By Marika Sboros
Norwegian researchers dispute the scientific pillar on which official dietary guidelines rest in most countries. It is the so-called diet-heart hypothesis that saturated fat causes heart disease.
The hypothesis just happens to be the pillar on which the Health Professions Council of SA (HPCSA) rests its case against scientist Tim Noakes. It also lies at the heart of the Australian Health Practitioner Regulation Agency (AHPRA) muting of orthopaedic surgeon Gary Fettke. AHPRA doesn’t want Fettke talking to patients about sugar now or ever again.
The Norwegian study is a small, well-designed, randomised controlled trial (RCT). Scientists consider RCTs the “gold standard” of research. The study authors say that a very-high-fat diet reverses obesity and disease risk. They also say that experts have greatly exaggerated alleged health risks of saturated fat for hearts. Here’s more:
The University of Bergen researchers’ study appears in the American Journal of Clinical Nutrition (AJCN). The title is Visceral adiposity and metabolic syndrome after very high–fat and low-fat isocaloric diets: a randomised controlled trial. They have dubbed it FATFUNC for short. Click here to view the study by scientists at the KG Jebsen Centre for Diabetes Research
The authors say it questions the validity of the hypothesis that has dominated for more than half a century. They say it disputes the belief that dietary fat, particularly saturated fat, is unhealthy for most people.
In a university press release, they say their data show strikingly similar health effects of diets based on either low-processed carbohydrates or fats. In the RCT, 38 men with abdominal obesity followed a dietary pattern high in either carbohydrates or fat. Of the fat, about half was saturated.
They measured fat mass in the abdominal region, liver and heart with accurate analyses. They also measured key risk factors for cardiovascular disease.
Click here to read: TEICHOLZ: HOW LOW-FAT DIETS CAN KILL YOU
“The very high intake of total and saturated fat did not increase the calculated risk of cardiovascular diseases,” says study author, professor and cardiologist Ottar Nygård.
Participants on the very-high-fat diet also had substantial improvements in several important cardiometabolic risk factors, he says. These included ectopic fat storage, blood pressure, blood lipids (triglycerides), insulin and blood sugar.
Both groups had similar intakes of energy, proteins, polyunsaturated fatty acids. They also had similar food types that varied mainly in quantity and minimised intake of added sugar. Researchers instructed all men in both groups to avoid hydrogenated vegetable fat, sugar, and foods with added sugar. They also instructed them to restrict the intake of highly processed foods and plant oils with high amounts of omega 6 fatty acids.
The researchers looked at effects of total and saturated fat in the context of a so-called “healthy diet”. That’s one rich in fresh, “lowly processed” and nutritious foods, including high amounts of vegetables and rice instead of flour-based products, says PhD candidate Vivian Veum.
The fat sources also derived from lowly processed foods – mainly butter, cream and cold-pressed oils.
Total energy intake was within the normal range. Even the participants who increased their energy intake showed substantial reductions in fat stores and disease risk. Thus, the findings indicate that the overriding principle of a healthy diet is not the quantity of fat or carbohydrates.
“It is the quality of the foods we eat,” says PhD candidate Johnny Laupsa-Borge.
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Controversy continues in nutrition science circles over the role of dietary saturated fat. Some cardiologists insist it is dangerous. They say it causes or promotes cardiovascular diseases by raising “bad” LDL cholesterol in the blood. Others, including British cardiology consultant Dr Aseem Malhotra, say that’s simply not true.
Even compared to most comparable studies, the Norwegian authors found no significant increase in LDL cholesterol with a high saturated fat intake. In addition, they found that the “good” HDL cholesterol tended to increase.
“These results indicate that most healthy people probably tolerate a high intake of saturated fat well,” says Nygård.
It may even be healthy, he says. That’s as long as the fat quality is good and total energy intake not too high.
Study lead author assistant professor Simon Nitter Dankel says experts have “greatly exaggerated” alleged health risks of eating good-quality fats. It may be more important to encourage reductions in processed flour-based products, highly processed fats and foods with added sugar.
Dankel led the study at Haukeland university hospital in Bergen with the director of the laboratory clinics, Prof Gunnar Mellgren. Dankel says future studies should examine which people or patients may need to limit saturated fat intake.
Where does that leave the HPCSA and AHPRA cases against Noakes and Fettke? Shakier than they were at the start, but that’s not difficult. The evidence grows to show that the diet-heart hypothesis does not stand up to scientific scrutiny.
In her groundbreaking book, The Big Fat Surprise, US science journalist Nina Teicholz takes down the hypothesis with characteristic, forensic attention to detail.
She shows how US physiologist Dr Ancel Keys embedded it in the national scientific psyche in the 1950s through sheer force of personality. Teicholz also shows what Keys did with competing hypotheses to his own. In particular, his reaction to a far more believable hypothesis: that sugar, not fat, was the likely cause of heart disease.
Keys knew that both couldn’t be right. Consequently, he did what he did best in such cases, says Teicholz. He bullied and attacked his way to supporting his own hypothesis.
The effects on public health, she says, have been nothing short of disastrous: pandemics of obesity, diabetes and heart disease.