For some reason that isn’t clear to me, the mainstream media and medical establishment seem very attached to the idea that organic produce is no healthier or safer than conventional produce.
They often point to a study performed at Stanford in 2012 as proof of this claim, as if it were the final word. After all, it’s Stanford!
New study confirms that organic produce is higher in antioxidants and lower in pesticide residues.
But it turns out the Stanford study wasn’t nearly as conclusive as the media made it out to be. I wrote an article critiquing it shortly after it was published, and Mark Sisson also weighed in.
In short, the Stanford researchers inexplicably omitted or undervalued certain nutrients from the comparison that have already been shown to be more concentrated in organic foods, such as vitamin C, polyphenols, and flavonoids. What’s more, according to the researchers own conclusion, “consumption of organic foods may reduce exposure to pesticide residues and antibiotic-resistant bacteria.” (1)
New Analysis of 343 Studies Finds That Organic Really Is Better
A new study published in the British Journal of Nutrition is the latest addition to the debate. It’s the largest meta-analysis (i.e. review of studies) that has been published on this topic to date, covering 343 individual studies looking at the composition of crops and food. (2)
The study found that organic crops had higher levels of certain antioxidants—such as phenolic acids, flavonols and anthocyanins—and that eating organic foods could boost a person’s antioxidant intake by up to 40% (the equivalent of two portions of fruits or vegetables a day).
Some “experts” have claimed these results are meaningless because “antioxidants are not essential nutrients.” But while antioxidants in plants may not be essential, in the sense that we cannot live without them, a growing body of evidence suggests that they are crucial for optimal health.
In fact, recent research has revealed that what we call “antioxidants” in plants are actually “pro-oxidants” that gently stress our bodies. Rather than killing us or making us sick, however, these compounds promote adaptations that make us healthier and stronger and may extend our lifespan. The science writer Moises Velasquez-Manoff describes this phenomenon in a recent article called “Fruits and Vegetables Are Trying To Kill You:
…these plant “biopesticides” work on us like hormetic stressors. Our bodies recognize them as slightly toxic, and we respond with an ancient detoxification process aimed at breaking them down and flushing them out.
Consider fresh broccoli sprouts. Like other cruciferous vegetables, they contain an antifeedant called sulforaphane. Because sulforaphane is a mild oxidant, we should, according to old ideas about the dangers of oxidants, avoid its consumption. Yet studies have shown that eating vegetables with sulforaphane reduces oxidative stress.
When sulforaphane enters your blood stream, it triggers release in your cells of a protein called Nrf2. This protein, called by some the “master regulator” of aging, then activates over 200 genes. They include genes that produce antioxidants, enzymes to metabolize toxins, proteins to flush out heavy metals, and factors that enhance tumor suppression, among other important health-promoting functions.
Some scientists have even gone as far as suggesting that antioxidants (or more accurately, “pro-oxidants”) are primarily responsible for the health benefit we get from eating plants. Thus, the finding that we may get 40% more antioxidants from eating organic produce is not insignificant.
Pesticide Residues and Toxic Metals Are Not Harmless
In addition to finding higher levels of antioxidants in organic produce, the study authors also found lower levels of cadmium—a toxic, heavy metal—and lower levels of pesticide residues. On average, cadmium and pesticide levels were 48% and 400% lower, respectively, in organic produce than in conventional varieties.
Cadmium (Cd) is a highly toxic metal that accumulates in the human body. It is classified as a category I carcinogen—which means it contributes to cancer development—and has been linked to an increased risk of everything from Alzheimer’s disease, to thyroid problems, to cardiovascular disease, to hormone imbalance. (3, 4, 5, 6) It’s fairly obvious, therefore, that we should do everything we can to minimize our exposure to cadmium.
The question of how exposure to pesticide residue in foods impacts human health is still controversial. That said, there is more than enough evidence to warrant caution—and that is especially true for children and pregnant women. Reports over the past few years have linked pesticide exposure in children to ADHD, intelligence/IQ, and numerous other problems. Researchers have also begun to identify mechanisms through which pesticides can disrupt the development of children even at very low exposures. (7)
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Why Local Trumps Organic When It Comes to Nutrient Content
As I’ve argued before, the most significant factor in determining the nutrient content of fruits and vegetables is not whether they are grown organically or conventionally, but how long they have been out of the ground before they are consumed.
Most of the produce sold at large supermarket chains is grown hundreds – if not thousands – of miles away, in places like California, Florida and Mexico. This is especially true when you’re eating foods that are out of season in your local area (like a banana in mid-winter in New York).
The problem with this is that food starts to change as soon as it’s harvested and its nutrient content begins to deteriorate.
Total vitamin C content of red peppers, tomatoes, apricots, peaches and papayas has been shown to be higher when these crops are picked ripe from the plant. (8) This study compared the Vitamin C content of supermarket broccoli in May (in season) and supermarket broccoli in the Fall (shipped from another country). The result? The out-of-season broccoli had only half the vitamin C of the seasonal broccoli. (9)
Jo Robinson goes into great detail on this topic in her excellent book, Eat On The Wild Side. In fact, she argues that the fruits and vegetables we eat today are almost unrecognizable to what our ancestors ate in terms of nutrient content, in part because of the effects of industrial food production.
So while it certainly makes sense to eat organic, if you’re interested in maximizing the nutrient density of your food, eating foods that are grown locally and consuming them as close to harvest as possible is even more important. This means shopping for produce at farmer’s markets or using a CSA, or even better, growing your own backyard fruits and veggies.
Final Thoughts and Recommendations
Before I share recommendations, it’s worth pointing out that this new study was funded by the European Union and the Sheepdrove Trust, an organic farming charity. One might argue that the involvement of the Sheepdrove Trust constitutes a conflict of interest.
Unfortunately, such conflicts are the rule rather than the exception in most nutritional and medical research. Critics of the Stanford study have pointed out that the Freeman Spogli Institute, which supported the research, has received millions of dollars in funding from Cargill (the world’s largest agricultural business) and the Bill & Melinda Gates Foundation, which has deep ties to agricultural and biochemical companies like Monsanto. In addition, one of the co-authors of the study, Dr. Ingram Olkin, has accepted money from the tobacco industry’s Council for Tobacco Research, which is a fraudulent front organization for Big Tobacco.
When a study is funded by an organization with a vested interest in the result, we should certainly be cautious when interpreting those results. However, such a funding source does not by definition make the study worthless. We can still evaluate it on its own merits.
With that in mind, I think the findings of this new, large study are sound and consistent with the majority of the previously published evidence—especially as it relates to higher levels of pesticide residue and heavy metals in conventional produce.
Here’s what I’d suggest given what we know:
- Buy organic, locally grown produce as much as possible. This typically means shopping at farmer’s markets and/or joining a local community supported agriculture (CSA) program.
- It’s particularly important for young children and women who are trying to conceive, pregnant, or breastfeeding to eat organic, because they are more susceptible to being harmed by pesticide residue and heavy metals.
- If you have limited access to organic produce, due to financial or geographical reasons, try to at least buy organic varieties of the fruits and vegetables that are grown with the highest amount of pesticide when grown conventionally. The Environmental Working Group maintains a list of these, which it calls the “Dirty Dozen”. It also maintains a list of the “Clean Fifteen”, which are the fifteen varieties of fruits and vegetables that are relatively safe to buy conventionally. You can see both lists here.
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I don’t live in the States but in Africa. Where I am, we have no idea of the conditions under which our veggies are grown. I suspect that most are heavily sprayed. Much in our local supermarket looks tired and wilted. We rejoice when our fresh produce is indeed fresh. Best we can do!
It would be extremely helpful to have the actual citations at the end of each of your articles. I am finding with some of the older articles that the links are broken or invalid and I am unable to locate the research article. Thank you!
Just a word on growing your own; absent living in a forest, growing a reasonable amount of food is relatively easy; the problem is finding out what grows best in your climate. Here in San Jose, I mainly grow tomatoes and Zucchini in buckets of home-made compost during the hot summer, but I also have some cucumbers and bell peppers. During the spring, salads are in. These are the easy ones. Peas are easy but also cheap in the supermarket and generally fine. Fava beans used to be good with me once I worked out that I needed to sow them earlier to avoid heat during the flowering period, but now they all get taken by the birds. Cabbages get infested by aphids.
The real simple one is fruit -although diabetics here might not want so much. We have apricots, lemons, grapes, apples, pomegranates peaches and persimmons, and neighbors have figs and plums. All without much effort at all. Trees pretty much look after themselves.
You might live in cooler climates, but you will hopefully have far more rain than we have here, and cool weather solves a lot of my pollination issues. So your radishes, summer lettuce, green beans, and so on might all do better than mine.
So give it a try – and grow some easy herbs, like Oregano and mint.
Being a Foodie I’ve always let my nose and taste buds do the walking in the grocery store. There’s no comparison in my mind because organic and freshly picked produce always, ALWAYS, smells and tastes better. I never put much stock in what the naysayer ‘scientific experts’ said because the smell and taste always told me there was a difference. I thank my grandmother for teaching me to always smell my produce in the store before buying it. To me, there is no comparison.
This article does not represent an accurate report of the meta-analysis. The researchers primary conclusion is that the existing data out there is hard to homogenize (which presents a serious problem for any meta-analysis). And while the means for many compounds may have leaned organic, the error bars encompassed 0% difference between conventional/organic for most of those. The review also found that conventional produce is a better source of protein that organic, but I don’t see that mentioned here. And the cadmium link is so very very weak, that it’s not even included in their weighted meta analysis because the handful of data points they had were so few and weak that they didn’t even include basic statistics like SD/SE. While 343 studies sounds really impressive, it’s important to note that they excluded 17,000 studies from their analysis – so there’s a lot they didn’t look at. And, for each individual piece of information, there are far fewer studies than that – for example the researchers note “it should be pointed out that (1) there are only eleven studies in which the frequencies of occurence of pesticide residues were compared, (2) eight of these studies focused on only 1 crop species, (3) no comparative studies for cereals, oilseeds, and pulses were identified in the literature review, and (4) the data available did not allow scientifically robust comparisons of the concentrations of pesticides.”
This is certainly an interesting paper, but the big story here is that we need better, more tightly controlled, experimental research protocols and studies done with specific and narrow focus in order to properly evaluate the differences between organic (which they point out is hard to pin down WHAT that means in each individual study examined) and conventional.
While it is certainly true that organically raised produce has many advantages over conventionally raised produce, it is still not the “top of the mountain” when it comes to plant foods. Numerous studies demonstrate that wild plants have higher nutrition, greater amounts of beneficial phytochemicals (e.g., antioxidants), better fatty acid ratios, and more fiber. I am surprised this is still not finding its way into recommendations for plant foods. Certainly, not everyone has access to them (but this is also true of organic produce for various reasons). And because many cannot identify wild plants is no reason not to share this information–it would provide incentive to learn about the real foods that have not been manipulated by humans. Thank you for your article.
I do buy local/organic and have for many years. In fact, this is the first year in 35 that I have not had my own garden due to other challenges in life. I miss it so much!! Thank goodness for locally grown organic farmers! We discovered even into winter that there are abundant crops, and I would like to put in a plug for fermented foods, which go a long way adding to nutrient profiles and in fact may reduce some harmful substances in foods according to info published in Mercola’s newsletter. Bacteria are our friends! (there are more of them than us!)
“For some reason that isn’t clear to me, the mainstream media and medical establishment seem very attached to the idea that organic produce is no healthier or safer than conventional produce.”
Let’s see if I can clear it up for you: SCIENCE!!
Oh, and one more thing: It might not be good to tout higher antioxidants in anything. Seems like they might aggravate cancer: http://www.sciencedaily.com/releases/2014/07/140710094434.htm
While you’re busy shouting science in all capital letters, it’s important to remember that any scientific experiment, study, or meta-analysis is done by humans that will bring their own beliefs and biases into the work, and these beliefs and biases don’t disappear just because you ignore them, or because scientific results are written in the passive voice (eg, “It was discovered…”). So that’s why you can have one study, funded by companies that use and make pesticides, that finds organic produce isn’t better, while a meta-analysis, funded by a charity that supports organic practices, finds that it is.
The problem is that this meta-analysis did not conclude that organic is healthier.
I live in Germany and a couple of months per Year in Italy.
In those countries conventionally or organically grown produce do not differ in taste, but they do in terms of pesticide residuals and at times of appearance. That is it.
Organic and conventional potatoes taste the same in Germany, as well as Onions, carrots, broccoli, lettuce, etc.
From a comment above, citing salads in Greece, and the article, I take that the quality of (South) European produce differs significantly from the US one.
I most definitely taste a difference between a cucumber bought in the supermarket and the cucumber sold in my local Demeter farmer’s shop (the latter being way better!).
And I taste a difference in their locally grown carrots – not as crunchy as the organic carrots from the supermarket. I have to admit, I stopped buying their carrots.
One thing we all seem to be forgetting is that:
1. This study was conducted in Britain
2. The soils are different from ours
3. The varieties of produce grown are different from ours
If we look at our history (or rather, theirs), we will see that pastoral farming practices are in large part still intact, and that “approved” types of fertilizer, pesticides, and even laws governing the use of the term “organic” are different than ours–theirs being more strict. Also, they have a vast history of death and disease which contributed to the formation of the soil they farm in today–plagues, wars, raw sewage, compost, dead animals, etc. We do not have so much a historical layering of occurrences, because the wars, plagues, and raw sewage were minimal (comparatively speaking).
We also bury our dead in lead-lined coffins, which don’t allow for the blending of decomposition matter and soil to interact, as well as keep Grandma’s ashes on the fireplace mantel in a decorative urn, instead of returning them to the ground.
This difference in soil replenishment is a big part of what makes organic produce much better than conventional…FOR BRITAIN. This doesn’t necessarily mean the same will and does happen over here.
Testing over here is apt to be more exact for our situation.
This was another meta-analysis of prior studies worldwide, not a study of organic foods grown in Britain.
I want to point out that food from “Farmers Market” might be local grown foods, etc. Certain vendors have been know to pick up consumable goods at a warehouse just like your local grocery store. You will have to make sure you know what you are looking at before you buy. I had vendors post “grown in Michigan” but it not from their farm or even local farm.
Definitely. Charlatans are a serious menace and the barriers to prevent the selling commercial produce as “organic” are minimal. I’ve long suspected that farmer’s markets and similar venues unwittingly play host to a few charlatans. State consumer protection agencies are toothless tigers (I used to work for one so I know) leaving buyers with the onerous task of tracing to the source. The Paleo sphere desperately needs resources to vet the legitimate growers and sellers.