Background – The in vivo glycaemic index (GI) testing of foods can give a broad range of results between laboratories and even within laboratories for the same food item. Demographic factors such as gender, ethnicity and age of participants may influence the glycaemic responses in the individuals to a standard Oral Glucose tolerance test (OGTT), hence may affect the determination of the GI value of foods.
Objective – To determine effect of age, gender and ethnicity of the subjects attending the GI testing site on their glycaemic response (GR) to a standard OGTT.
Design – Glucose response data was collected on 204 subjects of varying age, ethnicity and gender from multiple OGTT (minimum =3, maximum=11). The individuals were grouped based on their ethnicity into: Western European (n = 105), Asian (n = 83) and Indian and Middle Eastern (n = 16), as well as age groups: 18 - 26, 27 – 35 and 36- 45 years, and male and female gender.
Outcomes – There was no significant difference in the area under the curve (AUC) for the 50g glucose solution in Asian, Western European and Indian and Middle Eastern F (2, 201) = 10.3, P= 5.2. The blood glucose level in Indian and Middle Eastern subjects tended to return to the fasting level very slowly compared to other ethnicities. The effect of age on glucose responses was not significant. Statistical analysis also showed no significant differences in the AUC based on gender (57.3% female; 42.6% male), F (1, 202) = 0.42, P= 0.5.
Conclusion – Ethnicity, gender and age do not have significant influence on the GR and thus may have no impact on GI determination of foods.