Effects of Low Carbohydrate Diet Compared to Low Fat Diet in Reversing the Metabolic Syndrome Using NCEP ATP III Criteria; Randomized Clinical Trial
Effects of Low Carbohydrate Diet Compared to Low Fat Diet in Reversing the Metabolic Syndrome Using NCEP ATP III Criteria; Randomized Clinical Trial
The National Cholesterol Education Program Adult Treatment Panel-III (NCEP ATP III) definition of metabolic syndrome (MetS)is one of the most widely used criteria of metabolic syndrome. It incorporates the key features of hyperglycemia/insulin resistance, visceral obesity, dyslipidemia and hypertension. According to the NCEP ATP III guidelines, in our study, the participants having the metabolic syndrome if they possess three or more of the following criteria: abdominal obesity: Increased waist circumference, Elevated serum triglycerides, Reduced high density lipoprotein cholesterol (HDL), Elevated blood pressure both systolic blood pressure (SBP) and diastolic and Elevated fasting blood glucose.
Although the pathogenesis of MetS is strongly linked to excessive food consumption, in particular fat intake, still there is no consensus about the effects of low carbohydrate diet (LCD) versus low fat diet (LFD) on reversing the MetS and on its metabolic risk factors. However, concerns have been raised with regard to the macronutrient shift with high carbohydrate restriction and the substantial intakes of fats, which may present unfavorable effects on cardiovascular disease risk factors. Meanwhile the LFD has generally been supported by studies to have beneficial effects on these risk factors.
There is no consensus about the effects of LCD versus LFD on the metabolic syndrome. This study investigated the effects of LCD versus LFD on the obese peoples and followed up them for 6 months. Out of 289 obese adults apparently healthy were randomly chosen by a stratified multistage probability sampling method, 94 of them are agreed to participate in the study. They were assigned randomly into low carbohydrate and low-fat diet groups. Both groups were followed up for 6 months and the data were taken at baseline, after 3 months and 6 months of intervention. Ninety-four obese participants completed the intervention.
The metabolic syndrome (MetS) is a major and escalating public health and clinical challenge worldwide in the wake of urbanization, excess energy intake, increasing obesity, and sedentary life style. Metabolic syndrome a five-fold increasing the risk of type 2 diabetes mellitus (T2DM) and two fold increasing the risk of developing cardiovascular disease (CVD) over the next 5 to 10 years. Worldwide prevalence of MetS ranges from <10% to as much as 84%, depending on the region, urban or rural environment, population composition (sex, age, race, and ethnicity), and the definition of the syndrome used. The NCEP ATP III definition is one of the most widely used criteria of metabolic syndrome. It incorporates the key features of hyperglycaemia/insulin resistance, visceral obesity, dyslipidaemia and hypertension.
The treatment of metabolic syndrome intends to improve insulin sensitivity and correct the associated metabolic and cardiovascular abnormalities. During the past few years, several studies have evaluated the health effects of low carbohydrate-high protein diet (LCD), with emphasis on cardiovascular diseases versus low fat diet (LFD). Low-carbohydrate diet has become a popular strategy for weight loss and weight management in recent years. In addition, data from several randomized trials have demonstrated that LCD produced greater effects on weight loss and reducing cardiovascular and metabolic risk factors than LFD. A popular version of this LCD recommends extreme restriction of carbohydrate intake to less than 20 gram/day initially.
Although the pathogenesis of MetS is strongly linked to excessive food consumption, in particular fat intake, still there is no consensus about the effects of LCD versus LFD on reversing the MetS and on its metabolic risk factors. However, concerns have been raised with regard to the macronutrient shift with high CHO restriction and the substantial intakes of fats, which may present unfavorable effects on CVD risk factors. Meanwhile the LFD has generally been supported by studies to have beneficial effects on these risk factors.
The purpose of this study was to investigate the effects of a low carb diet compared to low fat diet on reversing and treating metabolic syndrome and their risk factors among a sample of obese adults in Erbil city/ Iraq Kurdistan.
This study is a randomized clinical trial conducted over 6 months, between (January and June 2017) with outcome assessments at baseline, at 3, and 6 months of intervention.
Eight hundred adults (≥18year old) of both gender (358 males and 442 females) are surveyed in the 12 population clusters in Erbil city to estimate the prevalence of MetS. The population frame of household of Erbil population based on all 12 offices of Family ID card in Erbil city. The randomized cluster sampling survey method of the houses is used for sample selection. Out of 289 obese adult participants who had the inclusion criteria to participate in the study, only 94 of them agreed to participate in the intervention (23 males and 71 females). Those 94 are randomly assigned into two groups, the LCD (n=54) and LFD (n=40) group. All the adult participants are completed a comprehensive medical examination and routine blood tests.
A modified questionnaire of world health organization (WHO) STEPwise approach to Surveillance of noncommunicable diseases (STEPS) was used in this study. The modified questionnaire included 25 questions on socio-demographic (9 questions), anthropometric measurements (7 questions) and biochemical measurements (9 questions).
According to the NCEP ATP III guidelines, in our study, the participants having the metabolic syndrome if they possess three or more of the following criteria is written in the following: Abdominal obesity: Increased waist circumference Men: > 102 cm, Women: > 88 cm, Elevated triglycerides > 150 mg/dL, Reduced HDL Men: < 40 mg/dL, Women: < 50 mg/dL, Elevated blood pressure > 130/85 mm Hg & Elevated fasting glucose > 100 mg/dL.
Individuals with history or diagnosed with diseases and health related issues like diabetes mellitus, hypertension, chronic skin disease, heart disease, hyperlipidemia, malignant disease, and rheumatoid arthritis and those who had undergone surgery during one month before the study are excluded in the study.
More than half of the participants (n = 54) were followed the LCD. In this diet program, the primary behavioral target was to limit carbohydrate intake. Therefore, the limited carbohydrate intake and unrestricted consumption of fat and protein are allowed. During the first two weeks of the intervention, participants were instructed to limit carbohydrate intake to 20-gram per day. After the first two weeks, the participants were instructed to gradually increase 5-gram of the carbohydrate intake every week.
Forty participants were followed the LFD. The primary behavioral target was to limit the overall energy intake (1200 kcal/d). They received instructions to increase calorie intake from 1200 to 1800 kcal per day (≤ 30% of calories from fat, <7% saturated fat).
All 94 participants completed the 6 months of intervention. They were followed up regularly by direct interview every two weeks by the researcher. Each follow-up session lasted 15 to 30 minutes. All of them were prescribed the same level of instruction concerning drinking 10-12 glasses of water /day and physical activity (principally walking), beginning at week 2, with 1 session of 30-45 minutes per day then increasing the duration of physical activity to reach at least 60 minutes /day.
An electronic weight scale (model 770: Seca, Germany) was used to measure the participants' weight to the nearest 0.1 kg. While the participants were asked to stand still without shoes, a measuring tape was utilized to measure their lightly clothed height to the nearest 0.5 cm. The formula used for calculating body mass index (BMI) was as following: BMI=weight(kg)/height(m2). The measurements were collected at baseline, at 3 months and 6 months.
Waist circumference (WC) was measured midway above umbilical between the distal border of the lowest rib and the superior border of the iliac crest at the end of a normal expiration. Measurements were done with the subject in upright position, without clothes, both feet touching the ground, and arms hanging freely. A non-elastic tape measure was placed directly on the skin on the waist line without putting pressure on the abdominal wall.
Blood pressure (BP) was measured by the researcher using an MDF Desk Mercury Sphygmomanometer (Model No: MDF 800), with cuff sizes based on measured arm circumference. Blood pressure checked after participants were asked to sit and take rest for 10 minutes. The measurements were collected at baseline, at 12 and 24 weeks.
Blood samples were obtained after participants fasted overnight (8-10 hours). Blood sample analyzed in the laboratory department of one of the two main hospitals in Erbil city, the Rzgary Teaching Hospital. The serum analyzed by the same laboratory and by the same device (BIOTECNICA BT4500 Full Automated Chemistry Analyser, 2016).
The adherence of the diet programs was done based on participants' self-reporting. Also, delivery of the intervention and assessment of the outcomes are not blinded.
Data on baseline characteristics of adult participants were expressed as means ± SD and/ or frequencies and percentage. The data checked for normal distribution by Shapiro-Wilk test; the p-value was 0.10 which indicates that the data was normally distributed. The study used t tests and Chi square test of association to compare baseline characteristics between both diet programs. When the expected count more than 20% of the cells of the table was less than 5, Fisher exact test was used. An independent samples t-test was used to compare the means of a normally distributed metabolic risk factors for both independent diet programs at the baseline and after 6 months of intervention. A two-way repeated measures ANOVA was used to compare differences of metabolic dependent variables between the two independent variables, the LCD & LFD, at baseline, after 3 months and after 6 months. To determine how much of an effect of intervention has had on the participants, the study used the following cut-offs to interpret the results: 0.14 or more are large effects, 0.06 are medium effects and 0.01 are small effects. A p-value of ≤0.05 was considered as the level of significance for all analyses. The Statistical Package for the Social Sciences (SPSS) software, version 22 was used for data analysis.
Inclusion Criteria:
ATP III guidelines:
Exclusion Criteria:
Individuals with history or diagnosed with diseases and health related issues like:
Those who had undergone surgery during one month before the study