Are nitrates and nitrites in foods harmful?
There is a lot of confusion about nitrates and nitrites in the diet. These are compounds found naturally in some foods (like vegetables) but also added to processed foods (like bacon) as a preservative. Some people believe that they are harmful and can cause cancer. However, the science isn’t as clear, and some studies suggest that they may even be healthy.
So ... what is the truth about nitrates/nitrites in the diet? First, what are nitrates and nitrites? In order to understand what nitrates and nitrites are, we need to review a bit of chemistry. I will try to keep it simple because it has been a while since that high school chemistry class.
These are two types of compounds, consisting of a single nitrogen atom bonded to a number of oxygen atoms.
• NITRATE: 1 nitrogen, 3 oxygens — chemical formula: NO3
• NITRITE: 1 nitrogen, 2 oxygens — chemical formula: NO2So... Nitr-a-tes have 3 oxygen atoms, while Nitr-i-tes have 2 oxygen atoms.
It seems that the nitrates themselves are relatively inert, until they are turned into nitrites by bacteria in the mouth or enzymes in the body. Nitrites are the key players here. They can either turn into Nitric Oxide (good) or nitrosamines (bad) — which we will cover in detail shortly
Nitrites are the reason cured meat is pink or red. Nitrites turn into ni- tric oxide, which reacts with the oxygen-binding proteins in the meat, changing its color. Without additives like nitrites, the meat would turn brown very quickly.
Nitrates and nitrites are found in all sorts of foods and are produced by our own bodies
Nitrates and nitrites are frequently added to processed meats like bacon, ham, sausages and hot dogs. They function as preservatives, helping to prevent the growth of harmful bacteria. They also add a salty flavor and improve the appearance of the meat products by giving them a red or pink color.
We do know that consuming processed meats is strongly linked to an increased risk of cancer in the digestive tract, and many people believe that the nitrates/nitrites are the reason for that. A good hot dog over the Fourth of July or Labor Day is not a bad thing. Everything in moderation is the key.
However, they are also found naturally in foods like vegetables that are generally perceived as healthy, and linked to a reduced risk of cancer. Vegetables are actually the biggest dietary source of nitrates by far. The amount you get from processed meat is small compared to vegetables.
Our bodies also produce nitrates in large amounts and secrete them into saliva. They seem to function as antimicrobials in the digestive system, helping to kill pathogenic bacteria like salmonella. Nitrates can even be found in drinking water in some areas. Fortunately for us here in Imperial Valley, the nitrate level is low. Nitrate amounts in drinking water are regulated.
Dietary nitrates/nitrites lower blood pressure and have major benefits for heart health
If nitrite loses an oxygen atom, it turns into nitric oxide, an important molecule. nitric oxide is a short-lived gas, which has various functions in the body. Most importantly, it is a signaling molecule. It travels through the artery wall and sends signals to the tiny muscle cells around the arteries, telling them to relax. Some of us need that relax cue. When these cells relax, our blood vessels dilate and blood pressure goes down. This is actually how the well-known drug nitroglycerin works. It is a source of nitrate, which quickly turns into nitric oxide and dilates the blood vessels. This can prevent or reverse angina, the chest pain that occurs when the heart muscle doesn’t get enough oxygen due to reduced blood flow.
Dietary nitrates and nitrites can also turn into nitric oxide, dilate the blood vessels and lower blood pressure. Studies have shown that nitrate supplements, such as beet roots or beet root juice, can reduce blood pressure by up to 4-10 mm/Hg over a period of a few hours. The effect may be weaker in women. Elevated blood pressure is one of the strongest risk factors for heart disease and stroke (the world’s biggest killers), so the importance of this cannot be overstated.
They are only a problem when they form nitrosamines ... which can happen during high-heat cooking
Unfortunately, there is a dark side to all of this. When nitrites are exposed to high heat, in the presence of amino acids, they can turn into compounds called nitrosamines. There are many different types of nitrosamines, and most of them are potent carcinogens (cancer causing). They are among the main carcinogens in tobacco smoke, for example.
Because most bacon, hot dogs and processed meat tend to be high in sodium nitrite and they’re high protein foods (a source of amino acids), exposing them to high heat creates the perfect conditions for nitrosamine formation. It’s important to keep in mind that nitrosamines mostly form during very high heat. Even though vegetables also contain nitrates/nitrites, they are rarely exposed to such high heat. Nitrosamines can also form during the acidic conditions in the stomach.
How to minimize your nitrosamine exposure without having to give up bacon
Nitrosamines are a well-known problem in processed meats, and manufacturers are required to limit the amount of nitrites they use. They are also required to add vitamin C, which inhibits nitrosamine formation. The processed meat eaten today contains about 80 percent less nitrites than it did a few decades ago. For these reasons, today’s processed meat may not be nearly as carcinogenic as it used to be.
But just to be on the safe side, there are some steps you can take to minimize your nitrosamine exposure even further without having to give up bacon.
You can choose quality bacon that is truly nitrate-free, not laden with celery salt or something similar that also contains nitrates. A lot of “nitrate free” bacon can even contain more nitrates than conventional bacon.
Another thing you can change is the way you cook your bacon. Frying it at a lower heat for longer will produce fewer nitrosamines than a higher heat for a shorter amount of time. Burnt bacon is the worst. According to one study, cooking bacon in a microwave is the best way to minimize nitrosamine formation.
So, cooking your quality bacon at lower heat or in the microwave, eating healthy vegetables, and eating a moderate amount of preserved meats is good for you. It also supports our local beef industry (all beef hot dogs), and the local vegetable and produce growers.