Rhode Island researchers say they have found strong evidence that links the level of nitrates in the environment and food supply to increases in deaths from such diseases as diabetes, Alzheimer’s, and Parkinson’s-all insulin-resistant ailments.
A research team at Rhode Island Hospital in Providence studied mortality rates from the above diseases, which are usually associated with aging. They found that age-adjusted increases in death rates from the diseases were paralleled by increases in exposure to nitrates, nitrites, and nitrosamines found in fertilizers and processed and preserved foods.
The researchers started out by studying mortality among 75- to 84-year-olds over a 37-year period. The diseases they studied included not only diabetes, Alzheimer’s, and Parkinson’s, but also cerebrovascular and cardiovascular diseases – all diseases considered typical of old age.
But they found that deaths from diabetes and the other two insulin-resistant diseases increased far more over almost four decades than deaths from cerebrovascular and cardiovascular diseases. In fact, the mortality rate among people suffering from cerebrovascular disease declined over the 37-year period.
Because the changes were so dramatic, said team leader Suzanne de la Monte, MD, MPH, the researchers began to suspect an environmental rather than a genetic cause. Further study showed that levels of nitrates and nitrites in the food supply and environment had also increased over the same span of time.
In short, the longer people were living, the more they were exposed to toxic substances that could lead to the three inflammatory diseases.
Nitrates and nitrites are chemical compounds that can be highly carcinogenic at high levels. Many food products, such as cured meats, fried bacon, beer, and cheese contain them. Other environmental sources include fertilizers, cosmetics, pesticides and the manufacture of rubber products.
When nitrites combine with other nitrites or proteins, they become nitrosamines, which are highly reactive at the cellular level, altering gene expression or causing damage to DNA. One of the bases of nitrosamines is sodium nitrate, a chemical added to meat and fish to assist with a range of tasks, including preservation, color and flavor enhancement, and the prevention of toxins.
The high temperatures involved in frying or flame broiling generate nitrosamines from sodium nitrate, and the researchers think that they create changes in the cells that are much the same as the alterations that occur in aging or diabetes. Because so many people eat foods that contain nitrates and nitrites, the Rhode Island scientists believe that they have found a major factor in the acquisition of diabetes, Alzheimer’s and Parkinson’s.
Based on those findings, the researchers recommend eliminating nitrites and nitrates in agriculture and food processing, as well as finding ways to prevent nitrosamine formation.
The study was published in the Journal of Alzheimer’s Disease (Volume 17:3 July 2009).