sells Montmorency cherry cordial & pills has presented as the strongest evidence it has on arthritis the following:
1. A paper on a surrogate endpoint for gout using sweet Bing Cherries based on 10 people.
2. A paper based on 18 people eating sweet Bing cherries looking at general inflammation markers
3. A paper on rats with no cherries but anthrocyanins, present in loads of fruit.
You can see for yourself that the evidence is weak to non-existent. Of course, that doesn't mean the evidence won't be there in the future, the point is they don't need it. They have people willing to be duped in to believing it works (placebo-effect alone), with the press as their willing conduits - it seems churlish not to put yet another fawning, uncritical Daily Mail link in time-honoured fashion, so here it is, from Sept 2008. Cut&paste-tastic.
You may be amazed, given my incredible tabloid headline writing skill that I didn't stoop to use a gag on 'cherry-picking the evidence'. That's because CherryActive have caught the eye of other dietary-minded bloggers such as HolfordWatch, who used it with conviction. An nutri-nonsense product that has Patrick Holford and Food for the Brain endorsing it, is almost guaranteed to be pimping pills to a gullible public in Holford's happy evidence-bending way.
It turns out they can't do maths either - have a look at the nutritional information on CherryActive's website. Show me someone who can put 21g of natural sugars (81 kCal) into 10kCal, and I'll show you someone who has done their sums wrong. Let's hope not too many dieters or diabetics rely on those numbers.
EDIT: May09: CherryActive, having been made aware of their mistake, have amended it to read 110 kcal, not 10.
Perhaps I should tell the CMI to go back and try again, give them another bite of the cherry, if you will.
Thanks to Chris Preston & Gadgeezer from Bad Science for their help.