“Nitrates” may make you think of school chemistry lessons or fertilisers. They’re probably less likely to be something you’d associate with dinner.

If you do think of nitrates in the context of food, it is probably a negative image that comes to mind – in particular, perhaps, the recent call for nitrate and nitrite preservatives to be banned from bacon and ham because of potential cancer-causing effects.

But the relationship between dietary nitrates/nitrites and health is a lot more nuanced than merely saying “they’re bad for us”. For example, the high natural nitrate content of beetroot juice has been credited with lowering blood pressure and enhancing exercise performance. Nitrates are also the active ingredient in some medications for angina, a condition in which reduced blood flow causes chest pain.

So are nitrates and nitrites actually bad for us?

You might also like:

• Are any foods safe to eat anymore?

• We don’t need nearly as much protein as we consume

• Is a low-salt diet healthy?

Nitrates and nitrites, such as potassium nitrate and sodium nitrite, are naturally occurring chemical compounds which contain nitrogen and oxygen. In nitrates the nitrogen is bonded with three oxygen atoms, while in nitrites the nitrogen is bonded with two oxygen atoms. Both are legal preservatives which suppress harmful bacteria in bacon, ham, salami and some cheeses. (Read more about how cured meats protect us from food poisoning).