Folic acid and vitamin B12 status of vervet monkeys used for nutritional research.

Plasma and red blood cell (RBC) folic acid levels, as well as plasma vitamin B12 levels were determined in Vervet monkeys (Cercopithecus aethiops). All the vervets were apparently healthy and without symptoms or lesions typical of folic acid and/or vitamin B12 deficiencies. Competitive protein binding radioassays were used to determine folate and vitamin B12 values in animals fed 4 different diets. The B12 levels for all the groups ranged between 866 and 5867 pg/ml and showed an inverse relationship with the FA measurements. The lowest mean RBC folic acid content in a group fed an atherogenic diet for 3 years was 12.8 ng/ml. For the other 3 diets, mean RBC folic acid levels were 90.7, 132.3 and 152.8 ng/ml, respectively. A megadose of 25.6 mg of folic acid per day for 99 days was given to 3 adult males. No obvious toxic effects were observed in these animals although mean RBC folic acid levels increased to 1013 ng/ml.