The plague of diabetes

Notícia publicada em:

  • 23 de Setembro de 2015

diabetes e pesticidadiabetes e pesticidaThe diagnosis of diabetes in adulthood is usually related to a diet high in sugar and fat. Combined with a sedentary routine, poor diet is a condition for the development of insulin resistance, the substance responsible for balancing the level of glucose in the blood. However, even healthy foods, such as fish and vegetables, can hide a little known villain: pesticides and other chemical compounds that persist for years in the soil and in the body of animals and can increase the chances of developing all kinds of metabolic syndrome in 61%.

The percentage was disclosed at the meeting of the European Association for the Study of Diabetes last week in Stockholm. A group of scientists examined 21 research that studied the relationship between pesticides and diabetes in more than 66 thousand individuals from different countries. “We were surprised with the consistency of the results across different subgroups and with sensitivity analysis, where the relative risk remains high”, said to Correio Evangelos Evangalou, researcher at the Public Health School of Imperial College, London, and one of the authors of the comparative work.

Evangalou points out that the articles analyzed do not explain the mechanism that can bind the pesticides to the disease. However, he also points out that there are other experimental studies — made with animal and in vitro tests — showing that pesticides can stimulate insulin resistance, which would lead to the development of type 2 diabetes. When specifically investigated the influence of these contaminants on the variation of this type of diabetes, the articles pointed to an increased incidence of up to 64%. “But it would be important to undertake a systematic review of the mechanisms of the development of diabetes through pesticides and organic contaminants in general”, ponders the researcher.

The analysis did not indicate whether genetic predisposition or other environmental agents aggravate the effect of pesticides on metabolism, but some factors indicate that patients with highest percentage of body fat may be more subject to diabetes caused by exposure to toxic compounds. This is because the insolubility of pesticides and other pollutants allows them to be stored for a long time in the fatty tissue of humans and animals.

“However, we also found a high concentration of pollutants in the adipose tissue of skinny people who have had a major exhibition (to these substances)”, explains Juan Pedro Arrebola, expert and researcher at the University of Granada. Arrebola held in 2013 a study with 386 patients from a hospital of Granada, in Spain, and noted that the presence of some toxic substances, such as DDT, can increase the chances of developing diabetes in up to four times.

Immune reaction
Scientists believe that these compounds cause an immune response that would lead to the metabolic problem. “Certain chemicals may exert an immunotoxic effect when binding to estrogen receptors, which induces chronic inflammation, reduces mitochondrial function, leads to the oxidation of fatty acids and to the increase of lipolysis, all factors related to insulin resistance syndrome”, explains Arrebola. Studies also show that pesticides can alter the function of the beta cells that produce insulin. This means that the long-term poisoning could lead also to diabetes type 1.

Another article of the Group of Juan Pedro Arrebola, published at the end of last year, demonstrated the relationship of organic pollutants with gestational diabetes. The study examined 107 women who had a history of illness and demonstrated a relationship between the concentrations of pollutants and insulin resistance developed by the body of most patients. The researchers believe that the subclinical condition might be offset by the increased production of insulin, which would explain the difficulty in relating the fasting glucose levels with pollutants.

Among the substances found in the body of patients who developed diabetes, there are compounds such as DDT and chlordane, two insecticides that had the use banned in most countries, but they remain present in animals and humans. On the list of so-called persistent organic pollutants (POPs), earning that name for just the long-term they take to disappear. DDT, for example, takes up to 30 years to disappear from contaminated soils and waters. Chlordane, which was formerly used for the extermination of termites, can be found decades later after applied in residences.

Fish are considered to be the major victims of these compounds, they end up concentrating themselves on seas near industrial areas and in the polar regions. While in humans the effects of pesticides are still being understood by scientists, in aquatic animals, the phenomenon is quite clear: the toxins affect the reproductive health of these animals and damage the entire food chain in which they are involved. These substances are also found in the adipose tissue of cows, vegetables and all kinds of species that had contact with a soil or contaminated food.

“Some of these compounds can persist for 15 to 20 years in the soil and parts of them are swept away by the rains into the interior of the water courses, which also receives them by industrial effluents, sewage, sediments, atmosphere and direct contamination”, explains Professor Sandra Rissato, from the Chemistry Department of the Universidade Estadual Paulista (Unesp). Rissato points out that it is difficult to have a clear notion of levels of POPs and other pesticides in agricultural products consumed in Brazil. “The difficulty lies in the fact that it is an invisible contamination. It is virtually impossible for the consumer to recognize a contaminated product”, she says. A possible way out for consumers, suggests the expert, is to opt for certified products of organic source and search for crop places with known history.

More susceptible

According to a survey done by the North American National Institute of Health (NIH), the professionals who work directly with the application of pesticides may have a greater risk of acquiring the disease in 200%. The greatest danger to health identified in the study is the tricloforn, still used to exterminate cockroaches and ticks. This insecticide can increase the chances of developing diabetes in nearly 250% for those who have had at least 10 exhibitions
to the substance.


International combat

In 2004,  Stockholm Convention entered into force, which determines a series of measures to be taken by countries to the elimination of Persistent Organic Pollutants (POPs). The document lists 12 substances that today have the production, commercialization and use controlled in 160 countries, including Brazil. The Convention determines that Governments promote the best technologies and practices for the management and disposal of POPs, as well as prevent their proliferation. Through the agreement, innovative technology options are offered, in addition to financial support for the search for replacement of these substances alternatives and sustainable development.

Source: Correio Braziliense.
Image: Uol.