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Title: The acute effect of macronutrients and micronutrients on appetite and satiety
Author: Al-Mana, Najlaa
ISNI:       0000 0004 8509 7760
Awarding Body: University of Surrey
Current Institution: University of Surrey
Date of Award: 2014
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Background: Obesity has become more prevalent in the last 20 years. Dietary fibre (DF) and calcium (Ca) as functional food-ingredients are linked through epidemiology to weight-management, but the impact of these as isolated ingredients in obesity is unknown. Objective: To investigate the short-term effects of DF from resistant starch (RS), or fenugreek (Fen), and Ca, on appetite, satiety and postprandial metabolism in overweight/obese subjects. Methods: In a series of appetite experiments, these functional ingredients were given to overweight/obese subjects as part of standardized meals with a concomitant measurement of subjective appetite ratings, acute energy intake (El), and postprandial metabolism. In each case, the treatment effect was compared to a matched control. Results: RS reduced the El at the subsequent ad libitum meal (ALM) (p=0. 02), but had no significant impact on satiety or hunger. Following RS, hunger and prospective food consumption was lower in the obese group versus the lean group (p= < 0. 001; p=0. 057 respectively). There were no significant differences in El at the ALM or over the 24h period. While obese subjects had higher insulin and C-peptide, their postprandial plasma GLP- 1 was lower (p=0. 009). Consumption of a fenugreek-enriched drink elevated the plasma glucose levels and remained above fasting levels for 4 hours postprandial (p=0. 02). This finding was combined with a reduction in energy intake at an ATM (p=0. 030). However, no significant differences over 24h were observed between treatment groups. Conversely, the Ca-enriched drink reduced El at the ALM (p=0. 017), decreased rated prospective consumption (p=0. 012), hunger (p=0. 05) and GLP- 1 (p < 0. 001). Conclusion: Acute consumption of DF and Ca reduced food intake, indicating an effect on short-term satiety. Our data suggest a weak relationship between satiety and GLP-1 secretion in obese individuals. Further studies are required to determine these mechanisms on appetite and to confirm whether the effect can be maintained in the longer-term.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available