WHO study points to excess cobalt as a probable cause of cancer – 08/14/2022

As a component of the vitamin B12 molecule, in small amounts, cobalt is essential for the proper functioning of the body. However, in excess, this chemical element can cause several diseases, usually associated with exposure to this mineral at work. Now, a study commissioned by the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO) brings more evidence to what was already suspected: cobalt can also cause cancer.

Published in the Lancet Oncology journal, the work was carried out by scientists from thirteen countries, including pharmacist-biochemist Thomas Prates Ong, professor at the Department of Food and Experimental Nutrition at the Faculty of Pharmaceutical Sciences (FCF) at USP and member of the Research Center in Food (FoRC). Thirty-one specialists from different areas (epidemiologists, biologists, chemists, toxicologists, pathologists, pharmacists, among others) participated in the study, with recognized experience in cancer research. Ong contributed in the areas of nutrition, cancer and epigenetics (hereditary changes that occur in genetic functions without changes in DNA).

Scientists reviewed hundreds of articles, analyzing the carcinogenicity of nine agents: cobalt (metal, soluble salts, two types of oxides, sulfides, and other cobalt compounds), antimony (trivalent and pentavalent), and tungsten for weapons ammunition ( contains nickel and cobalt). For cobalt metal and cobalt compounds, molecular particles of all sizes were included in the evaluation.

Evidence of association with cancer was sufficient for the metal, salts and a type of cobalt oxide. “Cobalt and antimony registered the highest carcinogenicity index in the IARC parameters, classifying them as probable carcinogenic elements. Tungsten, on the other hand, registered lower evidence, so it remains a possible carcinogen”, he says. “We concluded that cobalt induces the formation of tumors by providing an increase in inflammation and mutations. In addition, it modifies the epigenetic pattern by causing changes in the way cells proliferate, differentiate and die”, he adds.

food contamination

According to the study, “Cobalt is used in many industries, including in the manufacture of cutting and grinding tools, in pigments and inks, colored glass, medical implants, electroplating and, increasingly, in the production of lithium-ion batteries.” . For workers in these industries, exposure to cobalt occurs mainly through inhalation of dust and skin contact.

For the general population, ingestion of contaminated food is the main source of exposure, which can also occur from cigarette smoke, air pollution and medical implants. In the case of food, contamination usually occurs when residues from the manufacture of products that use cobalt reach rivers, soil and plantations. “It is a serious problem because it puts a large number of people at risk, with the consumption of contaminated food and water, and that is why the inspection process is very important”, says Ong.

A normal dietary intake of cobalt varies between 5 and 50 micrograms (mg) per day, with a blood plasma concentration of up to 0.2 mg/Liter. It is known that above 7 mg/L of plasma, symptoms of toxicity may occur and excess cobalt in the body is mainly eliminated through the urine.

The foods that contain the most cobalt are nuts, leafy vegetables, cereals, chocolate, coffee, fish and butter. Vitamin B12, which contains this metal, is found in meat and dairy products, but a daily intake of 2.4 ?g of this vitamin – an amount considered ideal by the National Academy of Medicine of the United States (known as the Institute of Medicine) – contain only 0.1 µg of cobalt. But, according to scientific evidence, the consumption of foods that naturally contain cobalt poses no health risks.

Text: FCF Communications Office

Add Comment