Researchers from France found that consuming high levels of nitrite, often used as a preservative in some meat products, is associated with the risk.
Nitrate and nitrite are compounds that naturally occur in soils, water, air, and plants. They are also commonly found in vegetables such as lettuce, spinach, and celery. These compounds are also used as a preservative in some meat products.
According to the CDC, most people are not exposed to nitrate and nitrite at a high enough level to cause health problems. However, the agency says that high nitrite consumption has caused cases of methemoglobinemia, or a decrease in the ability of blood cells to carry oxygen. High nitrate or nitrite levels also resulted in thyroid function changes in animal studies.
Research on the association of nitrites and nitrates with specific types of cancer has been inconclusive. Still, some evidence suggests there may be a link.
As a result of questions surrounding the health effects of nitrates and nitrites, some health authorities have called for limiting the use of these compounds in foods.
Now, a new study from scientists in France found that people who reported higher overall consumption of nitrite had an increased risk of developing type 2 diabetes. However, nitrate intake was not associated with an increased risk.
According to the study — published in PLOS Medicine — this is the first large-scale cohort study to suggest a direct association between additives-originated nitrites and type 2 diabetes risk.
To determine if nitrate and nitrite play a role in the development of type 2 diabetes, the researchers collected data from 104,168 participants in the prospective cohort NutriNet-Santé. This cohort study began in 2009 and gathers data including diet, lifestyle, and health factors of volunteer participants aged 15 or older.
Using statistical analyses, the research team calculated the participant’s nitrate/nitrite exposure using self-reported diet and health information.
During an average 7.3-year follow-up, 969 people developed type 2 diabetes. Overall, participants who consumed higher levels of nitrites from food additives — specifically sodium nitrite — had an increased type 2 diabetes risk compared to those who did not consume additives. In addition, nitrites from all sources were associated with a higher risk.
However, the scientists found no evidence of a link between nitrates from food, water, or additives and type 2 diabetes risk.
Still, the study authors say that because of the self-reported and observational design of the study and that participants generally had healthier lifestyle habits and higher socio-professional levels, more research is needed to confirm their results.
- CDC. Nitrate and Nitrite-ToxFAQs.
- Nutrients. Association between Dietary Nitrate, Nitrite Intake, and Site-Specific Cancer Risk: A Systematic Review and Meta-Analysis.
- PLOS Medicine. Dietary exposure to nitrites and nitrates in association with type 2 diabetes risk: Results from the NutriNet-Santé population-based cohort study.