Tag Archives: cardiovascular disease

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

Fat checking … sorry, fact checking

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As I was living vicariously on Facebook again this afternoon, I came across a forwarded page from nutritionist Christine Cronau. She was previewing tonight’s (Australian) ABC episode of Catalyst, on the topic of the low fat diet.

It’s not that she or the ABC are necessarily wrong about low fat diets. Some scientists have been sceptical of the evidence for low fat diets every since they were proposed in the late 1970’s [1]. Often, low fat foods have been manufactured with extra sugar to make them palatable again [2]. So while western consumers have been thinking they’ve been doing the right thing, they’ve probably been making the problem worse.

We’re also a society of carnivores, and the meat consumed in modern society is much higher in saturated fat. Plant and seafood based diets contain a high number of poly-unsaturated fatty acids (omega-3 and omega-6) which has also been a recommendation for our heart health, however a study in JAMA in 2012 suggested that high levels of omega-3 PUFAs did not protect from cardiovascular disease or reduce all cause mortality [3]. On the other hand, it appears that reviews of scientific research have suggested that saturated fat doesn’t pose a significant risk for cardiovascular disease or all-cause mortality either [4].

So it’s true that we may have to review exactly why plant based diets are good for us. What I raised an eyebrow at was her suggestion that, “What in the world did we do before cholesterol-lowering meds? Oh, that’s right, before we started mass producing sugar and back when we enjoyed plenty of saturated fat, heart disease was pretty much non-existent.”

This is a classic case of “two wrongs don’t make a right”. Sure, low fat diets are probably not the all-glorious panacea that they were touted to be, but suggesting that heart disease didn’t exist before the rise of sugar and low fat foods is grossly inaccurate. A quick glance at the data of the Australian Bureau of Statistics shows that heart disease peaked in the late 1960’s, which was coincidentally before we started mass producing sugar and back when we enjoyed plenty of saturated fat, and has since dropped significantly.

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Is that because of dietary guidelines recommending a low fat diet? There are many contributors to heart disease, so low fat diets can’t be singled out as the sole cause, especially in light of the reviews I discussed above. The reduction of smoking may be part of it, as smoking has dropped in the same amount of time, although a significant proportion of our population still smoke.

Whatever the reason, it isn’t a good reflection when you try and support your argument against a fallacy with a fallacy of your own. I haven’t read any of her other material, so her books maybe quite cogent. However, Ms Cronau’s Facebook post today provides a good example of how cognitive biases can sometimes blind us to facts that don’t agree with our chosen position, and why we all need to be careful when evaluating the evidence of “experts” on line.

References

  1. La Berge, A.F., How the ideology of low fat conquered america. J Hist Med Allied Sci, 2008. 63(2): 139-77 doi: 10.1093/jhmas/jrn001
  2. Malnick, E., et al. Low fat foods stuffed with ‘harmful’ levels of sugar. The Telegraph, 2014. http://www.telegraph.co.uk/health/healthnews/10668189/Low-fat-foods-stuffed-with-harmful-levels-of-sugar.html
  3. Rizos, E.C., et al., Association between omega-3 fatty acid supplementation and risk of major cardiovascular disease events: a systematic review and meta-analysis. JAMA, 2012. 308(10): 1024-33 doi: 10.1001/2012.jama.11374
  4. Hoenselaar, R., Saturated fat and cardiovascular disease: the discrepancy between the scientific literature and dietary advice. Nutrition, 2012. 28(2): 118-23 doi: 10.1016/j.nut.2011.08.017