Opinionista Ivo Vegter 20 October 2015

Fashionable food fears (part one)

From butter to sweeteners, carbohydrates to fat, and microwaves to factories, food fears surround us daily. Everyone has an opinion about what is good for you and what is bad for you, and most of those opinions are wrong. (Part one of a short series.)

Other than sex, there’s nothing we’re more neurotic about than food. It is perfectly understandable that we worry about what we eat.

Live fast, die young, and leave a good-looking corpse,” as the saying goes, loses a lot of its rebel thrill once you’re no longer young, or have young ones of your own to care for.

Everyone would like to be healthier, stronger, and feel younger. Everyone wants simple, easy-to-remember solutions to their dietary or medical concerns. Entire business empires are built on allaying fears of sickness, under-performance or death. And many of those are based on little more than sensationalism and lies.

Is there anything that takes the pleasure out of life faster than having to worry that your next meal is sodium-free, preservative-free, gluten-free, lactose-free, baked or grilled instead of fried, unprocessed, organic, raw, whole, low-GI, sugar-free, fat-free, low-carb and grass-fed?

Most of these simplistic labels are based on exaggerations or over-generalisations. It takes only one study, put in a nutshell for the masses by lurid tabloids, to start a food myth. Folklore passed down by oral tradition is venerated for its wisdom, despite the fact that old wives’ tales are derided as such for a reason. Purveyors of vitamin supplements, diets, and superfoods regale us with carefully-crafted marketing spiels, which are uncritically accepted and passed on to friends over lunch.

Once a myth takes hold in the public imagination, it is almost impossible to dislodge. Don’t cook with salt. Eggs are bad for you. Use margarine instead of butter (no, wait, the other way around). High-fructose corn syrup is worse than sugar, and honey is better. Artificial sweeteners cause cancer. Irradiated food is bad for you. Avoiding pesticide residue is a good reason to buy organic. Nutrition is a good reason to buy organic. Frozen food is not as good for you as fresh fruit and vegetables. Canned food is worse. And don’t even start with preservatives. Using a microwave will nuke you, your food, or both. Use a plastic cutting board instead of wood. Low-fat food is good for you. Low-carb food is good for you. Raw foods preserve enzymes and are better than cooked foods. Detoxing is good for you.

All of these notions are exaggerated or false. In this, the first of a short series, we’ll look at these fears.

Salt has long been accused of causing hypertension (high blood pressure) in some (but not all) people. Hypertension, in turn, is a risk factor in heart disease. The panic about salt led to official government warnings and shelves full of fashionably low-sodium products.

Although a speculative link between hypertension and salt intake had been established as early as 1904, the modern fear about salt is largely based on the work of a single researcher at Brookhaven National Laboratory, a physician named Lewis Dahl. In 1960, he pumped mice full of salt and discovered that this raised their blood pressure. Sure. Being force-fed large quantities of salt would raise my blood pressure too. I might even punch my feeder. But by 1970, Dahl felt confident enough to declare that processed baby food is rat poison.

The problem is that Dahl’s idea of “chronic salt intake” was a dose 60 times higher than humans actually consume. Subsequent studies within genetically similar populations – to rule out genetic factors in hypertension – have found no relationship between sodium intake and high blood pressure. Note: not a small relationship, or an uncertain relationship, but no relationship.

According to a feature in Scientific American that called for an end to what it calls “the war on salt”, a study that looked at the direct correlation between salt intake and heart disease, rather than hypertension, found that the more sodium people ate, the less likely they were to die of heart disease. Another study found that it was the balance between sodium and potassium, rather than the levels of each, that made all the difference. A third, as recent as 2007, found that “the effect of sodium and potassium intake on [cardiovascular disease] morbidity and mortality in Western societies remains to be established”.

In short, the science is inconsistent and inconclusive. There is some evidence to suggest that people with high blood pressure ought to reduce their salt intake, increase their potassium intake or both. Other research suggests only overweight people need worry. But there is just as much evidence that it doesn’t matter, and cutting salt intake can have negative consequences – ironically including raising blood pressure – too.

Such are the flimsy grounds on which major governments base recommendations developed at great expense to the taxpayer, and preached to us as if we’re children who must eat what we’re given.

You now get two bottles of soy sauce with your sushi: one with a red cap to signal danger, and one with a green cap to make you feel smug. But for all that smugness, you gain exactly no health benefits from choosing the sodium-free green version, and the salty red version might actually be better for you.

Eggs, I was told all my life, are a prime source of cholesterol, which clogs arteries and causes heart attacks. The warning was simple enough to understand even for a child: avoid eggs if you don’t want to die.

In the US, where you can buy egg whites and egg yolk separately (because Murica!), the whites are now more expensive than the yolks. There’s a shortage of the stuff, because of the celebrity-fuelled craze for albumen-only breakfasts. If it sounds awful to eat only egg white, fear not. Not only is the yolk the tastiest and most nutritious part of an egg by far, but the cholesterol won’t kill you either.

Confused? Yes, the American Heart Association figures you might be, because for decades it has maintained a general warning against foods containing cholesterol. But it recently changed its guidelines, following research that showed dietary cholesterol actually isn’t what raises blood cholesterol levels. The liver does, in response to the intake of saturated fats and trans-fats. These are often associated with cholesterol-laden food, and Occam’s razor turned out to be wrong in this case. This was a typical case in which correlation – that two factors coincide – did not imply causation – that one factor causes the other. Even people with high cholesterol can perfectly safely eat two or three eggs a week, provided they limit the saturated and trans-fats they eat. The rest of us can get away with an egg a day. And those yolk-free omelettes? Tasteless pretentiousness, nothing more.

Speaking of trans-fats … Trans-unsaturated fatty acids, to give them their full name, were developed in industrial food processing to keep oily substances solid at room temperature. The most common method is to hydrogenate vegetable oil. And one of the most common uses of hydrogenated vegetable oil was to make margarine, a butter replacement.

Although developed in the 19th century as an alternative to expensive butter, medical research about the link between saturated fats and cardiovascular disease led to a rise in its popularity. For decades, official advice was to opt for the mono-unsaturated or poly-unsaturated fats of margarine rather than the saturated fats of butter. Not knowing the difference, and trusting the experts, most people dutifully did so.

But many margarines turned out to contain trans-fats, which is now considered to be the worst possible kind of fat if you’re trying not to die of a heart attack. The American Heart Association recommends you keep your trans-far consumption below 1% of your daily calorie intake.

So everyone switched back to butter, which tastes a lot better in any case, and the Daily Mail, swinging wildly in the opposite direction, called margarine “chemical gunk”.

This is not a problem if portion sizes are limited. As long as less than 7% of your daily calories come from saturated fats, you should be okay. But it can quickly add up if you cook with butter, bake with butter, and eat butter on your sandwiches. This is why the South African Heart Foundation still recommends margarine, as long as it is soft. (Remember, hydrogenating oil, which is where trans-fats come from, makes the oil solid.) Short of reading the label, so you can be sure to avoid hydrogenated vegetable oil, this is fairly good advice. Equally good advice is to use light or whipped spreads – whether butter or not – whenever you can, keeping portion sizes the same.

In the end, however, the entire margarine versus butter fiasco was much ado about nothing. A dab of butter on your porridge isn’t going to kill you. I’ll bet it kept hundreds of bureaucrats occupied on the taxpayer’s dime to tell us otherwise, though.

The moral of the story, so far, is not to panic. It is rarely necessary to avoid something completely, and many health scares around food are nothing but sensationalist exaggeration. The human body is capable of dealing with small amounts of poison. That’s why we have a liver, kidneys and a spleen.

Indulging our fears, however – inspecting every label for suspected traces of toxicity, and fretting about what poisons we’re putting in our children’s lunch boxes – is only likely to lead to anxiety, depression and gastric trouble.

Oscar Wilde said: “Everything in moderation, including moderation.”

After all, our happiness demands not only that we minimise our fears, but that we treat ourselves now and again. There is no reason to believe that this will kill us. DM


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