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Biomedical subjects

S E Carlson

Publications and source records attributed to S E Carlson.

At least 37 records · Page 2Linked to original sources
PubMed1996

Effect of long-chain n-3 fatty acid supplementation on visual acuity and growth of preterm infants with and without bronchopulmonary dysplasia.

Healthy preterm infants fed formula with long-chain n-3 fatty acids (n-3 LCFAs) from marine oil have better early visual acuity but lower plasma phosphatidylcholine (PC) arachidonic acid (AA) and growth than infants fed formula containing linolenic acid (LLA) as the sole n-3 fatty acid. This randomized, double-blind trial was designed to study the effects of a different source of n-3 LCFAs and a shorter feeding interval on visual acuity (by Teller Acuity Card) and growth of preterm infants (n = 59; 747-1275 g birth wt), some of whom required long periods of supplemental oxygen and developed bronchopulmonary dysplasia (BPD). Infants were studied at 0, 2, 4, 6, 9, and 12 mo past term. Plasma PC AA, and normalized weight, length, and head circumference were not influenced by BPD or n-3 LCFAs except that n-3 LCFA-supplemented infants weighed less at 6 (P<0.05) and 9 (P<0.01) mo and had smaller head circumferences at 9 mo (P<0.05). Compared with control infants, however, those fed n-3 LCFAs had lower weight-for-length at 2, 6, 9, and 12 mo (P<0.0003, P<0.0114, P<0.0008, and P<0.006, respectively). n-3 LCFAs improved early (2-mo) but not later acuity among infants without BPD (P<0.02). Regardless of diet, infants with BPD had poorer grating acuity at 2 (P<0.0002) and 4 (P<0.04) mo but not thereafter.

Arachidonic Acid↗
PubMed1996

Arachidonic acid status of human infants: influence of gestational age at birth and diets with very long chain n-3 and n-6 fatty acids.

In three randomized, double-blind clinical trials, preterm infants were fed typical preterm or term formulas and experimental formulas supplemented with n-3 and n-6 long-chain fatty acids. The effect of these feedings on the concentration of plasma phosphatidylcholine arachidonic acid (AA), an indicator of AA status, was contrasted with equivalent data from infants born at term. Preterm infants appear to have poorer AA status than breast-fed term infants at the corrected ages of 0 and 2 mo. The addition of marine oil eicosapentaenoic acid (EPA) (0.3%) and docosahexaenoic acid (DHA) (0.2%) to formula further decreased AA status (Study 1). The same amount of marine oil DHA (0.2%) but with less EPA (0.06%) fed for a shorter interval did not decrease plasma phosphatidylcholine AA concentration compared with controls (Study 2). Preterm infants fed both AA (0.43%) and DHA (0.1%) had better AA status than controls. These observations are discussed in relation to evidence from these same studies that AA status and the n-6/n-3 rates are related to growth of preterm infants.

Arachidonic Acid↗
PubMed1996

Visual acuity and fatty acid status of term infants fed human milk and formulas with and without docosahexaenoate and arachidonate from egg yolk lecithin.

Preterm infants fed formulas with docosahexaenoic acid (DHA, 22:6n-3) during the interval equivalent to the last intrauterine trimester and beyond have higher circulating DHA and transiently higher visual acuity compared with infants fed formulas containing linolenic acid. In term infants several nonrandomized studies of infants receiving DHA from human milk suggest a relationship between DHA status and acuity, but the evidence for a cause-and-effect relationship is mixed. In the present study, term infants were randomly assigned to a standard term formula (n = 20) or the same formula with egg yolk lecithin to provide DHA (0.1%) and arachidonic acid (AA, 20:4n-6, 0.43%) (n = 19) at levels reported in milk of American women. A third group of infants was breast fed for > or = 3 mo (n = 19). Grating visual acuity (Teller Acuity Card procedure) and plasma and red blood cell (RBC) phosphatidylcholine (PC) and phosphatidylethanolamine (PE) DHA and AA were determined at corrected ages of 2, 4, 6, 9 (acuity only), and 12 mo past term = 40 wk postmenstrual age (PMA). At 2 mo breast-fed infants and infants fed the supplemented formula had higher grating acuity than term infants fed standard formula. As in preterm infants, the increase was transient. Plasma PC DHA and AA and RBC PE AA increased by 2 mo in supplemented infants, but RBC PE DHA in supplemented infants was not higher than in controls until 4 mo and beyond. Despite normal intrauterine accumulation of DHA and AA, infants fed formula with 2% linolenic acid and 0.1% DHA had better 2-mo visual acuity than infants fed formula with 2% linolenic acid.

Arachidonic Acid↗
PubMed1995

Plasma mineral concentrations in preterm infants fed a nutrient-enriched formula after hospital discharge.

OBJECTIVE: To determine whether prolonged feeding of preterm infant formula to preterm infants can accelerate recovery to normal plasma zinc levels without affecting plasma mineral homeostasis. DESIGN: Part of concurrent prospective feeding trials in a university hospital-based population. SUBJECTS AND INTERVENTION: Preterm infants (n = 33; birth weight, 1037 +/- 157 gm) were fed a preterm infant formula with higher concentrations of zinc, copper, calcium, magnesium, and potassium until 2 months past expected term, then a term infant formula. Term infants (n = 38; birth weight, 3318 +/- 401 gm) fed this term infant formula from birth were a reference group for comparison with study infants and with published values. Plasma mineral levels were analyzed by inductively coupled plasma atomic emission spectroscopy. RESULTS: Preterm infants fed a preterm infant formula after discharge from the hospital appeared to achieve normal plasma zinc concentrations by at least 2 months past term without adverse effects on mineral homeostasis.

Adolescent↗
PubMed1995

Insulin-like growth factor (IGF)-I and IGF-binding protein 3 during the first year in term and preterm infants.

Plasma IGF-I and IGF-binding protein 3 (IGFBP-3) were determined by radioimmunoassay in term infants (n = 51) at 0, 2, 4, 6, and 12 mo and preterm infants (n = 51) at -3 (28.4 wk postconceptional age), -2, -1.5, -1, 0, 2, 4, 6, 9, and 12 mo from expected term. The effects of gestational age at birth (term or preterm) and study age were determined by repeated measures analysis of variance and Fisher's least squares difference. In preterm infants, IGF-I increased between -3 and 2 mo from 0.75 to 10.4 nM, decreased between 2 and 9 mo to 7.3 nM, and increased again between 9 and 12 mo to 10.1 nM (p < 0.0001), whereas IGFBP-3 increased relatively little from -3 to 0 mo (14.2 to 30.2 nM, p < 0.05) and plateaued from 2 to 12 mo (49.8 to 62.3 nM). At 0 mo, IGF-I and IGFBP-3 were the same in term and preterm infants, but preterm infants had higher IGF-I from 2 through 12 mo (p < 0.05), higher IGFBP-3 at 2 and 4 mo (p < 0.05), and lower IGFBP-3 at 12 mo (p < 0.05). IGF-I and IGFBP-3 were correlated at most ages. First year IGF-I and IGFBP-3 are influenced by study age and by gestational age, even after adjusting for early birth.

Carrier Proteins↗
PubMed1994

Lessons learned from randomizing infants to marine oil-supplemented formulas in nutrition trials.

The effect of n-3 fatty acid intake on docosahexaenoic acid (22:6n-3) and arachidonic acid (20:4n-6) status, growth, retinal physiology, visual acuity, and development (Bayley Mental Developmental Index and Fagan Infantest) has been evaluated in infants randomized to a marine oil source of docosahexaenoic acid or to standard infant formula. This article will focus on the lessons learned in conducting these randomized trials--issues related to design, implementation, and interpretation. By addressing these issues it is hoped that several general concepts related to nutrition studies in infants can be explored that might prove useful to others who undertake clinical nutrition trials in general, and trials with n-3 and n-6 fatty acids in particular.

Arachidonic Acid↗
PubMed1994

Effect of vitamin A supplementation of intravenous lipids on early vitamin A intake and status of premature infants.

Preterm infants were randomly assigned to receive routine vitamin A supplementation (Regular A) or additional vitamin A in intravenous lipids (High A). Because infants with bronchopulmonary dysplasia (BPD) have poorer vitamin A status than infants who do not develop BPD, High A and Regular A infants were divided by BPD (no or yes) before determining the effects of treatment on intake and plasma concentration of retinol in the first month. Compared with infants without BPD, those with BPD received less retinol (RE.kg-1.d-1) if assigned to Regular A and more if assigned to High A (BPD by vitamin A interaction, P < 0.002). High A-BPD infants compared with Regular A-BPD infants had significantly higher plasma retinol concentrations in the first month. Retinyl palmitate appears to be an effective adjunct to routine vitamin A administration. Infants most likely to benefit from receiving vitamin A in intravenous lipids are those advanced more slowly to full enteral feeding.

Analysis of Variance↗
PubMed1994

Long-chain fatty acids and early visual and cognitive development of preterm infants.

Preterm infants fed formula supplemented with DHA were shown in two randomized, clinical trials to have improved visual acuity in the first half of infancy. In the second clinical trial, infants simultaneously supplemented with DHA and provided with a nutrient-enriched preterm formula had a higher Bayley MDI score at 12 months than controls fed preterm formula. These data are the first evidence that DHA alone can also improve performance on early tests of mental development. Because visual and behavioural development are improved by providing this single dietary compound, DHA appears to be conditionally essential for preterm infants. Nevertheless, we would like to insert a few words of caution. More information about long chain n-3 and n-6 fatty acid requirements and balance for developing human infants is needed. As formulas are designed to meet n-3 and n-6 fatty acid needs, controlled studies of biochemistry and function should continue.

Cognition↗
PubMed1993

Arachidonic acid status correlates with first year growth in preterm infants.

Diets deficient in the omega-6 fatty acid linoleic acid reduce arachidonic acid (Ach) concentrations and retard growth of developing animals and humans. Nevertheless, plasma phosphatidylcholine Ach concentrations declined from 84 +/- 23 mg/liter at birth to a nadir of 38 +/- 11 mg/liter at 4 mo of age in preterm infants fed commercial formulas with linoleic acid, and weight normalized to that of term infants fell progressively beginning at 2 mo of age. The nadir of plasma phosphatidylcholine Ach (31 +/- 7 mg/liter) and growth were further reduced by formula containing marine oil compared with the commercial formulas. Ach status (defined as the mean plasma phosphatidylcholine Ach concentration at 2, 4, and 6.5 mo) correlated with one or more measures of normalized growth through 12 mo. Ach status and maternal height accounted for as much as 59% of the weight variance and 68% of the length variance in infants fed standard formulas. Better Ach status was not from higher energy intakes. A conditional Ach deficiency in preterm infants may contribute to growth over the first year of life. On the strength of the relationship between Ach status and growth, we hypothesize that dietary Ach could improve first year growth of preterm infants.

Arachidonic Acid↗
PubMed1993

Visual-acuity development in healthy preterm infants: effect of marine-oil supplementation.

Docosahexaenoic acid (DHA; 22:6n-3) is important for normal visual development. We hypothesized that preterm infants fed formulas with marine oil as a source of DHA would have better visual acuity than infants fed formulas without marine oil, as measured by the Teller Acuity Card procedure. Marine oil (P < 0.001) and age (P < 0.0001) influenced visual acuity, by repeated-measures analysis of variance (ANOVA) corrected for the effect of subject. Marine-oil-supplemented infants had better visual acuity than those fed standard formulas at 2 and 4 mo of age, by Fishers' least-squares difference (LSD). Acuity of both dietary groups improved through 6.5 mo of age, then plateaued. Through 4 mo of age, acuity was inversely related to oxygen supplementation (log10 h) and positively related to DHA status, by general-linear-models (GLM) analysis. After 4 mo of age, birth weight and gestational age were the only variables consistently related to visual acuity by GLM. We conclude that marine-oil-supplemented formula improved visual acuity of preterm infants through 4 mo of age by improving DHA status.

Aging↗
PubMed1993

Nutrient needs of the preterm infant.

Preterm infants exhibit special nutrient needs that differ substantially from other patient populations. Special characteristics include increased energy and protein requirements that must be addressed to prevent tissue catabolism and support growth. The immaturity of some organ systems may also complicate the administration of nutrition support. This article describes important characteristics of enteral and parenteral nutrition as it applies to the preterm infant.

Enteral Nutrition↗
PubMed1992

First year growth of preterm infants fed standard compared to marine oil n-3 supplemented formula.

Very low birth weight (VLBW) infants (748-1390 g, n = 65) were randomly assigned to receive control or marine oil-supplemented formula when they achieved intakes > 454 kJ (110 kcal)/kg/d of a formula designed for VLBW infants. Study formulas with or without marine oil were provided until 79 wk of postconceptional age (PCA), first in a formula designed for preterm infants followed by a formula designed for term infants. Infants were studied at regular intervals through 92 wk PCA. Weight, length, and head circumference were determined by standardized procedures and normalized to the National Center for Health Statistics figures for growth of infants born at term of the same age and gender. Mean normalized weight, weight-to-length, and head circumference were greatest at 48 wk and decreased thereafter. The decline in normalized weight was greater in infants fed the marine oil-supplemented formula. Beginning at 40 wk, marine oil-supplemented infants compared to controls had significantly poorer Z-scores for weight, length and head circumference. In addition, birth order (negatively) and maternal height (positively) influenced weight and length achievement in infancy as shown previously in infants born at term.

Aging↗
PubMed1992

Effect of vegetable and marine oils in preterm infant formulas on blood arachidonic and docosahexaenoic acids.

Adding docosahexaenoic acid (DHA) (22:6n-3) to formulas is more effective than increasing formula alpha-linolenic acid (18:3n-3) in maintaining blood phospholipid DHA levels similar to those in breast-fed infants. However, in long-term trials supplementary DHA given as marine oil reduces blood phospholipid arachidonic acid (AA) in preterm infants. This effect is not seen in short-term trials unless the total n-3 intake from marine oil exceeds 0.5% of the total fatty acids. In addition, there is considerable variability among individual preterm infants in blood phospholipid AA and DHA levels that is not dependent on diet. Within dietary treatments, a significant positive correlation between AA and DHA concentrations suggests that factor(s) other than marine oil supplementation affect both AA and DHA status. Docosahexaenoic acid and AA concentrations in plasma phospholipids are significantly correlated with DHA and AA concentrations in red blood cell phospholipids, suggesting that the observed individual differences in DHA and AA within groups represent true differences in fatty acid status. Preterm infants appear to be vulnerable to a poor status of both DHA and AA; further feeding trials are needed to identify the optimal balance of fatty acids for feeding these infants.

Arachidonic Acid↗
PubMed1991

Vitamin A status of preterm infants during infancy.

Plasma retinol and retinol-binding protein (RBP) were measured in 67 enterally fed preterm infants (750-1398 g) at 33 +/- 2 wk postconceptional age (PCA), and at regular intervals during infancy. Retinol and RBP declined by 35 +/- 2 wk PCA and remained low at 38 wk after discharge, with the infants fed a term-infant formula. At 38 +/- 2 wk PCA, 48% (32 of 67) of these infants had plasma retinol concentrations less than 0.35 mumol/L. Mean retinol and RBP rose over the next 7 mo, but large numbers of infants (26 of 59 at 48 wk, 10 of 61 at 57 wk) had hyporetinolemia (0.35-0.67 mumol/L). Plasma RBP leveled off at 57 +/- 2 wk PCA and remained low (less than 0.95 mumol/L) in many infants throughout the first year of life. Lower plasma retinol and RBP concentrations at 33 and 38 wk correlated with longer periods of intravenous nutrition. At 57 and 69 wk, lower retinol and RBP correlated with higher birth order. Suboptimal vitamin A status may occur for many months after preterm infants are discharged from the hospital.

Age Factors↗