Friday, March 07, 2014
Saturated fat is not bad for health, says heart expert
The word is getting out -- at long last
NHS guidelines which advise cutting down on high fat foods like butter, cream and chocolate may be putting the public at risk and should be urgently revised, a leading heart scientist has warned.
Diets that are low in saturated fat do not lower cholesterol, prevent heart disease or help people live longer, Dr James DiNicolantonio insists.
He is so concerned about misinterpretation of ‘flawed data’ that he has called for a new public health campaign to admit ‘we got it wrong.’
British health experts and nutritionists backed his comments claiming that for too long ‘uncomfortable facts’ have been stifled by ‘dietry dogma. ’
Saturated fat is traditionally found in butter, cheese, fatty meat, biscuits, cakes and sausages.
But Dr DiNicolantonio, claims sugar and carbohydrates are the real culprits driving high cholesterol and the obesity epidemic and suggested that guidelines should be changed urgently.
“A public health campaign is drastically needed to educate on the harms of a diet high in carbohydrate and sugar.
“There is no conclusive proof that a low-fat diet has a positive effect on health. Indeed the literature indicates a general lack of any effect, good or bad, from a reduction in fat intake.
“A change in recommendations is drastically needed as public health could be at risk.
“We need a public health campaign as strong as the one we had in the 70s and 80s demonising saturated fats, to say that we got it wrong.”
DiNicolantonio points out that the ‘vilification’ of saturated fats dates back to the 1950s when research suggested a link between high dietary saturated fat intake and deaths from heart disease.
But the study author drew his conclusions on data from six countries, choosing to ignore the data from a further 16, which did not fit with his hypothesis, and which subsequent analysis of all 22 countries' data.
Nevertheless the research stuck and since the 1970s most public health organisations have advised people to cut down on fat.
“It seemingly led us down the wrong 'dietary road' for decades to follow", said Dr DiNicolantonio, of Ithica College, New York, writing in the BMJ journal Open Heart.
“This stemmed from the belief that since saturated fats increase total cholesterol (a flawed theory to begin with) they must increase the risk of heart disease."
Experts also believed the diet would lead to less obesity and diabetes - when the exact opposite was true, he added.
In 2009 the Food Standards Agency launched a campaign including a hard hitting television advert which showed a kitchen sink becoming clogged with fat, and suggested that it was having a similar effect on the arteries.
The FSA claimed that too much fat in the diet raises cholesterol levels in the blood, which is a risk factor for coronary heart disease, heart attacks, angina and stroke.
NHS guidelines suggest the average man should eat no more than 30g of saturated fat per day and women no more than 20g.
But Dr DiNicolantonio believes the switch away from fat towards carbohydrates has harmed public health. He suggests the rise in high-carb diet is responsible for the increase in diabetes and obesity epidemic in the US.
The best diet to boost and maintain heart health is one low in refined carbohydrates, sugars and processed foods, he recommended.
Brian Ratcliffe, professor of nutrition at Robert Gordon University, Aberdeen, welcomed his comments.
"For the last three decades, accumulating evidence has not provided strong support for the dietary recommendations regarding reducing fat and saturated fat intake," he said.
"DiNicolantonio does not even touch on the evidence which shows that low-fat diets (admittedly lower than the current recommendations) have been associated with poor mood and even depression.
"Many who adhere to dietary dogma have chosen to ignore the uncomfortable facts that did not fit the hypothesis."
Victoria Taylor, senior heart health dietitian at the British Heart Foundation, advised the public to take a more holistic approach to their diets.
"Fat is just one element of our diet. To look after our hearts long-term, we should look at our diet as a whole. Eating a Mediterranean-style diet rich in fruit, veg, pulses and fish will help lower cholesterol and reduce the risk of coronary heart disease."
However professor Tom Sanders, head of diabetes and nutritional sciences division in the School of Medicine at King's College London, said Dr DiNicolantoni's assessment misrepresented the scientific evidence.
"Refocusing dietary advice on sugar and away from fat modification and reduction is not helpful," he said.
Prof Bruce Griffin, Professor of Nutritional Metabolism at the University of Surrey, added: “To suggest that the theory relating saturated fat to increased total cholesterol is flawed, is nonsense, and contradicts 50 years of evidence-based medicine.
“A more balanced review of the overall evidence would reveal that the risks from saturated fat and refined sugars are not mutually exclusive, but co-exist together in our diet.”
The Scientific Advisory Committee on Nutrition (SACN) is currently reviewing the evidence on dietary carbohydrates and a consultation on new guidelines will begin this summer.
Alison Tedstone, Director of Nutrition and Diet at Public Health England, said: “The totality of the evidence suggests that high saturated fat intake is associated with raising total and low-density lipoprotein (LDL) blood cholesterol levels which, over time, could lead to an increased risk of developing heart disease.
“It is therefore reasonable to conclude that a reduction in saturated fat intake will lower total and LDL blood cholesterol which, in turn, may reduce the risk of developing heart disease."
Are burgers as bad as cigarettes? Unravelling the truth about diet and disease
I wrote on this yesterday but below are some more interesting comments
You’d be forgiven for looking warily at your bacon sandwich this morning, if you’ve seen headlines suggesting that a diet high in animal proteins is nearly as dangerous as smoking. Cheese and meat cause cancer! That carbonara is a time-bomb ticking in your stomach! Quick, go vegetarian!
The news is based on a study in the journal Cell Metabolism, which found that people who got more than a fifth of their daily calories from animal protein were 74 per cent more likely to have died during the study than people who ate less. We’re bombarded with food messages like this, which often seem to change from day to day. Dame Sally Davies, the Chief Medical Officer, has warned about the “addictive” potential of sugar, and the World Health Organisation said yesterday that recommended sugar allowances were too high; an editorial in the journal Open Heart, also published yesterday, suggested that the risk of saturated fats was overblown.
Every Christmas, suddenly, red wine and chocolate become good for us. Last year headlines screamed that eating three sausages a day raises your risk of dying of heart disease by three quarters. It’s hard to know what to make of it all, the what’s-curing-me-and-killing-me-today merry-go-round.
Can eating burgers really be as bad for you as smoking? Before answering that, it’s worth looking at how we know how bad smoking is.
In the late Forties, a man called Richard Doll was given the task of finding out what was behind the dramatic increase in lung cancer deaths. Originally, he and his colleagues thought it was probably the new practice of coating roads with Tarmac. But upon interviewing 649 men with lung cancer in 20 London hospitals, he found one remarkable fact: all but two of them were smokers (he also interviewed a smaller group of women, in which the divide was less dramatic but still very large). He promptly quit smoking. His research had found a simple fact: smoking causes lung cancer, and in fact is the cause of almost all lung cancer.
This caused great excitement. Researchers wondered if other cancers, or other diseases, could be linked as straightforwardly to lifestyle factors. The science of epidemiology – of the causes of disease in populations – had its greatest success since Dr John Snow showed that unclean water caused London’s cholera outbreaks in the 19th century.
But smoking was a low-hanging fruit. There aren’t very many straightforwardly poisonous things that lots of humans imbibe in large amounts and lots of humans don’t touch at all. Working out whether a particular food is good for you, for instance, is fantastically tricky: you can’t prescribe someone a course of celery for 20 years, and compare how well they do to someone on a celery placebo. You have to rely on people reporting what they eat, which they do only unreliably. And unless you have very large samples, it’s hard to tease out causes from mere correlations: how can we know whether celery makes you live longer, or whether people who eat celery tend to live healthier lives generally?
What’s more, the body is very complex, so plausible hypotheses about what will do you good and do you harm often turn out to be false. This is why you should ignore anyone who tells you that you ought to eat pomegranate or chia seeds because they’re good for your liver, or whatever. They have no idea what they’re talking about.
Epidemiologists have, however, been able to tease out broader-brush factors. Red meat, salt, sugar, fat and alcohol are all bad for you in large amounts; eating plenty of fruit and veg is good for you. But exactly how good and how bad, and how much of each you should have, is all very much in dispute. The Cell Metabolism study found a huge increase in cancer risk from animal-protein-rich diets, but most earlier research on related topics had found a far less dramatic impact, of between 10 and 15 per cent.
And that’s the key. None of these studies is the final truth; science is incremental, it learns by degrees, and epidemiology doubly so. Meat, in large quantities, is probably a bit more dangerous than we previously thought, but to say that it is suddenly as dangerous as smoking is to run far ahead of the evidence. And, of course, there are other differences: it’s very difficult to include cigarettes as part of a balanced diet, for instance.
Richard Doll’s discovery paved the way for a remarkable age of public health research, which has led to us knowing far more about what helps us live longer and what kills us than we did half a century ago. But the picture is usually cloudier than university PR departments like to admit. After decades of study, the best, most well-supported advice is still what your mother told you: eat your greens and get plenty of exercise.
Posted by jonjayray at 12:09 AM