Effect of Genetic Variation in Starch-digesting Enzymes on Digestibility and Glycemic Index of Cold and Hot Rice

Effect of Genetic Variation in Starch-digesting Enzymes on Digestibility and Glycemic Index of Rice Prepared in Different Ways

This study evaluates the effect of different methods of preparation (cooked and consumed hot vs cooked, cooled overnight and consumed cold) and variation in the activity of salivary amylase on the glycemic index and carbohydrate digestibility in healthy human subjects. The effect of genetic variation in small intestinal starch digesting enzymes on glycemic index and starch digestibility will also be assessed.

Inclusion Criteria:

• Males or non-pregnant females aged 18-75 years and in good health
• Eligible to receive income in Canada
• Have Ontario Health Insurance Plan or equivalent medical coverage.
• Previous donor of saliva using protocol reference number # 31093 or GIL-1670 (in which subject consents to measurement of salivary amylase activity and genetic variation in AMY1, SI and MGAM genes).
• Salivary amylase activity in the lowest tertile (<50 U/ml) or highest tertile (>105 U/ml) of salivary amylase activity of 40 subjects previously measured.

Exclusion Criteria:

• known history of AIDS, hepatitis, diabetes or a heart condition
• Allergy to rice, canola oil or sesame oil.
• use of medications (including, but not limited to, insulin or other antidiabetic drugs, systemic steroids, antipsychotics, protease inhibitors, antivirals, immunosuppressive agents and drugs affecting gut motility or digestion) or with any condition which might, in the opinion of Dr. Wolever, the Medical Director or GI Labs, either: 1) make participation dangerous to the participant himself (or herself) or to others, or 2) affect the results.
• individuals who cannot or will not comply with the experimental procedures or do not follow the instructions of GI Labs staff related to the safe performance of the experimental procedures