Sugar Intake: Anatomy of a StudySeveral studies have been conducted in the last years on the consumption of sugar and foods containing sugar, and these studies attract greater attention on media. Results of many studies on topics such as sugar-cancer relationship and fasting and postprandial mechanisms have a wide coverage on newspapers. Results of a study recently carried out in the USA have been covered worldwide. According to the study:
The study was carried out on 43 Latino and African-American children at an average age of 13.3, with obesity and metabolic syndrome, getting 28 percent of their daily caloric intake from sugar. These children were given foods prepared by the researchers for nine days. Required daily energy intake were calculated on the basis of weights of the children at that time. Total energy intake from sugar and fructose was reduced about 10 percent and 4 percent, respectively. Foods such as fruits, cereals, pasta and bread were used instead of those carbohydrates.
Diastolic blood pressure (pressure on the blood vessel wall, when the heart is relaxed) decreased by 5 mmHg, fasting triglyceride values by 46 percent, LDL (bad cholesterol) rates substantially by 0.3 mmol/L after the sugar reducing diet was applied. Children lost about 0.9 kg. Changes were observed even in metabolic parameters of those who did not lose weight. The study highlighted that this result cannot be clearly linked either to reducing the sugar intake or to reducing the fat amount that the children consumed.When this study carried out by Robert Lustig and his colleagues is reviewed scientifically, it would be useful to consider the following topics as well.
No control group was used in this study that consumed the same daily calorie amount in which calories from sugar were reduced. What could have happened if the children consumed the same amount of energy at home? Furthermore, reducing the fat consumption may lead to the same results on metabolic parameters.
Reducing the sugar intake, and adding other carbohydrates to the diet may lead to consuming more fiber. This condition may cause changes in cholesterol and insulin levels.
The study was applied to 43 children in a very short time. It is not known what outcomes it may reveal in a wider group or in a longer period.
Result of the study was linked more with reducing the fructose intake. However, fructose was not the only sugar reduced.
Together with the weight loss, there may be changes in parameters such as cholesterol or blood sugar levels. These changes, however, may result not only from the sugar intake, but also from other nutrient groups or solely from reducing the calorie intake.According to the National Health and Nutrition Examination Survey (2010) conducted in Turkey, daily consumption amount of foods with sugar is 29.14 g among children between the ages of 9-11, and 28.09 g between the ages of 12-14. According to the Dietary Guidelines for Turkey (2004) prepared in cooperation with the Ministry of Health and Hacettepe University, recommended daily sugar intake is 40 g for males, and 30 g for females both between the ages of 10-18. Recommended daily intake of foods such as honey, marmalade, molasses is 30 g for males and females within the same age group. Based on the report issued by the World Health Organization (WHO) on sugar consumption among children and adults, sugars naturally found in honey, white sugar, molasses and fruit juice as well as sugars added to foods by the food industry are regarded as “free sugar.” Sugar intake should be lower than 10 percent of the daily energy intake for adults and children. In other words, recommended daily intake for an individual with a normal Body Mass Index (BMI) should be equal to approximately 50 g (5 percent of the daily energy intake is equivalent to 25 g sugar).
Considering these scientific facts, results of a study should only be presented to the public based on scientific and objective facts and by unbiased scientists. As for this study, it is important to analyze the study from all perspectives. Otherwise both the public may be misled, and it may cause many speculative speeches and debates.
Lustig R. H., Mulligan K., Noworolski S., M., et al. Isocaloric fructose restriction and metabolic improvement in children with obesity and metabolic syndrome. Obesity 2015; DOI: 10.1002/oby.21371
National Health and Nutrition Examination Survey (2010), General Directorate of Health Research, Ministry of Health, Turkey http://www.sagem.gov.tr/TBSA_Beslenme_Yayini.pdf (November 18, 2015).
Dietary Guidelines for Turkey (2004), Annex 2, Table 3. Average daily amount of foods that will meet energy and nutrients (g/day)