When You Have Cancer, What You Eat Matters

 

What should a person with cancer eat? Some oncologists say, “Eat whatever you want. Doesn't really matter.” Nothing can be further from the truth. If the cancer comes back, almost certainly it's because the stem cells of the cancer regenerated the cancer. The good news is that there are foods that can kill these cancerous stem cells.

Every individual who is diagnosed with cancer wonders what did they do wrong that actually led them to develop cancer. It could be genetics, it could be environmental exposures, it could also be a lifetime of less than an optimal diet. A lot of different factors contribute to the mutations that happen in our body that result in the development of cancer.

It is true that some foods contribute to causing cancer, although it's very rare that it's a single food that does it. So what foods should you eat and what foods should you avoid that might be causing cancer?

There is a laundry list of foods that can increase the risk of developing cancer, and these include some disturbingly common foods like processed meat. Processed meat is actually classified as a class one carcinogen by the World Health Organization. Examples include sausages, hot dogs, deli meats, salami, ham, bacon, corn beef - all can increase your risk of developing cancer. If you eat them over time or eat too much of them... you have increased exposure to processed meat... it increases your risk for digestive cancers, including colon cancer.

Eating grilled food is not a good practice. Grilling any meat coats the meat with carcinogens, one being polycyclic aromatic hydrocarbons. These are carcinogens that form when the oils from the fat drips down onto the flame and smokes. That is what gives you that nice grilled meat taste. It is the rising smoke that contains the carcinogens that get deposited on the meat.

High grilling temperature also converts the amino acids that are found in the meat. High heat converts the proteins into another toxic carcinogen called hexacyclic amines. Both of these carcinogens show up as the black char that's left on the grates of your grill. So the next time you're grilling food make sure you really clean those grates from the last time you cooked because carcinogens remain on that grilled surface. When you put a fresh piece of meat or vegetables or fish on the grill, you're going to transfer that right onto your next meal. And don't stand over the grill too long. The smoke is going onto your face and into your lungs.

One thing you can do is marinate your steak using the juice from tropical fruits, which contain antioxidants. Or dust it with some cumin or turmeric. These antioxidants will help to neutralize harmful carcinogens that form. Of course, the best thing you can do is not eat any grilled food, or at least not too often.

So what foods should you eat if you've been diagnosed with cancer?

Unfortunately, most oncologists don't give their patients a scientifically useful answer to this question. In fact, some oncologists will say, "Eat whatever you want. Doesn't really matter. Just don't lose too much weight."

Nothing could be further from the truth, however. Food matters.

Your body is hardwired with health defense systems that help us naturally fight cancer. So when you have cancer, your health defenses have failed and now you've got to shore them back up and activate them so they can help the treatments fight cancer.

This isn't food versus medicine. It's food working with medicine. You want to eat foods to activate those health defenses. There are five health defenses. All of them help us fight cancer naturally and all of them can be activated by our food. So what are the five?

Angiogenesis - that's how our body grows blood vessels and is one of the defenses against cancers that cut off the blood supply feeding cancers.

The second health defense is our regeneration system. If you're getting cancer treatment like chemotherapy, targeted therapy, or having surgery, your body has to heal after the cancer's been killed off. And to heal properly, it regenerates from the inside. You can stimulate the second health defense with food.

Third is our gut microbiome. There should be 39 trillion healthy bacteria in our gut, mostly in our colon. Those healthy bacteria help to lower inflammation in your body. They help to boost immunity so you can actually fight off the cancer. All of this powerfully augments treatment when activated by food, no matter what cancer treatment that your doctor gives you. You want to eat the foods that will activate your defense system.

The next health defense against cancer is our own DNA repair and protection system. Cancer is basically a mutation of our own DNA... a mutated cell leads to more mutant cells. They pile up and now you've got a cancer, a tumor. So, a healthy DNA protection system defends against the mutant DNA by getting rid of it or fixing it so it doesn't actually become a full-blown cancer. You want your DNA protection system fixed... and foods can activate that too.

And finally, there is our immune system, which does a couple of interesting things. It eliminates inflammation when it needs to. Cancer is a highly inflammatory disease. When cancer meets inflammation, it's like pouring gasoline onto the embers of a fire. That's why you want to eat anti-inflammatory foods to lower inflammation.

The other thing you want to do with foods is to boost your immunity. Now, this is especially true if you're getting chemotherapy because it lowers your immune defenses. So you've got to counter that by boosting your immune system.

So... the five health defenses are angiogenesis, regeneration, gut health, DNA protection, and immunity/inflammation. And foods can powerfully influence all of these systems to help your body contribute to beating cancer. Pretty simple. Each of these systems can help tip the odds in your favor while you're getting treatment.

So, why doesn't your oncologist talk about this? Most doctors, including oncologists, haven't been trained to look at these health defenses. Doctors are trained to look at cancer as a bad set of cells that you have to kill using drugs. And food is not part of their traditionally taught tool box.

A study by oncologists of 826 people with stage three colon cancer undergoing regular treatment found that those people who ate two servings of tree nuts, that's two fistfuls of tree nuts every week, had a 57% improvement in survival. They got regular medical treatment, but they ate nuts and their survival improved.

Now, why would that be? Well, nuts have healthy fats that improve the immune system. Nuts are packed with dietary fiber that helps your gut microbiome, which lowers inflammation, which tips the odds in your favor of actually being able to beat the cancer. Not that surprising... but it just shows you how powerful food can be.

Another study of 249 people with various types of cancers who were all receiving the latest type of cancer treatment called immunotherapy – not chemo - where you use your own immune system to combat cancer, researchers in France found that those cancer patients who did not respond to immunotherapy were lacking a healthy gut bacteria which normally lowers inflammation and boosts your immune system. The one critical bacteria in our gut is called acromancia mucinaphil... which you grow by eating food.

The only way to naturally grow acromancia, which was found to be necessary if you want to respond to immunotherapy, meaning helping your own immune system fight off cancer, is by eating foods that grow acromancia, like pomegranates and cranberries and mangoes, and other foods like chili peppers and Chinese black vinegar. They all help to grow this useful, healthy, important, immune boosting, anti-inflammatory, metabolism pruning bacteria called acromancia mucinophila.

So, how do you know if you have acromancia in your gut? You can measure it with a gut microbiome test which is a test that comes in the mail. It's got a little tube that you're going to mail back to the lab and it's got a little swab which you take a sample of your poop with, put it into the vial, screw it shut, pop it in the mail. Voila! In a couple weeks you get an email with your results so you can see for yourself if you have that acromancia. Ask your doctor.

The other thing you can do with a gut microbiome test is to see if you have harmful bacteria in your gut that might be causing inflammation. You want to get rid of those and grow good ones like acromancia.

So you have been diagnosed with cancer. What should you eat?

First, not everyone is the same. Every cancer patient is going to be unique. Maybe there's a cancer patient who's had diabetes. They're going to need a different food approach than somebody with cancer who has celiac disease or an autoimmune disease. So, you have to really tailor it to yourself, but there are some general guidelines when it comes to selecting food as medicine in somebody who has cancer. So, what are some general principles?

Number one, we know that cancers grow blood vessels to feed themselves. So, it's important to know that you can eat foods that starve cancer by cutting off their blood supply. These are called anti-angiogenic foods. Angiogenesis is actually the process that the body uses to grow blood vessels and it will naturally grow good blood vessels to healthy organs. Whenever there's cancer, it will cut off the blood supply normally. However, if a cancer has already taken off and grown, somehow the blood vessels have been able to sneak around the defense and growing b its own blood vessels.

Research has shown that the moment blood vessels touch a cancer, that tumor can grow 16,000 times in just two weeks. So, this is a powerful trigger for cancer growth.

So, what do you want to eat? Some anti-angiogenic foods that cut off the blood supply to tumors are soy, tomatoes, green tea, coffee, oily fish with omega-3s or omega-3 supplements, all berries like raspberries, blueberries, strawberries, blackberries, and red grapes. Add to this list brassica vegetables like broccoli, cauliflower, kale, and bok choy which have naturally occurring anti-angiogenic cancer-starving substances. When you eat them, you're helping your body choke off that cancer tipping the odds in your favor if you are already receiving treatment.

The second thing involves remembering that you have a regenerative system where your body can regenerate good cells and get rid of bad cells. There is something called cancer stem cells and there are foods that can actually kill those cancer stem cells. Stem cells are a very, very dangerous cell because these are like baby cancer cells that live inside the cancer and help the cancer come back after it has been killed. You know that person that had cancer, had it successfully treated and they're then just watching and waiting. The doctor tells them let's just wait and see what happens. Big Mistake. What you should be doing is eating good foods and changing your lifestyle to put you in a cancer fighting mode.

When the cancer comes back, almost certainly it's because the stem cells of the cancer regenerated the cancer. Healthy stem cells can regenerate healthy organs, but cancer stem cells can also regenerate the cancer. The good news is that there are foods that can kill cancerous stem cells – like purple potatoes. The anthocyanins that make purple potatoes purple kill colon cancer stem cells. Green tea also kills cancer stem cells. So does coffee. Tree nuts like walnuts can also be helpful.

We know that a strong immune system can wipe out cancer cells too. So what are some immune boosting foods that you can eat to beat cancer? How about some broccoli sprouts? These are the three- to four-day-old little baby broccoli that powerfully stimulate your immune system. Blueberries also will boost your immune defenses so that you're more able to beat cancer. Chili peppers do that as well.

What about gut health? Remember that a healthy gut microbiome lowers inflammation. So, how do you actually get that to happen? If you eat pre-biotic foods, foods like polyphenols feed that your gut bacteria. Another pre-biotic is dietary fiber. When you're feeding the gut bacteria with polyphenols and dietary fiber the gut bacteria produce something called short-chain fatty acids which get in your blood and lower inflammation.

Remember inflammation is like pouring gasoline onto a fire. When you get the gut bacteria happy, they provide anti-inflammatory substances... short-chain fatty acids released into the bloodstream that calm down the fire.

So what are some of the high-fiber pre-biotic type of foods? Lentils, chickpeas, beans of any sort - white beans, black beans, etc. - mushrooms, even the lowly white button mushroom is good, avocado, and raspberries, which even though they're small, light, and hollow, pound-for-pound they're one of the best fruits with the most dietary fiber... and they taste great.

The other way you can actually get your gut healthier is to eat pro-biotic foods like fermented kimchi and sauerkraut. The bacteria in the full-fat yogurt will actually help to lower your blood cholesterol too.

from YouTube @DrWilliamLi on April 5, 2025

On YouTube, also watch these two videos by Dr. Sten Ekberg on what foods cancer patients should and should not eat: