Tag Archives: physical activity

Chemicals and Obesity

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The federal Centers for Disease Control and Prevention (CDC) has reported that obesity has been rising, even though Americans are consuming fewer calories.  This seems puzzling to many.  Changes in physical activity, the amount of calories burned, doesn’t appear to explain this discrepancy.  As stated by the co-author of the study, Dr. William Dietz, former CDC director of Nutrition, Physical Activity and Obesity, “It’s hard to reconcile what these data show, and what is happening with the prevalence of obesity.”

However, evidence is growing that chemicals in our food, water, and environment may be changing our bodies’ hormonal balances and metabolism.  Such chemicals are called endocrine disruptors.  When linked to hormonal disorders linked to obesity they are called obesogens (literally, “causer of obesity”) — see here for more on the obesogen hypothesis.

A recent scientific review summarizes data from experimental animals and humans which support an association of endocrine disrupting chemicals, such as diethylstilbestrol, bisphenol A, phytoestrogens, phthalates, and organotins, with the development of obesity.  The reviewers state, “The reasons for this sharp increase in overweight/obesity are not well understood but factors such as high fructose diets, genetics/epigenetics, increased maternal age, sleep debt, use of certain pharmaceuticals, and the built environment have all been proposed as playing a role.”  They conclude:

“The data included in this review support the notion that brief exposure early in development to environmental chemicals with estrogenic activity increases body weight gain with age and alters markers predictive of obesity in experimental animals. Furthermore, epidemiologic studies support the findings in experimental animals and show a link between exposure to environmental chemicals (such as estrogenic chemicals, BPA, PCBs, DDE, and persistent organic pollutants and heavy metals) and the development of obesity.Importantly, the use of soy-based infant formula containing the estrogenic component genistein has been positively associated with obesity later in life. Using the DES animal model as an important research tool to study “obesogens”, the mechanisms involved in altered weight homeostasis (direct and/or through endocrine feedback loops, i.e., ghrelin, leptin, etc.) by environmental estrogens can be elucidated. In addition, this animal model may shed light on areas of prevention. Public health risks can no longer be based on the assumption that overweight and obesity are just personal choices involving the quantity and kind of foods we eat combined with inactivity. It is quite possible that complex events, including exposure to environmental chemicals during development, may be contributing to the obesity epidemic.”

For more on how our corporate economy is contributing to our living in a chemical soup which can alter our physiology and metabolism, check out: Obesogens & Canned Tales: Lessons in Corporate Social Responsibility.

Sugar Causes Diabetes

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It’s official: sugar causes diabetes.  While this may seem intuitive, it has been debated for decades.  Now, a new study, using data from 175 countries over the last decade, shows that sugar is an independent risk factor for diabetes.  Sugar consumption explains variations in diabetes that are not explained by physical activity, overweight or obesity.  The sugar-diabetes link holds true even when considering total calories, food types (including fibers, meats, fruits, oils, cereals, alcohol), and several socioeconomic variables such as aging, urbanization and income.

The level of scientific confidence here is as strong as that which linked cigarettes and lung cancer in the 1960s.  Of course, we know that it took decades for the tobacco industry to actually admit the connection.  Hopefully, the sugar and food industries will not be so recalcitrant.

So, what’s the size of this effect? For the every equivalent of 12 ounces of sugar-sweetened beverage introduced per person per day into a country’s food system, the rate of diabetes goes up 1 percent.

For more on the what this means for food industry and health politics, check out this article: It’s the Sugar, Folks

Calcium and Vitamin D Supplementation: To Supplement or Not

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Supplementing with vitamins and minerals is a tricky subject. The most recent scientific review recommends that healthy women NOT take calcium and vitamin D supplements to prevent bone fractures. BOTTOM LINE: No evidence for benefit, some health risk.

My recommendation for bone health: bones are like muscle mass — USE IT OR LOSE IT! Get plenty of physical activity, and even some sunshine to get your vitamin D!

This article puts the latest recommendation in context with other scientific reviews: http://www.foodpolitics.com/2013/02/supplements-advice-about-calcium-and-vitamin-d-vs-osteoporosis/

A good default principle applicable to nutrition supplementation is the precautionary principle:

“if an action or policy has a suspected risk of causing harm to the public or to the environment, in the absence of scientific consensus that the action or policy is harmful, the burden of proof that it is not harmful falls on those taking an act.  This principle allows policy makers to make discretionary decisions in situations where there is the possibility of harm from taking a particular course or making a certain decision when extensive scientific knowledge on the matter is lacking. The principle implies that there is a social responsibility to protect the public from exposure to harm, when scientific investigation has found a plausible risk. These protections can be relaxed only if further scientific findings emerge that provide sound evidence that no harm will result.

In some legal systems, as in the law of the European Union, the application of the precautionary principle has been made a statutory requirement.” (Wikipedia)