Plant-Based Diets, Keto Diets, and Cancer

Here's some Lympho Bob trivia for you: 

The fourth most-read article on this blog is "Keto Diet and Lymphoma Treatment" from July 9, 2018.

(If you're curious what the most read article is, it's a kind of boring one from April 2021 in which I report on an oncologist's appointment and show you the Peace Garden at the cancer center that  go to. The top 3 all include photographs, which is something I don't usually do, but maybe I should start.)

I'm bringing this up because I want to report on an article from JAMA Oncology that looks at diet and how it affects cancer. It's not specifically about Follicular Lymphoma. It's not even reporting on original research. Instead, it looks back at a whole bunch of other studies that try to show if there is a relationship between diet and cancer. In particular, it looks at the research around two popular diets -- Keto diets and plant-based diets. I know that post about keto diets got a lot of hits, so it caught my eye. It actually came out about two months ago, but I've been waiting to write about it until I could read it carefully and think about it.

It's not surprising that this would be a popular topic. Based only on what I see in the online cancer discussion groups that I belong to, people are very interested in how the things that they eat might have an effect on their cancer -- especially whether or not their cancer can be cured through diet alone.

And we all know people who have had their lives legitimately changed by changing the food they eat. And there are plenty of people who profit off of those changes, making claims that certain diets, or even certain individual foods, will solve all kinds of problems. In my nearly 15 years of living with cancer, I've seen a whole bunch of people telling me to try certain foods, diets, and supplements -- or to avoid certain foods, diets, and supplements -- to cure my cancer. And they almost always include a statement like "They've done studies!" without telling me who "they" are or where I can find the particular studies. 

And when they do have an actual study, it's not a clinical trial, but instead something isolated in a test tube or petri dish, or tested on animals but not humans. 

The truth is, there is no solid scientific evidence that any food, or any diet, will cure your cancer after you've been diagnosed. That's one of the conclusions from the article. 

I certainly understand the desire to want to find an easy solution to a cancer diagnosis, especially a solution that allows us to do something. So much of being a cancer patient just seems to be sitting around waiting, even if we're not actually officially "watching and waiting." Taking control of at least one aspect of our lives and doing something to cure ourselves without drugs would be a wonderful thing. I remember reading Lance Armstrong's autobiography very soon after I was diagnosed. A few things are kind of burned into my memory. One is of him reading that a substance in broccoli might help control cancer, and his mom making him large heaping bowls of steamed broccoli every day. that sounded good to me. But it was ultimately chemotherapy that saved his life.

So if there are no studies that show that a keto diet or a plant-based diet will cure cancer, then is there any value in them?

Again, looking at the research that has been done, the answer is yes, there is some value.

Interestingly, that article from 2018 showed that a keto diet might help PI3K inhibitors be more effective. The keto diet cuts down on sugar, and that lack of sugar helps the inhibitor do its work. But that's very different from saying cutting down on sugar (a popular "cure" suggestion) will help. Cancer needs sugar to survive, so eliminating sugar will kill the cancer, right? But no. Unfortunately, our amazing bodies find ways to create glucose (sugar) all on their own. Our brains are very heavy users of sugar as well, and they manage to function just fine on a low-sugar diet. There are no easy answers, I'm afraid.

What the review of research found was that both keto and plant-based diets, while being almost complete opposites, both can result in some very good things that can help with cancer prevention --  weight loss, decreased inflammation, and decreased insulin levels.Again, that's a very different thing from saying it will cure cancer after it has been diagnosed.

And that's no small thing, even for those of us who have already been diagnosed with cancer. As we know, we are at a higher risk for developing secondary cancers. Following a diet that cuts that risk, and the risk of other health problems, is a very good thing. We'd all like to be around for a very long time. If we're looking for something to control, diet is a good way of doing that.

Interestingly, the review of research does compare the two diets and how well they may help to prevent cancer. The researchers come down on the side of a plant-based diet here: "Currently available data support plant-based diets as opposed to [keto diets] as part of a lifestyle associated with reduced cancer risk. In the postdiagnosis setting, there are currently no rigorously tested approaches that support the recommendation of any diet to treat cancer." Eat more fruits and vegetables and less meat and fat if your goal is to prevent cancer.

One of the problems with trying to figure out how diet affects cancer is that it's just a really hard thing to isolate. In other words, in a clinical trial, researchers can gather a group of people with a certain cancer and give them a particular treatment and test how well it worked. That's a lot harder to do with food. Most research is self-reported -- people tell the researchers what they have eaten. But because eating is something we do every day, it's very hard to convince a large group of people to be isolated for weeks or months to control what they eat. Even cancer patients have lives to live. People in clinical trials for, say, a monoclonal antibody go about their lives in between treatments. That's almost impossible to do with testing food as a treatment. As humans, we eat throughout much of the day, every day.

So one of the recommendations that the researchers make is that we do just that -- treat diet as a treatment to be tested rigorously, maybe by requiring patients to eat only food that is sent to them through a delivery service, for example.

And that's important to note. The researchers who wrote this article are not closing the door here, and saying food will never be a cancer treatment. Instead, they're saying that we need to do a better job of finding out whether or not it is. As different as they are, keto diets and plant-based diets do have benefits, and might have even more, if we can figure out how to measure them in a more rigorous way.

For now, the best advice is to continue to eat well, however you define that. A good diet won't cure us, but it can help prevent other health issues, can keep our bodies strong for when we need them to be (whether it's cancer-related or not), and maybe most importantly, can help us feel a little more in control than cancer makes us feel.

Also, I'm including a photo, because apparently that gets more readers.

Stay well.