Cutting down on saturated fat can shorten lifespan – study

Global study show higher consumption of fats reduce risk of death and stroke

Diets high in carbohydrates were associated with a 28 per cent greater risk of death. Photograph: IStock

Diets high in carbohydrates were associated with a 28 per cent greater risk of death. Photograph: IStock

 

Dramatically cutting your intake of dietary saturated fat is not recommended for good health and can even shorten your life, an international study has shown.

Scientists who investigated a global population of more than 135,000 people found that cutting saturated fat intake so that it accounted for less than 3 per cent of total calories increased death rates by 13 per cent.

Higher levels of consumption of fats of all kind reduced the overall risk of death by 23 per cent, stroke risk by 18 per cent and non-heart related mortality by 30 per cent.

Diets high in carbohydrates — accounting for 77 per cent of calories — were associated with a 28 per cent greater risk of death, although they did not affect rates of heart attacks and strokes.

The researchers compared people in the top fifth of fat and carbohydrate consumers with those in the bottom “quintile” over a period of 7.4 years. Study participants had an age range of 35 to 70 and came from 18 low, middle and high income countries.

Globally, the average diet consisted of 61.2 per cent carbohydrates, 23.5 per cent fats, including 8 per cent saturated fats, and 15.2 per cent protein.

Carbohydrate intake was highest in China, South Asia and Africa, while people who ate the most fat lived in North America, Europe, the Middle East and South-East Asia.

Results from the Pure (Prospective Urban-Rural Epidemiology) study were published in the Lancet medical journal and presented at the European Society of Cardiology Congress taking place in Barcelona, Spain.

Lead scientist Dr Mahshid Dehghan, from McMaster University in Canada, said: “The current focus on promoting low-fat diets ignores the fact that most people’s diets in low and middle income countries are very high in carbohydrates, which seem to be linked to worse health outcomes.

“In low and middle-income countries, where diets sometimes consist of more than 65 per cent of energy from carbohydrates, guidelines should refocus their attention towards reducing carbohydrate intake, instead of focusing on reducing fats.

“The best diets will include a balance of carbohydrates and fats — approximately 50-55 per cent carbohydrates and around 35 per cent total fat, including both saturated and unsaturated fats.”

During the study, 5,796 participants died and there were 1,649 deaths caused by heart and artery disease. The researchers recorded 2,143 heart attacks and 2,234 strokes.

Saturated fats

Saturated fats, typically found in animal products such as milk, cheese and meat, have traditionally been viewed as unhealthy and harmful to the heart and arteries.

But the study found that higher consumption of saturated fat reduced the risk of dying by 14 per cent and the risk of stroke by 21 per cent.

So-called “healthy” mono-unsaturated and polyunsaturated fats cut mortality by 19 per cent and 20 per cent respectively.

Saturated fat owes much of its bad reputation to the fact that it raises levels of “bad” low-density lipoprotein (LDL) cholesterol in the blood.

However, the Pure researchers found that higher intakes of saturated fat also raised levels of “good” cholesterol, or high-density lipoprotein (HDL) which protects arteries.

They also found that measuring LDL level was not a reliable way of predicting the likely effect of saturated fat consumption on the risk of cardiovascular events such as heart attacks and strokes.

The researchers said their findings did not support average global recommendations to limit total fat intake to less than 30 per cent of calories and saturated fat intake to less than 10 per cent.

Dr Dehghan said: “Limiting total fat consumption is unlikely to improve health in populations, and a total fat intake of about 35 per cent of energy with concomitant lowering of carbohydrate intake may lower risk of total mortality.

“In fact, individuals with high carbohydrate intake, above 60 per cent of energy, may benefit from a reduction in carbohydrate intake and increase in the consumption of fats.”

British nutrition expert Prof Susan Jebb, from Oxford University, pointed out that UK health guidelines already recommended obtaining up to 35 per cent of dietary energy from fat, and an average of 50 per cent from carbohydrates.

She said: “This paper considers the relationship between diet and health outcomes for predominately low and middle income countries.

“It found that a high proportion of carbohydrate in the diet (more than about 60 per cent of energy) was associated with higher death rates. Most of the current debate about diet and health has focused on cardiovascular mortality, but there were no significant associations between carbohydrate intake and major cardiovascular diseases. The apparent excess mortality among those consuming high carbohydrate diets was from non-cardiovascular deaths and is unexplained.”

PA