Glycaemic index and glycaemic load intake patterns in older Australian women

Aims:  Dietary glycaemic index and glycaemic load have been associated with risk of chronic diseases, yet limited research exists on patterns of consumption in Australia. Our aims were to investigate glycaemic carbohydrate in a population of older women, identify major contributing food sources and determine low, moderate and high ranges.
Methods:  Subjects were 459 Brisbane women aged 42–81 years participating in the Longitudinal Assessment of Ageing in Women. Diet history interviews were used to assess usual diet and results were analysed into energy and macronutrients using the FoodWorks dietary analysis program combined with a customised glycaemic index database.
Results:  Mean ± SD dietary glycaemic index was 55.6 ± 4.4% and mean dietary glycaemic load was 115 ± 25. A low glycaemic index in this population was ≤52.0, corresponding to the lowest quintile of dietary glycaemic index, and a low glycaemic load was ≤95. Glycaemic index showed a quadratic relationship with age ( P = 0.01), with a slight decrease observed in women aged in their 60s relative to younger or older women. Glycaemic load decreased linearly with age ( P < 0.001). Bread was the main contributor to carbohydrate and dietary glycaemic load (17.1% and 20.8%, respectively), followed by fruit (15.5% and 14.2%), and dairy for carbohydrate (9.0%), or breakfast cereals for glycaemic load (8.9%).
Conclusions:  In this population, dietary glycaemic load decreased with increasing age; however, this was likely to be a result of higher energy intakes in younger women. Focus on careful selection of lower-glycaemic-index items within bread and breakfast cereal food groups would be an effective strategy for decreasing dietary glycaemic load in this population of older women.