What do nitrates in meat do to your body?

November 8, 2025 •

4 min read

According to the World Health Organization's International Agency for Research on Cancer (IARC), ingested nitrates and nitrites under certain conditions are probably carcinogenic to humans. This distinction is crucial for understanding what do nitrates in meat do to your body, as their effect is highly dependent on their source—whether it's from processed meat or nutrient-rich vegetables.

Quick Summary

Nitrates in meat convert to nitrites, which can form carcinogenic nitrosamines, especially when cooked at high heat. The health impact differs significantly from nitrates found in vegetables, which offer cardiovascular benefits.

Key Points

Nitrosamines Formation: Nitrites in processed meats can react with meat proteins to form carcinogenic nitrosamines, especially when cooked at high temperatures.
Cardiovascular Benefits from Vegetables: Nitrates in vegetables, unlike those in meat, convert into beneficial nitric oxide, which can lower blood pressure and improve blood flow.
Antioxidant Protection: Antioxidants like vitamin C in vegetables inhibit the formation of harmful nitrosamines, a protection not provided by processed meats.
Source Matters: The health impact of nitrates is determined by their dietary source—vegetable nitrates are largely beneficial, while processed meat nitrates carry risks.
Beyond Nitrates: The health risks of processed meat also stem from high sodium, saturated fat, and other carcinogens formed during cooking.
Regulatory Control: The amount of nitrites added to processed meats is regulated, and companies often add inhibitors like vitamin C to reduce nitrosamine formation.

Unpacking the Role of Nitrates in Processed Meats

Nitrates (NO3) and nitrites (NO2) are compounds consisting of nitrogen and oxygen that exist naturally in the environment and are also added to cured meats for preservation. When you consume processed meats like bacon, ham, or deli slices, the nitrates added during curing are converted to nitrites by bacteria in your body. These nitrites have both a functional purpose—preventing the growth of harmful bacteria like Clostridium botulinum and maintaining the meat’s characteristic color and flavor—and a potential dark side, particularly when exposed to high temperatures.

The primary concern with nitrates in meat arises when nitrites react with the amino acids and proteins present in the meat to form N-nitroso compounds (NOCs), also known as nitrosamines. This process is accelerated by the acidic environment of the stomach and can be heightened when the meat is cooked at high heat, such as frying or grilling bacon. Nitrosamines are known carcinogens, and their formation is the main reason behind the link between high consumption of processed meat and an increased risk of certain cancers, particularly colorectal and stomach cancer.

The Nitrate-to-Nitrite Conversion Pathway

Ingestion: You consume food containing nitrates, from either vegetables or processed meats.
Saliva Circulation: The nitrates are absorbed into the bloodstream, and some are concentrated and secreted in saliva.
Bacterial Conversion: Bacteria on the tongue convert nitrates into nitrites.
Stomach Reaction: In the acidic stomach environment, these nitrites can react with amines from proteins to form carcinogenic nitrosamines.
Dual Pathway: Alternatively, in the presence of antioxidants, nitrites can form beneficial nitric oxide.

Vegetables vs. Meat: A Critical Difference

While processed meat often contains added nitrites, vegetables are actually the largest source of dietary nitrates for most people. Leafy greens, beetroot, and celery are especially rich in these compounds. However, the health impact of nitrates from these sources is vastly different. The reason lies in the presence of protective compounds like vitamin C and polyphenols in vegetables.

These antioxidants effectively inhibit the conversion of nitrites to harmful nitrosamines and instead promote the formation of nitric oxide (NO). Nitric oxide is a vital signaling molecule that helps relax and widen blood vessels, which in turn lowers blood pressure and supports overall cardiovascular health. Therefore, consuming nitrates from vegetables is associated with health benefits, whereas nitrates in processed meats are linked to risks due to the absence of these protective antioxidants.

Comparison: Nitrates in Processed Meats vs. Vegetables


Feature	Processed Meats (Bacon, Hot Dogs)	Vegetables (Spinach, Beetroot)
Source	Added as a preservative (e.g., sodium nitrite) during curing process.	Naturally occurring in the soil and absorbed by the plant.
Conversion Outcome	Forms carcinogenic nitrosamines, especially when cooked at high temperatures.	Forms beneficial nitric oxide (NO), thanks to co-occurring antioxidants.
Presence of Antioxidants	Low levels of protective antioxidants.	High levels of vitamin C and other antioxidants that block nitrosamine formation.
Health Implication	Associated with increased risk of certain cancers (colorectal, stomach) and cardiovascular disease due to high sodium.	Associated with cardiovascular benefits, lower blood pressure, and enhanced exercise performance.
Regulation	Levels are regulated to prevent excessive intake and require the addition of nitrosamine inhibitors like vitamin C.	Natural levels are generally not a concern, as the benefits of vegetable consumption far outweigh the risks.

The Broader Picture: Sodium and Carcinogens

It is important to recognize that the nitrates are just one piece of the puzzle when it comes to the health risks of processed meats. Many processed meats are also high in sodium and saturated fats, which are established risk factors for high blood pressure and heart disease. Furthermore, other cooking-related carcinogens, such as heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs), can form during high-temperature cooking methods like grilling or frying. These factors contribute to the overall negative health profile of processed meats, regardless of nitrate content. Therefore, experts often recommend limiting processed meat consumption and focusing on a diet rich in whole foods, particularly nitrate-rich vegetables, to promote better health outcomes.

Conclusion

The effect of nitrates on your body is not a simple good-or-bad narrative but depends heavily on their source. When consumed from vegetables, nitrates are beneficial for cardiovascular health. However, when they are added to processed meat and converted to nitrites, they can lead to the formation of carcinogenic nitrosamines, especially during high-heat cooking. The antioxidants naturally present in vegetables offer a protective effect that is absent in processed meats. By being mindful of your dietary choices and understanding these chemical differences, you can better manage your health and make more informed decisions about what you eat. To learn more about the distinction, see this publication on dietary nitrates from the American Journal of Clinical Nutrition.

Frequently Asked Questions

Nitrates (NO3) and nitrites (NO2) are both nitrogen-oxygen compounds. Nitrates are generally more stable, but when ingested, bacteria in the mouth and gut can convert them into more reactive nitrites. It is the nitrites that can then form either beneficial nitric oxide or harmful nitrosamines, depending on the source.

Nitrates and nitrites added to cured meats like bacon are considered bad in excess because they can form carcinogenic nitrosamines. High-heat cooking methods, such as frying bacon, increase the likelihood of this process occurring. The World Health Organization classifies processed meat as a Group 1 carcinogen.

Nitrates in vegetables are considered healthy because they are a major source of nitric oxide (NO) in the body, which helps to relax and widen blood vessels. The vegetables also contain antioxidants like vitamin C, which prevent the formation of carcinogenic nitrosamines from nitrates, promoting health rather than risk.

Methemoglobinemia is a blood disorder where hemoglobin is converted to methemoglobin, which cannot transport oxygen effectively. While a rare side effect of high nitrate exposure, it is most often a risk for infants who consume formula made with high-nitrate contaminated well water.

A 'naturally cured' label is misleading, as the meat is still cured with nitrates. Instead of synthetic sodium nitrate, manufacturers use natural sources like celery powder, which is high in nitrates. The body processes these nitrates the same way, and they can still form nitrosamines.

Yes, you can reduce your risk by limiting your intake of processed and cured meats, cooking at lower temperatures to minimize nitrosamine formation, and ensuring your diet is rich in antioxidants from fruits and vegetables. Reading labels and choosing products without added nitrates is also an option.

Nitrates from vegetables can positively affect heart health by increasing nitric oxide production, which helps relax blood vessels and lower blood pressure. Conversely, the high sodium and saturated fat often found in processed meats, which contain added nitrates, can increase the risk for high blood pressure and heart disease.