Dietary glycaemic load and odds of depression in a group of institutionalized elderly people without antidepressant treatment.

BACKGROUND: Depression is a very common disorder in elderly, especially in those institutionalized. Nutrition could play an important role in the onset and/or progression of depression, since the intake of carbohydrates with a high glycaemic index (GI) or diets with a high glycaemic load (GL) may increase the insulin-induced brain serotonin secretion.
OBJECTIVE: The aim of our study was to analyse the association between dietary GI and GL and the odds of suffering depression in institutionalized elderly people without antidepressant treatment.
METHODS: This cross-sectional study included 140 institutionalized elderly people from the Madrid region (Spain) (65-90 years of age) whose diets were recorded using a precise weighing method over seven consecutive days. Energy and nutrient intakes were recorded and the GI and GL calculated. The participants' affective capacity was assessed using the Geriatric Depression Scale (GDS). Subjects were grouped into non-depressed (GDS ≤ 5) and depressed (GDS > 5). Since GDS scores and gender were statistically associated (p < 0.01), the data were grouped considering this association.
RESULTS: Dietary GI (51.09 ± 3.80) and GL (97.54 ± 13.46) were considered as medium. The dietary GL was significantly higher in the non-depressed (100.00 ± 12.13) compared with the depressed group (93.97 ± 14.04, p < 0.01). However, a similar GI was observed between non-depressed (51.50 ± 3.29) and depressed groups (50.52 ± 4.46). Additionally, participants with a dietary GL placed in the second and third tertiles had a 67.4 % and 65.3 %, respectively, less odds of suffering depression than those in the first tertile. GDS scores and dietary GL were inversely related; therefore, an increase in one unit in the dietary GL scale decreased the GDS score by 0.058 units.
CONCLUSIONS: Glyaemic load is associated with a lower odd of depression.