Acta Pzdiatr Scand 68: 239-243, 1979
PLASMA AND RED BLOOD C E L L FOLATE IN BREASTFED INFANTS J. EK and E. M. MAGNUS From the Department ($Paediatrics, Rikshospitalei, and Kroghstfltien Department oj0.slo City Hospiiul, Oslo, Norway
ABSTRACT. Ek, J. and Magnus, E. M. (Department of Paediatrics, Rikshospitalet, and Kroghstetten Department of Oslo City Hospital, Oslo, Norway). Plasma and red blood cell folate in breastfed infants. Acta Paediatr Scand, 68: 239, 1979.-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 he the amount of folate necessary to maintain plasma and red cell folate concentrations similar to those found in breastfed infants. KEY WORDS: Infants, breastfeeding, plasma folate, red blood cell folate, red blood cell status
Folate is necessary for normal growth (4, 6), development (1) and function (2, 28) of the human organism. A prospective study on the folate status of infants and children related to other pertinent parameters was therefore undertaken. If possible, we wanted to define the optimal daily supply of the vitamin. This is the first report from a series of studies made in a developed urban community. We concentrate here on the folate levels in breastfed infants, and demonstrate that the infants seem to be protected against folate deficiency during the nursing period. Data illustrating the effects of normal physiological processes on plasma and red blood cell folate during the first year of life are also presented. MATERIAL AND METHODS The material in this study consists of 35 full-term infants borne by healthy mothers from the socio-economic middle class. The mothers were given 0.2 g iron daily from the third month of gestation, but no folic acid supplementa-
tion. None of them developed anaemia during pregnancy or lactation. The infants were breastfed for at least 6 months and up to 14 months, mean suckling period 7; months. After weaning, the infants were fed unboiled pasteurized cow’s milk. Vegetables, iron-fortified cereals containing 12.5 mg or more Fe++per 100 g cereal, meat, and fish, were gradually introduced at the age of 3 to 34 months. Vitamin supplementation with ascorbic acid (orange juice) and vitamin A and D (cod liver oil) was started one month after birth, initially 5 mg ascorbic acid, 3 750 IU vitamin A and 375 IU vitamin D, increasing to 15 mg, 7500 IU and 750 IU respectively, from 14 months of age. The infants were examined regularly by one of us (J. E.) 3-5 hours after their last meal. They were first seen within 2 days after birth, thereafter at monthly intervals ( + / one week). On each occasion a clinical examination was performed and a capillary blood sample drawn. The folate concentration in plasma and red blood cells was measured, and the infants’ haemoglobin, REX, VPRC, red cell indices, WBC, reticulocytes and blood smears were studied. The adult reference material consisted of 50 female (non-pregnant, non-lactating) and 50 male students and hospital staff, aged 19 to 50 (mean 274) years. Venous blood samples were drawn 3-5 hours after their last meal. The haemoglobin values were obtained by a manual oxyhaemoglobin method (7, 21), red and white blood cell counts by a Celloscope 401@ (Linson Instrument AB, A(.to Paedirrtr Scund 68
240
J . Ek and E. M . Mngnus
Table 1. Red blood cell stattts in breastfed infants dcrring ,first year of lifr, expressed as mean values with S.D. A.R.M.=adult reference material, S.D. =standard deviation Age (months) 0 1
2 3 4 5 6 9 12 A.R.M. female A.R.M. male
No. of obs.
Hb (g/dl)
RBC
34 35 35 35 35 35 35 34 34
17.7-tl.62 14.2k1.37 12.1k0.91 12.0k0.80 12.2k0.71 12.3k0.75 12.1k0.74 12.420.77 12.710.80 13.6ir0.64 15.4kO.62
5.53 kO.50 4.53"+0.48 3.96 " k 0.38 4.15 k0.34 4.32 ' k 0.48 4.47 k0.45 4.36 k0.47 4.60 k0.43 4.68 20.44 4.48 k0.33 4.95 f0.33
so 50
(X
10'2/1)
VPRC (1/1)
(fl)
MCV
0.578k0.060 0.417k0.041 0.356k0.027 0.357f0.022 0.363 k0.023 0.370 k0.020 0.367 k0.022 0.373 k0.02 1 0.380 k 0.022 0.41 1kO.022 0.457k0.021
104.7 k 8 . 9 92.7 +- 8.2 90.4"+7.6 86.6 k6.0 84.2 " f 6.8 83.5 k6.6 84.9 k9.1 82.0 k7.6 81.9 k6.7 92.0 k5.8 92.6 kS.3
'' 34 observations. Sweden), and the VPRC by using a microhaematocnt centrifuge for 3 minutes at 9400 revlmin at a mean of 6300 g. Heparinized capillary tubes were used. The haematological analyses were controlled by means of DADE@ CH.60TMAbnormal and Normal, Haematology Reference. Serum and red blood cell folate were determined as Lactobacillus casei activity (15). All results were analysed by BMDP statistical computer programs (3). The difference between groups of observations was tested by the Mann-Whitney test.
RESULTS The growth of the infants was normal and did not differ from the standards established for Norwegian (25) and Swedish infants (10). The haematological data are presented in Table 1. The values found in the 50 adult males used as controls were compatible with those reported for Norwegian men by Natvig & Vellar (20). The reference values found in adult females were compatible with those reported in Norwegian women without iron supplementation (20). The plasma folate concentrations (Fig. 1) were higher than in the adult reference material throughout the period of observation (p< 0.001). The red cell folate concentrations (Fig. 2) were also higher than in the adult reference material during the first year of life (p
PLASMA AND RED BLOOD C E L L FOLATE IN BREASTFED INFANTS J. EK and E. M. MAGNUS From the Department ($Paediatrics, Rikshospitalei, and Kroghstfltien Department oj0.slo City Hospiiul, Oslo, Norway
ABSTRACT. Ek, J. and Magnus, E. M. (Department of Paediatrics, Rikshospitalet, and Kroghstetten Department of Oslo City Hospital, Oslo, Norway). Plasma and red blood cell folate in breastfed infants. Acta Paediatr Scand, 68: 239, 1979.-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 he the amount of folate necessary to maintain plasma and red cell folate concentrations similar to those found in breastfed infants. KEY WORDS: Infants, breastfeeding, plasma folate, red blood cell folate, red blood cell status
Folate is necessary for normal growth (4, 6), development (1) and function (2, 28) of the human organism. A prospective study on the folate status of infants and children related to other pertinent parameters was therefore undertaken. If possible, we wanted to define the optimal daily supply of the vitamin. This is the first report from a series of studies made in a developed urban community. We concentrate here on the folate levels in breastfed infants, and demonstrate that the infants seem to be protected against folate deficiency during the nursing period. Data illustrating the effects of normal physiological processes on plasma and red blood cell folate during the first year of life are also presented. MATERIAL AND METHODS The material in this study consists of 35 full-term infants borne by healthy mothers from the socio-economic middle class. The mothers were given 0.2 g iron daily from the third month of gestation, but no folic acid supplementa-
tion. None of them developed anaemia during pregnancy or lactation. The infants were breastfed for at least 6 months and up to 14 months, mean suckling period 7; months. After weaning, the infants were fed unboiled pasteurized cow’s milk. Vegetables, iron-fortified cereals containing 12.5 mg or more Fe++per 100 g cereal, meat, and fish, were gradually introduced at the age of 3 to 34 months. Vitamin supplementation with ascorbic acid (orange juice) and vitamin A and D (cod liver oil) was started one month after birth, initially 5 mg ascorbic acid, 3 750 IU vitamin A and 375 IU vitamin D, increasing to 15 mg, 7500 IU and 750 IU respectively, from 14 months of age. The infants were examined regularly by one of us (J. E.) 3-5 hours after their last meal. They were first seen within 2 days after birth, thereafter at monthly intervals ( + / one week). On each occasion a clinical examination was performed and a capillary blood sample drawn. The folate concentration in plasma and red blood cells was measured, and the infants’ haemoglobin, REX, VPRC, red cell indices, WBC, reticulocytes and blood smears were studied. The adult reference material consisted of 50 female (non-pregnant, non-lactating) and 50 male students and hospital staff, aged 19 to 50 (mean 274) years. Venous blood samples were drawn 3-5 hours after their last meal. The haemoglobin values were obtained by a manual oxyhaemoglobin method (7, 21), red and white blood cell counts by a Celloscope 401@ (Linson Instrument AB, A(.to Paedirrtr Scund 68
240
J . Ek and E. M . Mngnus
Table 1. Red blood cell stattts in breastfed infants dcrring ,first year of lifr, expressed as mean values with S.D. A.R.M.=adult reference material, S.D. =standard deviation Age (months) 0 1
2 3 4 5 6 9 12 A.R.M. female A.R.M. male
No. of obs.
Hb (g/dl)
RBC
34 35 35 35 35 35 35 34 34
17.7-tl.62 14.2k1.37 12.1k0.91 12.0k0.80 12.2k0.71 12.3k0.75 12.1k0.74 12.420.77 12.710.80 13.6ir0.64 15.4kO.62
5.53 kO.50 4.53"+0.48 3.96 " k 0.38 4.15 k0.34 4.32 ' k 0.48 4.47 k0.45 4.36 k0.47 4.60 k0.43 4.68 20.44 4.48 k0.33 4.95 f0.33
so 50
(X
10'2/1)
VPRC (1/1)
(fl)
MCV
0.578k0.060 0.417k0.041 0.356k0.027 0.357f0.022 0.363 k0.023 0.370 k0.020 0.367 k0.022 0.373 k0.02 1 0.380 k 0.022 0.41 1kO.022 0.457k0.021
104.7 k 8 . 9 92.7 +- 8.2 90.4"+7.6 86.6 k6.0 84.2 " f 6.8 83.5 k6.6 84.9 k9.1 82.0 k7.6 81.9 k6.7 92.0 k5.8 92.6 kS.3
'' 34 observations. Sweden), and the VPRC by using a microhaematocnt centrifuge for 3 minutes at 9400 revlmin at a mean of 6300 g. Heparinized capillary tubes were used. The haematological analyses were controlled by means of DADE@ CH.60TMAbnormal and Normal, Haematology Reference. Serum and red blood cell folate were determined as Lactobacillus casei activity (15). All results were analysed by BMDP statistical computer programs (3). The difference between groups of observations was tested by the Mann-Whitney test.
RESULTS The growth of the infants was normal and did not differ from the standards established for Norwegian (25) and Swedish infants (10). The haematological data are presented in Table 1. The values found in the 50 adult males used as controls were compatible with those reported for Norwegian men by Natvig & Vellar (20). The reference values found in adult females were compatible with those reported in Norwegian women without iron supplementation (20). The plasma folate concentrations (Fig. 1) were higher than in the adult reference material throughout the period of observation (p< 0.001). The red cell folate concentrations (Fig. 2) were also higher than in the adult reference material during the first year of life (p
