Registered dietitian, Abby Courtenay, helps us better understand food processing additives – nitrates and nitrites.

I am sure you have heard the headlines about how processed meats are dangerous and that we should avoid them at all costs. Not only have they been linked to the recent listeriosis outbreak, but processed meats also contain food processing additives, called nitrates and nitrites, which many people are concerned about.

What are nitrates and nitrites and why are they used in food manufacturing?

Food is processed in different ways; one of these ways is curing. Curing is the process of adding sugar, salt, nitrates or nitrites to food with the aim of drawing out moisture through the process of osmosis.

Commonly used nitrates and nitrites include sodium nitrite, potassium nitrite, sodium nitrate and potassium nitrate. These can be added as a singular ingredient or in any combination with or without salt (NaCl or sodium chloride).

Nitrates, nitrites and other curing aids are added to meat and meat products to help improve their colour, texture and flavour (with the characteristic pink colour and saltiness of preserved meat being due to the nitrates/nitrites). They also prevent or delay unwanted bacterial growth, thus prevents the food from spoiling quickly. The maximum recommended levels of sodium nitrite salts allowed in cured meat is 200mg/kg, or in the case of side bacon 120mg/kg.¹

Is there a difference between nitrates and nitrites?

Nitrates and nitrites are compounds that are found naturally in some foods (mainly vegetables), but they are also added to other foods as a preservative. The difference between a nitrate and a nitrite is the amount of oxygen atoms they possess with a nitrate containing three atoms (NO₃) and nitrite containing two (NO₂). Nitrates are converted into nitrites through bacterial or enzymatic activity (in the body or in food processing). Nitrites are the active curing/preserving compound.^1,2

Why should I limit my consumption of nitrates/nitrites?

Nitrites are converted into nitric oxide and nitrosamines. Nitrosamines can also be formed inside your body from haem (in the low pH of your stomach). Nitrosamine compounds are known carcinogens (which means they are cancer causing)³.

It is vital to note that the amount of nitrates/nitrites found in processed foods is very little in comparison to the amount found naturally in some foods. However, processed foods are filled with other ingredients that are not healthful and this together with the cancer risk has led to the recommendation that you consume very little, if any, processed meats.³

Practical solutions to eat less nitrates/nitrites

Great alternatives to processed meats include fresh red meat (remember to limit this to no more than 350-500g cooked red meat per week, which equates to approximately 700-750g raw meat),⁴ poultry, fish, eggs, dairy and legumes. These options provide a good amount of protein and micronutrients at a lower risk. Some great ideas include:

• So, instead of lunch meats (like ham or polony), try roast chicken, egg mayo or cottage cheese on a sandwich.
• Replace your breakfast side of bacon or sausage with grilled minute steaks or slices of poached salmon. It will still taste great with your egg.
• Try a Sloppy Joe, which is a roll filled with savoury mince instead of choosing hot dog viennas.

References:

1. [Internet]. Wcrf.org. 2018 [cited 20 June 2018]. Available from: https://www.wcrf.org/sites/default/files/Cancer-Prevention-Recommendations-2018.pdf
2. Honikel K. The use and control of nitrate and nitrite for the processing of meat products. Meat Science. 2008;78(1-2):68-76.
3. Preventive control recommendations on the use of nitrites in the curing of meat products – Canadian Food Inspection Agency [Internet]. Inspection.gc.ca. 2018 [cited 20 June 2018]. Available from: http://www.inspection.gc.ca/food/sfcr/general-food-requirements-and-guidance/preventive-controls-food-businesses/meat/nitrites/eng/1522949763138/1522949763434
4. Limit red and processed meat [Internet]. World Cancer Research Fund. 2018 [cited 20 June 2018]. Available from: https://www.wcrf.org/dietandcancer/recommendations/limit-red-processed-meat

MEET OUR EXPERT

Abby Courtenay RD (SA) is an associate dietitian at Nutritional Solutions Grayston and Melrose. She graduated with a Bachelor of Dietetics at University of Pretoria and also holds a Masters’ degree in Nutrition from the University of Stellenbosch. Abby has a special interest in: women’s health, infant feeding and oncology.