Nitrates and nitrites are both chemical compounds that are important plant nutrients. They occur naturally in the environment, but can also be made synthetically. Nitrate itself is nontoxic. It can either be ingested or produced by the body. Once in the body, however, nitrates can be converted into nitrites, which are more toxic. Nitrite can interact with other compounds to form carcinogens.[1]

Both nitrates and nitrites are used as preservatives in many foods. Ingredient labels of processed foods will often have preservatives like potassium or sodium nitrate, as well as potassium or sodium nitrite. But these compounds can also occur naturally in many foods.

Risks of nitrates in food

So are nitrates bad for you? Nitrates themselves do not pose a significant health risk. However, nitrites do have the ability to contribute to carcinogen synthesis. The effect of nitrites on the risk of cancer in humans is debated and studies so far are controversial.[1] Compounds produced when nitrates and nitrites are metabolized do show carcinogenic activity in laboratory and human studies,[2] so they may be a risk to your health.

Researchers believe more research is needed to elucidate the risks of nitrates and nitrites on human health, and they conclude that intake of these compounds should be limited. Most people, however, ingest much fewer nitrates and nitrites than the recommended amount.[2] While eating a lot of processed foods and cured meats might expose you to excessive nitrates or nitrites, the benefits of eating more nitrate-rich vegetables probably outweigh the risks. You might do well to add a few more beets or spinach to your diet, as these nitrate-rich foods can lower your risk of cardiovascular disease.

Health benefits of nitrates from natural sources

While nitrites are not often found in natural plant sources of food, many vegetables can be high in nitrates. Natural sources of nitrates include beets, green leafy vegetables like spinach, celery, and radishes. Nitrate can be converted to nitric oxide (NO) in the body, which is an important signaling molecule.[2] One of the most important benefits of increased NO is a reduction in blood pressure.

Nitrate-rich foods lower blood pressure

NO helps lower blood pressure through blood vessel dilation, inhibition of platelet aggregation, and improving the health of blood vessel walls.[2] In one study, a meal of 250 mg spinach, rich in nitrates, lowered blood pressure and improved the stiffness of arteries in healthy men and women.[3] Another study in the journal Hypertension found that 250 mL of beet juice decreased blood pressure in healthy volunteers, and they attribute the effects to the nitrate content.[4] Researchers also found that there was at least a 5 mmHg decrease in systolic blood pressure in adults given beet juice. This reduction decreases mortality from stroke by 14% and from cardiovascular diseases by 9%.[5]

This research shows that nitrates are not all bad, but that they can, in fact benefit your health. Eating more beets, spinach, celery, and green-leafy vegetables high in nitrate can help to decrease your blood pressure and lower your risk of cardiovascular disease. Your best bet is to avoid excessive nitrate and nitrite additives by avoiding processed and cured foods.

Share your experience

What are your thoughts on the nitrate and nitrite debate? Do you avoid nitrates added to foods as preservatives? Share your thoughts in the comments section below.

[1] Toxicol Rev. 2003;22(1):41-51.

[2] Mol Nutr Food Res. 2014 Aug 27.

[3] Nitric Oxide. 2013 Nov 30;35:123-30.

[4] Hypertension. 2010 Aug;56(2):274-81.

[5] J Nutr. 2013 Jun;143(6):818-26.