ORIGINAL ARTICLE: HEPATOLOGY
AND
NUTRITION
Lutein and Preterm Infants With Decreased Concentrations of Brain Carotenoids
Rohini Vishwanathan, yMatthew J. Kuchan, zSarbattama Sen, and Elizabeth J. Johnson
See ‘‘Importance of Carotenoids in Optimizing Eye and Brain Development’’ by Henriksen and Chan on page 552.
diet. Further investigation on the impact of lutein on neural development in preterm infants is warranted. Key Words: brain, carotenoids, cognition, lutein, neural development, preterm infants
(JPGN 2014;59: 659–665) ABSTRACT Objectives: Lutein and zeaxanthin are dietary carotenoids that may influence visual and cognitive development. The objective of this study was to provide the first data on distribution of carotenoids in the infant brain and compare concentrations in preterm and term infants. Methods: Voluntarily donated brain tissues from 30 infants who died during the first 1.5 years of life were obtained from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Brain and Tissue Bank. Tissues (hippocampus and prefrontal, frontal, auditory, and occipital cortices) were extracted using standard lipid extraction procedures and analyzed using reverse-phase high-pressure liquid chromatography. Results: Lutein, zeaxanthin, cryptoxanthin, and b-carotene were the major carotenoids found in the infant brain tissues. Lutein was the predominant carotenoid accounting for 59% of total carotenoids. Preterm infants (n ¼ 8) had significantly lower concentrations of lutein, zeaxanthin, and cryptoxanthin in their brain compared with term infants (n ¼ 22) despite similarity in postmenstrual age. Among formula-fed infants, preterm infants (n ¼ 3) had lower concentrations of lutein and zeaxanthin compared with term infants (n ¼ 5). Brain lutein concentrations were not different between breast milk–fed (n ¼ 3) and formula-fed (n ¼ 5) term decedents. In contrast, term decedents with measurable brain cryptoxanthin, a carotenoid that is inherently low in formula, had higher brain lutein, suggesting that the type of feeding is an important determinant of brain lutein concentrations. Conclusions: These data reveal preferential accumulation and maintenance of lutein in the infant brain despite underrepresentation in the typical infant
Received December 10, 2013; accepted March 27, 2014. From the Carotenoids and Health Laboratory, Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, MA, yAbbott Nutrition, Columbus, OH, and the zDivision of Newborn Medicine, Department of Pediatrics, Mother Infant Research Institute, Tufts Medical Center, Boston, MA. Address correspondence and reprint requests to Rohini Vishwanathan, PhD, Carotenoids and Health Laboratory, Jean Mayer USDA HNRCA, Tufts University, 711 Washington Street, Boston, MA 02111 (e-mail: [email protected]). This study was funded by Abbott Nutrition (Grant No. USDA 58-1950-0014). Human tissue was obtained from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Brain and Tissue Bank for Developmental Disorders at the University of Maryland, Baltimore. M.J.K. is an employee of Abbott Nutrition. The other authors report no conflicts of interest. Copyright # 2014 by European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition DOI: 10.1097/MPG.0000000000000389
JPGN
Volume 59, Number 5, November 2014
C
arotenoids are plant pigments that cannot be synthesized de novo and are obtained from the diet. Of the 600 carotenoids identified in nature, only approximately 40 or so are present in the fruits and vegetables commonly consumed in the United States, and only approximately 25 are found in human serum and milk (1). Only lutein and its isomer zeaxanthin, which are oxygenated carotenoids or xanthophylls, preferentially accumulate in the macular region of the retina to form macular pigment (2). The macula is a yellowish region 5 to 6 mm in diameter in the posterior pole of the retina (3). It is unique to humans and other higher primates, and is responsible for their highly developed central visual acuity. Lutein and zeaxanthin protect the macula from short-wavelength blue light and oxidative stress (4–6). In infants, lutein and zeaxanthin may also play a role in the maturation of cells in the developing macula (7). Other biologically significant carotenoids include cryptoxanthin, a-carotene, and b-carotene, which have provitamin A activity, and lycopene, suggested to protect against prostate cancer. All of these carotenoids are also potent antioxidants (8). Lutein has been reported to be the predominant carotenoid in the brain of older adults, accounting for 30% of total brain carotenoids (9,10). This observation suggests that a preferential uptake of lutein into brain tissue as intake is typically low compared with other carotenoids in the US diet (2,9). Nonhuman primate and human studies indicate that both macular and brain concentrations of lutein and zeaxanthin are related to serum concentrations, an indirect measure of dietary intake, and that macular pigment optical density may be predictive of brain concentrations (9,11,12). A possible role for lutein and zeaxanthin in cognitive function was supported by the finding that macular pigment optical density was positively correlated with measures of cognitive function in older adults (13,14). Subsequent research revealed significant associations between brain lutein concentration and premortem measures of cognitive function in older adults (9). Finally, lutein supplementation was shown to significantly improve measures of cognitive function in older women (15). These findings support lutein’s role in cognitive function. Available evidence indicates that infant intake of lutein is highly variable and tends to be low in formula-fed infants and in children from ages 1 to 3 years (16). In breast milk–feeding infants this variability can be explained by differences in maternal intake and several factors that affect maternal carotenoid status, such as alcohol intake and smoking (17,18). Furthermore, mothers with obesity were found to have decreased concentration of carotenoids in breast milk compared with lean mothers (ongoing study at Tufts Medical Center), resulting in variable intake in infants. Consistent
659
Copyright 2014 by ESPGHAN and NASPGHAN. Unauthorized reproduction of this article is prohibited.
Vishwanathan et al
JPGN
with these observations, Bone et al (19) have shown that macular pigment density is highly variable in the infant retina. Because the developing infant brain is known to be sensitive to a wide range of nutritional deficiencies, it is important to describe the range of infant brain lutein concentrations. Premature infants are nutritionally unique given differences in feeding practices. They may be particularly vulnerable to lutein insufficiency, increasing the susceptibility of the immature retina and brain to oxidative stress. As a first step in the understanding of a possible role of lutein in early neural development, the objective of this study was to determine the distribution of carotenoids in the brain tissue of infant decedents during the first 1.5 years of life and to assess the differences in brain carotenoids between preterm and full-term infants.
METHODS Subjects Voluntarily donated brain tissue samples of otherwise healthy infants (without any brain and/or other systemic pathologies) who died during the first 18 months of life were obtained from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Brain and Tissue Bank for Developmental Disorders, University of Maryland (http://medschool.umaryland.edu/btbank). Tissues were identified using a unique numerical identifier, which obscured the identity of the decedent. Tissues were obtained from different regions of the brain, which included hippocampus (Hipp) and prefrontal (PFC), frontal (FC), auditory (AC), and occipital (OC) cortices. It is noteworthy that these regions of the brain are associated with memory (Hipp), executive function (PFC and FC), hearing (AC), and vision (OC). Decedents included both preterm (infants whose gestational age was 1 year old at the time of death. One was a 443-day-old preterm infant and the other was a 488-day-old term infant. Fifty percent of the infants died of SIDS, whereas the remaining 50% died of various other conditions that are listed in Table 1. Brain carotenoid concentrations were not significantly different between infants who died of SIDS and other causes (data not shown); hence, data for these groups of decedents were combined. There were no significant relations between carotenoid concentrations and either postmortem interval (time of death to storage) or date of collection. The major carotenoids detected in the infant brain were lutein (range 0–181.7 pmol/g), zeaxanthin (range 0–33.94 pmol/g), cryptoxanthin (range 0–35.29 pmol/g), and b-carotene range 0–88.19 pmol/g). The mean concentration of lutein was significantly greater than that of the other carotenoids (P < 0.05) in all the brain regions analyzed (Fig. 1). In the AC, lutein was marginally greater than b-carotene (P ¼ 0.074, n ¼ 11). In each brain region analyzed, the mean concentration of lutein was >40 pmol/g, whereas the mean combined concentration of zeaxanthin, cryptoxanthin, and b-carotene was 40 pmol/g. cis isomers were only detected for lutein and b-carotene. Although 17 decedents had detectable levels of cis lutein in at least 1 brain region analyzed, 13 decedents had no cis lutein isomer in any of the brain regions analyzed. It is noteworthy that the average ratio of trans to cis lutein of 18.6 to 1. 9-cis-bcarotene was detected in the brain regions of only 4 decedents. Lycopene was detected in only 3 decedents at concentrations of 39.19 pmol/g in the FC and 45.85 pmol/g in the Hipp for 1 decedent, 8.67 pmol/g in the FC and 16.07 pmol/g in the OC for the second decedent, and 13.04 pmol/g in the PFC for the third decedent. No a-carotene was detected in any tissue. Carotenoid concentrations generally fit this same luteinpredominant pattern for the 9 decedents who had tissue from all 5 regions of the brain (data not shown). Among these 9 decedents, zeaxanthin concentration was significantly higher in the AC than in the PFC (P < 0.05), and b-carotene in the AC and OC was significantly higher than in the Hipp and PFC, respectively (P 0.05). Infants born preterm (n ¼ 8) had significantly lower concentrations of lutein and zeaxanthin compared with term infants (n ¼ 22) in most of the brain regions analyzed (Fig. 2). In contrast, cryptoxanthin was significantly lower only in the Hipp, and b-carotene was not different in any of the brain regions. All of the preterm infants, except 1, had no cryptoxanthin in their brain www.jpgn.org
Copyright 2014 by ESPGHAN and NASPGHAN. Unauthorized reproduction of this article is prohibited.
JPGN
Volume 59, Number 5, November 2014
Lutein Is the Predominant Carotenoid in Infant Brain
TABLE 1. Subject characteristics
All subjects (n ¼ 30)
Preterm infants (n ¼ 8)
Term infantsy (n ¼ 22)
137 (21) 100.5 1–488
190 (41) 149.5 95–443
118 (24) 97 1–488
0.136
56.7 (2.8) 52.4 37.7–109.7 21 (70)
57.5 (5.2) 51 46.4–89.3 5 (63)
56.5 (3.4) 52.9 37.7–109.7 16 (73)
0.877
16 (53) 12 (40) 2 (7)
3 (38) 4 (50) 1 (12)
13 (59) 8 (36) 1 (5)
15 (50) 15 (50) 5 3 1 1 1 1 1 1 1 1
4 (50) 4 (50) 1 0 0 1 0 1 1 0 0 0
10 (45) 12 (55) 4 3§ 1 0 1 0 0 1 1 1
0.825
15.9 (1.1) 17.5 2–23
15.5 (2.4) 16.5 2–23
16.1 (1.2) 17.5 5–23
0.761
2 5 13 11
2 5 7 4
0 0 6 7
Age, days Mean (SEM) Median Range Postmenstrual age, wk Mean (SEM) Median Range Males, n (%) Race White, n (%) African American, n (%) Hispanic, n (%) Cause of death SIDS, n (%) Others, n (%) Bronchopneumonia Heart disease Pneumonia associated with meconium aspiration Dehydration Asphyxia by suffocation Asthma Bronchopulmonary dysplasia and respiratory distress syndrome Drowning Hyperthermia Multiorgan failure Time interval between death and tissue collection, h Mean (SEM) Median Range No. infants with undetectable levels of carotenoids in at least 1 cortex Lutein Zeaxanthin Cryptoxanthin b-Carotene
Pz
0.589
0.511
0.015
AND
NUTRITION
Lutein and Preterm Infants With Decreased Concentrations of Brain Carotenoids
Rohini Vishwanathan, yMatthew J. Kuchan, zSarbattama Sen, and Elizabeth J. Johnson
See ‘‘Importance of Carotenoids in Optimizing Eye and Brain Development’’ by Henriksen and Chan on page 552.
diet. Further investigation on the impact of lutein on neural development in preterm infants is warranted. Key Words: brain, carotenoids, cognition, lutein, neural development, preterm infants
(JPGN 2014;59: 659–665) ABSTRACT Objectives: Lutein and zeaxanthin are dietary carotenoids that may influence visual and cognitive development. The objective of this study was to provide the first data on distribution of carotenoids in the infant brain and compare concentrations in preterm and term infants. Methods: Voluntarily donated brain tissues from 30 infants who died during the first 1.5 years of life were obtained from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Brain and Tissue Bank. Tissues (hippocampus and prefrontal, frontal, auditory, and occipital cortices) were extracted using standard lipid extraction procedures and analyzed using reverse-phase high-pressure liquid chromatography. Results: Lutein, zeaxanthin, cryptoxanthin, and b-carotene were the major carotenoids found in the infant brain tissues. Lutein was the predominant carotenoid accounting for 59% of total carotenoids. Preterm infants (n ¼ 8) had significantly lower concentrations of lutein, zeaxanthin, and cryptoxanthin in their brain compared with term infants (n ¼ 22) despite similarity in postmenstrual age. Among formula-fed infants, preterm infants (n ¼ 3) had lower concentrations of lutein and zeaxanthin compared with term infants (n ¼ 5). Brain lutein concentrations were not different between breast milk–fed (n ¼ 3) and formula-fed (n ¼ 5) term decedents. In contrast, term decedents with measurable brain cryptoxanthin, a carotenoid that is inherently low in formula, had higher brain lutein, suggesting that the type of feeding is an important determinant of brain lutein concentrations. Conclusions: These data reveal preferential accumulation and maintenance of lutein in the infant brain despite underrepresentation in the typical infant
Received December 10, 2013; accepted March 27, 2014. From the Carotenoids and Health Laboratory, Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, MA, yAbbott Nutrition, Columbus, OH, and the zDivision of Newborn Medicine, Department of Pediatrics, Mother Infant Research Institute, Tufts Medical Center, Boston, MA. Address correspondence and reprint requests to Rohini Vishwanathan, PhD, Carotenoids and Health Laboratory, Jean Mayer USDA HNRCA, Tufts University, 711 Washington Street, Boston, MA 02111 (e-mail: [email protected]). This study was funded by Abbott Nutrition (Grant No. USDA 58-1950-0014). Human tissue was obtained from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Brain and Tissue Bank for Developmental Disorders at the University of Maryland, Baltimore. M.J.K. is an employee of Abbott Nutrition. The other authors report no conflicts of interest. Copyright # 2014 by European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition DOI: 10.1097/MPG.0000000000000389
JPGN
Volume 59, Number 5, November 2014
C
arotenoids are plant pigments that cannot be synthesized de novo and are obtained from the diet. Of the 600 carotenoids identified in nature, only approximately 40 or so are present in the fruits and vegetables commonly consumed in the United States, and only approximately 25 are found in human serum and milk (1). Only lutein and its isomer zeaxanthin, which are oxygenated carotenoids or xanthophylls, preferentially accumulate in the macular region of the retina to form macular pigment (2). The macula is a yellowish region 5 to 6 mm in diameter in the posterior pole of the retina (3). It is unique to humans and other higher primates, and is responsible for their highly developed central visual acuity. Lutein and zeaxanthin protect the macula from short-wavelength blue light and oxidative stress (4–6). In infants, lutein and zeaxanthin may also play a role in the maturation of cells in the developing macula (7). Other biologically significant carotenoids include cryptoxanthin, a-carotene, and b-carotene, which have provitamin A activity, and lycopene, suggested to protect against prostate cancer. All of these carotenoids are also potent antioxidants (8). Lutein has been reported to be the predominant carotenoid in the brain of older adults, accounting for 30% of total brain carotenoids (9,10). This observation suggests that a preferential uptake of lutein into brain tissue as intake is typically low compared with other carotenoids in the US diet (2,9). Nonhuman primate and human studies indicate that both macular and brain concentrations of lutein and zeaxanthin are related to serum concentrations, an indirect measure of dietary intake, and that macular pigment optical density may be predictive of brain concentrations (9,11,12). A possible role for lutein and zeaxanthin in cognitive function was supported by the finding that macular pigment optical density was positively correlated with measures of cognitive function in older adults (13,14). Subsequent research revealed significant associations between brain lutein concentration and premortem measures of cognitive function in older adults (9). Finally, lutein supplementation was shown to significantly improve measures of cognitive function in older women (15). These findings support lutein’s role in cognitive function. Available evidence indicates that infant intake of lutein is highly variable and tends to be low in formula-fed infants and in children from ages 1 to 3 years (16). In breast milk–feeding infants this variability can be explained by differences in maternal intake and several factors that affect maternal carotenoid status, such as alcohol intake and smoking (17,18). Furthermore, mothers with obesity were found to have decreased concentration of carotenoids in breast milk compared with lean mothers (ongoing study at Tufts Medical Center), resulting in variable intake in infants. Consistent
659
Copyright 2014 by ESPGHAN and NASPGHAN. Unauthorized reproduction of this article is prohibited.
Vishwanathan et al
JPGN
with these observations, Bone et al (19) have shown that macular pigment density is highly variable in the infant retina. Because the developing infant brain is known to be sensitive to a wide range of nutritional deficiencies, it is important to describe the range of infant brain lutein concentrations. Premature infants are nutritionally unique given differences in feeding practices. They may be particularly vulnerable to lutein insufficiency, increasing the susceptibility of the immature retina and brain to oxidative stress. As a first step in the understanding of a possible role of lutein in early neural development, the objective of this study was to determine the distribution of carotenoids in the brain tissue of infant decedents during the first 1.5 years of life and to assess the differences in brain carotenoids between preterm and full-term infants.
METHODS Subjects Voluntarily donated brain tissue samples of otherwise healthy infants (without any brain and/or other systemic pathologies) who died during the first 18 months of life were obtained from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Brain and Tissue Bank for Developmental Disorders, University of Maryland (http://medschool.umaryland.edu/btbank). Tissues were identified using a unique numerical identifier, which obscured the identity of the decedent. Tissues were obtained from different regions of the brain, which included hippocampus (Hipp) and prefrontal (PFC), frontal (FC), auditory (AC), and occipital (OC) cortices. It is noteworthy that these regions of the brain are associated with memory (Hipp), executive function (PFC and FC), hearing (AC), and vision (OC). Decedents included both preterm (infants whose gestational age was 1 year old at the time of death. One was a 443-day-old preterm infant and the other was a 488-day-old term infant. Fifty percent of the infants died of SIDS, whereas the remaining 50% died of various other conditions that are listed in Table 1. Brain carotenoid concentrations were not significantly different between infants who died of SIDS and other causes (data not shown); hence, data for these groups of decedents were combined. There were no significant relations between carotenoid concentrations and either postmortem interval (time of death to storage) or date of collection. The major carotenoids detected in the infant brain were lutein (range 0–181.7 pmol/g), zeaxanthin (range 0–33.94 pmol/g), cryptoxanthin (range 0–35.29 pmol/g), and b-carotene range 0–88.19 pmol/g). The mean concentration of lutein was significantly greater than that of the other carotenoids (P < 0.05) in all the brain regions analyzed (Fig. 1). In the AC, lutein was marginally greater than b-carotene (P ¼ 0.074, n ¼ 11). In each brain region analyzed, the mean concentration of lutein was >40 pmol/g, whereas the mean combined concentration of zeaxanthin, cryptoxanthin, and b-carotene was 40 pmol/g. cis isomers were only detected for lutein and b-carotene. Although 17 decedents had detectable levels of cis lutein in at least 1 brain region analyzed, 13 decedents had no cis lutein isomer in any of the brain regions analyzed. It is noteworthy that the average ratio of trans to cis lutein of 18.6 to 1. 9-cis-bcarotene was detected in the brain regions of only 4 decedents. Lycopene was detected in only 3 decedents at concentrations of 39.19 pmol/g in the FC and 45.85 pmol/g in the Hipp for 1 decedent, 8.67 pmol/g in the FC and 16.07 pmol/g in the OC for the second decedent, and 13.04 pmol/g in the PFC for the third decedent. No a-carotene was detected in any tissue. Carotenoid concentrations generally fit this same luteinpredominant pattern for the 9 decedents who had tissue from all 5 regions of the brain (data not shown). Among these 9 decedents, zeaxanthin concentration was significantly higher in the AC than in the PFC (P < 0.05), and b-carotene in the AC and OC was significantly higher than in the Hipp and PFC, respectively (P 0.05). Infants born preterm (n ¼ 8) had significantly lower concentrations of lutein and zeaxanthin compared with term infants (n ¼ 22) in most of the brain regions analyzed (Fig. 2). In contrast, cryptoxanthin was significantly lower only in the Hipp, and b-carotene was not different in any of the brain regions. All of the preterm infants, except 1, had no cryptoxanthin in their brain www.jpgn.org
Copyright 2014 by ESPGHAN and NASPGHAN. Unauthorized reproduction of this article is prohibited.
JPGN
Volume 59, Number 5, November 2014
Lutein Is the Predominant Carotenoid in Infant Brain
TABLE 1. Subject characteristics
All subjects (n ¼ 30)
Preterm infants (n ¼ 8)
Term infantsy (n ¼ 22)
137 (21) 100.5 1–488
190 (41) 149.5 95–443
118 (24) 97 1–488
0.136
56.7 (2.8) 52.4 37.7–109.7 21 (70)
57.5 (5.2) 51 46.4–89.3 5 (63)
56.5 (3.4) 52.9 37.7–109.7 16 (73)
0.877
16 (53) 12 (40) 2 (7)
3 (38) 4 (50) 1 (12)
13 (59) 8 (36) 1 (5)
15 (50) 15 (50) 5 3 1 1 1 1 1 1 1 1
4 (50) 4 (50) 1 0 0 1 0 1 1 0 0 0
10 (45) 12 (55) 4 3§ 1 0 1 0 0 1 1 1
0.825
15.9 (1.1) 17.5 2–23
15.5 (2.4) 16.5 2–23
16.1 (1.2) 17.5 5–23
0.761
2 5 13 11
2 5 7 4
0 0 6 7
Age, days Mean (SEM) Median Range Postmenstrual age, wk Mean (SEM) Median Range Males, n (%) Race White, n (%) African American, n (%) Hispanic, n (%) Cause of death SIDS, n (%) Others, n (%) Bronchopneumonia Heart disease Pneumonia associated with meconium aspiration Dehydration Asphyxia by suffocation Asthma Bronchopulmonary dysplasia and respiratory distress syndrome Drowning Hyperthermia Multiorgan failure Time interval between death and tissue collection, h Mean (SEM) Median Range No. infants with undetectable levels of carotenoids in at least 1 cortex Lutein Zeaxanthin Cryptoxanthin b-Carotene
Pz
0.589
0.511
0.015
