The purpose of the present study is to explore the influence of cooking methods of potatoes on post-prandial glycaemia and satiety in healthy older adults.
Each of the 5 study sessions will be at least 7 days apart. Either meal skipping, or one of three treatments of white potatoes (a) baked (with skin), (b) mashed, (c) fried French fries, or white bread, prepared on the day of testing, will be served to healthy older adults (65+ years). Participants will consume the equivalent to 1 medium sized potato (\~280 kcal) or an equivalent amount of calories from white bread. Glycemic response, insulin, incretin hormones (glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP)), dipeptidyl peptidase 4 (DPP4), and cholecystokinin (CCK) will be measured for 2 h (0, 15, 30, 45, 60, 90 and 120 min) following meal consumption, as well as mood and subjective appetite. An ad libitum test meal will be provided at 120 min to assess food intake suppression.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
20
Toasted, with canola oil added to match for fat content of French fries (13.9 grams), as well as being matched for energy (280 kilocalories) and available carbohydrate content (33 grams) of potato treatments.
Baked russet potato with canola oil added once baked to match for fat content of French fries, and also matched for the salt content of white bread (280 milligrams).
Mashed potatoes prepared from frozen, with canola oil added to match for fat content of French fries, as well as being matched for energy and available carbohydrate content of the baked potato.
School of Nutrition, Ryerson University
Toronto, Ontario, Canada
Ad libitum food intake (lunch, at 120 minutes)
Food intake will be determined by weighing the meal before and after serving. The net weight of the test meal will be converted to calories
Time frame: 120 minutes after meal consumption
Change from baseline glycemic response
Blood glucose (mmol/L). Blood glucose will be measured in whole blood using YSI 2300 STAT PLUS (YSI Incorporated, Yellow Springs, OH)
Time frame: baseline and then 15, 30, 45, 60, 90 and 120 minutes after meal consumption
Change from baseline insulin
Blood insulin (pmol/L). Insulin concentration in serum will be determined in duplicate via enzyme-linked immunosorbent assay kits (ELISA; Millipore, Billerica, Massachusetts).
Time frame: baseline and then 15, 30, 45, 60, 90 and 120 minutes after meal consumption
Change from baseline subjective appetite
Measured using visual analogue scale (mm). Each VAS is a 100 mm line where they will place a pencil mark to describe their feelings.
Time frame: baseline and then 15, 30, 45, 60, 90 and 120 minutes after meal consumption
Change from baseline mood
Measured using visual analogue scale (mm). Each VAS is a 100 mm line where they will place a pencil mark to describe their feelings.
Time frame: baseline and then 15, 30, 45, 60, 90 and 120 minutes after meal consumption
Change from baseline cholecystokinin (CCK)
Blood CCK (pmol/L). CCK concentration in serum will be determined in duplicate via enzyme-linked immunosorbent assay kits (ELISA; Millipore, Billerica, Massachusetts)
Time frame: baseline and then 15, 30, 45, 60, 90 and 120 minutes after meal consumption
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Prepared from frozen, matched for energy and available carbohydrate content of baked potato and salt content of white bread.
No food given
Change from baseline dipeptidyl peptidase 4 (DPP4)
Blood DPP4 (ng/mL). DPP4 concentration in serum will be determined in duplicate via enzyme-linked immunosorbent assay kits (ELISA; Millipore, Billerica, Massachusetts)
Time frame: baseline and then 15, 30, 45, 60, 90 and 120 minutes after meal consumption
Change from baseline glucose-dependent insulinotropic peptide (GIP)
Blood GIP (pmol/L). GIP concentration in serum will be determined in duplicate via enzyme-linked immunosorbent assay kits (ELISA; Millipore, Billerica, Massachusetts)
Time frame: baseline and then 15, 30, 45, 60, 90 and 120 minutes after meal consumption
Change from baseline glucagon-like peptide-1 (GLP-1)
Blood GLP-1 (pmol/L). GLP-1 concentration in serum will be determined in duplicate via enzyme-linked immunosorbent assay kits (ELISA; Millipore, Billerica, Massachusetts)
Time frame: baseline and then 15, 30, 45, 60, 90 and 120 minutes after meal consumption