The world is changing fast and to keep up you need local knowledge with global context.
If the latest US dietary guidelines prove anything at all, it’s how seductively enduring is the definition of insanity: doing the same thing over and over and expecting a different result. And when it’s scientists who are the ones demonstrating this crazy behaviour pattern, it bodes badly for public health worldwide. Other countries, including South Africa, slavishly follow the US guidelines. The 2016 guidelines that have just been published are updated every five years. They might just as well not have been. Last year, the US government’s very own expert dietary advisory group declared that dietary cholesterol was ‘no longer a nutrient of concern. It seemed that nutrition scientists were finally doing what all good scientist should do, and just as University of Cape Town emeritus professor Tim Noakes did in 2010, when confronted with the evidence proving that their popularly held belief was false: change their minds.
Sadly, no. The very same US dietary guidelines are not exactly egg-friendly, as Bloomberg columnist Faye Flam points out below. They are even stricter about cholesterol than when they came out five years ago. They still demonise saturated fat and recommend a high carbohydrate intake.That’s despite a growing body of evidence pointing to carbs (sugars) as prime movers of global obesity, diabetes and heart disease epidemics, and Banting, as low-carb, high-fat (LCHF) eating regimens are known, as safe, effective ways to reduce or prevent these life-threatening diseases. The evidence is so overwhelming, even a global investment bank, Credit Suisse, felt the need to speak about the need to acknowledge it.
Are fat-phobic scientists mad or just bad? Flam says it’s more likely a function of ‘the less than scientific beliefs’ some nutritionists hold. The Big Fat Surprise author Nina Teicholz in a report in the British Medical Journal in September 2015 comes to that conclusion and more in a scathing indictment of the science – or lack thereof – behind the US dietary guidelines. Auckland University public health professor Grant Schofield in New Zealand is equally critical of the guidelines. Schofield is co-author of What The Fat, with South African-born New Zealand registered dietitian Dr Caryn Zinn. Both say saturated fat does not deserve to be a pariah food. Noakes and other LCHF experts worldwide don’t claim it as a panacea for all the world’s nutrition ills. You don’t even have to be a Monty Python fan for it to make sense that if so many people have become so dangerously ill on high-carb, low-fat, especially low-saturated-fat diets, now is the time for doctors and scientists to do ‘something completely different’. – Marika Sboros
By Faye Flam
(Bloomberg View) – Last year, eggs were declared safe. After demonising the cholesterol in them for a generation, nutritionists finally acknowledged that there was overwhelming scientific evidence that eggs were not artery-clogging killers after all.
But wait. What’s this? The government’s latest nutrition guidelines came out this month and they’re not egg-friendly. They say people should consume as little cholesterol as possible. That’s even stricter than the 2010 standard allowing 300 milligrams a day, about the amount in one egg.
Scientists are supposed to change their minds when confronted with new evidence – whether it’s reclassifying Pluto as not quite a planet or admitting that Neanderthals contributed to the modern human gene pool.
When it comes to diet, though, even scientists sometimes get stuck in a rut. Then they drive the rest of us into a baffling morass of nutrition advice, in which the cholesterol paradox is a world-class stumper. Why would the same nutrition scientists who said last year that “cholesterol is not considered a nutrient of concern for overconsumption” keep warning people not to eat it?
The answer lies in some of the less than scientific beliefs held by nutritionists. Underlying their endeavor is the faith that there are good foods and bad foods – and that by strictly avoiding the bad foods we can conquer heart disease, cancer, and perhaps put off death itself.
That faith has led them to warn people away from anything that presents even the remotest possibility of causing harm. It’s a misuse of the precautionary principle: the idea that substances should be treated as dangerous until scientifically proven to be safe.
Reasonable precaution makes sense – most people expect extensive safety testing on new artificial sweeteners or drugs given to pregnant women for morning sickness, for example.
The danger in caution
Food choices can certainly influence health. There’s a strong consensus that too much sugar is a risk factor for obesity and diabetes, for example. But too much caution can do more harm than good.
The problem with applying the precautionary principle to food is that is that it fails to take account of alternatives. When told not to eat one thing, we reach for something else.
Provisional evidence that butter and cream caused heart attacks led to increased consumption of margarine and non-dairy creamer instead. Many heart attacks and bypass operations later, research determined that the trans fats in these substances were much worse.
Trans fats – aka hydrogenated vegetable oils – are manufactured through a process that renders them chemically distinct from the fats coming from plants and animals. For much of the 20th century, they were a major component of margarine as well as commercial pastries, processed foods and snacks. The stuff not only raises bad cholesterol, it lowers good cholesterol and boosts triglycerides.
The health strictures against eggs went along with a general demonisation of fats. So for years people ate more carbohydrates – a prescription that many experts now admit played a role in the current epidemic of obesity and type 2 diabetes.
Scientists painted such a fearsome picture of fat and cholesterol, said one heart specialist, that gummy bears and other candies were being promoted because they were fat-free.
Meanwhile there was never good evidence that eggs had more than a minor effect on blood cholesterol or that eating them in moderation was harmful.
Top heart specialists such as Dr Dan Rader at the University of Pennsylvania say humans break down most of the cholesterol in food. Most of the cholesterol in the bloodstream is made in the liver. The body uses it to make everything from cell membranes to sex hormones.
Some people develop abnormally high blood cholesterol because the mechanism for cleaning up the excess gets broken. The biggest risk factors for inadequate clean-up are genes, trans fats, and, to a lesser extent, saturated fats. Not eggs.
Why can’t the guidelines reflect this? The USDA’s explanation is that foods high in cholesterol also have lots of saturated fat. But that’s misleading. Eggs have very little saturated fat. The same goes for shrimp and shellfish – which, contrary to conventional wisdom, may not even be high in cholesterol.
Undeserved ‘deadly’ reputation
Oh, and about those saturated fats found in meat, poultry, cheese and butter – the kind the French eat while remaining quite healthy. Their deadly reputation may be exaggerated or undeserved.
The scientific literature is full of contradictory claims. A 2013 meta analysis concluded that cutting back on saturated fat didn’t help prevent heart disease. Some nutritionists say that study was misleading because people were substituting carbohydrates for saturated fat. (Who could possibly have led them to do that?)
The new guidelines tell people to replace the saturated fats with unsaturated fats – the stuff found in vegetable oils.
Much of the science of (the dangers) saturated-fat risk does not come from experiments. Instead, it’s based on observational studies that rely on self-reporting, which is notoriously unreliable. Dr Steve Nissen, head of cardiology at the Cleveland Clinic, said he doesn’t believe science knows yet whether saturated fats belong on the bad list and unsaturated fats on the good.
Other experts agree.
The reaction of many nutritionists was to say that the USDA didn’t make its recommendations scary enough. They blamed the food industry (The egg lobby must have been out on a company picnic). But if the nutritionists had their precautionary way, we’d all be subsisting on kale salad. With no cheese – and no assurance of living better or longer.
Cyril Ramaphosa: The Audio Biography
Listen to the story of Cyril Ramaphosa's rise to presidential power, narrated by our very own Alec Hogg.