Published July 10 2017
Since the 1970s, scientists have been studying the link between chemical exposure and weight gain. After numerous tests of certain chemicals and their effects on mice, scientists finally christened these chemicals “obesogens” in 2007. And this is what I’ll be discussing in this article, and of course I’ll talk about the relationship between obesogens and thyroid health.
Obesogens refer to a group of chemicals that have been shown to disrupt the endocrine system, leading to obesity. They can affect people of all ages, but they are more prevalent in young children. Obesogens are commonly referred to as being endocrine disruptors, which I have spoken about in other articles and blog posts, but up until this point I haven’t focused on how these chemicals can lead to weight gain and obesity.
Obesogens cause metabolism changes due to the effects they have on hormones in the body. For example, the chemicals can affect thyroid hormone production, which in turn will lower the metabolic rate and lead to weight gain. And while exposure to obesogens isn’t the primary cause of hypothyroidism, it’s a factor that needs to be considered in some cases. This is especially true for those who have a non-autoimmune hypothyroid condition.
Obesogens can also affect other hormones including resistin and leptin, which affect insulin sensitivity and satiety respectively. This shows that the effects of exposure to these chemicals can be adverse. Scientists are worried about obesogens because even the slightest exposure can have adverse effects.
There is a valid reason to worry, considering that these chemicals can be found in skin products, water, and food. Obesogens are all around us. Common sources of these chemicals include:
- Pesticides
- Nicotine
- Phthalates
- Bisphenol-A (BPA)
- Arsenic
We interact with these chemicals frequently, and while it’s impossible to completely avoid them, limiting exposure to them can be an effective way of combating obesogenic effects. When doing research I was surprised to see that arsenic was classified as an obesogen. And while arsenic is harmful in other ways, it also has been shown to impair white adipose tissue metabolism (1), which plays a big role in the onset of obesity.
How Do Obesogens Cause Weight Gain?
When you are following a weight loss plan strictly and you continue to gain weight, you could be facing the wrath of these notorious chemicals. Apart from the universally known role of storing and releasing energy, scientists have also unearthed another role of fat tissue: playing the role of releasing appetite and metabolism hormones. As a result, an effect on either the performance or nature of this cell is bound to cause adverse effects in the body.
So far, research has shown that this can happen in the following ways:
- Transformation of normal cells to fat cells
- Increased population of fat cells in body
- Higher fat content in fat cells
- Altered metabolic rate leading to more storage of calories
Weight gain is largely associated with risk factors in infant and fetal stages of development. Developmental exposure to certain chemicals has been proven to cause weight gain.
The link between smoking cigarettes during pregnancy and obesity has been subject to a number of studies. An example of this is the study “Maternal smoking during pregnancy and childhood obesity” by von Kries R etal (2). Approximately 40% of nonsmokers in America were still believed to harbor byproducts of nicotine in their blood as of 2008 (3), despite exposure to second-hand smoke reducing markedly in the last two decades.
That many smoking mothers deliver underweight children is not a secret. The children tend to catch up with their peers later in life. Scientists have since established a possible relationship between this kind of growth and exposure to obesogens.
Phthalates have also been known to promote weight gain in children through epigenetic modulation, antithyroid action and other mechanisms. In fact, one recent study showed that there might be a correlation between reductions in thyroid hormones and phthalate exposure in early life (4). Another study showed that exposure to phthalates influences thyroid function, as well as growth hormone homeostasis (5). Another study showed a relationship between diethylhexyl phthalate (DEHP) and obesity-related markers in early life (6).
Although I realize that most of the people with thyroid and autoimmune thyroid conditions are adults, there are more and more children being diagnosed with these conditions as well. And of course more and more children are overweight and obese these days. Plus, just because these studies involve children doesn’t mean that phthalates can cause similar effects in adults as well. While diet definitely can be factor when it comes to gaining weight, we can’t overlook the exposure to phthalates and other obesogens.
The Relationship Between Obesogens And Thyroid Health
The thyroid, with its numerous roles, is very sensitive to chemicals. I mentioned earlier how endocrine disrupting chemicals can interfere with the production of thyroid hormone. I also mentioned how these chemicals aren’t the cause of hypothyroidism in most people, as Hashimoto’s is the primary cause of this.
However, there is no rule that says that someone can’t have both problems. In other words, it’s not only possible, but very likely, that many people with Hashimoto’s Thyroiditis have difficulty losing weight not only because the effect of the immune system on the thyroid gland, but obesogens as well. And as I’ll discuss shortly, obesogens affect other hormones that can play a role in weight gain.
Although many people with hyperthyroidism and Graves’ Disease have problems gaining weight, this isn’t always the case. When I was diagnosed with Graves’ Disease I lost over 40 pounds, but some people with hyperthyroid conditions have difficulty losing weight. And while taking antithyroid medication can cause this problem, obesogens can also be a factor in some people with hyperthyroid conditions.
Obesogens are a ubiquitous challenge across the globe. Humans are exposed to the chemicals in the office, at home, in the supermarket, in drinking water, and in food. Unfortunately many readily available chemicals have endocrine-disrupting characteristics. For example, you will find phthalates in personal care products and in children’s products, and these can be a factor in obesity (7).
There are enough reasons to suspect that increased use of chemicals in recent times is related to the emergence and proliferation of thyroid health conditions. The global chemical industry was at a mere USD$171 billion in the 70’s (8), but it has surpassed USD$4 trillion by now.
Globally, environmental factors contribute to about 24% of all human disorders and diseases (9). Knowing the thyroid gland and by extension the endocrine system plays a role in many different health conditions, obesogens can be major factors.
As the production of manufactured chemicals has increased dramatically over the last two or so decades, incidences of endocrine system related diseases have increased too. For instance, developmental disability prevalence in America was at 12.84% in 1997, but it rose to 15.04% in 2008 (10). The same trend can also be said of surfactants, pesticides and a host of other chemicals.
While one can dispute the link between increased death rate and exposure to obesogens during this period, more wealth of evidence comes from numerous studies.
The Relationship Between Obesogens And Other Hormones
Many obesogens can mimic the female hormone estrogen, hence their name xenoestrogens. I mentioned BPA and phthalates earlier, as these are xenoestrogens with obesogenic effects. Two other examples of xenoestrogens include polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). Exposure to xenoestrogens can lead to some of the following conditions:
- Prostate problems
- Thyroid dysfunction
- Fibrocystic breasts
- Irregular menstruation
Some people with weight gain issues experience estrogen dominance, which I have discussed in other articles. This seems like a dual problem because once weight problems set in, production of excess estrogen may also take place. Men and women particularly in their middle ages are facing this perpetuating cycle, and it can be so frustrating. Also keep in mind that estrogen dominance doesn’t always mean an excess of estrogen, as someone who has normal estrogen levels but low progesterone is considered to be in a state of estrogen dominance as well.
Another negative aspect of xenoestrogens is that many of them are persistent pollutants, meaning that they don’t degrade easily. As a result, they will remain in fat cells, the prostate, breasts, and other storage sites in the body. These hormones have far reaching effects, not only changing body metabolism, but also disrupting the hormone system that comprises of testosterone, appetite control, insulin and cortisol, among others.
What Can Be Done To Minimize The Impact Of Obesogens And Eliminate Them From Our Body?
The fact that obesogens do not break down is one challenge in the efforts to counter them. Furthermore, they are widespread in the air, in plastics, in beauty products, etc. However, the fact that scientists have identified their nature is a step in the right direction. While we cannot reverse industrialization, we can do a few things to overcome the wrath brought on by these chemicals.
Many people get exposed to obesogens from fruits and vegetables through pesticides. The habit of cleaning these foods thoroughly before eating has never been more important. Furthermore, fruits and vegetables should only be purchased from reliable sources. Buying organic is the ideal solution, but some people don’t have access to organic produce, while others can’t afford to purchase organic fruits and vegetables on a regular basis. I have mentioned the Dirty Dozen and Clean Fifteen lists in the past, and while these lists aren’t perfect, sticking to foods on the Clean Fifteen list can help to minimize your exposure to pesticides.
Tap water is not safe from obesogens, as the pesticides may find their way into the water. In America, atrazine is common in tap water, along with dichlorodiphenyldichloroethylene (DDE), which is a breakdown product of DDT, and it has been linked to increased BMI in children (11). If you must use tap water, restrict it to bathing, and for drinking purposes purchase a good quality water filtration system, or another option is to drink spring water out of a glass bottle.
When it comes to bisphenol A (BPA) and phthalates, the prominent source is plastic. Personal products and food cans contain these chemicals. BPA is particularly notorious because it mimics estrogen. Since we cannot completely avoid exposure to these chemicals, the best remedy is to minimize exposure. Drink water from glass bottles as opposed to plastic. Replacing perfumes with essential oils can also help.
Earlier I mentioned how nicotine is considered to be an obesogen, and human health gets a massive beating from cigarette smoke. There is evidence that smoking during pregnancy can lead to obese children. This isn’t always the case, as my mother smoked cigarettes while pregnant with my younger sister, and she isn’t obese.
Of course most of my patients don’t smoke, let alone smoke during pregnancy. And most people who do smoke know that it’s best to quit. This is true for both those with hypothyroid and hyperthyroid conditions, but perhaps especially true for those with Graves’ Disease, as there does seem to be an increased correlation between smoking and Graves’ Disease.
Animal products can also carry obesogens. When you drink milk or eat meat, you could ingest these chemicals and suffer the consequences discussed above. While you need protein in your diet, you need to be more careful about the contents of your plate. Although many people with thyroid and autoimmune thyroid conditions avoid dairy, most of these people eat meat, and sometimes a lot of it since it’s allowed on an autoimmune Paleo diet. I eat meat as well, although I don’t eat meat with every major meal, and I try to eat plenty of vegetables.
So here are some of the things you can do to counter obesogens:
- Eat organic foods. I probably don’t have to discuss this further, as most people reading this understand the importance of eating as many organic foods as you can in order to minimize the exposure to these chemicals.
- Avoid plastic-wrapped foods. Although I don’t use “plastic wrap”, I’d be lying if I told you that I never buy food that’s in plastic containers. It’s very difficult to completely avoid plastic, although I’ve had a few patients go on a 30-day “plastic elimination” challenge.
- Avoid using pesticides in and around your home. This is another obvious one, although I realize that if someone has an infestation and a natural approach doesn’t work that there are times that using chemicals might be necessary. But many homes and businesses routinely have companies spray these chemicals on a regular basis. And just because these companies tell you that their pesticides are safe doesn’t mean this is true.
- Use natural cleaning products and cosmetics. I’ve also spoken about this many times in the past, as for obvious reasons you want to try to minimize the use of conventional cleaning products and cosmetics. There are plenty of good natural options out there.
- Do things to increase glutathione levels. Glutathione helps to support detoxification, and eating foods such as cruciferous vegetables and garlic can help, although you can also take supplements such as N-acetylcysteine, or an acetylated or liposomal glutathione supplement.
- Sweating/working out. This helps remove new obesogens before they are stored in fat cells, and it can also help to eliminate some of these toxins stored in your tissues. In addition to exercising, I’ve spoken about the benefits of infrared sauna therapy in previous articles.
In summary, numerous chemicals can lead to weight gain and obesity, and as a result they are labeled as being obesogens. This includes BPA, phthalates, pesticides, nicotine, and even arsenic. Obesogens can also act as endocrine-disrupting chemicals, and thus interfere with the production of thyroid hormone. And they can have a negative effect on other hormones as well. Although you can’t completely avoid exposure to obesogens, you can do things to reduce your exposure, while at the same time doing things to detoxify them from your body.
