Background: There is increased worldwide concern about the consequences of folic acid and vitamin B 12 deficiencies on health, which include megaloblastic anemia, neural tube defects and cardiovascular disease. Objective: This study intended to determine the prevalence of folic acid and vitamin B 12 deficiencies in vulnerable groups in labor and poor socioeconomic strata of the Venezuelan population. Methods: A total of 5658 serum samples were processed to determine folic acid and vitamin B 12 concentrations. The study involved three surveys performed during 2001-2002 and included infants, children, adolescents and pregnant women from labor and poor socioeconomic strata of the population. The method used was a radio immunoassay designed for the simultaneous measurement of serum folic acid and vitamin B 12 .Results: The prevalence of folic acid deficiency was higher than 30% for all groups studied, reaching 81.79% in adolescents. Vitamin B 12 deficiency was 11.4% in samples collected nationwide, but there was also a similar prevalence of high serum levels. The prevalence of folic acid and vitamin B 12 deficiencies in pregnant women reached 36.32 and 61.34%, respectively. Conclusion: This work shows that there is a high prevalence of folic acid deficiency, especially in women of reproductive age, pregnant adolescents and in the whole population studied in Vargas state. This situation requires immediate intervention as supplementation or food fortification programs.

This study provides new evidence that a local carrageenan injection induces a systemic response.