Do Not Eat Pawpaws

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

The pawpaw is the largest fruit native to North America, weighing up to two pounds (1 kg). Look at these beauties! You can just scoop it right out. Pawpaws taste like a mixture of bananas, mangos, and pineapples. They’re like a tropical banana mango custard but found in temperate forests across the eastern United States, nourishing humankind for thousands of years and now complete with their own pawpaw festivals. Papayas are sometimes called pawpaws, but they’re completely different fruits. The real pawpaw is also known as the dog banana, false-banana, Indiana banana, prairie banana, poor man’s banana, Ozark banana, Banango (I like that one), Indiana banana (has a nice ring to it, too), and the Kentucky banana.

Pawpaws are my favorite fruit, or should I say were my favorite fruit. One of the reasons I moved to rural Virginia was because the property had a whole grove of pawpaw trees. I was going to be set for life—that is, until I ate a few too many on the first harvest, became quite ill, and actually looked them up. Pro tip: in the future, look to see if a food is toxic before you eat lots of it. Little did I know, the pawpaw belonged to an infamous family of fruits that contains three different types of neurotoxins. I had actually done a video years ago warning people not to eat soursop, also known as graviola, but didn’t realize pawpaws were related.

The family includes soursop, guanabana, sweetsop, sugar apple, cherimoya, and custard apple, which are all linked to a neurodegenerative disease called progressive supranuclear palsy, which is like a treatment-resistant Parkinson’s, with hallucinations, widespread brain atrophy, and dementia. And consumption of these fruits is associated with about 20 times the odds of having this kind of atypical Parkinson’s syndrome. Expose rats to even a fraction of the dose the people were exposed to, and they develop the same kind of brain lesions you see on autopsy in human victims. And in several patients who stopped consuming these fruits, the progression of their condition ceased, and in one patient the symptoms even disappeared after a change of diet. There is an urgent need to raise public awareness about the neurotoxicity of this family of fruits, which are often ironically praised for their taste and medicinal values.

In fact, you can find dietary supplements containing these plants, promoted for their purported anticancer effects. And a soursop extract can inhibit cancer cell growth in a petri dish, but only at concentrations much higher than the amount that kills off brain cells. Even a low cumulative consumption may worsen disease severity and cognitive deficits in degenerative Parkinson’s type disease, as in 0.2 fruit-years, so that’s just one-fifth of a fruit a day for a year, or a single fruit a month for six years or just one fruit a year throughout your entire life. The bottom line is that these fruits could contribute to the development of degenerative Parkinsonism in humans, and so as a precaution, more restrictive public health preventive recommendations should be made regarding their consumption.

So okay, consumption of these tropical fruits potentially constitutes a serious public health problem, but what about pawpaws? Here’s the amount of the primary neurotoxin in soursop, aka graviola. Pawpaws have ten times more. So why aren’t pawpaw eaters getting sick? Well, it’s only ripe for a few weeks a year, so unlike the tropical fruit that can be eaten year-round, people may not have a lot of exposure to them. Fresh pawpaws aren’t really even sold commercially either since they bruise so easily, but now the fruit’s available in any season, sold as frozen pulp or jam, and there are the supplements out there too. Not to mention, if you’re like me, trees in your backyard.

When the U.S. Food and Drug Administration was asked about them, they noted that pawpaw has a long history of food use, and it didn’t have any evidence that the fruit was unsafe to eat. You’ll hear things like: “Currently, there have been no reports of neurogenerative diseases linked to the consumption of the pawpaw fruit,” until of course, there are. Progressive supranuclear palsy and pawpaw: Poor guy had trouble speaking and walking as his brain was atrophying in his skull. Tragically he actually died before they figured it out, but his wife disclosed that they owned pawpaw trees, and he had been eating dozens a year. And when researchers started looking, they indeed seemed to find a link between this neurodegenerative disease and pawpaw consumption in the United States. So alas, no more pawpaw for me.

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Motion graphics by Avo Media

• brain health
• cancer
• dementia
• fruit
• neurotoxins
• Parkinson's disease