Sodium Alginate Supplementation Plus HIIT and MICT Can Induce CCK and PYY Increment in Men With Metabolic Syndrome

Background: Abdominal obesity is a common phenomenon in metabolic syndrome (MetS). Inducing satiety by weight management plays an important role in reducing the risk of obesity and consequently MetS. This study was investigated effect of sodium alginate supplementation plus HIIT and MICT on CCK and PYY increment in MetS men. Methods: For this purpose, 40 men with MetS volunteered and were randomly divided into ve groups as follow: HIIT groups with supplement (n=8, 4*4 min bouts at 85-95% of HR peak , with 3 min of active recovery at 50-70% HR peak , 3 ses/week), HIIT (n=8, 4*4 min bouts at 85-95% of HR peak , with 3 min of active recovery at 50-70% HR peak , 3 ses/week), MICT with supplement (n=8, 30 min at 60-70% HR peak , 3 ses/week), MICT (n=8, 30 min at 60-70% HR peak , 3 ses/week) and control group (n = 8, no exercise). The HITT+S and MICT+S groups consumed 1.5 g of Sigma sodium alginate (made in the USA) solution in 100 mg of sweet water (7 g of fructose), 30 minutes before 3 main meals three days per week during 8 weeks. Results: After 8 weeks of interventions, CCK and PYY were markedly increased in the studied groups, this increase was signicantly greater in the HIIT+S than other groups. Also, the MetS Z score was signicantly decreased in all studied groups and this decrease was signicantly higher in the HIIT+S than other groups (P <0.05). Conclusion: The results showed that HIIT and MICT led to an overall improvement in men with MetS. However, combining sodium alginate supplementation triggers these improvements.


Introduction
Metabolic syndrome (MetS) encompasses a cluster of metabolic disorders including abdominal obesity, hypertension, dyslipidemia, and insulin resistance [1]. Among them, abdominal obesity is characterized by increased distribution of fat in the central area of the body, which potentially increases the risk of insulin resistance, hypertension, cardiovascular disease and cancer [2]. The National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) de nes the MetS as having at least three of these disorders: systolic and diastolic blood pressure (SBP and DBP) more than 130 and 85 mmHg, respectively, waist circumference (WC) more than 102 cm (for men) or 88 cm (for women), fasting blood sugar (FBS) more than 100 mg/dl. fasting triglyceride (TG) more than 150 mg/dl, high-density lipoprotein (HDL) cholesterol less than 40 mg/dl (for men) or 50 mg/dl (for women) [3]. Evidence suggests that adherence to regular physical activity and healthy dietary pattern may trigger changes in the expression of circulating appetite-related hormones and/or metabolites and sensations of hunger and satiety, and these responses also appear to depend on exercise intensity in which is important to weight management [4].
Cholecystokinin (CCK), Glucagon-like peptide-1 (GLP-1), Oxyntomodulin (OXM), peptide YY (PYY) (which are secreted from the small and large intestine), and pancreatic and amylin polypeptides (which both them are secreted from the pancreas) are hormones that affect appetite and hunger and satiety signaling [5]. Unlike other anti-appetite hormones, PYY increases energy consumption along with reducing appetite [6]. Therefore, it has been shown that increased PYY secretion after food consumption may decrease the risk of obesity [7].
High-intensity interval training (HIIT), and moderate-intensity interval training (MICT) are known to be among common non-pharmacological protocols for metabolism controlling and associated condition such as obesity by regulating hunger, satiety, and appetite perception [8].Several studies have reported the importance of MICT in improving body composition, cardiovascular tness, insulin resistance (IR), and lipid pro le [8][9][10]. While other investigations show similar physiological adaptation after either HIIT or MICT [11]. In addition to the bene cial effects of MICT and HIIT in appetite perception and plasma levels of appetite hormones [12], Matos et al (2017) reported contradictory results [13].
Furthermore, intake of dietary ber has been identi ed to preventive effects on the mentioned metabolic disorders especially obesity [14]. As a dietary ber, alginate is a jelly polysaccharide and a structural component extracted from brown seaweed. Sodium alginate is the most commonly used alginate, which has been widely used as an additive in the food industry in recent years. Consumption of sodium alginate seems to modulate human appetite by gelling it in the stomach [15]. Sodium alginate affects gastric emptying and promotes a feeling of satiety. consequence, stimulates the appetite hormones secretion (CCK, GLP-1, and PYY) [14,16].
Despite evidence for the positive adaptations following HIIT compared with MICT concerning aerobic tness and vascular function, it is still unclear which form of training is most effective for weight control, overall fat loss, or central adiposity [17]. Since limited studies have conducted on the interactional effects of sodium alginate supplementation with different exercise methods on weight loss, body fat, and appetite hormones in people with MetS [18], the present study aimed to investigate the effect of eight weeks of HIIT and MICT with sodium alginate supplementation on CCK and PYY levels in men with MetS.

Study design and Participants
This semi-experimental study was performed on forty men (18-34 years old) were selected according to our research criteria among volunteers (Fig. 1) Subjects with MetS based on the NCEP-ATP III [3] who had no history of cardiovascular disease, diabetes, thyroid, kidney, or cancer also did not have a regular exercise or diet plan for the past six months were included to this study. Initially we assessed 65 subjects in which 22 of them were excluded duo to not meeting inclusion criteria and wanting to participate in the study. After that 43 young men with MetS volunteered and were randomly divided into ve groups: HIIT, high-intensity interval training + sodium alginate supplementation (HIIT + S), MICT, moderate-intensity interval training + sodium alginate supplementation (MICT + S), and control (C) (Fig. 1). Considering the obtained random number table, subjects are chosen. After that, they allocate to control and intervention groups.

Measurements
The participants' height and Bodyweight (BW) were measured by using the Seca scale (made by Hamburg Germany) with a measuring accuracy of 0.5 cm and 100 g, respectively; body mass index (BMI) was calculated accordingly by dividing weight (kg) to height square (m 2 ). WC was measured on the top of the iliac crest by using a non-starched and exible tape with an accuracy of 1 cm [19]. Body fat percentage (BFP) was determined by using the bioelectrical impedance analysis (made in Korea, ZEUS 9.9 PLUS model). SBP and DBP was measured twice at 5 min intervals by using a Richter digital barometer (Richampion 1725145 made in Germany) from the right carotid artery and then the average was recorded [19].

Diet and exercise control
To minimize the effect of nutrition, all participants were asked to list all their food intake in the 24-hour food recall form 7 days before the rst blood sampling and they were asked not to change their normal diet. They were also asked to avoid intense exercise and alcohol and caffeine drinking 48 hours before the blood sampling. The results were analyzed by NUTRITIONIST IV software based on the United States Department of Agriculture Food Composition Table that was modi ed for Iranian foods. Table 1 shows the fat, protein, carbohydrate, and total energy consumption values.

Sodium alginate supplementation
The HITT + S and MICT + S groups consumed 1.5 g of Sigma sodium alginate (made in the USA) solution in 100 mg of sweet water (7 g of fructose), 30 minutes before 3 main meals for three days per week during 8 weeks intervention.

Exercise protocol
The HIIT and MICT were trained three times per week. Both HIIT and MICT were preceded by a 10 min warm-up and terminated with a 10 min cool-down. MICT sessions were 30 min at a target intensity of 60-70% HR or rated perceived exertion (RPE) of 11-13. The HIIT consisted of 4 bouts of 4 min intervals at 85-95% HR peak/RPE of 15-17, separated by 3 min active recovery at 50-70% HR peak (Fig. 2) [20].

Appetite perception questionnaire
To assess the subjective appetite, a Visual Analogue Scale (VAS) questionnaire was used. This questionnaire was used in most studies that measured the appetite indirectly. It consists of four questions that measured hunger, satiety, individual feeling to satiety, and individual feeling to eating desire. Subjects were asked to ll the questionnaire before exercise, immediately after exercise, 3-h postexercise, and 9-h post-exercise [20]. The questions are de ned as below: 1. How strong is your desire to eat? (very weak to very strong).
2. How hungry do you feel? (not hungry too as hungry as I've ever felt).
3. How full do you feel? (not full at all to very full).
4. How much food do you think you could eat? (nothing at all to a large amount).
The CCK levels (Zellbio kit, made in Germany with a sensitivity of 0.5 ng/l) and PYY levels (Zellbio kit, made in Germany with a sensitivity of 1. 5 Pg/ml) were measured using the ELISA method.

Data Analysis
All statistical analyses were performed using the SPSS statistical software (version 21; SPSS Inc., Chicago, IL, USA) in which was used at a signi cant level of P < 0.05. The Shapiro-Wilk's test was used for evaluating the normality of distribution. To compare the mean metabolic factors between and within groups, ANOVA and paired sample t-test were used, respectively. Tukey's post hoc test was used if signi cant differences were found.

Results
In current study, overall, 40 young men completed during the intervention study and three subjects were excluded because of not willing to continue, family and personal reasons. Based on the results, there were signi cant differences in the mean of age, BW and BMI between the pre-test and post-test conditions in the studied groups (Table 2).
After eight weeks intervention, BW and BMI were signi cantly decreased in four intervention groups (P < 0.001). The mean of BW was signi cantly different between the studied groups after intervention (P = 0.009). The results of Tukey's post hoc test showed no signi cant difference in BW and BMI between the studied intervention groups; there was a signi cant difference between the HIIT and MIIT + S and the control in the BW (Table 2).  The results of Table 4 show that appetite was signi cantly decreased in all four studied groups immediately, three, and nine hours after exercise compared to pre-exercise. Also, appetite immediately after exercise in all four studied groups was signi cantly less than three, and nine hours after exercise (P < 0.05). Appetite suppression immediately after HIIT was more than MICT (P < 0.05). *: Signi cantly different in comparison pre and post-test within the groups Appetite before exercise: Appetite changes immediately before exercise.
Appetite after exercise: Appetite changes immediately after exercise.
Appetite 3 h p: Appetite changes 3 hours after exercise.
Appetite 9 h p: Appetite changes 9 hours after exercise.
The results of Fig. 3 show that compared to the pre-test CCK concentration was signi cantly increased in HIIT + S, HIIT, MICT + S, and MICT + S. Also, there was a signi cant difference between HIIT + S and MICT + S compared to the control (P = 0.009, P = 0.023).
According to Fig. 4, PYY increased signi cantly in the HIIT + S, HIIT, MICT + S, and MICT compared to preexercise. Also, there was a signi cant increase in the MICT + S (P = 0.002) and the HIIT + S (P = 0.002) compared to the control.

Discussion
According to NCEPATP III guidelines, one of the primary treatments for all MetS risk factors is weight loss and increased physical activity [22]. The results of current study showed the improvements of subject's MetS Z score in the HIIT + S group was more than in the other studied groups. Ramos et al. (2017) compared the three types of exercise (HIIT1, HIIT4, MICT) and concluded that HIIT1 is more effective than HIIT4 and MICT in improving MetS and reducing z scores [23]. The mechanism responsible for improvement of MetS following exercise is likely related to changes in energy balance [24], circulating lipids, and insulin sensitivity [25]. Also, an increase in HDL may be due to increased activity of the lipoprotein lipase (LPL); the LPL enzyme in the conversion of VLDL to HDL works through increasing the C-HDL activity [26]. Exercise activities can stimulate lipid oxidation and inhibit lipid synthesis within the liver, which is mediated by activating the AMPK pathway. The stimulation and activation of this enzyme with increased AMP to ATP ratio in the tissue is another possible result of the physiological stimulus of exercise activity [27]. Sodium alginate supplementation is shown to improve insulin sensitivity, hyperinsulinemia, and hyperleptinemia, and attenuate in ammation in white adipose tissue and inhibit hepatic lipid synthesis. It also reduces oxidative stress and increases antioxidant enzyme levels in the However, increased anti-appetite agents (PYY, CCK) re ect the optimal effects of exercise on suppressing appetite and decrease total energy intake [31]. The main mechanism for PYY responses induced by exercise is not well understood [32].
Generally, PYY is known to be affected by signals such as CCK, gastric acid, calcitonin gene-related peptide, luminal bile salts, and insulin-like growth factor-1 [33]. Potential increases in sympathetic nervous system activity and catecholamines may also increase the PYY secretion from the intestinal cells. Exercise-induced PYY increment might reduce NPY receptors expression in orchid nuclei via acting on Y2 receptors in the hypothalamus [6]. It is to be noted that HIIT and MICT with or without supplementation improved MetS Z score in favor of the HIIT + S. Comparing MICT with HIIT, Ramos et al (2017) reported the reduction of the overall MetS Z score after HIIT [23], while, Bateman et al (2011) after MICT [34] and Batacan et al (2017) reported no signi cant improvement [10].
Increased hormone-sensitive lipase (HSL) activity induced by exercise through AMP kinase activation, increased epinephrine and glucagon activity, and downstream events cause lipolysis and free fatty acids released from adipose tissue and intracellular TG concentration [9]. Lipid oxidation provides strong evidence for the role of exercise adaptation in improving blood lipid pro les through [35] increased lipoprotein lipase (LPL) activity and hydrolyzing TG and LDL [9]. Compared to other groups, HIIT + S decreased FBS more signi cantly in this study.
An increase in PGC1α expression in skeletal muscle following exercise might be one of the possible mechanisms that increase glucose uptake from blood circulation, GLUT4 expression, and gluconeogenesis [35]. Exercise lowers blood glucose through insulin-stimulated and contraction-mediated pathways [36].

Conclusions
In summary, in the present study, after eight weeks of HIIT + S, HIIT, MICT + S, and MICT, signi cant increases were observed in CCK and PYY levels. Therefore, it can be concluded that exercise and sodium alginate supplementation may be effective in suppressing appetite, increasing appetite hormones, and decreasing the risk factors for MetS. Further studies are needed to determine the effect of HIIT and MICT on appetite hormones, at different intensities and durations, as well as different doses of sodium alginate supplementation.

Declarations
Ethics approval and consent to participate: The present study was approved by the Ethics Committee of Razi University at Kermanshah-Iran. The informed consent form was lled out by all participants.
Availability of data and materials: All data is available Competing interests: The authors declare that they have no competing interests. Funding: There were no funding supports.  Comparison between mean ± SD of CCK concentration between groups *: Signi cantly different in comparison pre and post-test within the groups ¥: Signi cant differences with the control Figure 4