Dietary glycaemic load, index may be tied to depression
While a cross-sectional relationship may not exist, cohort studies and clinical trials seem to reveal significant links between high dietary glycaemic index (GI) and load (GL) and depression, according to a recent meta-analysis.
Applying the selection criteria resulted in 11 eligible studies, of which six were cross-sectional in design, two were cohort studies and three were clinical trials. One cross-sectional study did not report odds ratios (ORs) and was therefore excluded from the meta-analysis.
Pooled analysis of the cross-sectional analyses revealed no significant impact of dietary GI on depression risk (OR, 1.01; 95 percent CI, 0.94–1.08), though there was significant heterogeneity of evidence. Meta-regression according to sex, study quality and adjustment for energy intake (controlled for or not in the studies) showed that none of these variables were responsible for the heterogeneity.
Random effects model analysis likewise did not significantly alter the initial findings (OR, 0.99; 0.78–1.28), nor did subsequent subgroup and sensitivity analyses.
Similar findings were obtained regarding the link between dietary GL and depression risk (OR, 0.93; 0.84–1.04), with no significant between-study heterogeneity. As such, random effects models produced no significant change in the initial findings (OR, 0.89; 0.75–1.05).
However, a subgroup analysis based on adjustment for body mass index (BMI) found a significant link between dietary GL and the likelihood of developing depression in studies that did not control for BMI (OR, 0.61; 0.43–0.88).
Similarly, pooled analysis of the cohort studies showed that dietary GI was significantly correlated with depression (HR, 1.13; 1.02–1.25), while clinical trials found a correlation between high GL consumption and depression score (weighted mean difference, 0.66; 0.28–1.04).