EarthTalk® | February 2015

Dear EarthTalk: How is it that antibiotics are being “overused,” as I’ve read, and what are the potential consequences? — Mitchell Chase, Hartford, CT

The development and widespread adoption of so-called “antibiotics” — drugs that kill bacteria and thereby reduce infection — has helped billions of people live longer, healthier lives. But all this tinkering with nature hasn’t come without a cost. The more we rely on antibiotics, the more bacteria develop resistance to them, which makes treating infections that much more challenging.

According to the U.S. Centers for Disease Control and Prevention (CDC), overuse of antibiotics by humans — such as for the mistreatment of viral infections — means these important drugs are less effective for all of us. Besides the toll on our health, researchers estimate that antibiotic resistance causes Americans upwards of $20 billion in additional healthcare costs every year stemming from the treatment of otherwise preventable infections.

A bigger issue, though, is our growing reliance on feeding antibiotics to livestock for growth promotion, weight gain and to treat, control and prevent disease. This increasingly common practice is a significant factor in the emergence of antibiotic-resistant bacteria, which the U.S. Food & Drug Administration (FDA) acknowledges can get passed onto humans who eat food from treated animals. The non-profit Environmental Working Group (EWG) reports that the majority of the ground beef and ground turkey sold in the typical American grocery store contains antibiotic-resistant bacteria.

Last year, 26 animal pharmaceutical companies voluntarily complied with an FDA request to re-label medically important antibiotics used in food-producing animals to warn against using them for growth promotion and weight gain. FDA also recommended that medically important antibiotics be prescribed by licensed veterinarians and only to treat, control and prevent disease. “We need to be selective about the drugs we use in animals and when we use them,” says William Flynn of the FDA’s Center for Veterinary Medicine. “Antimicrobial resistance may not be completely preventable, but we need to do what we can to slow it down.”

Still some worry that the FDA’s action doesn’t go far enough, given that farmers will still be able to administer antibiotics to their livestock for disease prevention. The fact that more and more livestock operations are switching over to Animal Feeding Operations (AFOs) whereby animals are confined in crowded enclosures (instead of allowed to graze at pasture) means that antibiotics will play an increasingly important role in disease prevention.

For its part, the FDA argues that since veterinarians need to authorize antibiotic use for disease prevention, farmers and ranchers are less likely to overuse antibiotics for their livestock populations. The same can be said about doctors’ limiting the prescription of antibiotics for their human patients, but only time will tell whether such newfound restraint is enough in the fast evolving arms race between bacteria and our antibiotics.

Of course, consumers can do their part by avoiding antibiotic medications unless absolutely necessary and eating less meat (or giving it up entirely) to help reduce demand.

CONTACTS: CDC,; EWG,; FDA Center for Veterinary Medicine,

Photo: Cyclonebill, Flickr CC
Avocado is one of the superfoods that contain good fat that is crucial for brain health.
Dear EarthTalk: What’s the skinny on fat these days? I saw a major magazine cover image recently that was suggesting fat wasn’t so bad for us after all? — Marcy Bellwether, Taos, NM

Going “fat-free” might seem like an effective, safe way to lose weight when considering that fat contains nine calories per gram, compared to four calories per gram in carbohydrates and proteins. But if you take into account the fact that approximately 60 percent of human brain matter consists of fats, eating reduced fat or fat-free foods high in sugar and refined carbohydrates no longer seems as appealing for our health.

“The brain thrives on a fat-rich, low carbohydrate diet, which unfortunately is relatively uncommon in human populations today,” reports David Perlmutter, author of Grain Brain. “Mayo Clinic researchers showed that individuals favoring carbohydrates in their diets had a remarkable 89 percent increased risk for developing dementia as contrasted to those whose diets contained the most fat. Having the highest levels of fat consumption was actually found to be associated with an incredible 44 percent reduction in risk for developing dementia.”

Granted, certain types of fats are more beneficial than others. “Good” fats include monounsaturated fats, found abundantly in olive oil, peanut oil, hazelnuts, avocados and pumpkin seeds, and polyunsaturated fats (omega 3 and omega 6), which are found in flaxseed oil, chia seeds, marine algae oil and walnuts.

“In the ’70s and early ’80s…we were not talking about low-fat diets. We were talking about replacing saturated fat with a healthy fat, polyunsaturated fat,” says Walter Willett, professor of epidemiology and nutrition at the Harvard School of Public Health. “But somewhere in the mid-1980s, we lost that message. It’s perhaps partly because some nutritionists felt it was too complicated to talk about different types of fat, and developed the notion we should just reduce all types of fat across the board.”

With over five million Americans currently living with Alzheimer’s disease, researchers are examining which dietary fats may help prevent dementia. Olivia Okereke at Brigham & Women’s Hospital tested how different types of fats affect cognition and memory in women. Over the course of four years, she found that women who consumed high amounts of monounsaturated fats had better overall cognitive function and memory. A study by researchers from Laval University in Quebec revealed similar findings: Diets high in monounsaturated fats increased the production and release of the neurotransmitter acetylcholine, which is critical for learning and memory. The loss of acetylcholine production in the brain has been associated with Alzheimer’s disease.

Unfortunately, canola oil, which is high in monounsaturated fats in its natural form, is often hydrogenated so it can stay fresh longer in processed foods. Partially hydrogenated oils — also known as Trans fats — were shown to be detrimental to memory in a recent University of California San Diego study. “Trans fats increase the shelf life of the food but reduce the shelf life of the person,” reports study author Beatrice Golomb.

Of course, a well-rounded diet with plenty of fruits and vegetables may still be the best way to stay healthy. But it’s good to know that a little fat here and there won’t kill you. In fact, it might well help you live a healthier, more productive life.

CONTACTS: David Perlmutter,; Harvard School of Public Health,; Brigham & Women’s Hospital,

Photo: Alpha, Flickr CC
That salami on your plate might look scrumptious, but Environmental Working Group warns it may contain nitrates linked to cancers of the stomach, esophagus, brain and thyroid.
Dear EarthTalk: What is the “Dirty Dozen Guide to Food Additives?” — Meredith LaGarde, New Orleans, LA

The Environmental Working Group (EWG), a non-profit dedicated to protecting human health and the environment through research, education and advocacy, launched its “Dirty Dozen Guide to Food Additives” in November 2014 to educate consumers about which food additives are associated with health concerns, which are restricted in other countries, and/or which just shouldn’t be in our foods to begin with. EWG hopes the new guide will help consumers avoid unhealthy foods and also influence policymakers to develop more stringent rules for food producers moving forward.

According to EWG, more than 10,000 food additives are approved for use in the U.S., despite potential health implications. Some are “direct additives” deliberately formulated into processed food; others are “indirect,” that is, finding their way into food during processing, storage or packaging. Either way, some have been linked to endocrine disruption, heart disease, cancer and a wide range of other health issues.

Topping EWG’s list are nitrates and nitrites, both typically added to cured meats (like bacon, salami, sausages and hot dogs) to prolong shelf-life and prevent discoloration. “Nitrites, which can form from nitrates, react with naturally occurring components of protein called amines,” reports EWG. “This reaction can form nitrosamines, which are known cancer-causing compounds.” The group reports links between nitrite and nitrate consumption and cancers of the stomach, esophagus, brain and thyroid.

The World Health Organization considers nitrites and nitrates to be probable human carcinogens; California’s Office of Environmental Health Hazard Assessment is now considering a similar designation. Interestingly, some nutritious foods like spinach and other leafy vegetables contain nitrates naturally, but EWG says that “human studies on nitrate intake from vegetables have found either no association with stomach cancer or a decreased risk.”

Another troubling but nevertheless common food additive is potassium bromate, used to strengthen bread and cracker dough and help such items rise during baking. But potassium bromate is listed as a known human carcinogen by the state of California and a possible human carcinogen by the International Agency for Research on Cancer. Animal studies have shown that regular exposure to potassium bromate can cause a variety of tumors, is toxic to the kidneys and can even cause permanent DNA damage.

Most of the potassium bromate added to foods converts to non-carcinogenic potassium bromide during the process of baking, but small but still significant unconverted amounts can remain, putting eaters everywhere at risk. EWG would like to see the U.S. government follow Canada’s and the European Union’s lead in banning the use of potassium bromate in foods altogether.

Other additives on the Dirty Dozen list include propyl parabens, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), propyl gallate, theobromine, diacetyl, phosphates and aluminum. Many artificial colors can also cause health issues, reports EWG, as can thousands of “secret flavor ingredients” that food makers add to foods without oversight in the name of protecting trade secrets. For more information on these foods and how to avoid them, check out EWG’s free “Dirty Dozen Guide” online.


Photo: NASA HQ, Flickr CC
Congressman Lamar Smith (R-TX), chair of the House Science, Space & Technology Committee, calls the Obama administration’s 2014 National Climate Assessment — which squarely pins the blame for global warming on human industrial activity– “a political document intended to frighten Americans into believing that any abnormal weather we experience is the direct result of human CO2 emissions.”
Dear EarthTalk: Are there still outspoken global warming deniers in Congress or the mainstream media? If so, what do they say when presented with scientific facts and anecdotal evidence pointing to an increasingly warming atmosphere? — Ben Charles, Cary, NC

Given the preponderance of data showing rising temperatures around the globe in recent decades — along with the increasing frequency of extreme weather events — it’s hard to believe there are still any climate change deniers. But a recent survey by the non-profit Center for American Progress found that some 58 percent of Republicans in the U.S. Congress still “refuse to accept climate change.” Meanwhile, still others acknowledge the existence of global warming but cling to the scientifically debunked notion that the cause is natural forces, not greenhouse gas pollution by humans.

One of the chief doubters in the U.S. House of Representatives is Texas Republican John Carter, who reports on his website that the United Nations’ Intergovernmental Panel on Climate Change (IPCC) and the East Anglia Climatic Research Unit in Great Britain –two of the world’s foremost authorities on the extent and severity of global warming — hid their own research results showing that world temperatures have not actually been rising, but in fact have been falling, over the past several years.

“We may or may not even be in a warming cycle,” says Carter. “Even if we are, scientific evidence does not conclude that activity by man plays any significant role.” Regardless, Carter supports more research and development of solar, wind, tidal and geothermal energy, along with the continued development of hybrid, natural gas and all-electric vehicles.

Another outspoken climate naysayer in Congress is House Science, Space & Technology Committee chair Lamar Smith, another Texas Republican, who calls the Obama administration’s 2014 National Climate Assessment (which squarely pins the blame for global warming on human emissions) “a political document intended to frighten Americans into believing that any abnormal weather we experience is the direct result of human CO2 emissions.” He adds that “the Obama administration feels compelled to stretch the truth in order to drum up support for more costly and unnecessary regulations and subsidies.”

Of course, the right side of the aisle in Congress isn’t the only place you’ll find climate change deniers. In a recent op-ed article that appeared on, scientist and author Daniel Botkin comments that the 2014 National Climate Assessment “ignores…the real history of life itself: endlessly changing, highly adaptable, and never subject to the kind of stasis that the climate change consensus imagines, wrongly, to be Nature’s ideal state.” Plenty of other conservative media voices on Fox News and elsewhere are vocal in their skepticism about humans’ (leading) role in climate change.

But regardless of how persuasive some of these pundits might sound, the facts speak for themselves. IPCC reports that human influence on the climate system is “clear,” with greenhouse gas emissions driven largely by economic and population growth skyrocketing to record levels and leading to atmospheric conditions unprecedented in at least the last 800,000 years. IPCC adds that greenhouse gas emissions are “extremely likely to have been the dominant cause of the observed warming since the mid-20th century” and that warming will be a “very likely” catalyst for increased heat waves, extreme precipitation events, warmer oceans and higher sea levels.

CONTACTS: U.S. Representative John Carter (R-TX),; U.S. Representative Lamar Smith,; FoxNews,; IPCC,

Photo: Marcia O’Connor, Flickr CC
Environmentalists hail biochar, a form of charcoal derived from baking biomass, as a savior of soils damaged by agricultural overuse and pollution that can sequester significant amounts of carbon dioxide in the process.
Dear EarthTalk: What is biochar and how can it help reduce my carbon footprint? — William Jarvis, Bethlehem, PA

Biochar is a naturally occurring, fine-grained, highly porous form of charcoal derived from the process of baking biomass — and it’s been associated with fertile soils for some two thousand years. “Biochar is found in soils around the world as a result of vegetation fires and historic soil management practices,” reports the International Biochar Initiative (IBI), a trade group representing the world’s burgeoning biochar industry. “Intensive study of biochar-rich dark earths in the Amazon has led to a wider appreciation of biochar’s unique properties as a soil enhancer.”

Indeed, researchers have been hard at work perfecting their own methods for manufacturing biochar by baking biomass in giant oxygen-free kilns. The resulting biochar can then be used as a soil amendment to help restore tired, compromised farmland, not to mention contaminated industrial sites, all the while taking carbon dioxide out of the atmosphere. A liquid by-product of the biochar production process can also be converted into a carbon-neutral “biofuel” that can displace other carbon intensive fuels.

Farmers can layer biochar into their fields where it becomes part of the soil matrix and helps retain water and essential agricultural nutrients like nitrogen, phosphorous and potassium. “You can basically think of it as a soil reef upon which abiotic and biotic phenomena happen,” says David Shearer, CEO of Full Circle Biochar, one of a handful of U.S. based biochar start-ups working to commercialize the age-old “technology.” Farmers like the fact that using biochar can lower their water and fertilizer bills as well as yield more and better quality agricultural products — leading to better market performance overall. “This is really a hedge for farmers,” reports Shearer. “It really helps them manage their financial risk and it helps them manage risk into the future around production.”

Beyond agriculture, biochar can also be used to clean up polluted land. “For example, if you have a mine that has contaminated soil adjacent to it, biochar…will allow you to remediate soils,” says Shearer. He adds that biochar also makes for an excellent filtration medium: “We know that activated charcoal has been used for millennia as a filter mechanism, and so there is discussion in the biochar community that maybe the first step is we’ll use it as a filtration media, and then we’ll move to agriculture as the cost of production of biochar comes down.”

As far as environmentalists are concerned, the greater the demand for biochar the better, given the fact that it is a potent storage mechanism for carbon dioxide that would otherwise head into the atmosphere and contribute to climate change. “The carbon in biochar resists degradation and can hold carbon in soils for hundreds to thousands of years,” reports IBI. “We can use this simple, yet powerful, technology to store 2.2 gigatons of carbon annually by 2050. It’s one of the few technologies that is relatively inexpensive, widely applicable and quickly scalable. We really can’t afford not to pursue it.”

CONTACTS: International Biochar Initiative (IBI),; Full Circle Biochar,



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