Which preservatives are linked to cancer?

December 14, 2025 •

4 min read

According to the World Health Organization's International Agency for Research on Cancer (IARC), ingested nitrates and nitrites are probably carcinogenic to humans under certain conditions, particularly when consumed in processed meats. The link between certain food additives and health concerns, including cancer, has prompted increased public awareness and regulatory scrutiny of commonly used preservatives. Understanding which additives carry potential risks is crucial for making informed dietary decisions.

Quick Summary

This article examines specific food preservatives, including nitrates, nitrites, BHA, BHT, and benzoates, that have been associated with potential cancer risks. It also covers related contaminants like acrylamide and formaldehyde-releasing agents, detailing the current scientific understanding of their health implications and providing actionable advice for minimizing exposure.

Key Points

Nitrates and Nitrites: Used in processed meats, these can form carcinogenic nitrosamines in the stomach and are linked to colorectal and stomach cancer.
BHA and BHT: These synthetic antioxidants are found in various packaged foods; BHA is classified as a possible human carcinogen based on animal studies.
Sodium and Potassium Benzoate: In acidic beverages containing vitamin C, these can react to form benzene, a known carcinogen, particularly when exposed to heat or light.
Acrylamide: This is a contaminant formed during high-temperature cooking of starchy foods and is considered a 'probable human carcinogen' by the IARC.
Formaldehyde Releasers: Preservatives like DMDM Hydantoin, found in cosmetics but sometimes in other products, release small amounts of carcinogenic formaldehyde over time.
Reading Labels is Crucial: Being aware of specific preservative names like BHA, BHT, and benzoates on product labels helps consumers make healthier choices and reduce exposure.

Understanding the Link Between Preservatives and Cancer

Preservatives are crucial for modern food production, helping to prevent spoilage and extend shelf life by inhibiting microbial growth. However, some of these chemical compounds have come under scrutiny due to potential links with increased cancer risk. It is important to distinguish between substances that are carcinogenic in their own right, and those that can form carcinogens under specific conditions, such as high heat or in combination with other ingredients. While regulatory bodies like the FDA in the U.S. and EFSA in Europe deem many additives safe at regulated levels, the evidence, often from animal studies, has sparked concern and led to bans in some countries. For health-conscious consumers, understanding the specific preservatives involved is the first step towards minimizing exposure.

Nitrates and Nitrites in Processed Meats

Nitrates and nitrites are salts used to cure meats like bacon, hot dogs, and deli slices. They are effective at preventing bacterial growth, including Clostridium botulinum, and preserving a product's pink color. However, when consumed, especially in the presence of protein, they can react to form N-nitroso compounds (nitrosamines) in the stomach.

Scientific Evidence on Nitrates and Nitrites

IARC classifies ingested nitrites and nitrates under conditions that result in endogenous nitrosation (their conversion into nitrosamines) as "probably carcinogenic to humans".
Consuming processed meats is consistently linked to a higher risk of colorectal cancer.
Studies have also found associations between high nitrite intake and an increased risk of stomach cancer.
Evidence also suggests links to breast and prostate cancer in some studies.

Butylated Hydroxyanisole (BHA) and Butylated Hydroxytoluene (BHT)

BHA and BHT are synthetic antioxidants used to prevent fats and oils from becoming rancid in foods like cereals, snack foods, and cured meats.

Scientific Evidence on BHA and BHT

The U.S. National Toxicology Program has classified BHA as "reasonably anticipated to be a human carcinogen" based on animal studies that showed it caused benign and malignant tumors.
The International Agency for Research on Cancer (IARC) also classifies BHA as a possible human carcinogen.
BHT, a chemical relative of BHA, has also been shown to have tumor-promoting effects in animals at high doses.
Beyond cancer, these additives have been linked to potential hormone disruption.

Benzoates: Sodium and Potassium Benzoate

Sodium benzoate and potassium benzoate are antimicrobial preservatives used in acidic foods and drinks, such as sodas, fruit juices, and salad dressings.

The Benzene Problem

A significant concern arises when benzoates combine with ascorbic acid (vitamin C) and are exposed to heat or light. This can lead to the formation of benzene, a known human carcinogen.
The FDA has worked with manufacturers to reformulate products and reduce benzene levels after some beverages exceeded the acceptable limit for drinking water.

Acrylamide: A Cooking Contaminant, Not a Direct Preservative

While not a preservative added directly, acrylamide is a process contaminant that deserves mention due to its carcinogenic properties and common presence in foods.

How it Forms and Risks

Acrylamide forms naturally in starchy foods, such as potato chips, french fries, and cereals, when cooked at high temperatures (e.g., frying, roasting, baking).
IARC classifies acrylamide as a "probable human carcinogen" based on animal studies.
The FDA and other organizations advise reducing acrylamide exposure by cooking starchy foods to a golden color rather than dark brown and by following package cooking instructions.

Comparison of Preservatives and Related Carcinogens


Preservative/Contaminant	Primary Source	Potential Cancer Link	Specific Risk	Regulatory Status (U.S.)
Nitrates/Nitrites	Processed meats (bacon, hot dogs)	Linked (via nitrosamine formation)	Colorectal, stomach, breast, prostate	Regulated; amount limits
BHA	Cereals, snacks, oils, cosmetics	Reasonably Anticipated Human Carcinogen (NTP)	Tumors in animal studies	GRAS status, under review
Sodium/Potassium Benzoate	Sodas, juices, dressings	Forms benzene (known carcinogen)	Benzene formation with Vitamin C	GRAS status, requires reformulation if benzene forms
Acrylamide	Fried/roasted starchy foods (e.g., fries, chips)	Probable Human Carcinogen (IARC)	Forms during high-heat cooking	Monitored, but not currently regulated in food
Formaldehyde-releasing Preservatives	Cosmetics, personal care, some foods	Human Carcinogen (IARC)	Release formaldehyde over time	Various regulations based on product type

How to Reduce Your Exposure to Preservatives with Cancer Links

Minimizing your intake of potentially harmful preservatives can be achieved through conscious eating habits. The following steps can help reduce your exposure:

Prioritize Whole Foods: Build your diet around fresh fruits, vegetables, lean proteins, and whole grains, which contain fewer synthetic additives.
Reduce Processed Meat Consumption: Limit your intake of cured and processed meats, which often contain nitrates and nitrites. Opt for fresh cuts of meat, poultry, or fish.
Read Labels Carefully: Become familiar with the names of preservatives to look for on ingredient lists. For example, check for BHA, BHT, sodium benzoate, and potassium benzoate, especially in combination with vitamin C.
Cook Smartly at Home: To reduce acrylamide formation, cook starchy foods to a lighter, golden color rather than browning them heavily.
Choose Alternatives: Many brands offer products free from specific synthetic preservatives, using natural alternatives like vinegar, salt, and spices for preservation.
Stay Informed on Regulations: Keep up-to-date with guidance from regulatory bodies like the FDA, as research is ongoing and new findings emerge that can change recommendations.

Conclusion

While the use of food preservatives is regulated to ensure safety, ongoing scientific research continues to reveal potential health implications, including links to cancer, for specific compounds. Nitrates and nitrites in processed meats, BHA and BHT in many packaged goods, and benzoates that can form benzene highlight the need for consumer vigilance. Additionally, process contaminants like acrylamide add another layer of consideration. By shifting towards a diet rich in whole, unprocessed foods and making informed choices about packaged goods, individuals can proactively reduce their exposure to potentially carcinogenic substances. Balancing convenience with careful consideration of ingredients is key to protecting one's long-term health.

Acrylamide and Cancer Risk from the National Cancer Institute

Frequently Asked Questions

No, not all food additives cause cancer. Many food additives are considered safe by regulatory bodies like the FDA within specified limits. However, ongoing research has raised concerns about a few specific preservatives and their potential links to cancer.

Avoiding all potentially harmful preservatives can be challenging, but reducing exposure is possible. Focusing on a diet of fresh, whole foods and minimizing consumption of highly processed items is the most effective strategy.

Nitrates are found naturally in many vegetables, but the risk comes from their conversion to nitrosamines, primarily in the stomach with other compounds found in cured and processed meats. Vegetables often contain antioxidants like vitamin C, which can inhibit this process.

Following tests by the FDA in 2005, many manufacturers reformulated their beverages to address the issue of benzene formation from benzoates reacting with vitamin C. While the risk is considered low in modern products, long-term studies are still limited.

Acrylamide is formed naturally when starchy foods are cooked at high temperatures. The risk is dose-dependent, and major health organizations like IARC consider it a "probable human carcinogen." Consumers are advised to cook foods like fries and toast to a lighter color to reduce formation.

You can check the ingredient list for preservatives known to release formaldehyde, such as DMDM hydantoin, imidazolidinyl urea, and quaternium-15. Opting for products labeled 'formaldehyde-free' is another option.

Yes, many foods are preserved using natural methods. Examples include salt curing, smoking, fermentation (producing lactic acid), and using antioxidants found in lemon juice or vinegar. These are generally considered safer options than synthetic alternatives.