6 July 2009
Processed foods linked to Alzheimer's and diabetes
by Kate Melville
Researchers at Rhode Island Hospital have found a substantial link between increased levels of nitrates in our food with increased deaths from diseases; including Alzheimer's, diabetes and Parkinson's. The controversial study, which contends that we have become the "nitrosamine generation," appears in the Journal of Alzheimer's Disease.
Led by Suzanne de la Monte, of Rhode Island Hospital, the researchers studied the trends in mortality rates due to diseases that are associated with aging, such as Alzheimer's, Parkinson's, diabetes and cerebrovascular disease, as well as HIV. They found strong parallels between age adjusted increases in death rate from Alzheimer's, Parkinson's, and diabetes and the progressive increases in human exposure to nitrates, nitrites and nitrosamines through processed and preserved foods as well as fertilizers. Other diseases including HIV-AIDS, cerebrovascular disease and leukemia did not exhibit those trends.
"We have become a 'nitrosamine generation.' In essence, we have moved to a diet that is rich in amines and nitrates, which lead to increased nitrosamine production. We receive increased exposure through the abundant use of nitrate-containing fertilizers for agriculture," said De la Monte. "Not only do we consume them in processed foods, but they get into our food supply by leeching from the soil and contaminating water supplies used for crop irrigation, food processing and drinking."
Nitrites and nitrates belong to a class of chemical compounds that have been found to be harmful to humans and animals. More than 90 percent of these compounds that have been tested have been determined to be carcinogenic in various organs. They are found in many food products, including fried bacon, cured meats and cheese products as well as beer and water. Exposure also occurs through rubber and latex products, as well as fertilizers, pesticides and cosmetics.
Nitrosamines are formed by a chemical reaction between nitrites or other proteins. Sodium nitrite is deliberately added to meat and fish to prevent toxin production; it is also used to preserve, color and flavor meats. Ground beef, cured meats and bacon in particular contain abundant amounts of amines due to their high protein content. Nitrosamines are also easily generated under strong acid conditions, such as in the stomach, or at high temperatures associated with frying or flame broiling.
Nitrosamines become highly reactive at the cellular level, which then alters gene expression and causes DNA damage. The researchers note that the role of nitrosamines has been well-studied, and their role as a carcinogen has been fully documented. The investigators propose that the cellular alterations that occur as a result of nitrosamine exposure are fundamentally similar to those that occur with aging, as well as Alzheimer's, Parkinson's and Type 2 diabetes mellitus.
"All of these diseases are associated with increased insulin resistance and DNA damage. Their prevalence rates have all increased radically over the past several decades and show no sign of plateau. Because there has been a relatively short time interval associated with the dramatic shift in disease incidence and prevalence rates, we believe this is due to exposure-related rather than genetic etiologies," explains De la Monte.
The study involved analyzing mortality rates and comparing them with increasing age and population growth, annual use and consumption of nitrite-containing fertilizers, annual sales at popular fast food chains, and sales for a major meat processing company, as well as consumption of grain and consumption of watermelon and cantaloupe (the melons were used as a control since they are not typically associated with nitrate or nitrite exposure).
The findings indicate that while nitrogen-containing fertilizer consumption increased by 230 percent between 1955 and 2005, its usage doubled between 1960 and 1980, which just precedes the insulin-resistant epidemics the researchers found. They also found that sales from the fast food chain and the meat processing company increased more than 8-fold from 1970 to 2005, and grain consumption increased 5-fold.
The authors contend that the increased prevalence rates of Alzheimer's, Parkinson's and diabetes cannot be explained solely on the basis of gene mutations. Rather, they believe they mirror the classical trends of exposure-related disease. Because nitrosamines produce biochemical changes within cells and tissues, it is conceivable that chronic exposure to low levels of nitrites and nitrosamines through processed foods, water and fertilizers is responsible for the current epidemics of these diseases and the associated increasing mortality rates.
"If this hypothesis is correct, potential solutions include eliminating the use of nitrites and nitrates in food processing, preservation and agriculture; taking steps to prevent the formation of nitrosamines and employing safe and effective measures to detoxify food and water before human consumption," De la Monte concluded.
Source: Journal of Alzheimer's Disease