Link between fast food and ‘bad’ cholesterol reinforced

Regular fast food consumption means more calories, less nutrients, suggests research published in Archives of Disease in Childhood. Compared with those who rarely ate takeaways, primary school children who consumed them more than once per week had significantly higher levels of low-density lipoprotein (LDL) (‘bad’) cholesterol, found the research team from the Population Health Research Institute, St. Georges, University of London.

Total cholesterol was also higher, but this effect was purely due to the higher LDL component, as HDL (‘good’) cholesterol was virtually identical in each group. Cholesterol patterns were similar among all ethnic groups.

Those who ate more than one takeaway per week (28% of subjects) had higher body fat mass and greater skinfold thickness than those who never or rarely consumed them (26%). They also had higher total energy intake, higher percentage energy intake from both total and saturated fat, and higher energy density from food intake.

Regular fast food consumers also had lower protein, starch and micronutrient (vitamin C, folate and iron) intakes, suggesting a dietary pattern rich in calories, but poor in nutrients. The unhealthy dietary patterns could have undesirable health consequences if continued into later life warned the researchers.

"The higher total cholesterol and LDL cholesterol concentrations observed in the frequent takeaway meal group, if sustained, are sufficiently large to increase long term [coronary heart disease] risk by around 10%," wrote lead author Dr. Angela Donin.

"These results suggest that further increases in take away meal consumption (and marketing directed at encouraging such increases) are likely to have adverse public health consequences and should be actively discouraged,” she added.

Study details

The children were an ethnically diverse group from 85 primary schools, which formed part of the Child Heart and health Study in England(CHASE) cohort.

The researchers interviewed 1948 subjects aged 9-10 from Birmingham, Leicester and London regarding the source of their meals, how often they ate takeaways and their usual diets.

The scientists used a 24-hour dietary recall method and employed photographs of certain foods to improve estimation of portion size and memory cues to assist the children’s recall.

Macronutrient intake (fat, protein, carbohydrate) and subcategories (e.g. saturated fat, sugar) were calculated as well as levels of certain vitamins and minerals.

The researchers also measured blood lipids, blood pressure, height, weight, waist circumference, body fat mass, and skinfold thickness.

Markers of diabetes

The study showed no difference in blood pressure between the study groups nor in markers of diabetes such as blood glucose, triglycerides, insulin and HbA1c (glycated haemoglobin). This might have been due to similar sugar intakes between groups.

These results were in contrast to previous studies in young American and Australian adults.

Saturated fat/ cholesterol link

Much previous research has found a link between saturated fat intake and raised LDL cholesterol levels. The researchers therefore performed sub-analysis to determine whether the higher total and LDL levels in those eating more than one takeaway per week could be explained by saturated fat intake.

After adjustments to the associations found in the main analysis, ”The differences in total and LDL cholesterol were reduced by ~20%and ~13%, respectively; the difference in total cholesterol became statistically non-significant,” observed the researchers.

Exercise

Although the study adjusted for gender, age, ethnic group and socioeconomic status, the study did not assess physical activity level among the subjects. It is well established that moderate levels of physical exercise can lower raise HDL, lower LDL cholesterol and triglycerides.

Previous research has also linked higher consumption of fast foods with sedentary lifestyle. It is thus possible that higher LDL results in this study might partially arise from lower levels of exercise in frequent takeaway consumers.

The exercise factor may be increasingly important, as “technological advances have also meant that it is now much easier to order and have delivered take away foods,” noted the researchers.

The ability to ‘click from the comfort of the sofa’, compared with a walk to the local takeaway may represent a further decrease in calorie expenditure to offset potential obesity-inducing effects of fast food.

Further research

The researchers emphasise that the study is observational and therefore cannot provide conclusive evidence that takeaway consumption causes high cholesterol or heart disease.

Nevertheless they advocate that further studies to strengthen the body of evidence are needed and that in the interim, the government should intervene to try to reverse the trend towards takeaway consumption.

“These findings highlight the need for further investigation (particularly prospective studies) of the associations between takeaway meals, dietary patterns and risk markers for chronic disease both in children and also in adolescents, who have much higher takeaway consumption rates,” propose the researchers.

“The government should be considering health protection initiatives to reverse the current trends in takeaway meal consumption, in the context of broader efforts to improve childhood diet and nutrition in home and school settings,” they conclude.

Source: Archives of Disease in Childhood
“Takeaway meal consumption and risk markers for coronary heart disease, type 2 diabetes and obesity in children aged 9–10 years: a cross-sectional study”
Authors: Angela S Donin, Claire M Nightingale, Chris G Owen, Alicja R Rudnicka, Derek G Cook, Peter H Whincup