On Monday a study from scientists at Stanford made headlines by concluding that there isn’t much health value in choosing organic food over conventional food. The headline didn’t surprise me in the least, I’ve seen similar ones at least a dozen times before, but there is still so much confusion among the general public around this topic that it’s worth revisiting in the wake of this new data.
Despite what organic zealots are telling you, this wasn’t a bad study. It was a meta-analysis that examined a number of relevant health measures comparing organic versus conventionally grown foods over the last several decades. They excluded processed foods from their analysis (this is a good thing), and looked at nutrient levels as well as pesticide contamination and antibiotic resistance in both produce and animal products. They were also careful about which organic standards were included in the study. Though the analysis has plenty of limitations (all meta-analyses do), their statistics were sound and the researchers were honest about their findings. What’s really annoying is how their results were interpreted by the media.
One problem is that the word “organic” is a huge umbrella that includes sustainable, biodynamic farming practices as well as huge-scale industrial operations that barely squeeze under the “certified organic” labeling standards. As a result there is a tremendous amount of heterogeneity (a scientific word for a wide range of differences) between the organic foods being tested, as well as the types of studies that are performed. As a result, it is difficult to measure consistent differences (aka statistical significance) between organic and conventional foods in this kind of study. Unfortunately, this doesn’t do much to further our understanding of how growing practices affect health.
The huge variance among farming practices that fit under the organic umbrella is not trivial. By far the largest segment of organic products on the market could be considered industrial organic, and the farms are closer to traditional industrial farms than most of us realize. Large organic farms are typically monoculture fields just like large conventional farms, though more crop rotation is required. Industrial organic poultry and beef farms also look oddly similar to conventional industrial feedlots, even if the animals are eating organic feed. In fact, both organic and conventional industrial farms are often owned by the same mega-corporations, and share the same bottom line of profit. There’s no reason to suspect that these industrial organic foods would be markedly more nutritious than conventionally grown foods.
In contrast, smaller biodynamic farms have extensive practices designed to build soil, improve robustness of crops and ensure bio and nutrient diversity. Instead of monocultures, these farms grow huge arrays of different vegetables and fruits. If a biodynamic farm raises animals they are given their natural, preferred diet of grass (for cows) or bugs and seeds (for birds). The animals are treated well and fed well, and are healthier as a result. If you want to learn more about the differences between conventional agriculture, big organic agriculture and biodynamic farming I highly recommend Michael Pollan’s excellent book, The Omnivore’s Dilemma, and Joel Salatin’s latest book, Folks, This Ain’t Normal.
Interestingly, despite the wide range in the quality of foods that qualify as organic, the Stanford study did find some significant differences. Organic produce contained significantly more phenols, the cancer fighting chemicals found in red wine, green tea, chocolate and many fruits and vegetables. However, this finding was glossed over in favor of the non-significant differences found between vitamin C, betacarotene and vitamin E levels in organic versus conventional foods.
It is reasonable to hypothesize that organic agriculture (at least in some cases) would be more nutritious because the soil standards for organics are much higher than for the depleted, synthetically fertilized conventional fields. Soil quality and weather (the raw ingredients) are by far the biggest factors in the nutrient levels of produce, with freshness and storage methods being next in line. Indeed, organic agriculture typically has more minerals and the Stanford team confirmed they contain significantly more phosphorus. But there is so much variety among plants, and from season to season, that you shouldn’t necessarily expect large, consistent differences in the levels of common vitamins like C and E from genetically identical plants.
That the Stanford team found measurable differences in total phenol content is pretty impressive. There are dozens of phenolic compounds that could benefit health in different and subtle ways. Nutrition science still can’t explain the benefits of all these nutrients, but having more of them certainly seems like a good thing.
Still lack of pesticides, not better nutrition, is the most commonly cited reason for buying organic over conventional foods. Pesticides are designed to kill things, and have been shown repeatedly to be dangerous for farm workers and other wildlife. They also accumulate more in the bodies of people who eat conventional produce compared to those who eat organic, and susceptible populations such as children, pregnant and nursing women, and the elderly are at particular risk. The Stanford study confirms organic agriculture has substantially fewer pesticide contaminations, but for some reason this finding was also glossed over since the conventional produce levels “didn’t exceed maximum allowed limits.” Logically, however, if limiting pesticide exposure is important to you (as it should be) organic produce is the better option.
The animal studies were even more encouraging. Small but significant improvements in fatty acid profiles were found for organic milk and chickens, which contained more healthy omega-3 fatty acids. More importantly, antibiotic resistant bacteria, the kind that are becoming more common (and deadly) in our own hospitals, were 33% more likely to be found on conventional meat products than on organic meat. Antibiotic resistant bacteria being created on industrial farms is one of the scariest threats to human health in modern history, and any measures that limit their proliferation should be seriously considered.
From this study it seems reasonable to conclude that organics, even industrial organics, are superior to conventional foods in some ways. Organic farms cannot use synthetic fertilizers or pesticides, sewage sludge (yes, human sewage is used on conventional food), irradiation or genetically modified organisms (GMOs), and must help maintain or improve soil quality. These practices are much better for the environment, significantly limit the amount of pesticides you are exposed to, reduce the proliferation of dangerous pathogens and may be more nutritious.
Organic agriculture certainly sounds like it has some advantages over conventional ag to me.
Do you buy organic? Why?