Can Air Pollution Really Make Us Fat?

air pollution

Several studies appear to show a disturbing correlation between airborne particles, obesity, and its associated diseases. Should we be concerned?

The Chinese capital of Beijing is known for many things. Visitors to this ancient city typically head to Tiananmen Square, which hosts the Forbidden City, the National Museum of China, and several other monuments. From there, they typically head to the lush green spaces of Beihai Park or the Summer Palace. Let’s not forget the Dashanzi Art District.

Today, China’s massive capital city, home to more than 21 million people, is known for more than its ancient sites, modern architecture and cultural relics. Sadly, Beijing has for many years suffered from serious air pollution. Primary pollutant sources include exhaust emissions—Beijing has more than five million motor vehicles—coal burning, dust storms from the north and local construction dust. In 2013, severe smog engulfed Beijing for weeks, elevating public awareness to unprecedented levels and prompting the government to final enact emergency measures.

Ambient (outdoor) air pollution like that seen in Beijing can, and often does cause immediate health problems, including cardiovascular and respiratory illness, added stress to heart and lungs, which must work harder to supply the body with oxygen, accelerated lung aging, diminished lung capacity and function, diseases such as asthma, type 2 diabetes (in children), bronchitis, emphysema, and cancer, and shortened life span. Pollution increases blood coagulability, the formation of blood clots.

If you’re somehow unmoved by talk of asthma, bronchitis, cancer, heart disease, people choking, mutated and damaged vegetation, and ozone depletion, then this next tidbit might catch your attention: Increasing scientific evidence links pollution to obesity. OK, so even if you’re unconcerned about heart disease, diabetes, and cancer, you might really start stressing out if you can’t button your pants or fit into that little black dress in time for your 25th high school reunion.

Last year, Duke University researchers published a study where both pregnant laboratory rats and their progeny were exposed to unfiltered Beijing air. The exposed rats gained more weight than those who breathed filtered air. The researchers also noted other concerning changes in mother and child, such as lung inflammation, cholesterol problems, and early signs of tissue damage.

Yes, I know what you’re thinking. These were lab rats—not humans—deliberately exposed to a noxious mixture of carbon monoxide, nitrogen dioxide, ozone, sulfur dioxide, particulate matters, lead, arsenic, asbestos, benzene, chlorine, bromine, halons, methane and many other unpronounceable chemicals. But how can we reasonably believe that inhaling the equivalent of car exhaust directly from the tailpipe wouldn’t have an adverse impact on our health? You may not be a rat, but seeing such changes during a relatively brief exposure to air pollution should make us all pause and consider what years of breathing pollution can do. Of course, air pollution is also about saving the planet. But what if there’s no one left to live on it?

The Duke Study wasn’t the first, nor will it be the last, to demonstrate a pollution-obesity association. A second animal study, this one involving mice, published in the journal Environmental Health Perspectives, found that exposing pregnant mice to tributyltin (TBT), commonly found in water pipes and plastic, increased their fat cell size and number and was also responsible for a corresponding fat accumulation in the liver. A 2011 study published in the American Journal of Epidemiology found that children in New York City (the Bronx and northern Manhattan specifically) born to mothers exposed to polycyclic aromatic hydrocarbons (PAH), a common air pollutant, had higher obesity rates, BMI, and body fat percentage. While more studies are probably needed to establish a pollution-obesity link, the evidence appears to be more than circumstantial.

Why Air Pollution?

What about air pollution leads to obesity, exactly? Well, it would be surprising if all the strange substances now floating in the air didn’t somehow affect our bodies’ finely tuned metabolic processes. The bacteria inhabiting our intestines form what’s called a “microbiome,” which science has now shown affects a several critical life functions, including digestion and fat cell metabolism. Air pollution impacts gut bacteria. A 2010 Cedars-Sinai study found that obese patients who test positive for methane on their breath had a significantly higher body mass index (BMI) than their peers. The Cedars Sinai study was significant because it was the first to show evidence of methane-producing bacteria in the gut and elevated BMI, indicating that bacteria may play a role in human obesity.

A related 2014 study in the peer reviewed journal Gut Microbes found that airborne particulate matter (PM), ingested via contaminated food, could alter gut microbiome and immune function “under normal and inflammatory conditions.” The researchers concluded that PM literally modifies our gut microbes’ form and function, demonstrating that pollutants affect the gastrointestinal tract. Continued research could lead to identifying airborne pollutants as potential risk factors, providing better long and short term patient care management.

What Can You Do?

I’ve always counseled my patients that obesity is an indication that something’s wrong in their lives. Some don’t want to hear this, as they may believe I’m casting aspersions or judging them too harshly. This is never my intention. There are many factors contributing to obesity’s ascent, from the food, drink and medications we put in our bodies to our environment, spiraling healthcare costs and even politics. Obese folks aren’t psychologically damaged. They don’t suffer from some strange, unknown mental defect. They don’t lack willpower or self-control. I’m not holding obese people accountable more than I hold diabetics accountable for their disease. But here’s a fact that’s not in dispute: Obesity’s rise is both a sign of the times and harbinger of tough times ahead if we don’t act now. I can guarantee that your life is going to get a whole lot worse if you don’t do something about your weight!

So perhaps everyone should heed these warnings. While some air quality measures have improved in certain locations, air quality remains bad or is even getting worse, especially in urban areas with significant low and middle income residents, according to 2016 World Health Organization report. Moreover, as new industries and practices emerge and grow, so do new types of air pollution. In the American Lung Association’s “State of the Air 2014” report, Pittsburgh made the top 25 list for all three measures of the poor air quality (ozone, year-round particle pollution, and short-term small particle pollution). Recently, fracking—a process used to extract natural gas from the ground—has paved the way for drilling into America’s enormous shale deposits, fueling a dramatic boom in U.S. oil production. Of course, this drilling has not come with a cost in the form of huge amounts of methane gas being released into the air.

The possible air pollution-obesity link suggests that we have to act now. At home products, including something called the G Code, a simple, at home test that profiles and inventories a person’s gut bacteria, might help, as can natural zeolites, which have been shown to counteract the effects of indoor air pollution. Clean air initiatives, including Bill Gates’ much heralded investments in and calls for clean and renewable energy technology, are not just about saving ourselves, but also preserving the planet for our children. Even if you don’t care about the future, which would be a crime, please think about what air pollution might be doing to you—and your waistline—today, and to future generations.

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