Your cycle Lifestyle Diet and nutrition

Flo Fact-Checking Standards

Every piece of content at Flo Health adheres to the highest editorial standards for language, style, and medical accuracy. To learn what we do to deliver the best health and lifestyle insights to you, check out our content review principles.

Food and Cancer: Is There a Link? An Eye-Opening Interview with Lauren Talbert

There’s been a lot of research conducted to find a correlation between certain foods and cancer. We interviewed Dr. Lauren Talbert, a clinical dietitian certified in oncology nutrition, to get some clarity on the subject and find out if there’s a link between certain foods and cancer.

Interview has been edited for clarity.

What foods influence the risk of cancer?

According to Dr. Talbert, certain foods and diets can indeed influence cancer, and there is also a link between obesity and cancer.

The American Institute for Cancer Research has said that about 40 percent of cancer cases in the US, which could be as high as 700,000 each year, could be prevented if their recommendations are followed with regards to diet, weight, and exercise.

“There are particularly certain cancers that have actually been linked to obesity. These would be esophageal, pancreatic, colorectal, endometrial, kidney, gallbladder, ovarian, liver, advanced prostate, stomach, mouth, and postpartum breast cancer. So basically, the cancers that I just listed — there is research that supports that obesity has an increased effect on the risk of developing them,” Dr. Talbert explains.

What are foods that can prevent cancer?

According to Dr. Talbert, the phytochemicals in plants, which give them their color, odor, and flavor, have been studied for their effect on cancer cells. Dr. Talbert gives an example:

“A carotenoid, such as lycopene, has been studied, and lycopene can be found in red, orange, and green fruits and vegetables — in things like broccoli, carrots, tomatoes, and leafy greens. And there's research to show that these phytonutrients can inhibit cancer cell growth, work as antioxidants, and also improve the body's immune response.

“Other plant-based foods — the way that I sort of explain it to people is if things have a stronger flavor or a bright color, generally, they have more antioxidants. So green, leafy vegetables, cruciferous vegetables, like cauliflower, Brussels sprouts, or broccoli, bright-colored orange vegetables, like pumpkin or winter squash — these all have particular phytochemicals that have been shown to fight cancer.”

Talbert - food and cancer

And essentially, the more plant-based foods you eat, the more phytochemicals you consume.

“And with respect to other foods, cancer is a disease that feeds in an inflamed state. So eating more anti-inflammatory foods, which includes the above-mentioned foods, but also things like fatty fish, can also help fight inflammation and possibly help with lowering cancer risk,” Dr. Talbert says.

Can a ketogenic diet help treat cancer?

According to Dr. Talbert, the ketogenic diet is not well-defined. “It varies from as low as 20 to 50 grams of carbohydrates a day. And just to give you an idea, the typical amount would be about 130 to maybe 150 grams that somebody consumes in a day.”

The ketogenic diet is low in carbohydrates and higher in fat and protein. The thinking behind it is that if you starve your body of carbohydrates, it will use your fat stores for energy.

The only solid research on the ketogenic diet and cancer suggests that it might be helpful for people with specific types of brain tumors. The brain functions on glucose, so the thinking is if you restrict glucose from your diet, it might help with specific types of brain cancer.

“But from what I've read, it's low in fiber, and it can affect our digestion and constipation. It's obviously very extreme and hard to follow. But the benefit of it for these patients that are so ill may not really outweigh the problems following it. It may prolong somebody's life, but you're pretty strict with this specific diet. In general, unless somebody has a particular type of brain cancer, it's not something that I would recommend,” Dr. Talbert says.

What impact does soy have on cancer?

As a certified oncology nutritionist, Dr. Talbert has worked particularly with women with cancer, so she has spoken a lot about soy.

Soy contains nutrients called phytoestrogens, which are plant estrogens. They look like estrogen under a microscope. Years ago, researchers predisposed rodents to breast cancer, and those that were given more soy isoflavones developed the cancer at a higher rate. Many people have extrapolated from that research that consuming soy causes cancer.

But since then, there have been studies that have shown that people who eat more soy have a lower risk of developing cancer and that cancer survivors, particularly breast cancer survivors, who eat more soy have lower risk of cancer recurrence.

Dr. Talbert says, “The message that I deliver is that the phytoestrogens in these soy foods do not act like human estrogen. They're completely different. And since these rodent studies, we've learned that rodents metabolize soy very differently than humans metabolize soy. So I think that people are confused about soy, possibly scared. I meet a lot of people who don't eat it.”

Soy is high in fiber, protein, potassium, magnesium, copper, manganese, and calcium, so it's a beneficial food to consume and a great way to get nutrients as part of a plant-based diet.

Can sugar and refined carbs impact the risk of cancer?

A common question that Dr. Talbert gets is if sugar feeds cancer. The truth is that sugar does feed cancer — it feeds all cells, cancerous or not.

If you eat excessive amounts of processed sugar, that can lead to obesity, and that has been shown to link to cancer.

“However, if you do eat excessive amounts of processed sugar, that can lead to obesity, and like I said before, that has been shown to link to cancer. When patients are asking me about sugar and cancer, I focus on consuming natural sugars that occur in fruits or even dairy products versus added sugars that may be added to cereals, desserts, or sugary drinks. It's not that sugar feeds cancer, but it's not a good idea to be eating a lot of added or processed sugars,” Dr. Talbert says.

What is the impact of red meat or processed meats on the risk of cancer?

Dr. Talbert says there's been a lot of research that shows that those who eat more red meat have an increased risk of colorectal cancer. The recommendation from the American Institute of Cancer Research is to consume 18 ounces or less of red meat per week.

There are three reasons why they think that red meat could increase cancer risk:

  • It contains heme iron, which may damage the lining of the colon.
  • It stimulates the production of n-nitroso compounds, which may be carcinogenic too.
  • It’s usually cooked at very high temperatures, which can produce two different types of carcinogens — heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs). 

Then there's processed red meat, which has been found to be even more harmful to your health. These are meats that have been preserved by smoking, curing, salting, or adding chemicals — so things like sausages, hot dogs, or deli meat.

“The research for processed meat is even more significant when it comes to cancer risk. I generally tell patients to try to avoid processed meat as much as they can. And whenever they are eating red meat, shift as much as they can towards a plant-based diet. Instead of having a beef burger for dinner, maybe once in a while use portobello mushrooms instead of beef,” Dr. Talbert suggests.

How does overcooked and grilled food impact the risk of cancer?

Dr. Talbert says that chemicals like HCAs (heterocyclic amines) are generally consumed when you cook at a high temperature. If you marinate something before cooking it, you can lower the amount of HCAs that are formed during the cooking process.

“The PAHs (polycyclic aromatic hydrocarbons) are deposited on the meat when the meat is smoked. If you put a steak on a grill and it's hot so it gets that char, the longer that it's on the grill, the longer that it's exposed to these PAHs. And that's basically the smoke from the grill coming up and creating this kind of charred, smoky look. So basically, if you can pre-cook your meat, say, you put it in the oven for a few minutes then you put it on the grill, you can lower the risk of getting so many PAHs,” she explains.

What’s the impact of vitamin supplements on the risk of cancer?

According to Dr. Talbert, you only need to take a vitamin to correct a deficiency. “Here in the US, we have a lot of vitamin D deficiency and vitamin B12 deficiencies as people age,” she says.

Dr. Talbert says that there's no research that shows that taking extra supplements in the form of a vitamin can lower your risk of cancer. 

“Years ago there was a study called the SELECT trial. They were looking at vitamin E and selenium with its role to reduce risk of prostate cancer in men. And what they found was pretty interesting. It was actually that those substances didn't decrease risk; they actually increase risk. Then there was also research looking at beta-carotene supplements with the same finding — that they actually increase risk of cancer,” Dr. Talbert says.

There is no research that shows that taking extra vitamin D is going to help prevent any cancer. But there is research showing that adequate levels of vitamin D can support your health with regards to cancer.

So it's best to try to get your vitamins from your diet. But if you can't — for example, if you're a vegan and you're not getting enough B12 — taking a supplement to correct the deficiency would be recommended. 

“But there's a lot of companies out there that are promoting their specific vitamins to fight cancer or prevent cancer. And to date, we don't know enough about that. You know, a big one would be vitamin D. You're basically taking vitamin D to correct its deficiency. There is no research that shows that taking extra vitamin D is going to help prevent any cancer. But there is research showing that adequate levels of vitamin D can support your health with regards to cancer,” Dr. Talbert says.

Choose your Flo