A few years back, National Public Radio ran a story on “Why Organic Food May Not Be Healthier for You." This was almost an exact repeat of a story NPR had run a couple of years earlier.  On both occasions, the media organization spotlighted a study that had analyzed the results of many other published, peer-reviewed studies.  This is known as a systematic review, and it’s often assumed to be a great way to get an overview of the scientific evidence to date.

The two systematic reviews scooped up by NPR were published in the September 2012 issue of the Annals of Internal Medicine and in the July 2010 American Journal of Clinical Nutrition, respectively.  In each case, the researchers systematically searched various databases for studies pertaining to the health-related benefits of consuming organic foods.  Out of hundreds of published investigations, they ended up with just a few studies that assessed health outcomes in people who were eating either organic or conventional food.

Those few studies showed no evidence that eating organically was linked with better health.  For example, when one study looked at whether eating organic food during pregnancy would influence the likelihood of eczema and other allergic conditions among the offspring, the researchers found no clear benefits.  Ditto for some other studies with other conditions.

Asking the Wrong Questions

Now, it’s important to understand that systematic reviews, as cool as they may appear, can be terribly misleading.  The main problem with the reviews mentioned above is that they drew from short-term studies only, no more than two years at most.  Even the NPR report acknowledged that this is “hardly enough time to document any particular health benefit”.  (And as we’ll see in a moment, it’s likely that the health effects of pesticides and other agro-chemicals are only relevant over the long term.)

Some studies have also claimed that nutrient levels in organically grown crops do not differ much from those of conventionally grown crops.  The problem here is that it’s a mixed bag, with some farms showing differences and others not showing.  But any seasoned organic farmers will tell you that even organic farms can differ greatly depending on what the farmer does to the soil. Not every organic farm is going to have the same ideal soil composition, and thus it’s best to consider farms on a case-by-case basis rather than trying to lump them altogether to get an average value.

A salient question, in my view, has to do with the downside of not eating organic foods.  In other words, what are the likely or proven harmful effects of a chemical-laden diet?  What happens to your health when you expose your body to pesticide and herbicide residues over decades?  The answer to this question has become a lot clearer in recent years, and it’s not a pretty one.

A Heavy Toll on the Aging Brain

The best-studied casualty in this context is the human brain, and specifically a brain that has accumulated toxic chemicals over five or more decades.  All of the more than 2000 pesticides on the market are well-established neurotoxins, meaning that they can be toxic to the brain and nervous system.

Shocking as it may sound, many studies have linked pesticide exposure (including diet- and household-related exposures) with the development of both Parkinson’s and Alzheimer’s disease, as reported in the August 2012 issue of Neurotoxicology.  Though precise causal connections remain a matter of speculation, the risks are clearly strongest for Parkinson’s disease, according to a September 2013 report published in the Annual Review of Pharmacology and Toxicology.

As the U.S. population ages, the burden of both Parkinson’s and Alzherimer’s  disease will continue to rise.  At this time, no drugs have been shown to slow the progression of Parkinson’s disease, and Alzheimer’s disease has proven to be nearly as intractable.  With ongoing reductions in Medicare reimbursement constantly on the horizon, the need to focus on prevention becomes ever more critical.

Breast Cancer Begins in the Womb

At the same time, we know that pesticides can imitate estrogens in our body, and some believe this may contribute to breast cancers and other female cancers.  Many pesticides can disrupt the normal metabolism of natural estrogen and even act as carcinogens.  These chemicals have been broadly referred to as xenoestrogens or endocrine-disrupting chemicals (EDCs).

Public health experts would jump on this last statement, arguing that there’s no consistent evidence that pesticides cause breast cancer or other estrogen-responsive cancers.  And they would be right.  The evidence is quite poor, with most studies showing no association.  Trouble is, if you study the genesis of breast cancer, you realize that most studies to date are missing the critical window of exposure, which is in utero or during pregnancy.

There’s strong evidence that pesticides may have their most profound cancer-promoting effects during embryonic development, because these EDCs disrupt the normal formation of the mammary gland.   Researchers at the University of North Carolina recently reported that pesticides and other EDCs “have been shown to disrupt normal mammary development and lead to adverse lifelong consequences, especially when exposures occur during early life.”  In addition, they say that these chemicals “can act directly or indirectly on mammary tissue to increase sensitivity to chemical carcinogens or enhance development of [breast] tumors,” as reported in the March 2013 Journal of Mammary Gland Biology and Neoplasia.

Even women already diagnosed with breast cancer could be worse off if they have high levels of pesticides and other EDCs in their breast tissues.   Several studies have indicated that these chemicals could worsen the prognosis for breast cancer patients.  In one study, pesticide concentrations were significantly higher in relapsing patients when compared to those patients who stayed in remission (sources cited at the end of this article).

Taking the Long View

None of the epidemiological studies of organic foods have assessed the long-term health impacts of maintaining such a diet, nor have they tracked the long-term outcomes for people who may have been exposed in the womb.  This is a serious problem in and of itself.  And yet, the media gets so enamored of systematic reviews of studies that will never show adverse effects simply because they’re short term and missing the critical windows of vulnerability.

The logistics of doing the right kinds of research are daunting.  Both breast cancer and neurodegenerative diseases like Parkinson’s can take decades to develop, and it is extremely costly to conduct such lengthy studies.  Are we really so short-sighted that we’re willing to overlook the potential long-term repercussions of consuming foods laden with chemicals that have well-known carcinogenic and neurotoxic effects?  I, for one, am not willing to wait until the data are in.  The chances of ever seeing such long-term studies are slim to nil.

Commonsense tells us that avoiding these chemicals is going to result in the best long-term health and disease prevention.  Part of this long-range perspective includes the environment, upon which the health of present and future generations ultimately depends:  Organic farming generates less pollution and generally has a far more benign environmental impact than conventional approaches.  In contrast, chemical-industrial agriculture consumes fossil fuel, water, and topsoil at unsustainable rates while also contributing to air and water pollution, soil depletion, fish die-offs, and diminishing biodiversity—including the demise of bees, monarchs and other pollinators upon which much of our food supply depends.

Sure, the public health advantages are debatable when you focus on the short-term studies that comprise the bulk of the evidence base .  Nevertheless, organic foods generally contain higher levels of certain nutrients, lower levels of pesticides, and most likely provide long-term health benefits for the consumer.  On that last point, you’ll simply have to trust your ancient gut sense (i.e., intuition).  You’ll hopefully find a way to trust the very same brain that evolved over millions of years on a pesticide-free diet.

Sources

Smith-Spangler C, Brandeau ML, Hunter GE, Bavinger JC, Pearson M, Eschbach PJ, Sundaram V, Liu H, Schirmer P, Stave C, Olkin I, Bravata DM. Are organic foods safer or healthier than conventional alternatives?: a systematic review. Ann Intern Med. 2012 Sep 4;157(5):348-66

Dangour AD, Lock K, Hayter A, Aikenhead A, Allen E, Uauy R. Nutrition-related health effects of organic foods: a systematic review. Am J Clin Nutr. 2010 Jul;92(1):203-10.

Kanthasamy A, Jin H, Anantharam V, Sondarva G, Rangasamy V, Rana A, Kanthasamy A. Emerging neurotoxic mechanisms in environmental factors-induced neurodegeneration. Neurotoxicology. 2012 Aug;33(4):833-7.

Goldman SM. Environmental Toxins and Parkinson’s Disease. Annu Rev Pharmacol Toxicol. 2013 Sep 16. [Epub ahead of print]

Macon MB, Fenton SE. Endocrine disruptors and the breast: early life effects and later life disease. J Mammary Gland Biol Neoplasia. 2013 Mar;18(1):43-61

Jenkins S, Betancourt AM, Wang J, Lamartiniere CA. Endocrine-active chemicals in mammary cancer causation and prevention. J Steroid Biochem Mol Biol. 2012 Apr;129(3-5):191-200

Charlier CJ, Dejardin MT.  Increased risk of relapse after breast cancer with exposure to organochlorine pollutants. Bull Environ Contam Toxicol. 2007 Jan;78(1):1-4

Ociepa-Zawal M, Rubis B, Wawrzynczak D, Wachowiak R, Trzeciak WH. Accumulation of environmental estrogens in adipose tissue of breast cancer patients. J Environ Sci Health A Tox Hazard Subst Environ Eng. 2010;45(3):305-12

Dangour AD, Dodhia SK, Hayter A, Allen E, Lock K, Uauy R. Nutritional quality of organic foods: a systematic review. Am J Clin Nutr. 2009 Sep;90(3):680-5.

Crinnion WJ. Organic foods contain higher levels of certain nutrients, lower levels of pesticides, and may provide health benefits for the consumer. Altern Med Rev. 2010 Apr;15(1):4-12.

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© 2017, Mark Nathaniel Mead