Plasma lipids and apolipoproteins in breastfed and formula-fed Swedish infants

This study was carried out to compare plasma lipid pattern in breastfed and formula-fed infants and the effects of exchanging breast milk for formula and of introducing weaning foods. Healthy infants, exclusively breastfed at least until 3 mo, were at this age randomly assigned to infant formulas with similar fat composition. Formula was gradually introduced when breastfeeding was discontinued. One group continued to breastfeed beyond 6 mo of age. All infants received the same weaning foods and were studied between 3 and 12 mo of age. Decreased plasma concentrations of total and low-density lipoprotein cholesterol (TC, LDL-C), apolipoprotein B (apo B) and A1 (p < 0.001), and of high-density lipoprotein cholesterol (p < 0.05) were found when breast milk was exchanged for formula before 6 mo. At this age plasma TC, LDL-C and apo B were lower in formula-fed than in breastfed infants (p < 0.001). These plasma lipids then increased (p < 0.01) when the intake of formula decreased and that of weaning foods increased. However, plasma TC and/or LDL-C remained lower at 12 mo in formula-fed than in breastfed infants (p < 0.05). Our results indicate that the plasma lipid profile of infants is highly responsive to the dietary nutrient intake, as indicated by the decrease in plasma lipids and apolipoproteins when breast milk was exchanged for formula and by the increase in these concentrations when the intake of weaning foods gradually increased.     

Protein intake and metabolism in formula-fed infants given Swedish or Italian weaning foods

The aim of the study was to compare protein intake and metabolism between infants from two countries given similar infant formulae but different weaning foods. Healthy Swedish and Italian infants were studied between 3 and 12 mo. Infants in both populations were assigned to 1 of 3 infant formulae, containing 13, 15 or 18/20 g l^-1 of protein, given in addition to Swedish or Italian weaning foods. Protein intake from weaning foods was higher in Italian than in Swedish infants at 6 and 12 mo, whereas protein intake from formula at 6 mo and from formula/milk at 12 mo was similar in both populations. Plasma isoleucine, leucine, lysine, histidine and valine at 6 mo were lower in Italian than in Swedish infants fed formula with 13 g l^-1 of protein. All essential plasma amino acids were similar in Italian and Swedish groups at 12 mo. Serum urea was similar at 6 mo in corresponding formula groups, but was higher at 12 mo in the Italian than in the Swedish formula group. Serum albumin and growth were normal in both populations throughout infancy. In conclusion, formula with protein content of 13 g l^-1 seems to provide sufficient protein intake when combined with Swedish or Italian weaning foods during the second half of infancy, as indicated by normal serum albumin and normal growth. However, the bioavailability of protein and amino acids from weaning foods, in addition to their protein content, should be considered, as indicated by some indices of protein metabolism in the Italian infants.     

Serum cholesterol ester fatty acids in 7- and 13-month-old children in a prospective randomized trial of a low-saturated fat, low-cholesterol diet: the STRIP baby project

To evaluate changes that occur in serum cholesterol ester fatty acid composition during the transition from typical infant feeding to a more adult type of nutrition, this study compared the effects on serum cholesterol ester fatty acids of breast milk or formula at the age of 7 mo with effects caused by 6-mo dietary intervention in 137 children. The intervention [Special Turku coronary Risk factor Intervention Project for children (STRIP baby project)] aimed at a reduction of saturated fat intake to 10% of energy after the age of 1 y without purposefully influencing total fat intake. Nutrient intakes were calculated from 3-d food records. At the age of 7 mo, i.e. before dietary education began, milk type markedly influenced dietary and serum cholesterol ester fatty acid composition (mean serum cholesterol ester 16:0 in breastfed vs formula-fed infants, 13.7% vs 12.0%, respectively, p < 0.001; serum cholesterol ester 18:2n-6 50.6% vs 57.6%, p < 0.001). At the age of 13 mo the calculated fat intake of the intervention and control children differed markedly but serum cholesterol ester fatty acid compositions in all children resembled closely those measured in 7-mo-old breastfed infants, e.g. at the age of 13 mo the relative proportions of 18:2n-6 were 49.9% and 51.1% in previously formula-fed intervention and control children, respectively, and 50.3% and 50.1% in previously breastfed intervention and control children, respectively. In conclusion, serum cholesterol ester fatty acid composition reflected differences in dietary fat quality (breast milk or formula) at the age of 7 mo, whereas dietary intervention as applied in the STRIP baby project had only a minimal effect.     

Long-chain polyunsaturated fatty acids in human milk and brain growth during early infancy

Long-chain polyunsaturated fatty acids are essential for growth and development, and their crucial role in the development of the central nervous system and in retinal function has been the subject of many studies. As the balance between n-6 and n-3 fatty acids has to be optimal, their concentrations in the milk given to infants who are exclusively breastfed is of major importance. In this study, the composition of fatty acids in mothers' milk and the growth rate of the infant brain were analysed. Nineteen mother-term infant pairs from Stockholm, Sweden, were studied from birth to 1 mo and 3 mo of age, during which time the infants were breastfed exclusively. The dietary intake of the mothers was calculated and found to concur with the recommended daily dietary allowances of Swedish lactating women as regards energy, protein, fat and carbohydrates. The amounts of linoleic acid and alpha-linolenic acid in the diet were similar to those reported for European and North American women. The ratio between arachidonic acid (AA) and docosahexaenoic acid (DHA) in the milk from Swedish mothers is approximately the same as in the brain of infants, and was found to be positively correlated with the rate of gain of the occipito-frontal head circumference and of the calculated brain weight at 1 mo (p < 0.01) and 3 mo (p < 0.01) of age, respectively. However, further studies are needed to establish the exact requirements of AA and DHA for optimal growth and development during early infancy in exclusively breastfed infants.     

Feeding practices of infants through the first year of life in Italy

AIM: To investigate infant feeding practices through the first year of life in Italy, and to identify factors associated with the duration of breastfeeding and early introduction of solid foods. METHODS: Structured phone interviews on feeding practices were conducted with 2450 Italian-speaking mothers randomly selected among women who delivered a healthy-term singleton infant in November 1999 in Italy. Interviews were performed 30 d after delivery and when the infants were aged 3, 6, 9 and 12 mo. Type of breastfeeding was classified according to the WHO criteria. RESULTS: Breastfeeding started in 91.1% of infants. At the age of 6 and 12 mo, respectively, 46.8% and 11.8% of the infants was still breastfed, 68.4% and 27.7% received formula, and 18.3% and 65.2% were given cow's milk. Solids were introduced at the mean age of 4.3 mo (range 1.6-6.5 mo). Introduction of solids occurred before age 3 and 4 mo in 5.6% and 34.2% of infants, respectively. The first solids introduced were fruit (73.1%) and cereals (63.9%). The main factors (negatively) associated with the duration of breastfeeding were pacifier use (p < 0.0001), early introduction of formula (p < 0.0001), lower mother's age (p < 0.01) and early introduction of solids (p = 0.05). Factors (negatively) associated with the introduction of solids foods before the age of 3 mo were mother not having breastfed (p < 0.01), early introduction of formula (p < 0.01), lower infant bodyweight at the age of 1 mo (p = 0.05) and mother smoking (p = 0.05). CONCLUSION: The duration of breastfeeding in Italy is still inadequate, as well as compliance with international recommendations for timing of introduction of complementary foods. National guidelines, public messages and educational campaigns should be promoted in Italy.     

Bile composition of adult baboons is influenced by breast versus formula feeding

We tested the hypothesis that infant cholesterol intake and breast- versus formula-feeding influence the bile cholesterol saturation index and bile acid conjugate composition in adult baboons at 7-8 years of age. We also measured the influence of the postweaning intake of dietary cholesterol and fat (saturated and unsaturated) on the effects of the infant diets. The 80 baboons were derived from six sires and 80 dams and randomly assigned at birth to breast-feeding or to one of three formulas containing about 2, 30, or 60 mg cholesterol/dl. After weaning at 16 weeks of age the animals were assigned to one of four adult diets, which contained 0.01 or 1.0 mg/kcal of cholesterol containing 40% of calories from saturated or unsaturated fat. The bile cholesterol saturation index was significantly higher at 7-8 years of age in baboons breast-fed as infants compared with those fed formula (87.0% versus 72.8%, p less than 0.004). The cholesterol saturation index was not significantly different among the three formula groups. Among baboons who were breast-fed and subsequently fed saturated fat as adults, the glycine/taurine (G/T) ratios of the bile acid conjugates were about three times those of baboons fed unsaturated fat (1.53 versus 0.47); whereas among formula-fed animals the type of fat did not influence the G/T ratio (interaction, p = 0.022). Adult baboons fed the three formulas in infancy had an inverse relationship of the G/T ratio to the level of formula cholesterol (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Individualized dietary counselling of families: serum cholesterol concentration and growth of children aged 7–13 months

We studied the effect of a change in dietary fat composition on serum total and high-density lipoprotein cholesterol and growth in healthy infants between 7 and 13 months of age. The intervention families ( n = 22) received individualized dietary counselling when the infant was 7, 8 and 10 months of age. The intervention diet was designed to have a fat content of 35–45 E%, of total energy intake in infants aged 7–12 months and 30–35 E% after 12 months of age. The ratio of saturated to monounsaturated to polyunsaturated fatty acids was designed to be 1:1:1. The children in the control group ( n = 23) were given no specific advice on the fat composition of the diet. Intake of polyunsaturated fatty acids was significantly higher in the intervention group than in the controls (5.9 E% versus 3.6 E%, p < 0.05). Serum total cholesterol concentration decreased significantly in the intervention group during the study from 4.16± 0.41 mmol/l to 3.86 ± 0,48 mmol/l ( p < 0.05). The infants of both groups grew like average Finnish children. Modification of dietary fat composition, as widely recommended for adults and older children to prevent coronary heart disease, decreases cholesterol values in infants without affecting their normal growth.     

Randomized double-blind controlled trial on the effects on iron status in the first year between a no added iron and standard infant formula received for three months

Recent research has not only questioned the necessity of iron supplementation in human milk substitutes prior to weaning, but also suggested some potential adverse effects. This study investigated the hypothesis that infant formula need not contain added iron in the first 3 mo. Healthy term infants were recruited into a double-blind controlled trial and randomized to receive either a new no added iron formula (New; <0.1 mg Fe 100 ml(-1)) or a standard formula (Standard; 0.5 mg Fe 100 ml(-1)) for the first 3 mo of life. A breastfed reference group was also studied. Iron status was assessed at 3 and 12 mo from heel-prick capillary blood samples evaluated by full blood-count analysis, including reticulocytes and serum ferritin. In total, 149 infants were entered (51 New, 49 Standard, 49 breastfed) with no differences between the groups in gender distribution, birthweight, gestation or numbers completing the study. There were no significant differences between the principal outcome measures: mean values for haemoglobin, mean cell volume and ferritin, between the two formula-fed groups, and the proportion with a haemoglobin level <11 g dl(-1) or ferritin <10 microg l(-1) did not differ. CONCLUSION: The use of a "no added iron" infant formula in place of an iron-fortified formula during the first 3 mo of life did not clinically affect iron status at 3 and 12 mo of age. The universal supplementation of formulae with iron during this initial period needs further consideration.     

Growth under privileged conditions of healthy Swedish infants exclusively breastfed from birth to 4-6 months: a longitudinal prospective study based on daily records of feeding

Aim: In most studies the methodology used to study growth in relation to breastfeeding patterns cannot ensure that exclusive breastfeeding has in fact occurred since birth. The aim of this study was to investigate the growth of healthy infants in Sweden in whom exclusive breastfeeding for the first 4-6 mo was ascertained through daily feeding records and to compare the results with the World Health Organization (WHO) "12-month breastfed pooled data set" and the Euro-Growth references for exclusively breastfed infants, as well as with the National Center for Health Statistics (NCHS)/WHO reference. Methods: 147 exclusively breastfed infants and 325 non-exclusively breastfed Swedish infants, with a birthweight of 33 kg, were included. The mothers had previous breastfed at least one infant for at least 4 mo. Weight was recorded fortnightly and length monthly. Results: Infants exclusively breastfed since birth showed similar growth in weight and height to that of the non-exclusively breastfed infants. During the first 6 mo of life the growth of exclusively breastfed infants was also similar to that of the infants regularly receiving formula at 12-16 wk of age, mostly in addition to breast milk. The monthly growth increments were fairly similar to those of the "WHO pooled breastfed data set" and the Euro-Growth references for exclusively breastfed infants. Conclusion: In an affluent society truly exclusively breastfed infants seem to have the same growth during the first half year of life as non-exclusively breastfed infants with a high breastfeeding rate.     

Association of 6 months of exclusive breastfeeding with higher fat‐free mass in infants in a low‐resource setting with high HIV prevalence in South Africa

Exclusive breastfeeding for 6 months is recommended by the World Health Organisation (WHO) for optimal health and growth of infants, but it is not a common practice in South Africa. A breastfeeding counselling programme was run to inform, encourage and support mothers to exclusively breastfeed their infants for 6 months, and mother–infant pairs were invited to participate in a research project to determine breast milk intake volumes using the dose‐to‐mother deuterium dilution stable isotope technique. This technique yields objective measurements of breast milk intake volumes and also enables determination of exclusivity of breastfeeding, which is most frequently determined by maternal recall and can be subject to bias. Exclusivity of breastfeeding at 6 weeks, 3 months and 6 months following birth of the infants was correlated with infant fat‐free mass at 12 months, which was determined by the dose‐to‐infant deuterium dilution stable isotope technique. Results showed that infants who were exclusively breastfed for 6 months had a higher per cent fat‐free mass at 12 months compared with infants who were not exclusively breastfed for 6 months (P < 0.05). This objective determination of both breastfeeding patterns and infant body composition gives weight to the WHO recommendation of exclusive breastfeeding for 6 months as it demonstrated adequate fat‐free mass in infants at 12 months, even in an area with high HIV prevalence. © 2016 John Wiley & Sons Ltd     

Differential modulation of the immune response by breast- or formula-feeding of infants

Spontaneous integrin expression on CD4+, CD8+ and CD19+ lymphocytes at 6 months was significantly lower in breastfed than formula-fed infants ( p < 0.05). In another study of 59 formula-fed and 64 breastfed 12-month-old children blast transformation and cytokine production by lymphocytes, and T cell changes were measured before and after measles-mumps-rubella vaccination (MMR). Before vaccination, lymphocytes of breastfed children had lower levels of blast transformation without antigen ( p < 0.001), with tetanus toxoid ( p < 0.02) or Candida ( p < 0.04), and lower interferon-γ production ( p < 0.03). Fourteen days after the live viral vaccination, only the breastfed children had increased production of interferon-γ ( p < 0.02) and increased percentages of CD56+ ( p < 0.022) and CD8+ cells ( p < 0.004). These findings are consistent with a Thl type response by breastfed children, not evident in formula-fed children. Feeding mode has an important long-term immunomodulating effect on infants beyond weaning.     

Maternal weight and sire group, not caloric intake, influence adipocyte volume in infant female baboons.

We tested the hypothesis that overfeeding with a high caloric (concentrated) formula increases growth without influencing adipocyte volume in preweaning infant baboons. Female infant baboons from three sires and 25 dams were fed either 67.5 kcal (normal formula) or 94.5 kcal (concentrated formula)/100 g Similac formula. Immediately before weaning (19 wk), adipocyte volume was measured in biopsied adipose tissue from omentum, flank, and popliteal depots. From birth until weaning, infants fed the concentrated formula consumed 20% more total calories, averaged 15% more calories/kg/wk, and gained 14% more weight than normally fed infants. Adipocyte volume differed significantly among different sites (omentum greater than popliteal greater than flank) and among different sire groups. Increased caloric intake alone did not increase adipocyte volume. There was a small but significant sire by infant formula interaction on adipocyte volume. When fed the concentrated formula, progeny from one sire had larger adipocytes than normally fed infants, whereas progeny from the other two sires had smaller adipocytes or adipocytes that were comparable to infants fed normal formula. Variability in adipocyte volume at 19 wk of age was best accounted for by maternal weight and sire group (omentum R2 = 0.334, p = 0.026; flank R2 = 0.532, p = 0.01; popliteal R2 = 0.482, p = 0.01) and not by caloric intake. These results suggest that the level of triglyceride deposition into adipocytes attained during preweaning growth is determined to a greater extent by genetic and other factors rather than caloric intake.     

Iron supplements reduce erythrocyte copper-zinc superoxide dismutase activity in term, breastfed infants

AIM: To investigate whether iron supplements compromise copper status in infants. METHODS: 214 healthy, term, breastfed Swedish and Honduran infants were randomized to (1) iron supplements (1 mg/kg/d) from 4-9 mo of age, (2) iron supplements from 6-9 mo, or (3) placebo. Blood samples were obtained at 4, 6, and 9 mo and analyzed for plasma copper (p-Cu) and, at 9 mo, for copper/zinc-dependent superoxide dismutase (CuZn-SOD) activity. RESULTS: P-Cu increased with infant age. At 9 mo, Honduran infants had significantly higher p-Cu (1.40+/-0.29 vs 1.09+/-0.22 mg/l, p<0.001) and CuZn-SOD activity (1.09+/-0.29 vs 0.93+/-0.21 U/mg Hb, p<0.001) than Swedish infants. Infants receiving iron supplements from 4-9 mo had significantly lower CuZn-SOD at 9 mo of age (0.95+/-0.27 vs 1.08+/-0.24 U/mg Hb, p=0.023) than those receiving placebo.CONCLUSION: There is a physiologic increase in p-Cu during the first 9 mo of life. Differences in copper status between Swedish and Honduran infants may be due to genetic or nutritional differences. Iron supplementation decreases CuZn-SOD activity, probably due to a negative effect on copper status. Possible clinical implications remain to be elucidated.     

Introduction of solids and formula to breastfed infants: a longitudinal prospective study in Uppsala, Sweden

The introduction of solids and formula was studied among 506 breastfed infants in Uppsala, Sweden, based on daily recordings during the first year. The mothers had previously breastfed at least 1 infant for at least 4 mo. Thirty-four per cent of the infants were introduced to solids before the age of 4 mo (4-6 mo is recommended in Sweden). Accustoming the infants to solids was a lengthy process. Life-table analyses showed a median duration of 28 d from the first introduction of solids to consumption of >10 ml daily, and 46 d before the infants ate > or = 100 ml of solids in 1 d for the first time. These durations were longer the younger the infant was at the introduction of solids. Thirty-two per cent of infants given formula consumed > or = 100 ml the first time it was given, and 49% did so within I wk, regardless of infant age. CONCLUSION: Parents and healthcare personnel need to be aware that accustoming breastfed infants to solid food is a lengthy process, and that there is a strong age effect on this duration. It is also important to consider what consequences the (usually) more abrupt introduction of formula might have on breastfeeding.     

The impact of peripartum factors on the onset and duration of lactation

Knowledge of peripartum indicators of those mother-infant pairs that are at increased risk of early failure of lactation may improve specific support of breastfeeding. Mode of delivery, labor complications, hyperbilirubinemia, milk intake and weight development were evaluated in healthy term infants in a hospital (n = 338). Delayed onset of lactation was observed in primiparae and in study participants with peripartum complications. The quantitative intake of human milk, assessed by test weighing 0-24 h and 24-48 h after the onset of lactation, was not significantly different between these groups. In addition, volume intake, weight gain and lactation success were tracked in 77 infants. Partial feeding of infant formula or an intake of <150 g of human milk per day 24-48 h after the onset of lactation was linked to weaning within 4 weeks. Ninety-one percent of the infants were exclusively breastfed at discharge; this value had declined to 49, 35 and 20% at 4, 12 and 20 weeks, respectively. Peripartum factors may contribute to early lactation failure; the long-term success of breastfeeding was predominantly determined outside the hospital.     

Effect of formula carbohydrate concentration on tolerance and macronutrient absorption in infants with severe, chronic diarrhea

To determine how the carbohydrate (CHO) content of "semielemental" formulas affects tolerance and macronutrient absorption, we enrolled 12 infants with severe diarrhea in two successive metabolic balance studies. The infants received, in random order, one of two isocaloric formulas that differed mainly in their CHO and fat concentrations. No significant differences were found between the two feeding periods for peak breath hydrogen levels and fecal osmolality. The low-CHO formula was tolerated better than the high-CHO formula, as indicated by a significantly lower stool output (mean +/- SD 387 +/- 230 vs 764 +/- 443 gm, respectively; p less than 0.05), and higher fecal pH (5.9 +/- 0.7 vs 4.9 +/- 0.5; p less than 0.05). Macronutrient absorption was greater during the ingestion of the low-CHO formula, as indicated by a significantly higher coefficient of fat absorption (p less than 0.005) and lower total fecal energy (mean +/- SD for high- vs low-CHO formula, 372 +/- 205 vs 207 +/- 102 kcal; p less than 0.05), which resulted from a lower CHO excretion (p less than 0.05). A correlation coefficient between the energy derived from CHO in feces and the total stool output was significant for both the high-CHO formula (r = 0.83; p less than 0.001) and the low-CHO formula (r = 0.7; p = 0.01). The CHO concentration of the special infant formula that we tested had an overriding effect on stool output and on fat and energy absorption.     

Breastfeeding and weaning practices in relation to nutritional status of infants.

During the critical period of infancy, breastfeeding and weaning practices play an important role in determining the growth of an infant. The present study investigates the issue by observing 225 infants from Low Socio Economic (LSE) class (n = 150) and High Socio Economic (HSE) class (n = 75) for weight, height, and feeding practices. Almost all artificially fed (AF) infants in LSE class were malnourished while this was not so in the HSE class. However, the proportion of malnourished children in the LSE class for partially breastfed (BF + AF) group was comparable with exclusively breastfed (BF) group and was significantly lower (p < 0.01) than AF group indicating protective effect of partial breastfeeding against risks of contamination associated with weaning foods in such communities: The real bottleneck thus appears to be the lack of knowledge of handling and giving weaning foods in adequate quantities. Educating mothers appears to be the meaningful solution for improving the nutritional status of infants in poor communities.     

Abnormalities in zinc homeostasis in young infants with cystic fibrosis

Low plasma zinc concentrations have been reported in approximately 30% of young infants with cystic fibrosis identified by newborn screening. The objective of this study was to examine zinc homeostasis in this population by application of stable isotope methodology. Fifteen infants with cystic fibrosis (9 male, 6 female; 7 breast-fed, 8 formula-fed) were studied at a mean (+/-SD) age of 1.8 +/- 0.7 mo. On d 1, 70Zn was administered intravenously, and 67Zn was quantitatively administered with all human milk/formula feeds during the day. Three days later, a 3-d metabolic period was initiated, during which time intake was measured and complete urine and fecal collections were obtained. Fractional zinc absorption, total absorbed zinc, endogenous fecal zinc, and net absorbed zinc were measured; fecal fat excretion was also determined. Fractional absorption was significantly higher for the breast-fed infants (0.40 +/- 0.21) compared with the formula-fed group (0.13 +/- 0.06) (p = 0.01), but with the significantly higher dietary zinc intake of the formula-fed group, total absorbed zinc was higher for those receiving formula (p = 0.01). In 1 infants with complete zinc metabolic data, excretion of endogenous zinc was twofold greater for the formula-fed infants (p < 0.05); net absorption (mg zinc/d) was negative for both feeding groups: -0.04 +/- 0.52 for breast-fed; -0.28 +/- 0.57 for formula-fed. Endogenous fecal zinc losses correlated with fecal fat excretion (r = 0.89, n = 9, p = 0.001), suggesting interference with normal conservation of endogenously secreted zinc. These findings indicate impaired zinc homeostasis in this population and suggest an explanation for the observations of suboptimal zinc status in many young infants with cystic fibrosis prior to diagnosis and treatment.     

Thymic size in uninfected infants born to HIV-positive mothers and fed with pasteurized human milk

AIM: To examine the size of the thymus in uninfected infants born to HIV-positive mothers and to study the effects of feeding by human donor milk on the size of the thymus in these infants. METHODS: The absolute and relative thymic size was assessed by sonography as thymic index (Ti), and the Ti/weight-ratio (Ti/w) at birth and at 4 mo of age in 12 healthy uninfected infants born to HlV-infected mothers. All infants were exclusively fed pasteurized donor milk. The results were compared with those obtained from a previous cohort of exclusively breastfed, partially breastfed and exclusively formula-fed infants. RESULTS: At birth the Ti was reduced in infants born to HIV-infected mothers in comparison with that in control infants but this difference disappeared when their birthweights were taken into consideration (Ti/w-ratio). At 4 mo of age the geometric mean Ti of infants fed donor milk was 23.8 and the mean Ti/w-ratio was 4.2. Compared with those of exclusively breastfed infants, the Ti and Ti/w-ratio of infants fed donor milk were significantly reduced (p < 0.01). The Ti/w-ratio increased in donor-milk-fed infants compared with that in the formula-fed infants (p = 0.02). CONCLUSION: At birth the size of the thymus was smaller in uninfected infants of HIV-positive mothers compared with infants of HIV-negative mothers but when birthweight was taken into account this difference disappeared. Feeding by human donor milk seemed to result in an increased size of the thymus at 4 mo of age compared with thymic size in infants that were exclusively formula fed.     

Long-chain polyunsaturated fatty acids in Chinese and Swedish mothers: diet, breast milk and infant growth

Long-chain polyunsaturated fatty acids (LC-PUFAs) are essential dietary nutrients required for the optimal growth and development of infants, particularly of the brain and retina. It is important for exclusively breastfed infants to receive milk of a correct balance between omega-6 and omega-3 fatty acids. In this study, we compared the composition of LC-PUFAs in the diet and milk of mothers and their infants' growth between Chinese and Swedish. Twenty-three and 19 mother-term infant pairs from a rural area of northern Beijing, China, and Stockholm, Sweden, who were 3 mo old and exclusively breastfed, were studied. The Chinese diet was higher in carbohydrate (17% of energy) but lower in protein (4% of energy) and fat (12% of energy) than the Swedish diet. The intake of Chinese mothers contained more linoleic acid (LA, C(18 ratio 2 omega-6)) and less arachidonic acid (AA, C(20 ratio 4 omega-6)), eicosapentaenoic acid (EPA, C(20 ratio 5 omega-3)) and docosahexaenoic acid (DHA, C(22 ratio 6 omega-3)) than that of Swedish mothers. The breast milk of the Chinese mothers had significantly higher LA and lower EPA and DHA levels than that of the Swedish mothers. However, in Chinese breast milk the AA level was significantly higher than that in Swedish breast milk. The recommended ranges of the ratios of LA to alpha-linolenic acid (LNA, C(18 ratio 3 omega-3)) and of AA to DHA in human milk are 5-10 and 0.5-1 compared with 23.0 and 3.1 in the Chinese breast milk, and 7.5 and 1.6 in the Swedish breast milk, respectively.Conclusion: The diet of the studied Chinese mothers is less balanced with regard to the levels of omega-6 and omega-3 polyunsaturated fatty acids (PUFAs) than that of the Swedish mothers, which is also mirrored in the breast milk of these mothers. The clinical relevance of the difference between the levels of LC-PUFAs in the breast milk of Chinese and Swedish mothers may be elucidated by a follow-up study of the cognitive and visual functions of the infants involved.