Purpose: A structural equation model (SEM) was used to test multiple and simultaneous relationships between socio-demographic factors, dietary patterns, biochemical levels of folate, vitamin B12, docosahexaenoic acid (DHA), and its effects on homocysteine (Hcy) level.
Methods: Socio-demographic and lifestyle characteristics, blood sample, anthropometric measurements, and a food-frequency questionnaire (FFQ) were obtained from 281 individuals of ISA-Capital study (Sao Paulo, Brazil). The dietary patterns (DP) were estimated using factor analysis with principal component's estimation based on the frequency of daily intake derived from the 38-item FFQ. The SEM considered a theoretical model where the DP were expected to be directly associated with Hcy level, and indirectly via biochemical levels of folate, vitamin B12, and DHA. The variables sex, age, ethnicity, and MTHFR C677T polymorphism were included in the model.
Results: The Prudent DP (- 0.12, p = 0.04) had a negative effect, while MTHFR C677T polymorphism (0.16, p = 0.01), age (0.22, p < 0.01), and being man (0.16, p = 0.01) had a positive effect on Hcy level. There were no indirect effects of any dietary patterns on Hcy level, neither via folate, vitamin B12, nor DHA. DHA was negatively associated with the Modern DP (- 0.12, p = 0.04) and positively associated with the Prudent DP (0.19, p < 0.01).
Conclusions: The DP mainly composed of fruits and vegetables, natural juices, potato/cassava/cooked cornmeal, fish, and chicken, which was negatively associated with the Hcy level in this population. These findings support the role of a healthy dietary pattern in health outcomes, rather than promoting specific foods or nutrients, for policy-based health promotion strategies.
Keywords: Folate; Homocysteine; MTHFR; One-carbon metabolism; Structural equation model.