Saturated fat: unfairly targeted?

A US cardiovascular researcher and doctor has made waves within both the medical and research sectors by publishing an editorial arguing that the theory that saturated fat raises cholesterol levels is false.

Dr James DiNicolantonio says that not only do low saturated fat diets do nothing to curb heart disease, current dietary advice to replace saturated fats with polyunsaturated fats is based on “flawed and incomplete” research from the 1950s.

Dr DiNicolantonio has called for an urgent review of dietary guidelines and an end to the vilification of saturated fat.

“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,” Dr DiNicolantonio said in a podcast.

The demonisation of saturated fats dates back to 1952, the editorial says, when a researcher suggested a link between high dietary saturated fat and heart disease. Dr DiNicolantonio says the researcher cherry-picked data to suit his theory, ignoring evidence to the contrary.

Dr DiNicolantonio says current recommendations to replace saturated fats with omega 6 fatty acids without also increasing omega 3 fatty acids could actually increase the risk of heart disease. He recommends that those with cardiovascular disease should not replace saturated fats with refined carbohydrates or omega 6 fatty acids - particularly those found in processed vegetable oils with high levels of corn or safflower oil.

He went on to argue that refined carbohydrates, not saturated fat, are behind the surge in diabetes and obesity in the US. Replacing saturated fat with carbohydrates can be harmful to heart health, Dr DiNicolantonio says.

“The assumption that a low-fat diet reduces the ‘bad’ cholesterol (ie, LDL) is an imprecise notion,” Dr DiNicolantonio wrote.

“While total LDL may be lowered with a reduced intake of dietary fat, if replaced with carbohydrate, this may increase sdLDL particles (ie, pattern B) which are more atherogenic than large buoyant LDL particles (ie, pattern A).

“Additionally, data indicate that a high saturated fat intake lowers sdLDL particles and raises large buoyant LDL particles.”

While Dr DiNicolantonio’s editorial has been popular in the media, a number of scientific experts disagree with his statements.

“This article rubbishes the relationship with saturated fat and CVD, misrepresents the scientific evidence and then goes on to put the blame on sugar,” said Professor Tom Sanders, head of the Diabetes and Nutritional Sciences Division in the School of Medicine at King’s College London.

“It is beyond reasonable doubt that elevated LDL (low-density lipoprotein) cholesterol is a major determinant of risk factor for cardiovascular disease. The saturated fatty acids palmitic, myristic and lauric acids raise LDL cholesterol in increasing order in meta-analysis human experimental studies. Sugar intake does not affect LDL cholesterol or blood pressure.”

Professor Brian Ratcliffe, Professor of Nutrition at Robert Gordon University in Aberdeen, said that while evidence does not support recommendations to reduce saturated fat, Dr DiNicolantonio “falls into his own trap by making a simplistic association” between increased refined carbohydrate intake and the rise in obesity.

“The latter has occurred across much of the developed world without such obvious associations with dietary carbohydrate. The most recent Cochrane review concluded that addressing the quality of fat in the diet could reduce cardiovascular events by 14% and perhaps that is worthy of consideration,” said Professor Ratcliffe.

“People eat foods, not nutrients. Dietary advice to avoid fatty meat products, choose reduced-fat dairy produce and to restrict intakes of cakes, biscuits and puddings, which are often both high in saturated fat and sugar, and to select foods containing unsaturated oils such as nuts, fish and vegetable oils remain good sense. Those who fail to learn the lessons of history are likely to repeat its errors,” concluded Professor Sanders.

Dr DiNicolantonio’s editorial is available from openheart.bmj.com/content/1/1/e000032.full.