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Dr Caroline Leaf: All scare and no science?

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On her social media feed today, Dr Leaf posted a meme implying that conventionally farmed food was toxic.

Dr Caroline Leaf is a communication pathologist and self-titled cognitive neuroscientist. Anyone who’s been following Dr Leaf will know from her frequent food selfies that she is an organic convert.

Dr Leaf is welcome to eat whatever she chooses, though not content to simply push her personal belief in organic foods, Dr Leaf is now actively criticising conventional food, publishing memes on her social media posts which imply that conventional produce is poisonous.

As I’ve written before, despite Dr Leaf’s blinding passion and quasi-religious zeal for organic foods, there is no evidence that organic food is any more beneficial than conventional food (Dangour et al, 2009; Bradbury et al, 2014). Indeed, there’s no magic to a healthy food lifestyle. Eat more vegetables. Drink more water. Conventional veggies and conventional water do just fine. Sage advice, even if it doesn’t lend itself to food selfies.

While organic zealots believe they have the high ground on the topic of food safety, the published science cuts through the hype. As noted by Smith-Spangler et al (2012), there is some evidence that there may be less pesticide residue on organically grown foods, but there is no significant difference in the risk of each group exceeding the overcautious Maximum Residue Limit.

Two points on the Maximum Residue Limit that are particularly important:

  1. The Maximum Residue Limit is extremely cautious, and most food tested is well below this already overcautious limit. The Maximum Residue Limit is set to about 1% of the amount of the pesticide that has no effect on test animals.   According to a recent survey of grapes done by Choice Australia, the amount of residue was well below the Maximum Residue Limit (about 1% of the Maximum Residue Limit on average) (Choice Australia, 2014). So on the average bunch of grapes in Australia, the pesticide residue is about one ten thousandth of the level that is safe in animals, and this pattern is the same across all conventional produce. Thinking in more practical terms, “a 68 kg man would have to eat 3,000 heads of lettuce every day of his life to exceed the level of a residue that has been proven to have no effect on laboratory animals … an 18 kg boy would have to eat 534 apples every day of his life to exceed a residue level that is not dangerous to laboratory animals. And an 18 kg girl would have to eat 13,636 kg of carrots every day of her life to exceed such a level.” (ecpa.eu, 2014)

    2. Organic foods have pesticides too. Granted, this is at lower levels than their conventional counterparts, but it’s there all the same (Smith-Spangler et al, 2012). I once had a lively discussion with an organic food zealot about the pesticides in organic farming. Her argument was that organic pesticides are safe because they’re “natural” poisons. So are arsenic, cyanide, belladonna and digitalis (foxglove), but why let the truth get in the way of ones opinion. Poisons are poisons whether they’re “natural” or not. The Maximum Residue Limit applies to organic foods just the same as conventionally farmed produce for that reason.

Another interesting thing … in the Choice survey, the organic grapes had no detectable pesticides, but so did conventionally farmed grapes bought at a local green grocer. So organic food zealots can’t claim that they have a monopoly on low pesticides in their foods.

Not that having lower pesticide residues means that organic foods are necessarily safer. Organically farmed produce has a higher risk of contamination from E. coli and other potentially toxic bacteria, depending on the farming method used (Mukherjee et al, 2007; Sample, 2011).

So to bring it all together, conventional produce has levels of pesticide residues so low that it would take an extra-ordinary feat of vegetarian gluttony to exceed a level that was still found to be non-toxic in animals. The risk to human health from conventional farming with pesticides is nanoscopic. Organic foods may have less pesticide, but they have a higher risk from enterotoxigenic bacteria.

Since there is nothing to fear from conventional foods, it seems irresponsible for Dr Leaf to promote the unscientific idea that conventional foods are poisonous. One wonders why Dr Leaf would engage in a campaign of fear against healthy, nutritious foods? Personal bias perhaps, although that doesn’t bode well for her credibility as an objective scientist. Another plausible reason could be marketing. Fear sells things, that’s Marketing 101. Gardner (2008) wrote, “Fear sells. Fear makes money. The countless companies and consultants in the business of protecting the fearful from whatever they may fear know it only too well. The more fear, the better the sales.”

Posts like today’s make Dr Leaf seem like all scare and no science. Publishing images with the skull and cross bones and the word “POISON” is certainly not attempting to allay anyone’s anxiety, and that fact that it‘s directly tied to a reminder of her upcoming book on food only makes shameless promotion all the more likely. I’m sure that a Godly woman of Dr Leaf’s standing wouldn’t stoop so low as to use fear and mistruth just to make better sales, but posts like today’s open her up to legitimate questions from others regarding her credibility and her motivation.

For her sake, I hope that she tightens up her future posts, and reconsiders her stance on the science of organic and conventional foods.

References

Bradbury, K.E., et al., Organic food consumption and the incidence of cancer in a large prospective study of women in the United Kingdom. Br J Cancer, 2014. 110(9): 2321-6 doi: 10.1038/bjc.2014.148

Choice Australia, 2014. <http://www.choice.com.au/reviews-and-tests/food-and-health/food-and-drink/groceries/pesticide-residues-in-fruit-and-vegetables.aspx&gt;

Dangour, A. D., Dodhia, S. K., Hayter, A., Allen, E., Lock, K., & Uauy, R. (2009). Nutritional quality of organic foods: a systematic review. Am J Clin Nutr, 90(3), 680-685. doi: 10.3945/ajcn.2009.28041

European Crop Protection Agency, 2014, <http://www.ecpa.eu/faq/what-maximum-residue-level-mrl-and-how-are-they-set>

Gardner, D., The science of fear: Why we fear the things we shouldn’t – and put ourselves in greater danger; 2008, Dutton / The Penguin Group, New York

Mukherjee, A., et al., Association of farm management practices with risk of Escherichia coli contamination in pre-harvest produce grown in Minnesota and Wisconsin. Int J Food Microbiol, 2007. 120(3): 296-302 doi: 10.1016/j.ijfoodmicro.2007.09.007

Sample, I., E coli outbreak: German organic farm officially identified. The Guardian, London, UK, 11 June 2011 <http://www.theguardian.com/world/2011/jun/10/e-coli-bean-sprouts-blamed>

Smith-Spangler, C., Brandeau, M. L., Hunter, G. E., Bavinger, J. C., Pearson, M., Eschbach, P. J., . . . Stave, C. (2012). Are organic foods safer or healthier than conventional alternatives? A systematic review. Ann Intern Med, 157(5), 348-366.

Dr Caroline Leaf and the organic foods fallacy

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Organic foods. They are amazingly popular. More than a million Australians buy organic foods regularly, and several million more buy it occasionally. The retail value of the organic market is estimated to be more than $1 billion annually. The assumption made by most people is that because it’s so popular, organic foods must be good for you, or at least have something going for them to make them worth all the hype.

Of course, just because something’s immensely popular and has a billion-dollar turnover doesn’t necessarily mean it’s beneficial (One Direction is a case-in-point).

In fact, despite organic foods being touted by their supporters as healthier, safer, and better for the environment than normal foods, actual scientific evidence fails to show any significant difference. I wrote about this earlier in the year (see: Borderline Narcissism and Organic Food). Since then, another large prospective trial deflated organic food’s bubble, with a British study showing no change in the incidence of cancer in women who always ate organic foods versus those who never ate organic foods [1].

The dearth of benefit from organic foods wouldn’t be so bad if they were just another guy in the line-up, something neutral and inert. Unfortunately, not only can organic produce be contaminated if farmed incorrectly [2, 3], but they come at an extraordinary premium, sometimes costing four times more than their conventional counterparts (Borderline Narcissism and Organic Food).

Dr Caroline Leaf is a communication pathologist and a self-titled cognitive neuroscientist. A couple of months ago, she let slip her intention to publish a book in 2015 about food. Who knows what she’ll actually say, but if today’s social media meme is anything to go by, it will likely follow the same pattern of her other teachings.

Today, she wrote, “Research shows that dark organic CHOCOLATE lowers blood pressure, improves circulation, increase HDL (“good”) cholesterol, reduce the risk of heart attack and stroke, and increases insulin … and … recent research has even suggest it may prevent weight gain!”

As I discussed recently, Dr Leaf does herself a disservice by not citing her sources. It’s very brave to write in a public forum that dark chocolate reduces the heart attack and stroke, since this could be interpreted as medical advice, which she is not qualified to give. As for the actual effects of dark chocolate, there is not a lot of quality evidence on dark chocolate on its own. A 2011 meta-analysis of general chocolate consumption on cardiovascular risk did indeed show a relative risk reduction of 37% [4]. But before you prescribe yourself two dark chocolate Lindt balls twice a day, consider that a relative risk reduction of 37% isn’t a big effect. Plus, the recommended 50 grams of 85% organic dark chocolate to attain the small benefit for your cardiovascular health contains just over 300 calories/1280 kJ (the average can of Coke contains 146 calories/ 600 kJ), and is 30% saturated fat (http://caloriecount.about.com/calories-green-blacks-organic-dark-chocolate-i110689). So any health benefit that may be associated with the poly-phenol content is likely nullified by the high saturated fat and calorie count.

What concerns me about Dr Leaf’s future foray into dietetics is that little word sitting quietly in her opening sentence: “organic”. Dr Leaf is an organic convert. But rather than act like a scientist that she claims to be, she preaches from her biases, ignoring the evidence that organic food is all hype and no substance, encouraging Christians everywhere to pay excessive amounts of money for something that’s of absolutely no benefit. Dr Leaf is welcome to eat whatever she chooses, but encouraging organic eating without clear benefit is more hindrance than help for most of her followers.

References

  1. Bradbury, K.E., et al., Organic food consumption and the incidence of cancer in a large prospective study of women in the United Kingdom. Br J Cancer, 2014. 110(9): 2321-6 doi: 10.1038/bjc.2014.148
  2. Mukherjee, A., et al., Association of farm management practices with risk of Escherichia coli contamination in pre-harvest produce grown in Minnesota and Wisconsin. Int J Food Microbiol, 2007. 120(3): 296-302 doi: 10.1016/j.ijfoodmicro.2007.09.007
  3. Sample, I., E coli outbreak: German organic farm officially identified. The Guardian, London, UK, 11 June 2011 http://www.theguardian.com/world/2011/jun/10/e-coli-bean-sprouts-blamed
  4. Buitrago-Lopez, A., et al., Chocolate consumption and cardiometabolic disorders: systematic review and meta-analysis. BMJ, 2011. 343: d4488 doi: 10.1136/bmj.d4488

Borderline Narcissism and Organic Food

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Every time I go to the supermarket, I’m always amazed at the every-growing supply of “organic” products.  In fact, not just the supermarket, but everywhere I go, one of the first things out of the mouth of the sales assistant is, “and it’s organic.”

Organic food has gone gang-busters in the last decade.  It is currently worth around $200–$250 million per year domestically and a further $50–$80 million per year in exports, with an expected annual growth of up to 60 per cent. In 2010, the retail value of the organic market was estimated to be at least $1 billion.

Consumer demand for organic food is growing at a rate of 20–30 per cent per year, with retail sales increasing 670 per cent between 1990 and 2001–02. It is estimated that more than six out of every ten Australian households now buy organic foods on occasion (Better Health Channel, 2013).

It’s not cheap either.  I did a single price point comparison to see what the difference was between similar organic and conventional foods.  A 411g can of “Muir Glen” brand diced organic tomatoes on Organics Australia Online (http://www.organicsaustraliaonline.com.au/category173_1.htm) cost $4.28.  An equivalent product, “Annalisa” brand 400g can of diced tomatoes cost $1.00 at Woolworths Online (http://www2.woolworthsonline.com.au/#url=/Shop/SearchProducts%3Fsearch%3Ddiced%2Btomato%2Bcanned).

Allowing for the slight difference in size, that’s still a 400% premium, just because something is tagged as organic.

Given the massive price premiums and it’s overwhelming popularity, you’d assume there is something miraculous about organic food.  Like, it possessed some magical healing properties, or that it was the elixir of life.

Yet in the hard light of day, the aura of organic food turns out to be a shimmering mirage.  When critically examined by the power of science, organic food is found to be lacking.  It’s all hype, and no substance.

So why do people buy and consume organic produce?  Usually because they believe that organic foods are healthier (that is, they have more nutrients) or safer (or they believe that there are less pesticides or chemicals), that organic foods taste better, and that organic farming is better for the environment (Hughner, McDonagh, Prothero, Shultz, & Stanton, 2007).

But as it turns out, organic foods have essentially the same nutritional content as their conventionally farmed equivalents (Dangour et al., 2009).  There is some evidence that there may be less pesticide residue on organically grown foods, but there is no significant difference in the risk of each group exceeding the overcautious Maximum Residue Limit (Smith-Spangler et al., 2012).  So organic foods can’t be claimed to be significantly safer than conventional foods either.

The other positive attribute pushed by organic proponents is that organic farming is much better for the environment than conventional farming.  But far from the stereotype, organic foods aren’t saving the planet from the evil greed of the multi-national corporations and their earth-raping large scale conventional farming techniques.

Tuomisto, Hodge, Riordan, and Macdonald (2012) concluded their meta-analysis of research into European farming by saying, “This meta-analysis has showed that organic farming in Europe has generally lower environmental impacts per unit of area than conventional farming, but due to lower yields and the requirement to build the fertility of land, not always per product unit. The results also showed a wide variation between the impacts within both farming systems. There is not a single organic or conventional farming system, but a range of different systems, and thus, the level of many environmental impacts depend more on farmers’ management choices than on the general farming systems.”

In other words, the impact on the planet has nothing to do with the food that’s grown, but the farmers who grow it.

That’s three strikes for organic food.  It isn’t healthier, safer, or better for the planet.  There’s nothing to organic food that justifies the enormous premium that is charged for them, except the egocentric inflation that comes from believing that “being organic” is superior.

Like going to the Opera or driving a Prius, “being organic” is just another outlet for borderline narcissism.

The take home message: If you care for your health or the environment, buy conventionally farmed food.  There’s no difference to organic food, except the price.

References

Better Health Channel. (2013, Oct 17). Organic Food.   Retrieved Jan 24, 2014, from http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/organic_food

Dangour, A. D., Dodhia, S. K., Hayter, A., Allen, E., Lock, K., & Uauy, R. (2009). Nutritional quality of organic foods: a systematic review. Am J Clin Nutr, 90(3), 680-685. doi: 10.3945/ajcn.2009.28041

Hughner, R. S., McDonagh, P., Prothero, A., Shultz, C. J., & Stanton, J. (2007). Who are organic food consumers? A compilation and review of why people purchase organic food. Journal of consumer behaviour, 6(2‐3), 94-110.

Smith-Spangler, C., Brandeau, M. L., Hunter, G. E., Bavinger, J. C., Pearson, M., Eschbach, P. J., . . . Stave, C. (2012). Are organic foods safer or healthier than conventional alternatives? A systematic review. Ann Intern Med, 157(5), 348-366.

Tuomisto, H. L., Hodge, I. D., Riordan, P., & Macdonald, D. W. (2012). Does organic farming reduce environmental impacts?–A meta-analysis of European research. Journal of environmental management, 112, 309-320.