Plasma and red cell folate concentrations (Lactobacillus casei activity) have been studied in 43 women during pregnancy. Iron, but no folic acid supplement was given. The plasma folate concentrations decreased significantly during pregnancy and were lower than in the reference cases at term. The red cell folate concentrations were compatible with the reference material during early pregnancy, and significantly higher than the reference material at term. A significant decrease was observed during the last two months of pregnancy. The plasma folate and the red cell folate concentrations at different stages of pregnancy were correlated and a relationship was demonstrated between these parameters at different stages of pregnancy. The hemoglobin concentrations were compatible with the reference material during early pregnancy and at term. One hundred and sixty-six women were also studied at term to evaluate the effect of repeated pregnancies on the folate status. Repeated pregnancies did not influence the plasma and red cell folate concentrations at term. We conclude that the folate intake is adequate to meet the increased requirements during pregnancy, and folic acid supplementation is therefore not recommended as a routine in normal pregnancies in this population.

B₁₂ analogues, homocysteine, methylmalonic acid (MMA), and unsaturated transcobalamins, all potential markers of vitamin B₁₂ status, were analyzed in blood and cerebrospinal fluid (CSF) from 22 patients with primary degenerative dementia of Alzheimer type. The level of active vitamin B12 in serum correlated significantly with serum homocysteine, serum MMA, and CSF homocysteine. CSF B₁₂ correlated significantly with serum homocysteine and serum MMA. The ratio of analogues and active vitamin B₁₂ concentrations in serum (analogue/active B₁₂ ratio) correlated significantly with serum homocysteine, serum MMA and CSF B₁₂. This study had no control group. However, based on available reference values, high concentrations of homocysteine and MMA in serum and unsaturated transcobalamin II in plasma were interpreted as evidence of vitamin B₁₂ depletion or deficiency. Such high concentrations were found in a significant number of patients. In 9 patients, vitamin B₁₂ injections were administered. After treatment, serum homocysteine levels fell significantly. We conclude that vitamin B₁₂ analogues, homocysteine, MMA, and transcobalamins may be useful as markers in studies aimed at clarifying the role of vitamin B12 deficiency in dementia disorders.

We have studied growth, red blood cell status and folate concentrations in plasma and red cells in a group of 35 breastfed infants during the first year of life. Folic acid supplementation was not given to the mothers during pregnancy or lactation, and none of them developed megaloblastic anaemia. The growth and red blood cell status of the infants were both normal. At birth, and throughout the period of observation, the folate concentrations in plasma and red cells were significantly higher than in the adult reference material. A positive correlation between plasma and red cell folate was demonstrated. During the latter part of pregnancy and lactation the foetuses and infants seem to be protected against folate deficiency. We regard the folate status of normal breastfed infants as optimal. The optimal supply of the vitamin in artificial nutrition should be the amount of folate necessary to maintain plasma and red cell folate concentrations similar to those found in breastfed infants.

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