A Nutritionist's Take On the Stanford Organic Study

Photo by Josh Moody
By now, you've probably heard all the hubbub about the Stanford study that showed organic food to be no more nutritious than conventional food. And you've probably seen the subsequent backlash of scores of bloggers and health advocates defending organic food as a means to avoid toxins. 

Of course, avoiding toxins is important, but as a nutritionist, I couldn't help but step back and re-examine the study's basic claim that organic foods aren't as nutritious. 

Because it's total bullshit.

America is stuck in a cycle of denial when it comes to health, and this study just contributes to a completely whacked lack of perspective. 

Let's examine the actual study and I'll give you some examples.

Firstly, this wasn't a study in the sense that the authors actually went into the fields, picked some organic apples and some conventional ones, and measured nutrition content. It was a "systematic review" of 240 previously conducted studies. The 240 actual studies that were reviewed were conducted as far back as 1966 and were sourced from groups such as the U.S. Department of Agriculture's database. 

I mean, you can almost stop right there. Studies conducted in the 60s, 70s, 80s or even the 90s don't tell us much about the nutrition content of conventionally-grown foods today. Conventional farming technologies have changed drastically even in the past 10 years. And it's not unreasonable to wonder whether the U.S. Department of Agriculture has a vested interest in funding or aggregating studies that 'prove' that conventional produce is as nutritious as organic. If organic was proven to be more nutritious, taxpayers might be dismayed that their money was subsidizing low-quality food and thereby potentially contributing to malnutrition, chronic illness and rising health care costs.

For lack of a better word, it really is a clusterfuck.

But for the sake of this blog post, let's assume that the data that was aggregated was current and that it came from wholly unbiased sources.

6 of the reviewed studies measured blood and urine for antioxidant levels (carotenoids, polyphenols, vitamins E and C content) and found no difference between subjects on an organic diet versus those on a conventional diet. They were randomized, controlled trials - the best kind - so the data may be valid. Let's look closer at one, just for fun. I didn't look at all of them, I just chose this one randomly, so maybe I just got lucky. But here's an actual statement from the abstract of one of these 6 studies:

"When results were expressed as fresh matter, organic tomatoes had higher vitamin C, carotenoids, and polyphenol contents (except for chlorogenic acid) than conventional tomatoes." (Caris-Veyrat, C. et. al, 2004)
That sounds like more nutrition to me!

The abstract of this study goes on to reveal that the scientists then took these tomatoes, pureed them, and fed them to two groups of subjects - one organic, one conventional (I couldn't find any information as to how big the two groups were - larger sample sizes always equate to more reliable research findings). After 3 weeks of consumption of 96g/day of the tomato puree (about 3.4 oz, or less than half a cup), "no significant difference ... was found between the two purees with regard to their ability to affect the plasma [blood] levels of the two major antioxidants, vitamin C and lycopene."

Aha - so the organic tomatoes are actually more nutritious, but after 3 weeks of eating less than 1 serving per day, no difference could be determined in blood samples. OK, wait. I have a few questions: what else were the study subjects eating? Were they all eating the same diet every day to maintain consistency so that the tomato puree was truly the only variable? And is 96g really a large enough serving to see a significant difference? How long was the tomato puree stored before it was consumed? Different diets could conceivably confound the results of the study, and exposure to oxygen could have denatured the antioxidant content in the tomatoes before they even got to the subjects to eat.

As you can see, evaluation of these studies is trickier than it looks. If I had all the time in the world, I would love to go through each one of the reviewed studies, email the scientists and get answers to all my questions. But while that would be interesting and educational, I could also simply rely on all the other evidence that eating organic is more nutritious - and save myself a lot of time.

The Rodale Farming Systems Trial, a 30-year ongoing comparison of organic and chemical agriculture, found that organic soil is better equipped to hold onto and store nutrients. The Rodale Institute stops short of claiming that organic produce is more nutritious, but reason suggests that it must be if it's grown in soil that's more nutritious.

Michael Murray and Joseph Pizzorno, naturopathic doctors and leading health experts, claim in their book The Encyclopedia of Healing Foods that there are more nutrients in organic food and soil: 
"In a 1988 review of thirty-four studies that compared organic with conventionally grown foods, organic food was found to have higher protein quality in all comparisons, higher levels of vitamin C in 58 percent of all studies, and 5 to 20 percent higher mineral levels for all but two minerals. ... Organically grown foods also contain higher amounts of plant-protective compounds, such as flavonoids and caotenoids, which are highly desirable for human consumption."
In addition, they suggest that free-range animal products contain less fat overall, more omega-3 fatty acids, and "ten times as much conjugated linoleic acid (CLA) as grain-fed animals." CLA is an anti-cancer compound and may also reduce the risk of heart disease. (Murray, M., Pizzorno, J., & Pizzorno, L., 2005).

And despite the headlines to the contrary, the Stanford review did find several organic items to be more nutritious than their conventional counterparts. The study reports that "organic milk may contain significantly more beneficial omega-3 fatty acids" and "organic chicken contained higher levels of omega-3 fatty acids than conventional chicken." In addition, organic foods were shown to contain significantly more phosphorous (essential for growth, bones, detox, energy & DNA) and phenols (antioxidants that prevent against free radical damage, chronic illness and degenerative disease).

And the Stanford review found other benefits - for example, "children who consumed dairy products of which more than 90% were organically produced had a lower risk for eczema at age 2 years than children who consumed dairy products of which less than 50% were organically produced." Regardless of nutrition content, we want our kids to be healthy, right?

Then there's the problem of antibiotic resistance, which the CDC calls "one of the world's most pressing public health problems" and the WHO calls an urgent "growing threat." According to the study, "Consumption of organic foods may reduce exposures to ... antibiotic-resistant bacteria." 

To make a very, excruciatingly long story short (by the way, thanks for reading this far), it is this nutritionist's belief that, based on the research, eating organic actually IS more nutritious. In addition, eating organic is known to protect against disease, lower your toxic load, and be more environmentally sustainable.

Which brings us to the final barrier: cost. Organic can be SPENDY! But don't fret - I have some helpful tips. First, the Environmental Working Group publishes an excellent resource called the "Dirty Dozen" that will help you prioritize which foods to buy organic. In addition to the produce they list, meats and dairy products should be at the top of your list, since conventionally-raised animals not only eat non-organic feed, but may have been treated with hormones and antibiotics too. You might also consider a Community-Supported Agriculture share. CSAs will deliver local produce to your doorstep at prices much lower than those you'll find at Whole Foods. Find one near you here. And don't forget about your local farmer's market. Talk to the farmers - even if the food there isn't certified organic (it's a lengthy, challenging and costly process to become certified organic), the farmers will tell you if they grew it without pesticides. Sometimes if you go at the end of the day, you can get great discounts on the food that didn't sell that morning. You can also become an advocate for organic food - if U.S. agriculture was truly a free market, it's less likely that organic foods would cost so much more than conventional. You can "vote with your fork" by buying organic, but remember that you can also vote with your vote by supporting legislators who will help make healthier food accessible to everyone.

Bottom line: don't be fooled by poor journalism. Eating organic will always be a powerful step towards a healthier you. Mangia!

Murray, M., Pizzorno, J., & Pizzorno, L. (2005). The Encyclopedia of Healing Foods. Designing a Healthy Diet. New York: Atria.

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