The Risks and Benefits of Pomegranate Juice

Pomegranates have been used in a variety of traditional medical systems throughout history, known as “a pharmacy unto itself” in Ayurveda. Pomegranate juice does enhance the healthspan and lifespan of fruit flies and has been shown to increase sirtuin expression in patients with diabetes, but what can it do clinically?

A four-week pilot study with a few dozen participants found that pomegranate juice appeared to improve verbal memory; so, the POM Wonderful company funded a trial randomizing hundreds of individuals middle-aged and older to a year of its pomegranate juice or pomegranate-flavored sugar water. The researchers were unable to replicate the verbal memory effect, and the only significant difference was a drop in the ability to learn visual information in the “Kool-Aid” group. If you insist on drinking a sugary beverage, pomegranate juice won’t impair your brain function like fruit-free sugar water, but why not devote those calories to something that could actually boost your brain like blueberries?

A study of a cup (240 ml) a day for osteoarthritis seemed to improve osteoarthritis symptoms, but the control group wasn’t given a placebo intervention (they were just told to continue their usual diet). The placebo effect can be extraordinary in osteoarthritis. Effectively doing nothing can cause a 75 percent reduction in pain, 71 percent improvement in function, and 83 percent improvement in joint stiffness. So, when pomegranate juice respectively offers only 8 percent less pain, 19 percent better function, and just 43 percent improved joint stiffness, you might be better off just taking a sugar pill.

Placebo treatments can also offer substantial relief for angina chest pain, calling into question the veracity of a no-placebo-control study claiming an improvement in chest pain symptoms after drinking pomegranate juice for five days. When more properly put to the test, no improvement in artery function was found acutely or after weeks of pomegranate juice consumption. One randomized controlled trial even found an increase in LDL cholesterol, suggesting the daily pomegranate juice was worse than nothing. Ironically, there may be a way to improve blood flow, but indirectly, and in a bad way.

Viagra (sildenafil) is metabolized by a drug detoxing enzyme in your intestine known as CYP3A4, of which both pomegranate juice and grapefruit juice are inhibitors. Described as “a pharmacologist’s nightmare,” grapefruit suppresses the enzymes that help clear more than half of commonly prescribed drugs, and so, less drug clearance means higher drug levels in the body. Now, this can be good, if you want a 23 percent better caffeine buzz from your morning coffee, for instance, or your doctor wants to help you save thousands of dollars boosting the effects of expensive drugs instead of just peeing them down the toilet. You also get a 23 percent increase in the bioavailability of Viagra after drinking two cups (500 ml) of grapefruit juice (though you also get a slight delay in the maximum peak in the bloodstream, from about 45 minutes to around 70 minutes, A fatty meal can delay the Viagra peak to two hours.)

Seville (bitter) orange juice has the same effect on Viagra (but not lemon juice). What about pomegranate? Pomegranate juice increases the bioavailability of Viagra in rats and perhaps a little too well in people based on case reports with titles like “When the fire won’t go out”—painful erections lasting as long as eight hours after mixing pomegranate juice with the drug “refractory to…ice packing” (don’t try this at home).