Potassium_nitrateLook at any packet of processed meat and you will probably find nitrates listed there somewhere. Used commonly as a preservative, they also enhance the color and flavour of foods. But are they harmful to our health?


What are Nitrates?

Nitrates (NO3) and nitrites (NO2) occur naturally in foods and nitrates are easily converted into nitrites and vise versa. Made of Nitrogen and Oxygen atoms, nitrates have 3 oxygen atoms while nitrites have 2 oxygen atoms.

Nitrates are a salt or ester of nitric acid, or any compound containing the univalent group –ONO 2 or NO 3. When we talk about nitrates in food we are usually referring to fertilizers composed of potassium nitrate or sodium nitrate or nitrates that are added directly to foods as they are being processed.

Using too much nitrates in fertilizers can produce foods high in nitrate. Similarly, ingestion by animals of foodstuffs treated with nitrates can carry through the foodchain (e.g. in the milk of cows or the bacon of pigs).

Food manufacturers also add nitrates to foods to extend their shelf life, inhibit the growth of mould and improve color and taste. Many highly processed meats appear pink due to the presence of nitrates.

Nitrates have generally been approved by food authorities the world over with the usual lack of research into their long term effects. The two main forms of nitrite and nitrate are sodium and potassium nitrite and sodium and potassium nitrate which can also appear as E numbers E250, E249, E 251 and E 252 respectively.

Natural foods such as beetroot, celery and lettuce can contain natural nitrates.




OK, But what do Nitrates do to my body?

Hot Dogs - Definitely not what you think.
Hot Dogs – Definitely not what you think.

There is some debate as to the exact effect of nitrates on the body. In naturally occurring amounts they are harmless (eat a bag of lettuce every day for ten years and you’ll be just fine) but in unnaturally occurring amounts (such as in sausages, hotdogs, meatballs etc) the effect on the body over the longer term is highly questionable. Like every other additive to food, the effect of consuming nitrates and nitrites in high quantities on a regular basis over a long period of time has not been analysed, yet the additives have been declared food safe.

Synthetic (i.e. man made) nitrates in particular are commonly the ones found as a food preservative. During cooking (i.e. using high temperatures) or in the highly acidic environment of the stomace, nitrites can convert into nitrosamines. Over 90% of nitrosamines are carcinogenic. Incidentally, nitrosamines are used in the manufacture of some cosmetics, pesticides and nearly all rubber products.

Nitrates can also cause methemoglobinemia, expecially in young children. This is when the nitrates harm our hemoglobin rendering it unable to carry oxygen leading to ‘blue baby syndrome’.

Should I avoid nitrate laden foods?

Yes. To give you a short answer. Nitrates occur naturally in plants to varying degrees but it is unlikely that you are regularly exposing lettuce and beetroot to high heat every day and converting them into nitrosamines. Even if you do cook these foods, you are probably not having fried beetroot every day.

Processed meat on the other hand is something that we consume on a regular basis. Nearly all processed meats will contain nitrates if offered for sale raw. Cooked meats will contain nitrates and probably nitrosamines. Far better to insist on organic foods that have not been subject to nitrates in their food or been treated with nitrates prior to being offered for sale.