Do you remember the terror of the yolk? In the late 1960s, the American Heart Association suggested eliminating them from our breakfasts and limiting us to three eggs a week.
Since then, many other foods have joined the Good Foods Go Bad Club, whether they truly deserve membership or not. White bread, pasta and white rice are on the brink in some circles. You may have heard warnings about eggplant, tomatoes, and potatoes, all three of which belong to the “nightshade family” of plants that have been blamed for causing inflammation.
It should be noted that eggs have since been redeemed. Most food fears along these lines are usually undone or debunked.
So it’s worth asking: How are foods labeled as ‘toxic’?
James McCormack, professor of pharmaceutical sciences at the University of British Columbia and author of The Nutrition Proposition, says scientific literacy is a big part of the problem. Few of us understand the dose levels of toxins and the risks to human health.
“There is no safe level,” McCormack said. “Too much water can kill you. Bottom line, the dose makes the poison.”
Eggplants, for example, contain an alkaloid that could potentially make us sick, but to feel sick you would have to eat at least a dozen whole raw eggplants. (Some estimates are even higher.)
Another reason foods are associated with toxicity, McCormack says, is the lack of high-quality evidence in the nutrition field.
“Whenever you hear about how eggs are good or bad for you, or that fat is good for you or bad for you, or even how bad highly processed foods are, people usually just compare the highest rates of consumption to the lowest. ‘ McCormack said. “In cohort studies, we almost never see a significant difference when we look at the people in the middle who eat an average amount of the foods studied.”
Weak evidence and a lack of certainty are leading to debate among experts, opening the door for people to tout some foods as “super” and denigrate others as “toxic.”
Or both, as in the case of a new food crisis, the “low ox” diet, which is gaining traction. There’s more than one voice claiming that dietary oxalate (a natural compound found in plants) causes a range of problems from osteoporosis, inflammation, thyroid problems to vulvar pain, but the most well-known proponent is Sally K. Norton, whose recently published book, Toxic Superfoods: How Oxalate Overload Is Making You Sick – And How to Get Better, had 59 copies at the Toronto Public Library at last check.
Which superfoods? Spinach, blackberries, bran, almonds and sweet potatoes to name a few.
Dietary oxalate is an even more confusing dietary issue than most, as people suffering from kidney stones are sometimes advised to eat a diet lower in oxalate. Not always, mind you. After I had a large kidney stone removed, my nephrologist told me not to worry about whether or not to eat spinach. The most important thing, he said, is to drink plenty of water.
Diet can be confusing for the reasons McCormack explained, as can a strong cultural tendency to be afraid of food. McMaster University historian Harvey Levenstein argued in his 2012 book Fear of Food: A History of Why We Worry About What We Eat that we are less Having faith in our food when the majority of us moved away from the farms we used to live on.
Levenstein argued that since our brains are wired to focus on avoiding poisonous plants, the omnivore’s dilemma, we’re programmed to be anxious and expend a lot of mental energy on our food choices. So calling something “toxic” directly feeds our worst fears and makes it easy to spark interest.
“The biggest word on the book cover is ‘toxic,'” said Jessica Mudry, an expert in nutritional history and an associate professor at Toronto Metropolitan University, referring to the Norton book on dietary oxalate. “And the second most important word is ‘superfood,’ so it’s a rhetorically sound move to say that all the things that everyone says are healthy could poison you.”
Mudry also noted the book’s lack of peer-reviewed sources, a list of symptoms that includes joint pain, allergies, low energy and many other things that almost everyone experiences at some point, and the claim that it’s next to impossible Diagnose oxalate poisoning.
McCormack doesn’t think most people who sell toxic food theories are cynical. He said many people are walking down health rabbit holes, misunderstanding dose levels and the importance we should place on low-quality evidence studies.
“It bugs me when people say in no uncertain terms that this is the way to eat, whether it’s the carnivore diet, the low-carb diet, the low-fat diet or, I don’t know, the sexy pineapple diet,” he said. “But unfortunately, I really think people believe their admonitions.”
The only solution is to become better consumers and not fall for fad diets based on thin research.
“We’ll probably never get definitive evidence on the diet,” McCormack said. “So we kind of stick with what we have.”
Toronto-registered nutritionist Christine Hooper, founder of the Butterfly Effect website for people with irritable bowel syndrome, said she finds dietary fears fascinating because they can be so persuasive.
“People always turn everything on themselves, even if they’re not susceptible to a medical condition,” Hooper said. “I think it’s just another example of how variety in your diet is key; that way you don’t overdose on anything. If you listened to all the food scares, you wouldn’t be able to eat anything.”
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