Can certain foods cause or prevent cancer?
The short answer is no, there is no food that will stop or directly cause cancer. However, there is evidence that some foods may increase risk of getting cancer and some reduce risk of developing the disease. In this blog, we discuss dietary and lifestyle changes you can make to better your health, decrease risk of developing cancer while also protecting against other conditions such as cardiovascular disease and type 2 diabetes. The American Association for Cancer Research stated that between 30%-40% of cancers can be prevented by adequate nutritional food, exercise, and maintaining a healthy weight.
**Disclaimer these articles are meant for informational purposes please check with your provider before making any changes to your diet**
What lifestyle changes can be made to decrease chances of developing cancer?
Stop consumption of fast food: Eating fast food is associated with weight gain and obesity, both risk factors for developing cancer [1]. It also can lead to other chronic conditions like cardiovascular disease and type 2 diabetes. Eating fast and processed foods may contribute more to premature death than cigarettes nowadays.
Limit intake of red and processed meat: Research shows that red and processed meat has a significant effect on cancer. A study from Harvard found that the risk of colorectal cancer increases by about 16% when you consume 50g/day of processed meat, and by 12% for every 100g/day of red meat.[2] Make sure you do not completely eliminate meat from your diet because it contains a lot of necessary nutrients. Instead of eating red and processed meat, a better choice would be seafood or poultry.
Maintain a healthy weight: In the past few decades, obesity rates in America have significantly increased. In 2003, about 33% of adults were classified as overweight and obese in America, and in 2023 that rate has increased to about 42% [3]. If this trend continues, researchers predict that more than half of the US will be obese by 2030.
We know that obesity is an important risk factor for developing many types of cancer. Higher BMI is linked to an increased risk for cancer The CDC stated that there are 13 cancers associated with being overweight and obese.[4] Some examples include kidney, ovarian, liver, pancreatic, thyroid, and breast cancer.
*A healthy weight is classified by a BMI range between 18.5-24.9 however, individuals should not solely rely on BMI to determine their health.
Eat a healthy diet: It sounds so simple, but a healthy diet is the most effective method for preventing not just cancer, but a whole multitude of health complications. Eating healthy potentially lowers cancer risk by 10-20%. [5] The Office of Disease Prevention and Health Promotion defines eating healthy as following a healthy eating pattern that includes a wide variety of nutritious foods and beverages while making sure you are getting the right number of calories everyday.
Limit alcohol consumption: Since alcoholic beverages are linked with several types of cancer, eliminating or reducing consumption is a small but effective change you can make to your diet. There has not been any studies done to see if one alcohol presents higher risk for cancer than others, the CDC said that all alcoholic beverages, liquor, beer and wine are linked with cancer. The less you drink, the lower your cancer risk becomes so it’s important to cut down or completely eliminate alcohol usage.
Eat a wide variety of whole grains, fruits, and vegetables: Dietary fiber and whole grains are great ways to lower chances of developing colorectal cancer. Dietary fiber can also prevent weight gain and obesity, a risk factor for cancer. A wide variety of fruits and vegetables reduces risk of chronic conditions including cancer, and helps maintain a healthy weight.
The American Heart Association listed the following recommended daily amounts for these food groups [6]:
Six servings of grains: One serving is equal to a slice of bread, 3 cups of popped popcorn, or ½ cup of cooked rice or pasta. Try to find whole grain products instead of refined grains for the healthier choice.
Two and a half servings of vegetables: One serving is equal to 1 cup of cut vegetables, 2 cups of raw leafy greens, or 1 cup of 100% vegetable juice
Two servings of fruit: 1 cup of cut fruit, ½ cup of dried fruit, or 1 cup of 100% fruit juice
What foods can increase risk of cancer?
There is no food that will directly cause cancer, however some foods can increase risk of developing the disease. This post will focus on foods and beverages that have been linked to increased risk of cancer, and some healthier substitutions to incorporate into your diet.
Red meat
Research has revealed that red meat is linked to a few different types of cancer such as colorectal and bowel cancer. Some of the most common red meats include beef, pork, and lamb. The International Agency for Research on Cancer (IARC) classified red meat as a probable carcinogenic in 2015.[7] One study showed that for every 120g/day (840g/week if consumed everyday) of red meat, there is a 24% increase in cancer risk.[8] That same study theorized that if red meat consumption is decreased by about 70g per week, so about 770g per week or 110g/day the risk of colorectal cancer would also decrease by 7-24%, with that being said the study did not recommend actually consuming that much red meat on a weekly basis.
The American Institute for Cancer Research and the World Cancer Research Fund both recommend consuming no more than 3 portions of red meat per week or about 340-510 grams (12-18 ounces) when cooked [9]. Instead of consuming red meat on a regular basis, a better choice would be seafood or poultry.
To reduce the risk of these cancers, make sure you are getting enough fiber. The American Institute for Cancer Research recommends consuming at least 30g of dietary fiber everyday, but for each 10g increase it lowers risk of colorectal cancer by 7% [10] (discussed more in a later article)
Processed meat
The IARC declared processed meat as carcinogenic to humans in 2015 [11], and the World Health Organization classified it as a “Group 1 carcinogen” which means that there is enough evidence to say it can cause cancer in humans. Processed meats are risk factors for many types of cancers, but the two most prominent ones are colorectal and stomach cancer.
Some examples of processed meats include bacon, ham, sausage, hot dogs, lunch meats, and salami. While there is not a recommended amount of processed meat to eat, the National Health Service (NHS) says to try and consume less than 70 grams per day.
Try to substitute processed meats with a healthier alternative like seafood, tofu, or beans. We usually consume processed meats because they are the most convenient and “on the go”, but a sliced chicken breast or thigh and ground turkey burgers are quick meals to prepare that could last a couple of days.
A lot of typical pizza toppings are processed meats, switching these out with some healthier choices like pineapple (although this isn’t for everybody!) mushrooms that have been prepared in a variety of ways, peppers, and any other vegetable you’d like is an easy and effective way to cut down on processed meats.
Diets high in salt
Diets high in salt are associated with a few different cancers including stomach, oral, and nasopharyngeal cancer. High sodium diets often include fish, meat, or vegetables that have been pickled or preserved in salt.
The World Cancer Research Fund proposed that salt itself can damage the stomach lining and cause lesions [12]. Too much salt increases risk for an infection called Helicobacter pylori (H. pylori) which is known to be a cause of stomach cancer [13]. These claims are consistent with a systematic review conducted on the effect of salt intake and risk of gastric cancer. The researchers also discussed that the amount of nitrate in salty foods may be related to its carcinogenic effects [14]. It’s important to note that not all nitrates are bad. The naturally occuring nitrates found in vegetables are okay and can actually benefit heart health. Be sure to look out for nitrates and nitrites on food labels, some less salty foods still contain nitrates.
Both the FDA and the American Heart Association recommend adults (14+) to consume no more than 2,300mg of sodium per day [15] or about 1 teaspoon of table salt [16]. The AHA is starting to move towards lowering the daily recommended amount to about 1,500mg. While it can be hard to measure salt intake because it is hidden in so many foods, you can still measure the amount of salt you are adding to your own meals. Sea salt is less processed and contains more nutrients than regular iodized salt, so it may be a better choice. They both have the same sodium value [17] The Mayo Clinic stated that both the salts contain 40% sodium content when measured by weight [18].
To combat risk of these cancers make sure you are eating more fruits, vegetables, and fiber specifically high in vitamin C and folate.
Alcohol
The World Health Organization stated in 2020 that 4% of cancers diagnosed are related to alcohol consumption. In the United States alone, there are around 75,000 cancer cases each year linked to alcohol [19].
Alcohol contains ethanol which is the carcinogen that contributes to many types of cancer. For example, ethanol can increase estrogen in the body, which is one of the risk factors for developing breast cancer [20]. High amounts of acetaldehyde, from the breakdown of ethanol in the body, is linked to head, neck, liver, and esophageal cancer. [21] Eliminating or cutting down alcohol consumption is the only way to get rid of this risk factor.
Sugary drinks and artificial sweeteners
The sugary drink category encompasses sodas, energy drinks, sweetened waters (like Kool-aid), coffee and tea products with added sugars, and some milk products such as chocolate milk. Some products that are marketed as “healthier” like diet sodas may not contain sugar, but are often sweetened with artificial sweeteners which still can cause obesity and type 2 diabetes, indirectly increasing cancer risk. One study published found significant evidence linking sugary drinks to cancer. They found for every 100 ml of sugary beverage consumed per day increased overall cancer risk by 18%.[22] The study was done over a 5 year period but the researchers explained that this outcome would occur over a longer period of time with chronic consumption of these beverages. For reference, a regular 12 oz can of soda contains about 355 ml, the Big Gulp from 7/11 is about 950 mls (32oz), and a grande size drink from Starbucks is about 470mls (16oz).
These artificial sweeteners are marketed as healthy because they contain higher levels of sweetness but lower calories compared to regular sugar, therefore people consume less because of the extra sweet flavor.
People associate artificial sweeteners as a healthy alternative so they may reward themselves for the lost calories with some sort of treat, making the use of the artificial sweetener virtually ineffective and increasing weight gain.[23] An example of this would be saying since you are drinking a diet or zero sugar soda, it is okay to eat more cookies.
Dr. David Ludwig, an obesity and weight loss specialist at Boston Children’s Hospital, explained that people can build up a tolerance to intense sweeteners, which may alter the taste of less sweet options like fruits or vegetables and make them unpalatable.[24] This means that you will be more likely to choose the less healthy and less nutrient-dense option which you will probably have to consume more of to get full.
Eliminating sugary drinks, whether that be with regular sugar or artificial sweeteners will improve your chances of a healthier lifestyle and decrease your cancer risk. If you are not a fan of just drinking plain water there are still ways to avoid the sugary drinks. Try drinking sparkling water so you still get the fizz of a soda. You can also add slices of fruit to make flavored water, they even make special cups and pitchers for this where you can add the fruit to a small compartment.
What foods decrease risk of developing cancer?
Let’s look at some of the foods/food groups that can decrease risk of developing cancer and contribute to an overall healthier lifestyle as well as prevent risk of other diseases.
Whole Grains/Fiber
The American Institute for Cancer Research stated that consuming at least 30 grams of fiber everyday will reduce chances of developing colorectal cancer, and eating six ounces of whole grains everyday decreases colorectal cancer risk by 21%. This is backed up by another study done that found eating 10g more fiber per day lowered risk of colorectal cancer by about 10% [25]
Eating whole grains also helps cardiovascular health and reduces chances of type 2 diabetes [26].
There are a lot of simple ways to incorporate more whole grains into your diet:
Switch to brown rice instead of white: Brown rice contains natural vitamins and minerals that your body needs and has much more fiber than white rice. Make sure you are taking the proper steps to remove some of the arsenic in the rice, rinsing it before you cook it and using plenty of water to cook it.
Make your sandwich on whole grain bread instead of white bread: Like the brown rice, whole grain bread is much more nutrient dense than the white bread and has a lower glycemic index.
Choose the whole grain pasta option: Not only are you getting more fiber in your diet, whole grain pasta contains less calories and carbs contributing to an overall healthier diet.
Vegetables with Allium
Researchers are looking at possible associations between diets high in allium and how it reduces risk of cancer, more specifically gastric cancers. The exact mechanism of how allium affects the body is still not fully understood, but scientists have come up with a few hypotheses. Allium-containing vegetables contain organic sulfur compounds that activate some enzymes that will detoxify carcinogens[27]. Allium may also disrupt the cell division of gastric cancer cells, reducing the risk for the cancer to spread [28] A study done to examine this found that garlic supplementation greatly reduced gastric cancer development and reduced risk of gastric cancer death [29].
Vegetables with allium include:
Garlic
Onions (all types!)
Shallots
Chives
Leeks
To get the full benefit from allium vegetables make sure they are chopped and minced, allow them to rest for a bit before cooking. Eating these vegetables raw can also be good for you, as it preserves all of the nutrients and medicinal properties.
Citrus
Citrus fruits act as a medicinal component for many ailments, such as cardiovascular disease. Researchers are finding that it could also decrease cancer risk. The fruit itself and the peel contain high levels of vitamin C, folate, and flavonoids, a compound that possesses antioxidant, anti-inflammatory, anti-viral, and may have anticarcinogenic properties.
High plasma concentrations of vitamin C have been linked to reduce risk of stomach cancer [30]. Quantitative systematic review showed that eating high amounts of citrus fruits can significantly reduce risk of stomach cancer. They found that eating at least three servings per week reduced risk of stomach cancer by 28% [31].
Another meta analysis done in 2015 came to the conclusion that there was a significant reduction in esophageal cancer associated with citrus consumption [32]. The effects of citrus on cancer rates is something still being studied, but for now it is best to follow the daily recommended amount of vitamin C.
The National Institute of Health suggests 75mg for women and 90mg for men. For reference, there is about 70 mg of vitamin C in one medium orange. Some citrus fruits like grapefruit can interact with some medications like the statins so be sure to check with your provider about a safe amount to consume!
Berries
While more research still needs to be done, there are some promising studies that indicate berries can decrease cancer risk. The reason for this is because they are packed with antioxidants. These antioxidants provide some protection against cell damage that may lead to lung, skin, esophageal, or breast cancer [33]. Berries also contain compounds called polyphenols, which work alongside the antioxidants to protect tissues of the body against oxidative stress which is one of the factors for cancer development [34]
One study done under the Department of Cancer Biology at City of Hope found that tumor size significantly decreased in mice that were fed blueberry powder compared to the mice that had no blueberry. They also found that the spread of cancer was significantly decreased in the mice that had blueberry powder. [35]
Adding berries into your diet can have a positive impact on your health. Associate professor at Harvard Medical School, Dr. Eric Rimm recommends having at least three servings (½ cup) of berries per week [36].
In summary, it is important to consume a wide variety of fruits, vegetables, and grains. Eating a well rounded diet also ensures that you are getting the most protection against different ailments and illnesses!
References
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3 USAFacts. (2023, March 21). US obesity rates have tripled over the last 60 years. USAFacts.
https://usafacts.org/articles/obesity-rate-nearly-triples-united-states-over-last-50-years/
4 Centers for Disease Control and Prevention. (2023, August 9). Obesity and cancer. Centers for Disease Control and Prevention. https://www.cdc.gov/cancer/obesity/index.htm
5 Harvard School of Public Health. (2023, February 2). Preventing cancer. The Nutrition Source. https://www.hsph.harvard.edu/nutritionsource/cancer/preventing-cancer/
6 Suggested servings from each food group. American Heart Association. (2023, December 18). https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/nutrition-basics/suggested-servings-from-each-food-group
7 Key, T. J., Bradbury, K. E., Perez-Cornago, A., Sinha, R., Tsilidis, K. K., & Tsugane, S. (2020). Diet, nutrition, and cancer risk: what do we know and what is the way forward?. BMJ (Clinical research ed.), 368, m511. https://doi.org/10.1136/bmj.m511
8 Aykan N. F. (2015). Red Meat and Colorectal Cancer. Oncology reviews, 9(1), 288. https://doi.org/10.4081/oncol.2015.288
9 Limit consumption of red and processed meat - american institute ... American Institute for Cancer Research. (n.d.). https://www.aicr.org/cancer-prevention/recommendations/limit-consumption-of-red-and-processed-meat/
10 Collins, K. (2018, September 21). Facts on fiber and whole grains. American Institute for Cancer Research. https://www.aicr.org/resources/blog/ask-the-dietitian-get-your-facts-right-on-fiber-and-whole-grains/
11 Key, T. J., Bradbury, K. E., Perez-Cornago, A., Sinha, R., Tsilidis, K. K., & Tsugane, S. (2020). Diet, nutrition, and cancer risk: what do we know and what is the way forward?. BMJ (Clinical research ed.), 368, m511. https://doi.org/10.1136/bmj.m511
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13 Key, T. J., Bradbury, K. E., Perez-Cornago, A., Sinha, R., Tsilidis, K. K., & Tsugane, S. (2020). Diet, nutrition, and cancer risk: what do we know and what is the way forward?. BMJ (Clinical research ed.), 368, m511. https://doi.org/10.1136/bmj.m511
14 Wu, X., Chen, L., Cheng, J., Qian, J., Fang, Z., & Wu, J. (2022). Effect of Dietary Salt Intake on Risk of Gastric Cancer: A Systematic Review and Meta-Analysis of Case-Control Studies. Nutrients, 14(20), 4260. https://doi.org/10.3390/nu14204260
15 How much sodium should I eat per day?. American Heart Association. (2024, January 5). https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/sodium/how-much-sodium-should-i-eat-per-day
16 FDA. (n.d.). Sodium in your diet. U.S. Food and Drug Administration. https://www.fda.gov/food/nutrition-education-resources-materials/sodium-your-diet#:~:text=Americans%20eat%20on%20average%20about,recommended%20limits%20are%20even%20lower
17 Zeratsky , K. (2023, July 8). Is sea salt healthier than table salt?. Mayo Clinic. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/sea-salt/faq-20058512#:~:text=Sea%20salt%20is%20available%20as,amounts%20of%20sodium%20by%20weight.
18 Wergin, A. (2023, December 22). Is sea salt healthier than table salt?. Mayo Clinic Health System. https://www.mayoclinichealthsystem.org/hometown-health/speaking-of-health/is-sea-salt-healthier-than-table-salt
19 Awareness of alcohol’s Link to cancer lagging. National Cancer Institute. (2023, January 18). https://www.cancer.gov/news-events/cancer-currents-blog/2023/cancer-alcohol-link-public-awareness
20 Awareness of alcohol’s Link to cancer lagging. National Cancer Institute. (2023, January 18). https://www.cancer.gov/news-events/cancer-currents-blog/2023/cancer-alcohol-link-public-awareness
21 Awareness of alcohol’s Link to cancer lagging. National Cancer Institute. (2023, January 18). https://www.cancer.gov/news-events/cancer-currents-blog/2023/cancer-alcohol-link-public-awareness
22 de Lorgeril, M., Salen, P., & Rabaeus, M. (2020). Sugary drinks and cancer risk. Translational cancer research, 9(5), 3172–3176. https://doi.org/10.21037/tcr-2020-003
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24 Strawbridge, H. (2020, January 29). Artificial sweeteners: Sugar-free, but at what cost?. Harvard Health. https://www.health.harvard.edu/blog/artificial-sweeteners-sugar-free-but-at-what-cost-201207165030#:~:text=Artificial%20sweeteners%20may%20play%20another,nutritious%20food%2C%20and%20gain%20weight.
25 Key, T. J., Bradbury, K. E., Perez-Cornago, A., Sinha, R., Tsilidis, K. K., & Tsugane, S. (2020). Diet, nutrition, and cancer risk: what do we know and what is the way forward?. BMJ (Clinical research ed.), 368, m511. https://doi.org/10.1136/bmj.m511
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29 Forma A, Chilimoniuk Z, Januszewski J, Sitarz R. The Potential Application of Allium Extracts in the Treatment of Gastrointestinal Cancers. Gastroenterology Insights. 2021; 12(2):136-146. https://doi.org/10.3390/gastroent12020012
30 Key, T. J., Bradbury, K. E., Perez-Cornago, A., Sinha, R., Tsilidis, K. K., & Tsugane, S. (2020). Diet, nutrition, and cancer risk: what do we know and what is the way forward?. BMJ (Clinical research ed.), 368, m511. https://doi.org/10.1136/bmj.m511
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33 MD Anderson Cancer Center. (2018, May 15). 5 foods that help Lower your cancer risk. MD Anderson Cancer Center. https://www.mdanderson.org/publications/focused-on-health/foods-lower-cancerrisk.h29Z1590624.html#:~:text=%E2%80%9CBerries%20are%20a%20wonderful%20source,%2C%20lung%2C%20breast%20and%20esophagus.
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36 Eat blueberries and strawberries three times per week. Harvard Health. (2013, July 1). https://www.health.harvard.edu/heart-health/eat-blueberries-and-strawberries-three-times-per-week