New research from Edith Cowan University (ECU), Australia, led by Dr. Nicola Bondonno, has found that nitrate from plants can lower the risk of death from various causes, including heart disease and cancer. On the other hand, nitrates from animal products and processed meats can lead to a higher mortality risk.
Nitrate and nitrite are found in food and drink; their sources could be plants, processed meats (added as additives), drinking water, or animal products, where they naturally occur, and their consumption impacts human health in various ways.
The source matters
To shed light on the topic, the study researched whether the health outcomes associated with nitrate and nitrite consumption differed depending on the source of these compounds.
After examining 52,247 participants from the Danish Diet Cancer and Health Study, calculating their nitrate and nitrite intake based on food composition data and national databases for drinking water quality, the researchers suggest that the source of nitrate matters.
“…nitrate can go down two different pathways when introduced into the body”
Plant-based nitrates appear to be beneficial, while nitrates from other sources might pose health risks. The study found that moderate to high intakes of nitrate-rich vegetables reduce the risk of all-cause, cardiovascular disease (CVD), and cancer-related mortality by 14% to 24%. According to the study, the reason behind this outcome is that vegetable antioxidants seem to convert plant nitrates into nitric oxide, which benefits cardiovascular health.
Notably, the research reinforced the mounting evidence that there is no cancer risk associated with nitrate-rich vegetables including leafy greens and beetroot, as it has been commonly believed.
Harmful nitrosamines
Meanwhile, the researchers found that other sources of nitrates might be converted into potentially harmful nitrosamines, which are carcinogenic.
For example, according to the study, higher intakes of naturally occurring animal-sourced nitrate were linked to a 9% and 12% higher risk of all-cause and CVD-related mortality, respectively. At the same time, naturally occurring animal-sourced nitrite was associated with an increased risk of all-cause, CVD-related, and cancer-related mortality by 25%, 29%, and 18%, respectively.
“…nitrate may also go down a second pathway, forming a group of compounds called nitrosamines, which are considered to be carcinogenic”
In the case of processed meat-sourced nitrates and nitrites, the researchers suggest an increase in the risk of all-cause and cancer-related mortality by 12% to 22%.
Curiously, participants with a higher intake of tap water-sourced nitrate were associated with higher all-cause and CVD-related mortality but not cancer-related mortality.
The pathways of nitrate
Although the research couldn’t pinpoint plant-based nitrate as the sole factor in promoting human health — as vegetables contain other compounds linked to lower risks of cardiovascular disease, cancer, and diabetes — the study emphasizes the importance of consuming more nitrate-rich vegetables to reduce mortality risks. It encourages a diet rich in vegetables and reduced processed meat.
Dr. Bondonno told ECU Newsroom, “In simplistic terms, nitrate can go down two different pathways when introduced into the body. One is to form a compound called nitric oxide, which has been shown to improve blood flow, lower blood pressure, and support overall cardiovascular health.
“But nitrate may also go down a second pathway, forming a group of compounds called nitrosamines, which are considered to be carcinogenic and are linked to cancer. It is thought that the antioxidant compounds in vegetables push nitrate towards the first pathway.”
The complete study can be found here.
