Robert, Sathyasurya Daniel
(2018)
Investigation of selected foods added with fenugreek that controls postprandial blood glucose in healthy volunteers.
PhD thesis, Universiti Sains Malaysia.
Abstract
Increasing evidence suggests that functional foods may benefit those with
chronic diseases such as diabetes, obesity, cardiovascular disease and cancer.
Preliminary animal and human trials suggest possible hypoglycemic properties of
fenugreek when taken orally. The purpose of this study was to determine the chemical
composition of fenugreek, to investigate the effects of fenugreek on postprandial plasma
glucose (PPG) and satiety among overweight and obese individuals. Galactomannan
content of the test foods and the ability of fenugreek seed in reducing glycemic response
and glycemic index (GI) when added into buns and flatbreads were also investigated.
During the first phase of this randomized controlled crossover trial, 14 overweight or
obese subjects were studied in the morning after overnight fasts on four separate
occasions. Glycemic responses elicited by 50 g carbohydrate portions of white bread and
jam with or without 5.5 g of fenugreek and fried rice with or without 5.5 g fenugreek
were determined over 2 h. The main endpoint was the incremental area under the plasma
glucose response curve (IAUC). In the second phase of this study 10 healthy human
subjects (5 men, 5 women) were given 50 g glucose (reference food, twice); buns (0%
and 10% fenugreek seed powder); and flatbreads (0% and 10% fenugreek seed powder)
on 6 different occasions. Finger prick capillary blood samples were collected at 0, 15,
30, 45, 60, 90, and 120 minutes after the start of the meal. The palatability of the test
meals were scored using Likert scales. Results revealed that fenugreek seed powder
contained considerable levels of protein (32.5%), carbohydrate (46.4%), total dietary
fibre (TDF) (39.6%), soluble dietary fibre (SDF) (23.8%) and insoluble dietary fibre
(IDF) (15.8%). Adding fenugreek to both foods significantly reduced the IAUC
compared to the food alone: white bread and jam, 180±22 versus 271±23 mmol × min/L
(P=0.001); fried rice, 176±20 versus 249±25mmol × min/L (P=0.001). Fenugreek also
significantly reduced the area under the satiety curve for white bread with jam (134±27
versus 232±33mm × hr, P=0.01) and fried rice (280±37 versus 379±36mm× hr, P=0.01).
On the other hand, the incremental areas under the glucose curve value (IAUC) of buns
and flatbreads with 10% fenugreek (138±17 mmol x min/L; 121±16 mmol x min/L)
were significantly lower than those of 0% fenugreek bun and flatbreads (227±15 mmol x
min/L; 174±14 mmol x min/L, P= < 0.01). Addition of 10% fenugreek seed powder
reduced the GI of buns from 82±5 to 51±7 (P<0.01) and to the GI of flatbread from
63±4 to 43±5 (P<0.01). Furthermore the galactomannan content of fenugreek added
flatbreads and buns were 1.54±0.02% and 3.06±0.03 % respectively. It is concluded
that fenugreek significantly decreased the PPG response and increased satiety among
overweight and obese individuals. In addition, this study demonstrated that by replacing
10% of refined wheat flour with fenugreek seed powder significantly reduces the
glycemic response and the GI of buns and flatbreads.
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