Objective: We evaluated the efficacy of the Coronary Health Improvement Project (CHIP) at lowering depression by modifying selected daily nutrients from food.
Methods: A randomized controlled trial was used, with 348 participants 24 to 81 y of age from metropolitan Rockford, Illinois. Participants were assessed at baseline and at 6 wk and 6 mo of follow-up. The Beck Depression Inventory (BDI) was used to measure depression.
Results: Those in the intervention group compared with the control group were 63% more likely to show a decrease in BDI through 6 wk (P < 0.0001) and 34% more likely to experience a decrease through 6 mo (P < 0.0001). Baseline levels of saturated fat were negatively associated with BDI (P < 0.0001) after adjusting for age, sex, exercise, body mass index, and exercise. Decrease in saturated fat over the study period was directly associated with a decrease in BDI. Increase in pyridoxine (B6) was also associated with a decrease in BDI. The intervention indirectly lowered BDI by lowering saturated fat and increasing dietary pyridoxine (B6). It also directly lowered BDI, possibly because of social interaction, positive reinforcement, and distraction.
Conclusion: The CHIP, which improves daily nutrients from food and cardiovascular risk factors, also lowers depression.