Pom-oh-so-Wonderful! Pomegranate Juice and Immunotherapy

One day a few months ago, as I was perusing the aisles of whole foods (which used to be a favorite pre-coronavirus pastime), I randomly decided to buy some pomegranate juice. I’m not big on juices generally, because I’m a proponent of eating the fiber-filled whole fruits instead, but pomegranates can be harder to incorporate routinely into a diet. So, knowing the mega-dose of antioxidants that pomegranates offer, I decided what the heck and bought the juice (and knew my kiddos would be ecstatic about JUICE! which Kensley calls “ganite juice”).

Later that very same week, I was reading a new book (now a favorite) called “Eat to Beat Disease,” by Dr. William W. Li (find the book on Amazon here), and read about the fascinating link between the intake of pomegranate juice and the growth of a healthy gut bacteria that makes a person more likely to respond successfully to cancer immunotherapy (amazing!). 

The bottom line is pomegranate juice helps create a healthy gut microbiome that results in a more successful response to immunotherapy treatment.

When we think of cancer treatment, for most of us, the first thought is of chemotherapy, which is focused on killing cells.  While effective in treating cancer for many, it can also have the unfortunate effect of damaging the immune system.  Unlike chemotherapy, immunotherapy harnesses one’s own immune system to fight cancer.  But immunotherapy won’t work for everyone, particularly if one’s immune system is compromised.  However, as Dr. Li discusses extensively in his book, our gut microbiome is directly linked to our immune system, and small changes to help improve our gut microbiome can greatly impact our immune system’s ability to do its job effectively. 

It makes total sense that what we ingest determines the composition of our gut microbiome.  As they say, we are what we eat (or drink)!  Many great minds even argue that the gut microbiome is not just our “second” brain, but our “first” brain.   Up to 90% of serotonin, which is our body and brain’s “feel-good” hormone and neurotransmitter, is produced in our gut microbiome!  (check out one of the many articles discussing this phenomenon here). So what we eat, and in turn the makeup of our gut microbiome, is directly related to our brain function.  I always knew that we need glucose for our brain to function, but I think it’s amazing to think that our belly may be the real brain in charge!

Because of this connection, there have been many studies analyzing the gut flora (of which there are trillions) to identify specific bacteria that may be linked to disease or disease prevention.  A study from 2015 identified a specific healthy gut bacteria called Akkermansia that was present in cancer patients who successfully responded to immunotherapy treatment.  In other words, the patients whose gut microbiomes contained this healthy gut bacteria responded favorably to immunotherapy treatment and were able to use their own immune systems to successfully fight and defeat the cancer.  This same study showed that the patients lacking this bacteria did not respond to the immunotherapy treatment.  So, how can we ensure we have this healthy bacteria in our gut?  This is where pomegranate juice makes its entrance!

The bottom line is pomegranate juice helps create a healthy gut microbiome that results in a more successful response to immunotherapy treatment – it creates an environment where Akkermansia likes to thrive.  Pomegranates are high in a bioactive group called ellagitannins, which encourage Akkermansia to grow.  Ellagitannins also metabolize into another bioactive called urolithin-A, which has antioxidant, anti-inflammatory, and anticancer properties.  And Akkermansia is thought to be responsible for this metabolization process.  So it’s a nice little circle of life! 

What is also awesome is that this pom-oh-so-wonderful effect is not limited to pomegranate juice!  Studies have shown the same result from cranberries, which are also high in ellagitannins (though apparently eating cranberries in their whole fresh or frozen form is best to get the benefits from the skin and seeds that are often lost in processing).  And other similar fruits like Concord grapes have the same effect.  And stone fruits (think peaches, apricots and mangoes) contain chlorogenic acid, another bioactive that promotes the growth of Akkermansia.

At the end of the day, the message seems clear, and much bigger than the specific benefits of pomegranate juice—what we eat and drink matters.  It matters not just to our physical shapes, but to the vitality of what many consider to be the true determinant of our short and long-term health—our gut microbiome. 

So, as Dr. Li (and most physicians) emphasize, adhere (the best you can) to the following three principles to maximize the health of your gut microbiome, and therefore the health of your body and mind:

1. Load up with dietary fiber from whole foods (so, not metamucil);
2. Eat less animal protein (bring on the tofu!); and
3. Eat more fresh, whole foods, and avoid processed foods (i.e. shop mostly in the perimeter of the grocery store!)

We can never be perfect, but we can try to be better, and this is a good place to start.

Ultimately, I’d like to think it was more than coincidence that led me to decide arbitrarily to buy pomegranate juice for the first time, and to learn a few days later of this amazing cancer-fighting link.  I’d like to think it was serendipitous.  So let’s raise a glass… of pomegranate juice!

Cheers!