Infant Milk Intake Research Articles

Effects of Single-Hole and Cross-Cut Nipple Units on Feeding Efficiency and Physiological Parameters in Premature Infants

The purpose of this study was to compare the amount of total milk intake, feeding time, sucking efficiency, heart rate (HR), respiratory rate (RR), and oxygen saturation (SpO2) of premature infants when fed with either signal-hole or cross-cut nipple units. Twenty stable infants admitted to a level II nursery in a tertiary care center with gestational ages averaging 32.2+/-3.2 wks were enrolled. Subjects had an average postmenstrual age of 34.1+/-1.6 wks, and average body weight of 1996+/-112 gm. A crossover design was used and infants were observed for two consecutive meals separated by a four-hour interval. They were bottle fed with equal feeding amounts using a single-hole and cross-cut nipple administered in random order. Results showed that infants fed with single-hole nipple units took more milk (57.5+/-8.3 ml vs. 51.6+/-9.5 ml, p=.011), had a shorter feeding time per meal (11.5+/-4.9 min vs. 20.9+/-5.0 min, p<.001), and sucked more efficiently (5.8+/-2.5 ml/min vs. 2.7+/-1.0 ml/min, p<.001) compared to those fed through cross-cut nipples. Infants using cross-cut nipple units had a higher RR (44.4+/-4.6 breaths/minutes vs. 40.8+/-4.9 breaths/minutes, p=.002) and SpO2 (96.1+/-1.4% vs. 94.6+/-3.2%, p=.044) than those using single-hole nipples. Oxygen desaturation (SpO2<90% and lasting for longer than 20 sec) and bradycardia were not recorded in either group of infants during feeding. Compared to using cross-cut nipple units, premature infants using single-hole nipple units take more milk and tend to tolerate feedings better. A single-hole nipple may be a choice for physiologically stable bottle-fed premature infants.

Accuracy and precision of test weighing to assess milk intake in newborn infants

Background: Test weighing is commonly used to estimate milk intake in newborn infants. Objective: To assess the accuracy and precision of test weighing in clinical practice. Methods: Infants fed by...

Assessment of Body Composition and Breast Milk Volume in Lactating Mothers in Pastoral Communities in Pokot, Kenya, Using Deuterium Oxide

Background: In sub-Saharan Africa, the practice of breast-feeding infants is common. Records documenting the intake of breast milk amongst infants are limited. This study evaluated the association between maternal body composition and the intake of breast milk in infants from the pastoral communities within Pokot, Kenya. Methods: The study was conducted in 10 lactating mothers who were participating in a longitudinal study aimed at determining maternal body composition, iron stores and vitamin A status during the third trimester pregnancy and four months after they had given birth. Maternal and infant anthropometric measurements were made, and maternal blood samples were taken to determine serum retinol and ferritin levels. Infant milk intake and maternal fat-free mass (FFM) and percent body fat (% BF) were measured using ‘the dose to the mother method’. A measured deuterium oxide (²H₂O) dose was given to the mother. Urine and breast milk from the mother, and saliva samples from the infant, were collected on days 1, 8 and 14 after dosing. Results: The mean (± SD) maternal mid upper arm circumference (MUAC) and body mass index (BMI) were 21.8 (0.9) cm and 18.6 (1.0) kg/height (m²), respectively. Infant weight and weight/age Z score were 4.956 (0.874) kg and –1.750 (0.77), respectively. Throughout the study, the infants gained 20 (4) g/day in body weight and had a milk intake of 555 (22) ml/day. The energy intake of the infant was 1,602 (148) kJ/day and was lower (p < 0.05) than the 2,404 (423) kJ/day estimated requirement by the FAO/WHO/UNU. The maternal FFM, %BF, Hb, Hct, ferritin and retinol were 32.8 (3.1) kg, 17.24 (7.0), 11.5 (1.3) g/dl, 33.9 (4.9), 16.2 (0.1) µg/l and 0.894 (0.16) µmol/l, respectively. Infant milk intake was significantly and positively correlated to maternal pregnancy triceps (r = 0.679) p < 0.05) and pregnancy MUAC (r = 0.725) p < 0.05). Maternal pregnancy MUAC was an important predictor of infant breast milk intake. Conclusion: Data on volume of breast milk consumed by the infants suggests, at least for this group of infants, that adequate growth may not be achieved. There is a possibility that lactating mothers practicing exclusive breast-feeding and living under harsh conditions may experience periods of low breast milk volume. Body composition and biochemical findings among this group of Pokot mothers indicate dietary inadequacies that require nutritional intervention.

Infant diet and type 1 diabetes in China

Infant milk and food introduction may be linked to type 1 diabetes risk in high incidence populations. Dietary data through age 12 months was collected for 247 type 1 diabetic cases and 443 controls in China, a low incidence population, to determine if milk and solid food intake differed. Age range at introduction to milk and formulas was similar in cases and controls but solid food introduction more often occurred before age 3 months in cases. Logistic regression analyses showed soy milk formula consumption at 4–6 (OR=2.0; 95% CI: 1.1–3.4) and 7–12 months of age (OR=1.5; 95% CI: 1.0–2.1) was associated with a twofold higher risk of type 1 diabetes, while steamed bread consumption (4–6 months, OR=0.44; 95% CI: 0.28–0.68; 7–12 months, OR=0.48; 95% CI: 0.34–0.69) and higher SES (4–6 months, OR=0.55; 95% CI: 0.39–0.78; 7–12 months, OR=0.57; 95% CI: 0.40–0.83) were negatively associated. Drinking cow’s milk at 7–12 months (OR=0.60; 95% CI: 0.43–0.85) was negatively associated with type 1 diabetes while consuming vegetables at 4–6 months (OR=1.5; 95% CI: 1.0–2.2) was positively associated. Results suggest that infant milk and solid food intake are associated with type 1 diabetes in China. Prospective studies may determine how these dietary factors impact disease etiology, particularly for at-risk-populations.

Ultrasound imaging of milk ejection in the breast of lactating women.

Currently, the methods for assessing milk ejection in women include serial sampling of plasma oxytocin and measurement of intraductal pressure, both of which are invasive and may induce stress. We hypothesized that milk ejection would cause an increase in milk-duct diameter that could be observed noninvasively with ultrasound, and this could be used to investigate the physiology of milk ejection in women. One milk duct was scanned in the unsuckled breast in 2 groups of mothers: group BB (n = 21) for the beginning of a breastfeed and group EB (n = 24) for the entire breastfeed. A duct also was monitored for a 5-minute period on 2 separate days in the absence of factors that may induce milk ejection in group EB to provide a baseline duct diameter. Milk intake at a breastfeed was measured by test weighing. A significant increase in milk-duct diameter was observed when milk ejection was sensed and/or the infant changed its swallowing pattern in both groups. Multiple increases and decreases (mean: 2.5 per breastfeed; standard deviation: 1.5; n = 62) in duct diameter occurred in group EB. Duct diameter remained relatively stable between breastfeeds (coefficient of variation: 1.4%-8.3%). Infant milk intake was positively related to the number of milk ejections (r2 =.365; n = 57). Ultrasound is an objective, noninvasive technique for detecting milk ejection by observing an increase in milk-duct diameter. However, this technique requires an experienced ultrasonographer, adequate imaging time, and surroundings conducive to breastfeeding. Multiple milk ejections were common during breastfeeding, although they were not sensed by mothers. The number of milk ejections influenced the amount of milk the infant consumed.

Monthly Growth and Milk Intake of Japanese Infants Exclusively Breast-fed up to Three Months Old

The recent reports pointed out that growth of breast-fed infants in the early stage, up to the 3rd month in particular, is faster than the widely used WHO/CDC standards, though the interrelations between their growth and the amount of milk intake during the first 3 months have seldom been investigated. Based on the measurements of body weight and milk intake for 13 Japanese breast-fed babies on the 30th, 60th and 90th days after birth, this paper aims to compare their growth patterns with those in the previous reports, which treated Caucasians except one for Japanese, as well as the WHO/CDC standards. The comparison revealed that the breast-fed babies grow faster than the WHO/CDC standards in the first 2 months, attributing to their large amounts of milk intake. This study suggests necessity of making growth curves exclusively for breast-fed babies.

A Comparison of Intakes of Breast-Fed and Bottle-Fed Infants during the First Two Days of Life

Objective: In the first days of life, breast-fed infants consume minimal amounts of milk; this may be explained by substrate limitation (limited milk output) and/or by self-limitation (through low appetite and/or suck-swallow competency). The spontaneous milk intake of unrestricted formula-fed infants has not been studied to date. We compared the spontaneous formula intake of unrestricted formula-fed infants to that of breast-fed infants over the first 48 hours of life. We hypothesized that 1) spontaneous formula intake of unrestricted infants is much higher than that of breast-fed infants and 2) spontaneous formula intake correlates positively with gestational age or birthweight.Methods: We studied 43 healthy, term infants. By maternal choice, 15 infants were exclusively breast-fed and 28 were formula-fed ad libitum every four hours. Breast-fed infants were weighed before and one hour after initiation of feeding, and intake was calculated from the difference between the measurements and corrected individually for the infant’s normal postnatal decrease in body weight. Bottles offered to formula-fed infants contained 60 cc, and the remainder was carefully measured. Intakes were expressed as cc/kg/d, and weight changes as % of birthweight. Statistical methods included Student’s t tests and stepwise regression analysis.Results: Breast feeding on Day 1 was 9.6±10.3 (mean±SD) vs. 18.5±9.6 cc/kg/d in formula-fed infants (p=0.011); on Day 2 it was 13.0±11.3 vs. 42.2±14.2 cc/kg/d (p<0.001). Breast-fed infants lost significantly more weight on Day 2 (p=0.015). In multiple regression, when the dependent variable was the second-day intake, the significant independent variables were group (higher intake in the formula-fed group), weight loss (the higher the weight loss, the lower the intake), and first-day intake (the higher the first-day intake, the higher the second-day intake).Conclusion: Newborn infants offered formula ad libitum every four hours consumed much larger amounts than breast-fed infants fed according to the same schedule. In addition, weight loss was more marked in breast-fed infants on Day 2 of life.

Patterns of milk and food intake in infants from birth to age 36 months: the Euro-growth study.

Little detailed information is available on feeding practices of infants in Europe. The Euro-Growth Study is a longitudinal, observational, multicenter study of milk feeding, the introduction of complementary solid foods, and vitamin and mineral supplementation. Current practice is compared with international feeding recommendations. Healthy term infants (n = 2,245) were recruited at birth or during the first month of life. Dietary records were completed at the ages 1, 2, 3, 4, 5, 6, 9, 12, 18, 24, 30, and 36 months by semiquantitative dietary recall. At the age of I month, 52% of the infants were exclusively breast fed and 26% were exclusively formula fed. At the age of 9 months, 18% of infants were fed only cow's milk. At the ages of 3, 4, and 5 months, 50%, 67%, and 95% of infants were fed solid foods, respectively. Feeding practices vary considerably throughout Europe. High rates of breast-feeding initiation are found in Umea, Sweden, and in Athens, Greece; and low rates in Dublin, Ireland, in Toulouse, France, and in Glasgow, United Kingdom. The use of cow's milk as the main milk drink before the age of 12 months is still common in certain European centers.

Bone mineral density changes during lactation: maternal, dietary, and biochemical correlates

The objectives of this study were to characterize the effects of lactation and weaning on maternal bone mineral density (BMD) and on biochemical markers of bone turnover, and to determine the effects of dietary intake, milk output, and other maternal factors on changes in BMD. Twenty-six fully lactating and eight nonlactating women were followed longitudinally through 7 mo postpartum; the lactating women were followed through postweaning. Maternal dietary and supplement intake data, infant milk intake measurements, blood and urine samples, and midradius and L2-L4 vertebral BMD measurements were obtained 0.5, 3, 5, and 7 mo postpartum. Biochemical analyses included measurements of calciotropic hormones, 24-h urinary excretion of calcium, markers of bone formation and resorption, estradiol, and prolactin. Estimated maternal demands for calcium excretion in milk were met by a combination of high calcium intake (from diet and supplements, 1500 +/- 460 mg/d at 0.5 mo for lactating women) and a decline of approximately 4% in vertebral BMD between 0.5 and 3 mo postpartum. Postweaning BMD (n = 15) at this site approximated initial values. Two factors were positively associated with vertebral BMD, estradiol (P < 0.001) and calcium intake (P = 0.03), whereas two factors were negatively associated, parity (P = 0.03) and protein intake (P = 0.01). In these well-nourished women, the results suggest that the extent of bone loss associated with lactation and its recovery postweaning are negatively influenced by parity. The results also suggest that the bone loss may be attenuated by a generous dietary ratio of calcium to protein.

Human milk intake and growth faltering of rural Mesoamerindian infants

To determine whether growth faltering during early infancy was attributable to inadequate intake of human milk, the nutrient intakes and growth of 30 Otomi infants from Capulhuac, Mexico, were studied at 4 or 6 mo of age. Growth was monitored monthly from 1 through 6 mo of age. The 2H dose-to-the-mother method was used to measure human milk intake. Energy, protein, lactose, and fat concentrations in milk were analyzed by standard techniques. Mean (+/- SD) human milk intakes were 885 +/- 145 and 869 +/- 150 g/d at 4 and 6 mo, respectively. Protein and lactose concentrations in milk were normal but fat and consequently energy concentrations were abnormally low. Energy intakes averaged 81 +/- 14 kcal.kg-1.d-1 at 4 mo and 72 +/- 14 kcal.kg-1.d-1 at 6 mo. Growth faltering by 6 mo was evidenced by the significant decline in growth velocities and National Center for Health Statistics Z scores. Weight gain at 6 mo was 8.1 +/- 3.5 g/d and length gain was 1.0 +/- 0.34 cm/mo. Weight-for-age and length-for-age Z scores were -0.81 +/- 0.94 and -1.51 +/- 0.83, respectively. Growth velocities were not significantly correlated with nutrient intakes. Growth faltering among the Otomi infants despite energy intakes comparable to those of breast-fed infants in more protected environments may have resulted from an increase in the need for nutrients or from a growth-limiting nutrient, other than energy, in their diet.

Validation of the deuterium oxide method for measuring average daily milk intake in infants

The deuterium oxide elimination method for measuring average daily milk intake was validated against measured formula intake in 16 studies of 11 infants in a metabolic ward. Deuterium oxide (approximately 0.10 g/kg body wt) was given orally. Deuterium enrichment was measured in urine samples collected predose, as available for 6-h postdose for TBW determination, and at 24 h and 5-10 d postdose for HDO elimination calculated according to the two-point method. Urine samples were vacuum distilled, water was reduced to hydrogen gas, and deuterium enrichment was measured by isotope-ratio mass spectrometry. Milk intake was measured throughout the elimination period from prefeeding and postfeeding bottle weights (n = 12) or volumes (n = 4). Without corrections for atmospheric water influx, milk intake was overestimated by 76 g/d (6%). With corrections for estimated metabolic water production, isotopic fractionation, and atmospheric water influx, deuterium measured 98% +/- 3% or 1300 g milk intake/d compared with actual milk intake of 1329 +/- 206 g/d.

Measurement of the milk intake of breast-fed infants.

Infant test weighing and maternal test weighing are two independent methods for determining milk intake by the breast-fed infant. The sources of error in both these test weighing methods were examined with particular emphasis on the importance of evaluating and correcting for evaporative water loss (EWL). EWL ranged from 3 to 94% of the mother's change in weight after a single breast feed and from 3 to 55% of the infant's change in weight after a single breast feed. Correcting for EWL during a breast feed involved determining the time between the pre- and postfed weighings and measuring the rate of EWL after breast feeding. Significant correlations (p less than 0.001) were found between milk volume intake measured by test weighing the mother and correcting for maternal EWL, and milk volume intake measured by test weighing the infant and correcting for infant EWL. An improved method for measuring 24-h milk intakes by maternal test weighing using a sensitive electronic balance and correcting for EWL is described. The milk intakes, corrected for EWL, ranged from 690-1,041 g/24 h. If no correction for EWL was made then the average overestimate of milk intake by maternal test weighing was 14 +/- 6%.

Growth, body composition and breast milk intake of Swedish infants during early life

The growth and breast milk intake of 22 healthy completely breast fed Swedish infants (9 girls, 13 boys) during the first 10 wk of life are reported and were found to be similar to those of other healthy breast fed populations of infants. Also the body composition (body fat and lean body tissue) was estimated by an anthropometric method at the age of about 10 and 65 days. It was found that the breast milk intake correlated significantly with weight and fat gain but not with gain in lean body tissue or with gain in length. These findings suggest that energy rather than protein intake limited growth in this group of infants. Also the results confirm the fact that the capacity for fat retention is high during early life and show that the size of fat stores is related to breast milk intake.

Breast Milk Volume and Composition During Late Lactation (7–20 Months&gt;

Breast milk composition of 119 samples collected by 46 women during months 7–20 of lactation was compared with composition of 101 samples collected at 4–6 months. Breast milk intake of 10 infants was determined by test‐weighing for 1 or more months during months 7–16 of lactation. Longitudinal decreases in milk concentrations of zinc, copper, and potassium, previously documented for the first 6 months, continued into the second 6 months, while protein, iron, and sodium concentrations showed no further decline. Lactose, fat, calcium, and magnesium concentrations were similar to those in earlier stages of lactation. Weaning was associated with significant changes in milk composition: When milk volume fell below 300 ml/day, there was an increase in protein and sodium and a decrease in lactose, calcium, and zinc. Breast milk intake of infants not supplemented with cow's milk or formula averaged 875 ml/day (93% of total energy intake) at 7 months and 550 ml/day (50% of total energy intake) at 11–16 months. Total energy intake increased from 610 to 735 kcal/day, but energy intake per kilogram remained constant at a relatively low 70–79 kcal/kg/day. Our results suggest the need for further studies of nutrient intake and requirements of breast‐fed infants during late lactation.

Breast milk volume and composition during late lactation (7-20 months).

Breast milk composition of 119 samples collected by 46 women during months 7-20 of lactation was compared with composition of 101 samples collected at 4-6 months. Breast milk intake of 10 infants was determined by test-weighing for 1 or more months during months 7-16 of lactation. Longitudinal decreases in milk concentrations of zinc, copper, and potassium, previously documented for the first 6 months, continued into the second 6 months, while protein, iron, and sodium concentrations showed no further decline. Lactose, fat, calcium, and magnesium concentrations were similar to those in earlier stages of lactation. Weaning was associated with significant changes in milk composition: When milk volume fell below 300 ml/day, there was an increase in protein and sodium and a decrease in lactose, calcium, and zinc. Breast milk intake of infants not supplemented with cow's milk or formula averaged 875 ml/day (93% of total energy intake) at 7 months and 550 ml/day (50% of total energy intake) at 11-16 months. Total energy intake increased from 610 to 735 kcal/day, but energy intake per kilogram remained constant at a relatively low 70-79 kcal/kg/day. Our results suggest the need for further studies of nutrient intake and requirements of breast-fed infants during late lactation.

Breastfeeding Performance and Child Survival

This paper reviews factors influencing the impact of breastfeeding on child survival and details issues in the measurement of the nutrient intake anti-infective properties and contraceptive effect of breastfeeding. It is argued that a better understanding of what benefits breastfeeding brings in a specific environment will help policy makers to assess its value and to identify likely problems associated with not breastfeeding in the individual setting. The duration of breastfeeding and timing of introduction of supplements the pattern of suckling the type and manner in which supplements are given and the infection load within the environment all influence breastfeeding performance and its impact on child health and child survival. Each of these factors is discussed and documented in detail. Direct and indirect measurements of the impact of breastfeeding are examined by focusing on 1) nutrient intake in relation to quantity of breast milk; 2) the anti-infective properties of breast milk; and 3) the contraceptive effect of breast feeding through post partum abstinence and birth spacing. Several methods of measuring infant milk intake and lactation performance have been used with varying success. They include mechanical measures of milk from the breast (most direct); weighing the baby before and immediately after the breastfeeding session; the deuterium dilution technique a noninvasive approach to measuring breast milk intake; and an assessment of adequate child growth. Measurement of the anti-infective properties of breast milk needs to take into account both the direct (immunologic) and indirect (sterile) benefits. Because of the difficulties of measuring ovulation under field conditions the period of anovulation is usually estimated by the duration of postpartum amenorrhea. The use of suckling frequency to determine when resumption of menses is likely to occur within a population is probably the most accurate indirect means of measurement though not the most practical. Through the use of data on breastfeeding patterns demographers have used mathematical formulas to estimate the duration of amenorrhea. To assess the effect of breastfeeding on child survival through its birth spacing effect it would be necessary to compare populations who stop breastfeeding early with those who stop later within the same sociocultural group. Finally in attempting to make comparisons of populations undergoing changes in the duration of breastfeeding the impact of societal factors affecting child nutrition and health must be considered. As modernization occurs the duration of breastfeeding is often reduced. However findings suggest that the influence of breastfeeding on child survival is dependent on the local ecological context and on how it influences the intervening variables such as differences in availability of health services.

Milk and nutrient intake of breast-fed infants from 1 to 6 months: relation to growth and fatness.

Dietary intake, milk composition, growth, and activity were monitored monthly for 20 breast-fed infants from 1 to 6 months. Breast milk intake (of infants receiving no more than 50 kcal from other foods) ranged from 341 to 1,096 ml/day, with mean intake increasing from 673 to 896 ml/day from 1 to 6 months. Energy intake per kilogram body weight averaged 113 kcal/kg/day at 1 month, decreasing to 85-89 kcal/kg/day at 5-6 months--considerably lower than the recommended 115 kcal/kg/day. At 6 months, all infants except one were above the 10th percentile of weight-for-age. Nutrient content of milk samples was similar to previously reported values. Protein, iron, zinc, copper, sodium, and potassium levels declined during the first 6 months. Intakes of iron, zinc, calcium, and magnesium were lower than recommended allowances for infants. Weight-for-length and weight gain were significantly correlated with total energy intake, but not with activity level, during the first 6 months.

Milk and Nutrient Intake of Breast‐Fed Infants from 1 to 6 Months

Summary:Dietary intake, milk composition, growth, and activity were monitored monthly for 20 breast‐fed infants from 1 to 6 months. Breast milk intake (of infants receiving no more than 50 kcal from other foods) ranged from 341 to 1,096 ml/day, with mean intake increasing from 673 to 896 ml/day from 1 to 6 months. Energy intake per kilogram body weight averaged 113 kcal/kg/day at 1 month, decreasing to 85‐89 kcal/kg/day at 5‐6 months—considerably lower than the recommended 115 kcal/kg/day. At 6 months, all infants except one were above the 10th percentile of weight‐for‐age. Nutrient content of milk samples was similar to previously reported values. Protein, iron, zinc, copper, sodium, and potassium levels declined during the first 6 months. Intakes of iron, zinc, calcium, and magnesium were lower than recommended allowances for infants. Weight‐for‐length and weight gain were significantly correlated with total energy intake, but not with activity level, during the first 6 months.

Evaluation of the deuterium dilution technique against the test-weighing procedure for the determination of breast milk intake

A noninvasive isotopic method for the determination of milk intake in breast-fed infants was evaluated against the conventional method of test-weighing. In experiment 1, 48-h breast milk intake was estimated concurrently by the test-weighing procedure and by the deuterium dilution technique. In experiment 2, the isotopic method, modified to minimize fluctuations in water flux, was evaluated against a 24-h test-weighing. In experiment 1, the mean 48-h milk intake estimated by the isotopic method (1616 +/- 353 ml) was significantly higher than that measured by the test-weighing procedure (1449 +/- 234 ml) (p less than 0.01). In experiment 2, 24-h milk intake as determined by test-weighing and deuterium dilution averaged 878.0 +/- 188.1 and 690.7 +/- 141.4 ml/day, respectively, and differed significantly (p less than 0.001). The ability of the deuterium dilution method to predict values obtained by the test-weighing procedure was unsatisfactory for individual estimations. These experiments indicate that the deuterium dilution technique is unacceptable for the determination of breast-milk intake in individuals, but may be satisfactory for a population estimation.

Study on lactation performance of Burmese mothers

Quantity and proximate composition of breast milk from Burmese mothers of low socioeconomic group at three stages of lactation were studied. Protein content (total N X 6.38) of breast milk at 1 to 4 months of lactation was significantly higher than that of 7 to 12 months but there were no significant differences in milk fat, lactose, and energy among three stages of lactation. No significant differences in proximate composition of breast milk were observed between well-nourished and malnourished groups. Potential milk output of mothers belonging to well-nourished group was significantly higher than the corresponding values for milk intake of infants.