Pom Reading: Myths & Facts About Pomegranate Juice & Your Health
There has been a spate of recent news coverage about the health claims of pomegranate juice, following the news that the Federal Trade Commission is suing the makers of Pom Wonderful for making unsubstantiated health claims.
So who’s right? Is the FTC correct to put the kibosh on Pom Wonderful’s misleading advertising? Or is Pom Wonderful largely reporting truthful, scientifically-based claims about the potent powers of the pomegranate? Here at Posit Science we consistently strive to separate science fact from myth, so that people can make informed decisions about their health, fitness, and lifestyle choices. I decided to turn my science lens on this issue and dig deeper to see if I could sift through the myths, facts, and claims to make some sense of this kerfuffle.
Let’s take a look at some of the claims the FTC takes issue with in the suit, and the research behind Pom Wonderful’s assertions:
“Drinking Pom Wonderful leads to a 30% decrease in arterial plaque…”
This figure is cited in a published study in the journal Clinical Nutrition, but the study size was quite small–only 10 people receiving the pomegranate juice. As well, the ad copy is a bit misleading as the article states “…(pomegranate juice) resulted in a significant IMT reduction, by up to 30%, after 1 year” while the ad copy says “leads to a 30% decrease” without the “up to” qualifier. (IMT here means intima-media thickness, a scientific term for the measurement of arterial wall thickness.) So this claim is citing a very small study and referencing the top-most result instead of a mean result. A study with 10 active participants is more like a pilot study, warranting further research in a study with more people, preferably hundreds or even thousands. On the pro-Pom side, the research protocol is sound and not only did those who drank the Pom Wonderful show up to 30% reduction in IMT… those in the control group who didn’t drink pomegranate juice saw a small increase in their IMT of 9%.
Unfortunately for Pom, there is a second study in the The American Journal of Cardiology with 289 subjects that largely denies the findings of the much smaller study. In this study, those who drank pomegranate juice vs. a placebo did NOT have a significant reduction in their IMT. However, in about one third of the people in a subset of the group–those with higher risk factors for cardiovascular disease–did show a slowing in the progression of their IMT growth. This is not nearly such an impressive finding as the “up to 30% reduction” found in the Clinical Nutrition study.
This seems to be a classic case of cherry-picking and publicizing the better result even though it’s based on a smaller study. Regardless, this topic seems to show at least a modicum of promise and certainly warrants further studies.
“…and 17% improved blood flow.”
The 17% figure comes from a study in Preventive Cardiology and looked at The subjects were well controlled for variance and the methodology appears sound. After 3 months of daily pomegranate juice intake, the active participants showed an average 17% improvement in myocardial perfusion and the placebo control group showed an average 18% worsening in MI–which could reasonably be represented as a 35% relative difference between groups.
There is another small study in the journal Atherosclerosis that looked at 10 hypertensive adults and found some related data. Unfortunately this was not just a very small pool of subjects, but they were also not well controlled–they were on different drug regimens, two were diabetic, two had high cholesterol, and so forth. Considering that the methodology being so uncontrolled, I don’t think it’s worth consideration.
“Pom juice may improve erectile dysfunction.”
First let me point out that the language here is not strong: it says “may improve.” This is common language for us here at Posit Science when we discuss findings on things for which there is some scientific evidence but not a large body of established, clinically significant and rigorous research. However, the study cited by Pom, from International Journal of Impotence Research, did not find a statistically significant difference in erectile function when 53 subjects drank pomegranate juice vs. a placebo juice, although there was a non-significant trend of pomegranate juice improving function slightly more. Interestingly enough, most of the people in the study reported better erectile function whether they were on the Pom or the placebo.
There is another study that was conducted in rabbits that suggests that oxidative stress may be a key problem in a certain type of erectile dysfunction, and therefore antioxidant rich compounds like pomegranate juice may alleviate this issue and ultimately improve the dysfunction… but the finding is preliminary at best.
This being said, the use of “may improve” is not offensive to me because it makes no promises, although further studies could just as readily show that pomegranates have no effect on ED as they could show a positive effect.
“Pom juice products can slow the progression of prostate cancer by lowering the level of antigens in the body called PSAs.”
In my opinion, this represents one of the best supported claims. It’s important to note that the study only looked at people who had already had prostate cancer and been treated with surgery or radiation. After their treatment, they drank the juice every day for two years. Their PSA “doubling time”, a measure of prostate cancer progression, was slowed from 15 months (control group) to about 4 1/2 years. A 6-year evaluation showed a doubling time of nearly 7 years. Because this only looks at people who have had prostate cancer, the finding may not be relevant for those who have never had it. The active group, again, was not huge, but it was a respectable 45 people and well controlled for a variety of factors.
So what should the average consumer do about pomegranates and pomegranate juice? At this stage Pom Wonderful seems to be overstating their claims somewhat, but I wouldn’t say they are out and out lying. Some of their presentation of the data is misleading or cherry-picked and most is based on studies that used a very small group of people. Still, the preponderance of good early data leads me to believe that regular consumption of pomegranates or pomegranate juice almost surely does offer some health benefits, although to be exactly sure what they are and how much pomegranate is needed, more large-scale controlled trials will have to be done. I think that Pom actually has some reasonably legitimate claims here (prostate cancer and blood flow) but unfortunately, they are promoting some sketchy claims as well (arterial build-up and erectile dysfunction.)
In all of these studies, no one in the groups that were assigned to drink pomegranate juice were harmed by the consumption. This is an important piece to note because even if it’s eventually shown that there are no significant health benefits (which I doubt), there is also no risk in the consumption. In thinking about this from a personal standpoint, I probably won’t start eating pomegranates every day… but if my husband or father had prostate cancer I think I’d try to get them on the pomegranate path, just in case.
Interestingly enough, at least for someone like me, who is interested in brain health and nutrition, I couldn’t find any Pom Wonderful ads that made brain health claims. While Pom Wonderful doesn’t talk about any brain health studies, there are several published studies on the topic. Most look at the benefits of high concentrations of antioxidants and resveratrol.