What you may have heard

A story from 2013 of a 10-year-old girl with extreme stomach distress became front-page news after her physician attributed her sickness to eating spicy chips. The physician said that the harsh chemicals in these chips cause corrosion in the throat and stomach, causing stomach ulcers and potentially throat cancer.

What science tells us

According to the Environmental Working Group (EWG), the 3 ingredients of biggest concern in spicy chips are red 40 lake, blue 1 lake, and yellow 6 lake. 

Epidemiological Evidence

Studies have shown that Yellow 6, Red 40, and Blue 1 have no carcinogenic effects in humans, and the FDA has substantiated this claim (FDA).  There have not been studies that evaluate consumption of spicy chips and cancer risk.

Laboratory Evidence/ Supportive Evidence

There is limited laboratory evidence that shows a relationship between spicy chips and cancer. 

IARC Carcinogen Classification:

Not classified.

How to reduce your risk

Artificial colors are used to increase the appeal of foods that have little nutritional value, so one easy way to identify if a food product is lacking in nutrients is to look for food coloring.

There is currently no evidence that spicy chips are linked to corrosion in the throat and stomach, and by extension, there is no evidence that ingredients in these chips are linked to cancer. However, these chips are high in saturated fats (which can raise the level of cholesterol in the blood) and LDL cholesterol (which increases your risk of heart disease and stroke) (AHA). Eating a high amount of foods low in nutrients and high in fat can also lead to obesity and extra weight, which can also raise the risk of heart disease, stroke, diabetes, and some cancers.

Bottom line

It is not likely that consumption of spicy chips increases cancer risk. However, these chips are high in saturated fats and should be eaten in moderation to avoid risk of heart disease, stroke, and other diseases.

What you may have heard

You may have heard that acrylamide (an ingredient in some foods) increases cancer risk.

What science tells us

Acrylamide is a chemical that is used in industrial processes, such as the production of paper, dyes, and plastics, and consumer products, such as food packaging and adhesives. Acrylamide is also found in foods such as french fries, potato chips, crackers, bread, cookies, and black olives. A major acrylamide exposure source is tobacco smoke. People who smoke have 3-5 times the levels of acrylamide exposure in their blood than non-smokers (NCI).

The International Agency for Research on Cancer (IARC) classifies acrylamide as a probable human carcinogen and the US Environmental Protection Agency (EPA) classifies acrylamide as likely to be carcinogenic to humans (NCI).

Epidemiological Evidence

The claim that acrylamide is likely to be carcinogenic to humans is largely based on animal studies and more research is needed to say conclusively that acrylamide is linked to increased risk of cancer in humans.

Laboratory Evidence/Supporting Evidence

High levels of exposure to acrylamide can interfere with DNA repair. The binding of sulfhydryl groups can inactivate proteins involved in DNA repair, which can cause mutations to occur. Laboratory evidence for acrylamide as a cancer-causing agent needs to be further evaluated (Exon). Some animal studies have shown that exposure to high levels of acrylamide can cause cancer (FDA).

IARC Carcinogen Classification:

Group 2A (Probably carcinogenic to humans)

How to reduce your risk

For the vast majority of people, the major source of acrylamide they will encounter is from cigarette smoke. Avoiding cigarette smoke can lower your exposure to acrylamide and other harmful chemicals (NCI). In food, acrylamide level varies dramatically depending on cooking time, manufacturer, method, and temperature of the cooking process. Decreasing cooking time, avoiding heavy crisping or browning, blanching potatoes before frying, not storing potatoes in a refrigerator, and post-drying (drying potatoes in a hot-air oven after frying) may decrease acrylamide levels of some foods (FDA).

It is still unclear that levels of acrylamide in foods raise cancer risk, but there are precautions you can take to decrease your acrylamide exposure (ACS):

• limit foods that may be high in acrylamide: french fries, potato chips, cookies, and toast;
• limit frying and roasting (boiling and steaming do not produce acrylamide);
• soak raw potato slices in water for 15-30 minutes before frying or roasting;
• cook potatoes and bread to a lighter color; and
• avoid storing potatoes in the refrigerator

Bottom line

More research is needed to confirm whether acrylamide causes cancer in humans.

What you may have heard

Products that contain palm oil, namely hazelnut spreads, are one of the most recent foods to be flagged as potentially carcinogenic.

What science tells us

Products containing palm oil, which can contain 3-Monochloropropane-1,2-diol esters (3-MCPD) and glycidyl esters (GE), have been flagged as possibly carcinogenic but only when heated 392 degrees Fahrenheit (FDA). Manufacturers have reported that brand-name hazelnut spreads are processed below 392 degrees. As a result, the U.S. Food and Drug Administration (FDA) has stated that they pose no cancer risk (FDA).

Epidemiological Evidence

Epidemiological studies have been conducted to examine whether a relationship exists between palm oil and cancer. Currently, there is no evidence in human studies that hazelnut spread or palm oil consumption increase the risk of cancer.

Laboratory Evidence/Supporting Evidence

Animal studies have also been conducted to examine if palm oil causes cancer. Some studies suggest that when the palm oil is heated at high temperature, it can cause cancer.

IARC Carcinogen Classification:

Not classified.

How to reduce your risk

Because of the added palm oil, hazelnut spreads are high in saturated fats. Saturated fats raise the level of cholesterol in the blood, which increases your risk of heart disease and stroke (AHA). Eating too much fat can lead to obesity, which also raises the risk of heart disease, stroke, diabetes, and some cancers.

Bottom line

Hazelnut spreads do not have any known carcinogenic effects. These foods are high in saturated fats, though, and should be consumed in moderation (ACS).

What you may have heard

Aspartame consumption can cause cancer.

What science tells us

With rising competition to make food sweet and appealing, as well as lower in calories, many companies switched from normal sucrose (table sugar) to sugar substitutes or artificial sweeteners like aspartame, one of the most widely used artificial sweeteners. Aspartame is similar to sugar, but it is sweeter than sugar, and can be found in different foods and beverages (ACS).

Epidemiological Evidence

Many studies have investigated whether or not artificial sweeteners and Aspartame have caused cancer (NCI), but no connection between cancer risk and Aspartame consumption has been found (ACS).

Laboratory Evidence/Supporting Evidence

There is no laboratory evidence that aspartame consumption leads to an increase in cancer risk.

IARC Carcinogen Classification:

Not Classified.

How to reduce your risk

Choose a sweetener that is FDA approved. These sweeteners have been studied extensively and are safe to consume. For example, sucrose (table sugar) and Aspartame are both good options, because they are FDA approved and have been proven to have little cancer risk, if any (ACS).
Consuming Aspartame or sugar-rich foods is often linked to higher chances of becoming obese, especially if they are not eaten in moderation. Obesity, or high BMI, has been linked to various types of cancers. Obese individuals have chronic inflammation, which, over time, can cause DNA damage that leads to cancer. They are also more likely to have other conditions or disorders that contribute to chronic inflammation: for example, Barrett’s esophagus, gallstones, ulcerative colitis, and hepatitis (NCI). To avoid excess body fat, it is important to maintain a healthy diet and have a goal of 150-300 minutes of weekly moderate physical activity (walking, running, hiking, etc.) (Mayo Clinic).

Bottom line

Eating food that contains Aspartame may not increase your cancer risk; however, a diet with excess sugar or Aspartame could have harmful health effects.

For further information on this topic, read, “What is worse, a soda or a beer?” in the Harvard Gazette and watch “Healthy Hydration” Beverage Choices and Cancer Risk,” co-hosted by the Zhu Center for Global Cancer Prevention and the Harvard T.H. Chan School of Public Health Office of Communications.

What you may have heard

Consuming the wax on fruits and vegetables can increase your risk of developing cancer.

What science tells us

Fruit wax, which is highly diluted, contains fungicides to inhibit mold growth, sugar cane, beeswax, carnauba wax, and resins.

Epidemiological Evidence

Chemicals such as pesticides associated with fruit production may contain carcinogens, but there is no evidence from human studies that exposure to fruit or vegetable wax contains chemicals that cause cancer when consumed by humans.

The Environmental Protection Agency (EPA) is responsible for ensuring that all pesticides or fungicides meet the Food Quality Protection Act (FQPA). The EPA states that fruits and vegetables treated with pesticides are safe and that they can be consumed “with a reasonable certainty of no harm to infants and children, as well as adults” (EPA). The EPA constantly monitors new and existing pesticides to ensure they may be consumed.

Fruit wax is monitored by the U.S. Food and Drug Administration (FDA). The FDA states that manufacturers and retail businesses must follow specific guidelines in the Federal Food, Drug, and Cosmetic Act (Federal Food, Drug, and Cosmetic Act (FD&C Act). This includes the use of safe and edible ingredients in the coating of any products and minimizes the risk of harmful coatings found on fruits and vegetables (FDA).

Laboratory Evidence/ Supportive Evidence

There is limited laboratory evidence on the effects of fruits and vegetable wax on animals. 

IARC Carcinogen Classification:

Not classified.

How to reduce your risk

The FDA does not approve any carcinogenic coatings used on food products. If there is a coating, it has been reviewed and ruled safe to consume by the FDA.

If you would still prefer to avoid eating the waxy coating, there are fruits that do not contain a coating. Often, products label whether they have a coating in their ingredients. If this is not listed on the product, it is often listed on the website of the product.
These coatings may also be easily removed under running water or, if the coating is water repellent, by peeling. Rinsing and peeling your fruits and vegetables is a great way to ensure that you do not eat the waxy coating.

Bottom line

Coatings on fruits and vegetables are not dangerous under FDA and EPA guidelines, but rinsing off or peeling produce helps to remove the wax.

Watch these short videos from the USDA and FDA about washing and handling fresh produce, and click on the links below for more information.

What you may have heard

Alcohol consumption increases your risk of cancer.

What science tells us

Alcoholic beverages containing ethanol are considered to be psychoactive substances by the WHO (WHO). It can cause harmful effects on the body. Alcohol consumption leads to a buildup of acetaldehyde, which is a toxic byproduct of ethanol (pure alcohol). In the liver, ethanol is converted into acetaldehyde, and a large presence of acetaldehyde interrupts the binding process of DNA, causing cells to not replicate correctly. Consumption of alcohol also causes tissue damage, which makes surface level cells more susceptible to the absorption of carcinogens.

Epidemiological Evidence

There is strong agreement that alcohol use can cause several types of cancer, and it has been classified as a Group 1 carcinogen (meaning that it is cancer-causing in humans) by the International Agency for Research on Cancer (IARC)  (ACS). There is a strong “dose-response association” between alcohol use and cancer (the more alcohol a person drinks regularly over time, the higher a person’s risk is of developing an alcohol-associated cancer):

• Head and neck: Moderate drinkers have 1.8-fold higher risk of oral cavity and pharynx (throat) cancers and 1.4-fold higher risk of larynx (voice box) cancers than non-drinkers. Heavy drinkers have 5-fold higher risk of oral cavity and pharynx cancers and 2.6-fold higher risk of larynx cancers (NCI).
• Esophageal: Compared with those who do not drink alcohol, the risk ranges from 1.3-fold higher for light drinkers to nearly 5-fold higher for heavy drinkers (NCI).
• Liver: Heavy alcohol drinking is associated with approximately 2-fold increased risk of two types of liver cancer (hepatocellular carcinoma and intrahepatic cholangiocarcinoma) (NCI).
• Breast: The cancer risk increase is greater in moderate drinkers (1.23-fold higher) and heavy drinkers (1.6-fold higher) (NCI).
• Colorectal: Moderate to heavy alcohol drinking is associated with 1.2- to 1.5-fold increased risk of cancers of the colon and rectum, compared with no alcohol consumption (NCI).

Laboratory Evidence/Supporting Evidence

Animal studies, particularly among mice, have shown that high alcohol consumption leads to the formation of tumors (NIH).

IARC Carcinogen Classification:

Group 1 (Carcinogenic to humans; “Ethanol in alcoholic beverages”)

How to reduce your risk

If someone drinks alcohol, it should be in moderation (NCI). Moderate alcohol drinking is up to 1 drink per day for women and up to 2 drinks per day for men. Heavy alcohol drinking is defined as having 4 or more drinks on any day or 8 or more drinks per week for women. For men, heavy alcohol drinking is defined as 5 or more drinks on any day or 15 or more drinks per week.

Bottom line

Drinking alcohol increases risk of multiple types of cancer. US guidelines recommend moderate drinking (up to 1 drink per day for women and up to 2 drinks per day for men).

For further information on this topic, read, “What is worse, a soda or a beer?” in the Harvard Gazette and watch “Healthy Hydration” Beverage Choices and Cancer Risk,” co-hosted by the Zhu Center for Global Cancer Prevention and the Harvard T.H. Chan School of Public Health Office of Communications.

What you may have heard

Consuming high-fat diets decrease cancer risk. 

What science tells us

The notion that high fat diets decrease cancer risk stems from early research on diet and cancer. Countries with high “healthy fat” intake, such as countries along the Mediterranean Sea, have lower rates of cancer. But after further study, the differences in cancer risk no longer seem related to fat consumption (AICR). Overall eating choices matter as does the type and quality of fat in a diet. Recently, high-fat diets have become popular as a way to lose weight and prevent cancer risk. However, other experts warn that eating too much fat (and the wrong type of fat) may increase your cancer risk.

Epidemiological Evidence

Many epidemiological studies of dietary fat have been undertaken. More research is needed to better understand which types of fat should be avoided and how much of each fat alters cancer risk. Although monounsaturated, polyunsaturated, and trans fatty acids have been studied for a number of years, their effects on cancer risk are still unclear.  The World Cancer Research Fund has summarized there is only limited or suggestive evidence for increased cancer risk and total fat or saturated fat consumption.

Laboratory/Supporting Evidence

One study conducted on pregnant female mice showed that a high-fat diet resulted in the presence of breast cancer (Nguyen et al.). However, the research is still limited, and further research is needed to examine the effect of high fat diets on animal studies.

IARC Carcinogen Classification:

Not classified.

How to reduce your risk

Fat is the most concentrated source of calories, so it is easy for small portions to add up to excess calories. If those extra calories lead to weight gain, it is a very real concern for cancer risk; obesity is a risk factor for a wide range of cancers. Some tips to reduce your risk follow.

• Limit fat from foods associated with cancer risk, such as red meat and processed meats.
• Center your meals around vegetables, fruits, whole grains, and beans, which offer a wide range of healthy fats, nutrients, protective phytochemicals, and dietary fiber.
• Consume plant-based foods (such as nuts and avocados) that are naturally high in fat.
• Low-fat diets are no better than other calorie-cutting diets for weight loss or avoiding weight gain (AICR).

Bottom line

There is not strong evidence that high-fat diets cause or prevent cancer. Focusing on overall nutrient intake and eating patterns is the best way to reduce diet-related cancer risk.

Check out this article from the Harvard Gazette about our World Cancer Week panel discussion on nutrition and cancer risk, and watch a recording of the conversation below.

What you may have heard

Consuming MSG increases your risk of cancer.

What science tells us

MSG is one of the most common food additives. Generally, MSG gives an umami (meat-like) scent and is often added to savory foods to improve their taste and smell (Niaz et al.).

Epidemiological Evidence

MSG has been thoroughly researched, and there have not been any links found between consuming MSG and cancer risk (Niaz et al.). Other studies, however, have looked at possible toxic effects of MSG for the body. Studies have linked MSG consumption to obesity, central nervous system disorders, liver damage, and reproductive malfunctions. While MSG has not been shown to increase the risk of cancer, it might lead to other harmful health effects (Niaz et al.).

Laboratory Evidence/Supporting Evidence

The effects of MSG have been studied in animal models, however, there are limited studies investigating if MSG causes cancer in animals (Zanfirescu et al.).

IARC Carcinogen Classification:

Not classified.

How to reduce your risk

MSG research has not shown a link to cancer risk. But experts recommend avoiding products that contain MSG because it can lead to other harmful health effects. Check the ingredients of the food you eat, especially “savory” products, as those are most likely to have MSG (Niaz et al.).

Bottom line

MSG does not appear to cause cancer or increase cancer risk.

What you may have heard

Eating charred or burnt meat can increase your risk of cancer.

What science tells us

Charring or burning meat, poultry, or fish over high temperatures causes heterocyclic amines (HCAs) to form. Meat that is cooked above 300 ºF and for a long period of time causes HCAs to form (NCI).

Epidemiological Evidence

HCAs can cause genetic damage and increase a person’s risk of stomach and colorectal cancers (Cedars-Sinai). Several epidemiological studies have shown a positive correlation between HCAs and cancer risk (Sugimura). Other animal studies have also shown the carcinogenicity of HCAs with breast, colon, and prostate cancer development in rodents (Sugimura).

Laboratory Evidence/Supporting Evidence

The laboratory evidence for HCAs in cancer is consistent with that of the epidemiological evidence.

IARC Carcinogen Classification:

Group 2A/2B (possibly/probably carcinogenic to humans: various Heterocyclic amines – HCAs)

How to reduce your risk

To reduce your risk of colorectal cancer, avoid processed meats, limit red meat, and swap plants for meats. Avoid charring or burning meat, poultry, or fish (MD Anderson). Try the following tips for reducing the amount of charred or burnt material that sticks to your food.

• Lightly oil the grill.
• Lower the temperature (either by spreading the coals evenly or increase the distance between your food and the coals).
• Scrub the grill after each use.
• Use a marinade: This helps reduce HCA formation by as much as 96% (MD Anderson).
• Trim fat from the meat. This can reduce exposure to cancer-causing polycyclic aromatic hydrocarbons (PAHs) that form when the fat drips onto the heat source. The PAH fills the smoke that coats and enters your food. Choosing lean cuts can decrease your exposure when grilling.

Bottom line

Grilling at high heat and eating charred meat, poultry, or fish can increase risk of colorectal cancer. To decrease your risk, swap plants for these meats, or avoid charring or burning meat, poultry, or fish.

What you may have heard

Consumption of processed meats can increase the risk of cancer.

What science tells us

Processed meat has been changed through curing, smoking, salting, fermentation, or other processes to help preserve it or enhance flavor. Processed meats are most commonly made of pork or beef, such as bacon, sausage, ham, bologna, hot dogs, and deli meats such as chicken and turkey.

Epidemiological Evidence

In 2015, the International Agency for Research on Cancer (IARC) concluded that processed meat is a Group 1 carcinogen, which means that it is carcinogenic (or cancer-causing) to humans, based on evidence for increased risk of colorectal cancer (IARC). Recent studies also suggest a possible role of processed meat in increasing risk of breast cancer and prostate cancer, though more research is needed. It is unknown if there is a safe level for eating processed meat.

Laboratory Evidence/Supporting Evidence

Some animal studies have also shown the presence of colon cancer among rat studies which further supports the epidemiological evidence (Lyon).

IARC Carcinogen Classification:

Group 1 (Carcinogenic to humans)

How to reduce your risk

The American Cancer Society (ACS) reports that at least 18% of all cancers and about 16% of cancer deaths in the U.S. are related to excess body weight, physical inactivity, and/or poor nutrition (ACS). Healthy eating includes foods that are high in nutrients, in amounts that help get to and stay at a healthy body weight. Limit or avoid red and processed meats, sugar-sweetened beverages, highly processed foods, and refined grain products. Instead, choose proteins such as fish, poultry, and beans (ACS).

Bottom line

Limit or avoid red and processed meats and replace them with proteins such as fish, poultry, and beans.

Watch these videos from the Dana-Farber Cancer Institute and the World Cancer Research Fund for more information on processed meat and red meat.