Eat This, Ministry of Controversy, Science Says

Stanford Organic Study Ignores Variety Differences

More nutritious because of the holes? Possibly.

Rant readers, please welcome Dr. John Reganold of Washington State University, who has done groundbreaking work demonstrating the value of organic agriculture, including studies that show a correlation between the quality of the soil and the quality of the food it produces. In the wake of the recent furor over a Stanford University review study comparing the healthfulness of organic and non-organic foods, which found little evidence that organic foods are more nutritious, I asked him for his thoughts on the Stanford group’s conclusions. 

Q: What do you think of the Stanford organic study?

A: Since 2000, there have been at least 12 review studies—meta-analyses of previous studies—looking at the nutritional quality of organic versus conventionally grown foods. And nine of these studies have found some evidence that organic food is more nutritious. Just three have concluded that there is no consistent difference or that there is a lack of strong evidence. Another study led by Dr. Kirsten Brandt of Newcastle University that I think is the best study found that organic fruits and vegetables are more nutritious. It didn’t receive much press when it was published last year, by the way.

One of the differences between the two review studies was whether they included comparisons between different varieties of the same crop, which can vary greatly in terms of nutrition. In the Stanford study, 60% of the comparisons used were between the same cultivar, so presumably 40% were not. Brandt was more picky and only compared like cultivars.

Looking at the big picture, I’m glad the Stanford group did the study. They are spurring debate, and I think that is good. While they found that there is a lack of strong evidence for the nutritional superiority of organic foods, they also found that consuming organic food can reduce your exposure to pesticides and antibiotic-resistant bacteria.

Q: The New York Times piece about the Stanford study mentioned that it neglected to include the strawberry study you led. That study found that there is a connection between the nutritional quality of strawberries–as well as their flavor–and soil quality, including the biomass and activity of soil microbes. And that on both fronts, organic wins. In the past, you also were part of a long-running apple study that connected the quality of the fruit with the greater diversity of nematode species in organic soil. Do you think we’ll ever establish once and for all the connection between healthier food and healthier, livelier soil?

A: People think that if you have healthy soil, you have healthy food, but it’s very difficult to prove. In the case of strawberries, we did show that healthier soils produce healthier food. Does that mean that healthier soils produce healthier food in general? We can’t say that.

Q: The Stanford study didn’t mention flavor. Your research is unusual in that it considers flavor–and has found that organic does taste better.

A: There haven’t been many taste tests done. My strawberry study did find better flavor in the organics. But the results of other taste tests have not been conclusive.

Q: Okay, as a gardener, I know my homegrown organic produce tastes better than supermarket food, and I have faith that it’s more nutritious, too, thanks to my beautiful soil and all the creatures in it. But I do find that Stanford study disheartening.

A: Keep on gardening! The Stanford study did find some results that suggest that organic food is better for your health. You’re also reducing the environmental costs of your food, in part because you don’t have to drive to the store to buy it. And that connection to the land that we develop when we grow our own food improves our feeling for the whole planet.

Posted by on September 14, 2012 at 4:31 pm, in the category Eat This, Ministry of Controversy, Science Says.
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21 Responses to “Stanford Organic Study Ignores Variety Differences”

  1. kermit says:

    Michelle, even if organic food doesn’t turn out to be significantly more nutritious, it’s healthier for Mother Earth and safer. Also, we invariably eat or preserve it fresher than grocery store produce. Also, too, we get more exercise and fresh air. These are significant.

  2. To all of the faithful organic gardeners out there, take heart! There will probably never be conclusive agreement on either the comparable taste of organic versus “conventional” produce OR their respective nutritional value. Then again, there are those who will argue over whether global warming and evolution are real. Relative taste is far too subjective an aspect to be the sole determining factor when making your choice. And as mentioned in the article above, there are a myriad of apples being compared to oranges (excuse the pun). Consider this: when given an option which is mindful of the long established mechanisms of the planet, that considers the proven interdependencies of the natural world, it is at the least a very good bet.

  3. In taste test studies I would question where did the industrial produce come from for the studies. Did it come from the supermarket or more directly from the factory where it may have been allowed to ripen for the test before normal harvest and shipping?

    You can’t tell me a tomato that tastes and feels like wax fruit or a giant red strawberry with zero flavor that come from the store taste the same as the ripe juicy tomatoes I grow or the normal sized strawberries that have an actual zing for the taste buds. The difference in flavor and texture are worlds apart.

    How about zero exposure to pesticides in my fine produce. If it is going to need some treatment, chemical or organic, I won’t grow it.

    Now granted I am comparing a home garden to organic and industrial food production and that is not quite the same as either.

  4. Sandra Knauf says:

    This study is inconclusive, and flies in the face of common sense. Ignore it. It’s only in the news because it’s controversial. What about all the new “discoveries” they’ve made regarding food in the last couple of decades–antioxidants and other properties they didn’t know about before? Now we’re getting into biodynamic farming (the idea which has been around for almost a century). We live in a country where GMOs are not only in almost every single processed food, but they are not even labeled, for God’s sake! Food science is in its infancy (by choice) and mostly run by multinational corporations.

    I think about the article that came out recently on the human genome and how scientists thought that some genes were “junk genes” with no real purpose –before “discovering” everything is significant. That says a lot about the state of science. I love science, but it has a long way to go as far as being what it needs to be to properly serve humankind.

  5. greg draiss says:

    Again is organic garlic from China as good as regular garlic from the states. All these surveys ignore the total ECOnomic/Carbon footprint. Is it really better to import organics than regular stuff grown here. Was the Chinese USDA organic garlic shipped on hybrid trucks and ships powered by the wind? DOUBTFUL.

    Organic is so passe’ when compared to the total footprint. The nice thing about the eco/carbon footprint is the smaller the footprint the less economic impact as well as eco-system impact.

    THE TROLL

  6. Jason says:

    The fresher the food, the better the taste and quality. Being organic may or may not make a difference, I don’t know. But it does seem clear that organic gardening and farming is better for the environment.

  7. Flavour is primarily governed by the chosen variety. Whether a variety has been bred especially for good flavour or whether it has been bred for commercial growers who are more interested in visual high quality and heavy crops. Good flavour or not is further governed by the water content. If a crop is forced on with extra warmth and extra water and extra soluble feed its internal structure will not be as dense with not much dry matter and will have more water in its internal structure – therefore less flavour.

    If crops are grown naturally in the open without too much irrigation and we rely just on rain then the growth will be slower and the dry matter higher and therefore a better flavour because the flavour is intensified in the denser internal structure. That reason explains why home grown produce nearly always tastes better. The home gardeners who are organic will believe it is their organic methods causing the better flavour but it isn’t. It is the slower rate of growth and less artificial irrigation. The inorganic home gardener will have tasty vegetables too for the same reasons. I know it! I have just eaten the best tasting sweet corn Ive ever tasted off of my veg plot and it was fertilized with inorganic fertilizer as well as some organic fertilizer. It did not have any artificial irrigation during the growing period. Not just this year but in all the previous years I use both organic and inorganic but I do not irrigate unless there is a prolonged drought (which is rare here) All of my veg has been best taste this year except one variety of potato. The variety was to blame and not the growing method as all the other varieties tasted great and were grown exactly the same way.

    Another reason home grown tastes better is because it can be picked and eaten within 1 or 2 hours of even minutes, where as commercially grown veg is picked and then transported a long way for packing. And then distributed hundreds of miles around the country. The shop veg may well have been picked 4 or 5 days before it reaches the shop. Once off the plant tasty sugars turn to not tasty starch in some veg. Dehydration begins once off the plant.

    • Michele Owens says:

      Colin, amazed that you are using artificial fertilizer. Why on earth would you need that stuff, when a little compost makes everything explode?

      Yes, I am not a big irrigator, either. However, flavor is not just about the variety and a willingness not to pump things up with too much water or artificial nitrogen.

      It’s about the soil, too. I’ve planted the same variety 45 minutes apart–and it can be transcendent in one garden and not so impressive in another.

      • Michele

        The reason I do use some artificial fertilizers is because over the years I have realized that organic fertilizers alone cannot deliver entirely the plants requirements. I have also learned that the need varies a lot from one soil to another with some soils being naturally fertile.

        The main reason I use some inorganic fertilizers is because they are more predictable and accurate in how they work. Organic fertilizers rely on soil temperature and soil bacteria to work and it can be a long time before the effect is seen or they may be irregular in how the nutrient is released. The plants do not care whether their nutrients come as organic or inorganic as long as they get fed what they need when they need it.

        I agree with you that soil must be in good shape with the correct amount of humus for good structure and drainage and water retention. A decent worm population keeps soil airated and distributes organic matter through the soil. A humus content of 8% to 15% is ideal. Too much humus and the soil becomes choked with it and stops funtioning as a good mineral based soil should. Not all crops like a soil laden with compost and manure.

        Manure provides most of the trace elements and helps to hold them and retains water in dry periods. So I do appreciate the need for plenty of organic matter in the soil.

        Sometimes a little quick acting nitrate is just what the plants need as a tonic to get them growing, especially leaf crops. Sulphate fertilizers supply the much needed sulphur which used to just drop out of the sky many years ago as industrial pollution but now we are in the days of clean air and here sulphur content in the air is now only 1/10th what it was in 1980 so adding sulphur as a fertilizer is now essential.

        I like to use NPK liquid feeds regularly during the growing period. the ones I use are all blended from various proportions of Ammonium Nitrate, Urea, Potassium Nitrate, Mono-Ammonium Phosphate, Calcium Nitrate, Magnesium sulfate plus soluble trace elements. These fertilizers are all quick acting, soluble, accurate and predictable. I use organic fertilizers more as base dressings when I’m preparing the soil.

        I do add a lot of compost and manure and leaf mould to my soil but I regard it as a soil conditioner rather than a supply of nutrient. I am not aware that my methods of fertilizing has ever spoiled the flavour or nutrition of any veg I have grown over the many years of growing. I wouldn’t call myself an organic gardener but neither would I call myself an inorganic gardener. I just do a mixture of the two to grow the best veg I can, as well as small amount of fruit and some cut flowers. I do like good quality. I do not like my fruit and veg to come with maggots.

        Some organic gardeners practice companion planting to try and deter pests but I have never seen it work very effectively. I do not grow a huge range of different veg but only the ones I like eating. do not grow herbs at all and very few flowers, so for me I can’t adopt the companion planting method without growing many things I do not even want.

        I really would like to see a 100% organic garden looking 100% and producing veg as well as can be. So far I have never seen an organic gardener with veg or fruit or anything else which I think comes up to standard. The crops always look starved and in desperate need of some feed and pest damage is always in evedence. personally I do not knowingly do anything environmentally damaging although I admit I never stop learning new things.

        • Also Michele

          When you say plant the same thing 45minutes apart and one does well and the other doesn’t are you refering to planting according to the ”Moon Phases” Some people say a certain date when the moon is at a certain position will mean crops grow and when planted at the wrong moon phase they will not grow. i believe there is some scientific evedence to back up the theory but I have never looked in to it.

          If you mean because soil condition varies greatly in just a short walk then yes I am well aware of that. A soil can be pH6 at one end of the garden and pH7 at the other and that alone will effect how well plants will grow. And it does prove how important good soil preperation is.

        • Michele Owens says:

          You must be kidding! My vegetables are gorgeous, with nothing but a sheet mulch of organic matter.

          The symbioses between plants and soil microbes are amazingly subtle and effective, the product of many, many years of co-evolution. Of course, those microbes can do the job of feeding your plants.

          How do you think we humans grew food before Haber-Bosch?

          • They will grow to some degree but whether they grow as well as might do is unlikely. Wild plants grow in the wild as wild plants do, but they will not be like cultivated plants which can achieve the greatest potential when properly fed.

            Growing veg, even as an amateur is still about cultivation and is just a downscaled form of farming. The whole idea is to put the human touch to it and improve on where nature left off. Therefore growing crops is about best quality and best yield and flavour and has no relationship to how wild plants grow.

            I know of gardeners here who never ever dig but just put down a new layer of organic matter each year. It is without doubt that the no dig method is an inadequate method of growing. I have never seen anything grown by the no dig method which looked better for it. Although I’m not saying it hasn’t happened somewhere, I’m just saying I’ve never seen with my own eyes. Soil must have deep cultivation to ever produce the best crops in my experience. Only in hot countires where soil erotion is a problem is the ‘no tillage’ method as they call it preferable.

            There is also the problem many people have of not having enough organic matter available to do that method. Unless a plant is native to somewhere like a woodland it is not supposed to grow in pure organic matter. The mineral content should be the main part of the soil for most plants. Too much organic matter will create a very acidic soil which then has to be brought back to life with the addition of powdered chalk or ground limestone. If soil becomes too acidic not only does many nutrients lock up but the worms also leave. Earth worms hate acidic soil.

        • greg draiss says:

          Colin I agree with you on the need sometimes for inorganic ferts. The cost of organics is sometimes prohibitive in one needs to get so many pound per ace to be profitable. The advances in “slow coating” chemical ferts to mimic organics is a winner.

          Nothing however beats a top dressing of compost to keep the soil healthy. Organics in the garden have their best use when it is understood how they keep the soil structure and integrity intact.

          They do little with the taste of a crop since like you said plants cannot tell the difference between chemical and organic ferts. Since the end form entering the plant as “plant food” is the same regardless of its’ being organic or chemical it is foolish to think that organic ferts make food taste better.

          The TROLL

          • Colin UK says:

            Greg

            I think all your points are well balanced and in the correct measure. Like me you avoid the hysterical rhetoric which comes from people who come down totally on one side or the other.

            Yes of course the correct and most balanced method, as well as the most productive method of growing is a combination of organics and inorganics. Totally organic gardeners should not claim all things environmentally friendly as their own, and demonize other gardeners as environmentally unfriendly who do not follow the organic gardening rule book to the letter.

            For example the vast majority of organic fertilizers are very low strength in terms of percentage of active ingredients – usually anything from 2% to 15%. Inorganic fertilizers are usually anything from 15% to 60% active ingredients. The amount of 2% strength fertilizer added to the soil needs to be 30 times as much as a 60% strength fertilizer and therefore 30 times the bulk and 30 times the weight. Therefore I will assume it takes 30 times the amount of fossil fuels to transport it in 30 times the amount of trucks. In terms of environmental friendlyness I wonder if organic gardeners ever concider things like that.

            Like you say organic fertilizers are generally more expensive, especially if you compare the price verses the percentage of active ingredient.

            I am not inclined towards allowing myself to be drawn into a gardening belief system where facts are swept aside if they conflict with the image and rhetoric.

            Huge amounts of organic matter may well be possible for a amateur who is gardening in a small garden but I cannot see how there can ever be enough organic matter available to adequately cover thousands / millions of acres.

            We do mix up amateur gardening and commercial growing here which probably isn’t helpful. Amateur gardeners and commercial growers don’t and can’t go about thing the same way.

            Amateur organic gardeners are certainly not in any position to preech to commercial growers about how to grow crops. Feeding a nation is very different to growing a bit of veg in a few square yards in the back garden.

          • Colin S UK says:

            Greg

            Another method of growing which is the complete opposite to ”organic only” growing is ”hydroponics”. When I was working in tomato glasshouses the tomatoes had previously for many decades been grown in peat filled growbags. But peat extraction is ruining the environment and it releases lots of co2 so peat use is gradually being phased out in EU and alternatives are taking over. So the tomato growing was changed over to ‘hydroponics’ which in the commercial growing trade is called NFT (nutrient film technique) The tomatoes grow perfectly well on NFT and taste just as good (this was not recently but back in the 80s when I was young but the NFT is still the way it is done).

            There is very little transportation needed because of having no bulky materials like growing media and bulky insoluble fertilizers and therefore the system saves on using non renewables like diesel and packaging and peat. It is in fact a totally inorganic growing system and yet it is the most environmentally friendly I can think of. Therefore I do not accept the belief that inorganic must mean bad for the environment.

  8. Monish says:

    In light of the fact that the Stanford study did contrast sharply with others, and now this exclusion of varietal influence, does lead one to question the studies authors….
    Love this last sentence-”That connection to the land that we develop when we grow our own food improves our feeling for the whole planet”
    ~Thank you Dr Reganold

  9. Flavour is primarily governed by the chosen variety. Whether a variety has been bred especially for good flavour or whether it has been bred for commercial growers who are more interested in visual high quality and heavy crops. Good flavour or not is further governed by the water content. If a crop is forced on with extra warmth and extra water and extra soluble feed its internal structure will not be as dense with not much dry matter and will have more water in its internal structure – therefore less flavour.

    If crops are grown naturally in the open without too much irrigation and we rely just on rain then the growth will be slower and the dry matter higher and therefore a better flavour because the flavour is intensified in the denser internal structure. That reason explains why home grown produce nearly always tastes better. The home gardeners who are organic will believe it is their organic methods causing the better flavour but it isn’t. It is the slower rate of growth and less artificial irrigation. The inorganic home gardener will have tasty vegetables too for the same reasons. I know it! I have just eaten the best tasting sweet corn Ive ever tasted off of my veg plot and it was fertilized with inorganic fertilizer as well as some organic fertilizer. It did not have any artificial irrigation during the growing period. Not just this year but in all the previous years I use both organic and inorganic but I do not irrigate unless there is a prolonged drought (which is rare here) All of my veg has been best taste this year except one variety of potato. The variety was to blame and not the growing method as all the other varieties tasted great and were grown exactly the same way.

    Another reason home grown tastes better is because it can be picked and eaten within 1 or 2 hours of even minutes, where as commercially grown veg is picked and then transported a long way for packing. And then distrubuted hundreds of miles around the country. The shop veg may well have been picked 4 or 5 days before it reaches the shop. Once off the plant tasty sugars turn to not tasty starch. Dehydration begins once off the plant.

  10. More……

    Health benefits and higher nutritional value of organically grown produce is also as case of not letting opinion get in the way of facts. The same will apply as with flavour. A slower rate of growth and higher dry matter will intensify the nutrients we get from veg. Whether inorganic or organic if the crop has been grown naturally at a natural rate of growth without extra irrigation and feed it will have a more intensified flavour and more intensified nutrient content.

    If we are talking about organic being healthier because it is free of pesticide sprays then that may or may not be the case. Organic produce very often is sprayed with organic derived pesticides and very often inorganic produce is not sprayed. Also chemical sprays have varying persistancy. Some contact only / knock down sprays (rather than the systemic ones) do not enter the plant or remain on the plant. They will be gone a long time before we eat the crop and will not be at all damaging to our health.

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