Remember the egg yolk scare? In the late 1960s, the American Heart Association suggested cutting them out of our breakfasts and limiting ourselves to three eggs per week.
Since then, a lot of other foods have joined eggs in the “good foods gone bad” club, whether or not they really deserve membership. White bread, pasta and white rice are on the outs in some circles. You may have heard warnings about eggplants, tomatoes and potatoes, all three of which are in the “nightshade” family of plants that have been blamed for causing inflammation.
Eggs, it’s worth pointing out, have since been redeemed. Most food scares along these lines are usually rolled back or debunked.
So it’s worth asking: how do foods get labelled “toxic?”
James McCormack, a pharmaceutical sciences professor at the University of British Columbia and the author of “The Nutrition Proposition,” says that scientific literacy is a big part of the problem. Few of us understand dose levels of toxins and human health risks.
“There’s no safe level of anything,” said McCormack. “Too much water can kill you. The bottom line is that the dose makes the poison.”
Eggplants, for example, do contain an alkaloid that could potentially make us ill but, to feel sick, you’d have to eat at least a dozen whole raw eggplants. (Some estimates are even higher.)
Another reason that foods get associated with toxicity, McCormack explained, is the lack of high-quality evidence in the nutrition field.
“Whenever you hear that eggs are good for you or bad for you, or that fat is good for you or bad for you, or even how bad ultra-processed food is, people are typically only comparing the highest consumption rates to the lowest,” said McCormack. “With cohort trials, we almost never see a significant difference when we look at the people in the middle who eat an average amount of whatever food is being studied.”
Weak evidence and a lack of certainty leads to debate among experts, which opens the door for people to champion some foods as “super” and vilify others as “toxic.”
Or both, as is the case with a new food scare, the “Low Ox” (low oxalate) diet that is gaining traction. There’s more than one voice claiming that dietary oxalate (a natural compound found in plants) is causing a range of problems, including osteoporosis, inflammation, thyroid problems to vulvar pain, but the best known proponent is Sally K. Norton, whose recently released book, “Toxic Superfoods: How Oxalate Overload Is Making You Sick — And How to Get Better,” had 59 holds in 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, since people who experience kidney stones are sometimes advised to eat a lower oxalate diet. Not always, mind you. After I had a large kidney stone taken out, my nephrologist told me not to worry about whether or not to eat spinach. The most important thing, he said, was to drink a lot of water.
Nutrition can be confusing for the reasons that McCormack explained, as well as a strong cultural tendency to be afraid of food. McMaster University historian Harvey Levenstein’s 2012 book “Fear of Food: A History of Why We Worry About What We Eat” laid out the case that when the majority of us moved away from the farms we used to live on we grew less trusting of our food.
Levenstein argued that we’re hard-wired to be anxious and spend a lot of mental energy on our food selection, since our brains are designed to focus on avoiding poisonous plants, the omnivore’s dilemma. Calling something “toxic,” then, feeds right into our worst fears and makes it easy to generate interest.
“The largest word on the cover of the book is ‘toxic,’” said Jessica Mudry, an expert in the history of nutrition and associate professor at Toronto Metropolitan University, in reference to the Norton book on dietary oxalate. “And the second largest word is ‘superfoods,’ so it’s a rhetorically savvy move to say all the things everybody says are healthy may be poisoning you.”
Mudry also noted the book’s lack of peer-reviewed sources, a list of symptoms that include joint pain, allergies, low energy and a lot of other things that almost everyone has at one point or another, and the claim that it’s next to impossible to diagnose oxalate poisoning.
McCormack doesn’t think most people selling theories about toxic foods are being cynical. He said there are a lot of people going down health rabbit holes, misunderstanding dose levels and the significance we should give to low-quality evidence studies.
“It bugs me when people say quite definitively 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 sadly, I truly think people believe their admonitions.”
The only solution is to get better as consumers about not falling for fad diets based on thin research.
“We’re not likely ever going to get definitive evidence for nutrition,” said McCormack. “So we’re kind of stuck with what we’ve got.”
Toronto registered dietitian Christine Hooper, founder of the Butterfly Effect website for people with irritable bowel syndrome, said she finds nutrition scares fascinating because of how powerfully persuasive they can be.
“People always apply everything to themselves even if they aren’t prone to a condition,” said Hooper. “I think it’s just another example of variety in your diet being the key; that way you aren’t overdosing on anything. If you listened to all the nutrition scares, you wouldn’t be able to eat anything.”
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News Source: https://www.thestar.com/life/health_wellness/2023/03/17/now-spinach-is-bad-for-you-decoding-the-low-ox-diet-the-latest-health-craze.html