Cancer is the leading cause, after heart disease, of death in the United States. We all know someone who has cancer.
In this Episode
- CJ Anderson
- Sarah Winslow, MD
By eating in a way that promotes a healthy immune system, exercising regularly, not smoking and taking care of your mental health, you can help promote an anticancer environment in your body. Some might call this naïve, but it is real and empowering.
Let’s talk about anticancer eating.
What exactly is cancer?
To understand why what we eat matters, it helps to understand what cancer is. This also helps us understand why there is no “cure” for cancer.
Cancer is abnormal unregulated growth in the body. The cells in our body are constantly replicating, and mistakes are made. Cancer cells are made accidentally every day in one’s body. Our bodies have mechanisms in place that attack abnormal cells and keep these mistakes from causing cancer. These mechanisms are carried out by our immune system.
What we eat affects our cell health and immune system health. When we eat healthy foods that decrease inflammation and maintain a healthy immune system, our body is best equipped to fight and even prevent the start of cancer.
Our cancer-fighting cells flow throughout the body looking for problems. They recognize early cancer or cancer-causing mutations and destroy them.
These cells work best when our body is fed well and protected from toxins and inflammation. In an environment of inflammation, the body is in a state of repair. In this environment, mistakes are more likely to be made in this process, which can lead to cancer.
In a state of inflammation, oxidants are formed. These compounds can mess up cell signals at the molecular level and cause mutations.
By decreasing inflammation and eating an antioxidant-rich diet, the immune system and the body is better able to regulate itself. They have less potential for cancer-causing mistakes and are best able to fix ones that are made.
There are lots of well-known links between cancer and inflammation such as inflammatory bowel disease and colon cancer, HPV and cervical cancer, or even chronic reflux and esophageal cancer. In a normal immune response the body’s cells release signals that promote regrowth. This response stops when your body is healed. But in a chronically inflamed process this can keep happening unchecked and promote cancer growth.
Eating an anticancer or anti-inflammatory diet
- Eat low-sugar and low-glycemic index foods
- Consume less meat and fewer animal foods
- Add lots of plant-based foods
- Include more of the most potent anti-inflammatory foods
What does sugar and glycemic index have to do with cancer?
Cancer feeds on sugar. All those busy cells thrive in sugary environments since they are working extra hard and need the sugar/carbohydrates to fuel them. By eating a low sugar diet, or, to be really aggressive, a low-carb diet, cancer cells have less to run on.
High-glycemic index foods are foods that spike your blood sugar quickly. These can be sugary foods like candy or foods with a lot of carbohydrates and little fiber, fat or protein. Examples of high-glycemic index foods include white bread, juice, white rice and tortillas.
When you eat high-glycemic index foods, insulin and insulin-like growth factor (IGF) are released. These stimulate cell growth and are associated with higher cancer risk. This mechanism could be one reason the commonly used diabetes medication Metformin is associated with lower cancer rates.
So…just eat meat?
Meat isn’t the answer either. Eating animal products can promote inflammation. Meat and other animal products contain omega-6 fats that promote inflammation. While they contain omega-3, which reduces inflammation, these healthy fats can also be consumed by plant sources like walnuts and flax seed.
Meat that is raised nonorganically or fed corn and soy tends to be higher in the pro-inflammatory omega-6. Animals fed grass have higher anti-inflammatory omega-3 content.
These animals also consume pesticides from their feed, which means their meat may contain metabolites of toxins that need to be studied more to see if they are associated with cancer.
Animals also contain hormones just like us and sometimes even get extra hormones (to grow bigger or to continue making milk). This could play a role in hormone-sensitive cancers like some breast cancers and other cancers.
Red meat and processed meats are especially bad. They contain nitrates and heterocyclic amines, which are associated with colorectal, pancreatic and prostate cancer. The World Health Organization has classified processed meats like hot dogs, sausages and bacon as probable carcinogens, or cancer-causing substances. More information on this can be found on the American Cancer Society website.
Eating a plant-based vegan or vegetarian diet will help you avoid the inflammatory and hormone effects that meat and dairy can have. For ideas on eating more plant-based, see this quick start guide.
If you still want some meat, choose grass-fed, organically raised meat in moderation, which is going to be healthier than eating conventionally raised meat. It is more expensive, but if you are eating meat less frequently and saving that money, you can splurge on organic, grass-fed meat.
Foods with extra cancer fighting power
- Green tea is rich in polyphenols, which reduce some irregular growth processes needed for cancer growth. Coffee is also an antioxidant, but green tea is even more potent. If you want to step up your morning routine, switch from coffee to green tea.
- Turmeric is a popular anti-inflammatory and probably best used by the body when consumed with foods. It works well in curries and vegetables and soups.
- Flax is also high in healthy omega-3s and is linked to lower cancer rates. It is on Dr. Greger’s daily dozen of foods to include daily to promote health. You can track these foods using Dr. Greger’s app (available on iTunes and Google Play).
- Dark chocolate is a favorite antioxidant to consume. Choose dark chocolate—more than 70 percent cocoa—and eat it in moderation to avoid too much sugar
- Vitamin D is also associated with lower risk of cancer. Unfortunately, people in Oregon and Washington tend to be low in vitamin D. Most adults, especially in this part of the country, probably would benefit from taking a vitamin D supplement of 600–1000 units daily. However, people’s vitamin D levels vary a lot, so it’s a good idea to discuss your levels with your doctor and possibly have your levels checked. Anecdotally, many newly diagnosed cancer patients have lower vitamin D levels. Some local oncologists recommend 2000 units a day for some patients with cancer.
- All vegetables and fruit tend to be anti-inflammatory. Each food has its own unique properties and reasons for being healthy. The bright colors of the food often does reflect the potent properties of the food so eating a variety of colors is helpful. For example, by eating a salad that contains red tomatoes, orange and yellow bell peppers, leafy greens, blueberries and purple grapes, you can really eat the rainbow.
The list could go on, but the point is simple: If you eat a diet with lots of fruits and vegetables and less meat and sugary processed foods you will be eating in an anticancer way. The more variety you get, the more anticancer and anti-inflammatory properties benefits you get.
It probably is best to eat organic if you can, but that shouldn’t scare you away from eating vegetables if you can’t afford to eat organic. If you can only afford to buy some foods organic, reference, this list of the Dirty Dozen of produce that contain higher levels of pesticides.
So the bottom line is this: Eat lots of vegetables and fruit. As Dr. Michael Greger, author of How Not to Die, says, “The more you eat the healthier you are.”
What about getting more studies on this?
Some of these guidelines don’t have a lot of evidence behind them because there haven’t been many studies of people randomized to eat more vegetables versus eating the standard American diet. The vegetable industry doesn’t have the money to fund these studies.
However, there is enough evidence to suggest these kinds of dietary changes can make a difference. Are you willing to gamble with your own health while waiting for more studies to be done to show that eating less sugar, less meat and more vegetables could save your life?
Each time you eat, you have the choice to promote cancer or promote health. You get to choose. If you need a mantra to remind you how to eat, try Michael Pollan’s famous quote that sums up so much: “Eat food. Not too much. Mostly plants.”
- How not to die
- Anticancer: A New Way of Life
- Dr. Greger’s Daily Dozen App
- What do you know about Vitamin D? (Podcast)
Author: Sarah Winslow, MD
I practice primary care medicine with Adventist Health in the Fishers Landing clinic in Vancouver, WA. I’m passionate about helping patients make positive lifestyle changes to improve their health.