Air pollution 'causes obesity'

Controversy erupted after a group of researchers claimed an increase in the concentration of carbon dioxide (CO ₂ ) in the air is one of the reasons for the massive epidemic.

The University of Copenhagen team in Denmark recruited 6 men to perform a test. They asked six people to enter special rooms, where the team could adjust CO ₂ concentrations. After 7:30, the male group is allowed to eat food comfortably. The team found that men in the room with high levels of CO ₂ absorbed 6% more calories than those in the room with normal CO ₂ levels, Livescience reported.

Arne Astrup, a researcher at the University of Copenhagen's Obesity and Nutrition Department, thinks acidity in human blood increases and blood pH levels decrease due to elevated CO ₂ concentrations in the air. Because of the acidity in the blood, the nerve cells of orexin - the type of cell that handles cravings, and are very sensitive to the acidity of the blood - are more active, making people eat more. So the bigger the amount of CO2 in the air, the easier it is for people to be obese.

Air pollution makes the obesity epidemic raging

The Astrup group's theory helps them explain the reality of the weight of many animals, including humans, gradually increasing over the past half century. A study published last year showed the weight of 8 animals increased in the past 50 years, although their diets remained unchanged during that time.

'The data that we have does not support Astrup's hypothesis. Medical experts have not noticed any changes in human blood pH over time , 'said Devanjan Sikder, a professor at the Sanford-Burnham Institute for Medical Research in the US.

The human body needs to maintain blood pH between 7.35 and 7.45 to bring enough oxygen to the tissues.'A small change in pH levels - for example, from 7.4 to 7.38 - is possible , ' said Dr. David Katz, director of Yale University's Center for Disease Prevention and Research at America, affirmed.

Katz said the obesity epidemic broke out because people ate too many unsuitable foods and exercised too little. Unusual hypotheses can explain the cause of obesity in a population, but they cause people to forget the two main culprits of obesity.

Dr. Minisha Sood - an endocrinologist from Lenox Hill Hospital in New York City, USA - said obesity is a complicated phenomenon and has many causes.

'In the context of the current obesity epidemic, I think blaming air pollution is a dangerous act , ' Sood commented.

Sood said that in all circumstances, people still have to pursue a healthy and scientific lifestyle to maintain a reasonable weight.