Obesogens are artificial chemicals believed to contribute to obesity.
They are found in various food containers, baby bottles, toys, plastics, cookware and cosmetics.
When these chemicals enter your body, they can disrupt its normal function and promote fat gain ().
Over 20 chemicals have been identified as obesogens and this article covers some of the most important ones.
Obesogens are a category of endocrine disruptors — chemicals that can interfere with your hormones ().
Some endocrine disruptors exert their effects by activating estrogen receptors, which can cause harmful effects in both women and men.
Estrogen receptors are thought to be "promiscuous," meaning that they will bind to anything that looks even remotely like an estrogen ().
Some obesogens have not only been linked to obesity, but also to birth defects, premature puberty in girls, demasculinization in men, breast cancer and other disorders.
Unfortunately, many of these effects happen in the womb. For example, when pregnant women are exposed to these chemicals, their child’s risk of becoming obese later in life may increase ().
Below is a discussion of 5 obesogenic chemicals that may be present in your home at this very moment.
Bisphenol-A (BPA) is a synthetic compound found in many types of products, including baby bottles, plastic food and beverage containers, as well as metal food cans.
It has been in commercial use for many decades, but recent studies have shown that high levels may cause harm to both lab animals and humans ().
BPA’s structure resembles estradiol, which is the most important form of the female sex hormone estrogen. As a result, BPA binds to estrogen receptors inside the body ().
It appears that the time of greatest sensitivity to BPA is in the womb. Interestingly, 96% of pregnant women in the US test positive for BPA in their urine ().
Multiple studies have associated BPA exposure with weight gain and obesity, in both lab animals and humans (, , , ).
BPA exposure has also been linked to insulin resistance, heart disease, diabetes, neurological disorders, thyroid dysfunction, cancer, genital malformations and more (, , , ).
While all scientists agree that BPA causes harm at high levels, there is still some debate over whether it’s harmful at the low levels found in food.
The regulatory authorities of the United States and European Union estimate that the levels of BPA in food are too low to cause harm in humans. At least, food exposure to BPA hasn’t been proven to cause harm (, , ).
Yet, it is still unclear whether low levels of BPA can affect human development in the womb. More studies are needed before it can be known for sure.
Nevertheless, countries such as Canada and Denmark find the evidence concerning enough that they've set laws to reduce the amount of BPA in consumer products.
I have listed some methods to minimize your exposure to BPA (and the other obesogenic chemicals) at the bottom of the article.
Summary Bisphenol-A (BPA) has been linked to obesity and many other diseases in humans, although not all scientists agree that the low levels found in food cause harm. It is primarily found in plastics and canned foods.
Phthalates are chemicals used to make plastics soft and flexible.
They are found in various products, including food containers, toys, beauty products, pharmaceuticals, shower curtains and paint.
These chemicals can easily leach out of plastics and contaminate foods, the water supply and even the very air we breathe ().
A Swedish study found that children can absorb airborne phthalates from plastic floor material through the skin and respiratory tract ().
In a study by the CDC, most Americans tested positive for phthalate metabolites in their urine ().
Like BPA, phthalates are endocrine disruptors, affecting the hormonal balance in your body (, ).
Phthalates may be contributing to increased susceptibility to weight gain by affecting hormone receptors called PPARs, which are involved in metabolism ().
Studies in humans have shown that phthalate levels in the body are associated with obesity, increased waist circumference and insulin resistance (, , ).
It appears that men are particularly susceptible. Studies show that phthalate exposure in the womb leads to genital malformations, undescended testicles and low testosterone levels (, , , , ).
One study found that phthalate metabolites in the blood correlated with type 2 diabetes ().
Many government and health authorities have begun taking action against phthalates, with the state of passing laws that instruct toy manufacturers to stop using phthalates in their products.
Summary Phthalates are chemicals found in many plastic products. Some studies show a link between phthalate exposure and obesity, type 2 diabetes and genital malformations in boys.
Atrazine is one of the most widely used herbicides in the US.
It has been banned in Europe for over a decade because of groundwater contamination ().
Atrazine is also an endocrine disruptor and several studies show that exposure correlates with birth defects in humans (, , ).
In the US, there is an overlap between the areas that use the most atrazine and the prevalence of obesity.
It has been shown to damage mitochondria in rats, decreasing the metabolic rate and increasing abdominal obesity ().
Of course, correlation does not equal causation and studies are still a long way off from proving that atrazine is a significant contributor to obesity in humans.
Summary Atrazine is a commonly used herbicide. Several studies have associated atrazine exposure with an increased obesity risk, and high levels may promote weight gain in mice.
Organotins are a class of artificial chemicals used for various industrial purposes.
One of them is called tributyltin (TBT). It is used as a fungicide and applied to boats and ships to prevent the growth of marine organisms on the hull. It is also used in wood preservatives and some industrial water systems.
Many lakes and coastal waters are contaminated with tributyltin (, ).
Tributyltin is harmful to marine organisms and has been banned by various regulatory authorities ().
Some scientists believe that tributyltin and other organotin compounds can function as endocrine disruptors and contribute to obesity in humans by increasing the number of fat cells ().
In one test-tube study, tributyltin was found to cause the rapid growth of fat cells and reduce their production of leptin ().
In another study in mice, tributyltin exposure for 45 days caused weight gain and fatty liver disease ().
There is also evidence that exposure to tributyltin in the womb may increase the number of fat cells, which may promote fat gain ().
Summary Organotins, including tributyltin, are compounds that have been shown to cause weight gain and fatty liver disease in mice. They may signal to stem cells to turn into fat cells.
Perfluorooctanoic acid (PFOA) is a synthetic compound used for various purposes.
It is a constituent of non-stick cookware made with Teflon and also found in microwave popcorn ().
PFOA has been found in the blood of more than 98% of Americans ().
It has been associated with various diseases in humans, including thyroid disorders, low birth weight and chronic kidney disease (, , , ).
In one study in mice, exposure to PFOAs during development led to increased insulin, leptin and body weight during mid-life ().
However, whether PFOAs really contribute to obesity in humans remains to be seen.
Summary Perfluorooctanoic acid is found in non-stick cookware and other products. It is also associated with various diseases in humans and one mouse study shows that prenatal exposure leads to weight gain in mid-life.
There are many endocrine-disrupting chemicals and covering all of them is beyond the scope of this article.
It is downright impossible to avoid them completely, because they are literally everywhere.
However, there are a few simple things you can do to dramatically reduce your exposure and minimize your risk of later complications.
- Avoid foods and beverages that have been stored in plastic containers.
- Use stainless steel or quality aluminum water bottles .
- Do not feed your babies from plastic bottles. Use glass bottles instead.
- Instead of non-stick cookware, use cast iron or stainless steel.
- Use organic, natural cosmetics.
Of course, eating healthy, exercising, getting quality sleep and avoiding stress are still the most important factors when it comes to your health.
Only you can decide whether going through extreme lengths to avoid chemicals is worth the inconvenience and extra cost.
But if you are a pregnant woman or plan on becoming pregnant, consider avoiding exposure to these chemicals. It might have an effect on the future health of your baby.
Summary Avoiding obesogens completely is impossible, but you can reduce your exposure by avoiding food or drinks stored in plastic containers. Also consider using cookware made of stainless steel or cast iron.
It's important to keep in mind that the effects of these chemicals are far from being proven. Most of the data is observational and based on studies in lab animals
I do not know whether these chemicals will ever be proven to cause harm, but I am personally not going to wait around for that to happen.
It's better to be safe than sorry.