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Vassilopoulou E, Venter C, Roth-Walter F. Malnutrition and Allergies: Tipping the Immune Balance towards Health. J Clin Med 2024; 13:4713. [PMID: 39200855 PMCID: PMC11355500 DOI: 10.3390/jcm13164713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2024] [Revised: 08/04/2024] [Accepted: 08/05/2024] [Indexed: 09/02/2024] Open
Abstract
Malnutrition, which includes macro- and micronutrient deficiencies, is common in individuals with allergic dermatitis, food allergies, rhinitis, and asthma. Prolonged deficiencies of proteins, minerals, and vitamins promote Th2 inflammation, setting the stage for allergic sensitization. Consequently, malnutrition, which includes micronutrient deficiencies, fosters the development of allergies, while an adequate supply of micronutrients promotes immune cells with regulatory and tolerogenic phenotypes. As protein and micronutrient deficiencies mimic an infection, the body's innate response limits access to these nutrients by reducing their dietary absorption. This review highlights our current understanding of the physiological functions of allergenic proteins, iron, and vitamin A, particularly regarding their reduced bioavailability under inflamed conditions, necessitating different dietary approaches to improve their absorption. Additionally, the role of most allergens as nutrient binders and their involvement in nutritional immunity will be briefly summarized. Their ability to bind nutrients and their close association with immune cells can trigger exaggerated immune responses and allergies in individuals with deficiencies. However, in nutrient-rich conditions, these allergens can also provide nutrients to immune cells and promote health.
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Affiliation(s)
- Emilia Vassilopoulou
- Department of Nutritional Sciences and Dietetics, School of Health Sciences, International Hellenic University, 57400 Thessaloniki, Greece
- Department of Clinical Sciences and Community Health, Univertià degli Studi die Milano, 20122 Milan, Italy
| | - Carina Venter
- Pediatrics, Section of Allergy & Immunology, University of Colorado Denver School of Medicine, Children’s Hospital Colorado, Box B518, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Franziska Roth-Walter
- Messerli Research Institute, Department of Interdisciplinary Life Sciences, University of Veterinary Medicine Vienna, Medical University of Vienna and University of Vienna, 1210 Vienna, Austria
- Institute of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria
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Roth-Walter F, Berni Canani R, O'Mahony L, Peroni D, Sokolowska M, Vassilopoulou E, Venter C. Nutrition in chronic inflammatory conditions: Bypassing the mucosal block for micronutrients. Allergy 2024; 79:353-383. [PMID: 38084827 DOI: 10.1111/all.15972] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 11/14/2023] [Accepted: 11/27/2023] [Indexed: 02/01/2024]
Abstract
Nutritional Immunity is one of the most ancient innate immune responses, during which the body can restrict nutrients availability to pathogens and restricts their uptake by the gut mucosa (mucosal block). Though this can be a beneficial strategy during infection, it also is associated with non-communicable diseases-where the pathogen is missing; leading to increased morbidity and mortality as micronutritional uptake and distribution in the body is hindered. Here, we discuss the acute immune response in respect to nutrients, the opposing nutritional demands of regulatory and inflammatory cells and particularly focus on some nutrients linked with inflammation such as iron, vitamins A, Bs, C, and other antioxidants. We propose that while the absorption of certain micronutrients is hindered during inflammation, the dietary lymph path remains available. As such, several clinical trials investigated the role of the lymphatic system during protein absorption, following a ketogenic diet and an increased intake of antioxidants, vitamins, and minerals, in reducing inflammation and ameliorating disease.
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Affiliation(s)
- Franziska Roth-Walter
- Comparative Medicine, The Interuniversity Messerli Research Institute of the University of Veterinary Medicine Vienna, Medical University Vienna and University Vienna, Vienna, Austria
- Institute of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Roberto Berni Canani
- Department of Translational Medical Science and ImmunoNutritionLab at CEINGE-Advanced Biotechnologies, University of Naples "Federico II", Naples, Italy
| | - Liam O'Mahony
- Department of Medicine, School of Microbiology, APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Diego Peroni
- Section of Paediatrics, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Milena Sokolowska
- Swiss Institute of Allergy and Asthma Research (SIAF), University of Zürich, Davos, Switzerland
- Christine Kühne - Center for Allergy Research and Education (CK-CARE), Davos, Switzerland
| | - Emilia Vassilopoulou
- Pediatric Area, Fondazione IRCCS Ca' Granda-Ospedale Maggiore Policlinico, Milan, Italy
- Department of Nutritional Sciences and Dietetics, International Hellenic University, Thessaloniki, Greece
| | - Carina Venter
- Children's Hospital Colorado, University of Colorado, Aurora, Colorado, USA
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Vornov JJ, Peters D, Nedelcovych M, Hollinger K, Rais R, Slusher BS. Looking for Drugs in All the Wrong Places: Use of GCPII Inhibitors Outside the Brain. Neurochem Res 2019; 45:1256-1267. [PMID: 31749072 DOI: 10.1007/s11064-019-02909-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 11/06/2019] [Accepted: 11/08/2019] [Indexed: 12/12/2022]
Abstract
In tribute to our friend and colleague Michael Robinson, we review his involvement in the identification, characterization and localization of the metallopeptidase glutamate carboxypeptidase II (GCPII), originally called NAALADase. While Mike was characterizing NAALADase in the brain, the protein was independently identified by other laboratories in human prostate where it was termed prostate specific membrane antigen (PSMA) and in the intestines where it was named Folate Hydrolase 1 (FOLH1). It was almost a decade to establish that NAALADase, PSMA, and FOLH1 are encoded by the same gene. The enzyme has emerged as a therapeutic target outside of the brain, with the most notable progress made in the treatment of prostate cancer and inflammatory bowel disease (IBD). PSMA-PET imaging with high affinity ligands is proving useful for the clinical diagnosis and staging of prostate cancer. A molecular radiotherapy based on similar ligands is in trials for metastatic castration-resistant prostate cancer. New PSMA inhibitor prodrugs that preferentially block kidney and salivary gland versus prostate tumor enzyme may improve the clinical safety of this radiotherapy. The wide clinical use of PSMA-PET imaging in prostate cancer has coincidentally led to clinical documentation of GCPII upregulation in a wide variety of tumors and inflammatory diseases, likely associated with angiogenesis. In IBD, expression of the FOLH1 gene that codes for GCPII is strongly upregulated, as is the enzymatic activity in diseased patient biopsies. In animal models of IBD, GCPII inhibitors show substantial efficacy, suggesting potential theranostic use of GCPII ligands for IBD.
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Affiliation(s)
- James J Vornov
- Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
- Medpace, Cincinnati, OH, USA
| | - Diane Peters
- Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
- Department of Molecular and Comparative Pathobiology, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
| | - Mike Nedelcovych
- Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
| | - Kristen Hollinger
- Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
| | - Rana Rais
- Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
| | - Barbara S Slusher
- Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA.
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA.
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA.
- Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA.
- Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA.
- Department of Oncology, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA.
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Abstract
Nine compounds are classified as water-soluble vitamins, eight B vitamins and one vitamin C. The vitamins are mandatory for the function of numerous enzymes and lack of one or more of the vitamins may lead to severe medical conditions. All the vitamins are supplied by food in microgram to milligram quantities and in addition some of the vitamins are synthesized by the intestinal microbiota. In the gastrointestinal tract, the vitamins are liberated from binding proteins and for some of the vitamins modified prior to absorption. Due to their solubility in water, they all require specific carriers to be absorbed. Our current knowledge concerning each of the vitamins differs in depth and focus and is influenced by the prevalence of conditions and diseases related to lack of the individual vitamin. Because of that we have chosen to cover slightly different aspects for the individual vitamins. For each of the vitamins, we summarize the physiological role, the steps involved in the absorption, and the factors influencing the absorption. In addition, for some of the vitamins, the molecular base for absorption is described in details, while for others new aspects of relevance for human deficiency are included. © 2018 American Physiological Society. Compr Physiol 8:1291-1311, 2018.
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Affiliation(s)
- Hamid M Said
- University of California-School of Medicine, Irvine, California, USA.,VA Medical Center, Long Beach, California, USA
| | - Ebba Nexo
- Department of Clinical Medicine, Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark
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Abstract
Our knowledge of the mechanisms and regulation of intestinal absorption of water-soluble vitamins under normal physiological conditions, and of the factors/conditions that affect and interfere with theses processes has been significantly expanded in recent years as a result of the availability of a host of valuable molecular/cellular tools. Although structurally and functionally unrelated, the water-soluble vitamins share the feature of being essential for normal cellular functions, growth and development, and that their deficiency leads to a variety of clinical abnormalities that range from anaemia to growth retardation and neurological disorders. Humans cannot synthesize water-soluble vitamins (with the exception of some endogenous synthesis of niacin) and must obtain these micronutrients from exogenous sources. Thus body homoeostasis of these micronutrients depends on their normal absorption in the intestine. Interference with absorption, which occurs in a variety of conditions (e.g. congenital defects in the digestive or absorptive system, intestinal disease/resection, drug interaction and chronic alcohol use), leads to the development of deficiency (and sub-optimal status) and results in clinical abnormalities. It is well established now that intestinal absorption of the water-soluble vitamins ascorbate, biotin, folate, niacin, pantothenic acid, pyridoxine, riboflavin and thiamin is via specific carrier-mediated processes. These processes are regulated by a variety of factors and conditions, and the regulation involves transcriptional and/or post-transcriptional mechanisms. Also well recognized now is the fact that the large intestine possesses specific and efficient uptake systems to absorb a number of water-soluble vitamins that are synthesized by the normal microflora. This source may contribute to total body vitamin nutrition, and especially towards the cellular nutrition and health of the local colonocytes. The present review aims to outline our current understanding of the mechanisms involved in intestinal absorption of water-soluble vitamins, their regulation, the cell biology of the carriers involved and the factors that negatively affect these absorptive events.
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Affiliation(s)
- Hamid M Said
- School of Medicine, University of California-Irvine, Irvine, CA 92697, USA.
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Powers HJ. Vitamin requirements for term infants: considerations for infant formulae. Nutr Res Rev 2009; 10:1-33. [PMID: 19094256 DOI: 10.1079/nrr19970003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To provide the informed health professional with an up to date evaluation of the current thinking regarding requirements for vitamins in infant feeds. ESTABLISHING CRITERIA FOR ADEQUACY: Vitamin adequacy in the neonate is currently defined in terms of circulating levels of a vitamin or of the activity of a vitamin dependent enzyme in the erythrocytes. Although these measurements have their value there is a need to develop biochemical, physiological or clinical markers of well defined specific function. For some vitamins there is a risk of deleterious effects of very high intakes: risk of toxicity needs to be taken into consideration when making recommendations for inclusion in infant formulae. BREAST MILK AS THE 'GOLD STANDARD': Breast milk concentrations of vitamins have been used as the criteria of adequate intake by neonates. This may not always be justified. Greater consideration needs to be given to differences in bioavailability of vitamins from breast milk compared with formula feeds, of the influence of season, and of stage of lactation, on the stated composition. EXPERIMENTAL APPROACHES Animal studies have provided limited information regarding effects of different levels of intakes on current status indices in the neonatal period. There are few reports of randomized controlled studies into the effects of different levels of vitamins and these rely heavily on biochemical criteria of adequacy. RECENT DEVELOPMENTS The inclusion of beta-carotene into formula feeds for premature babies is an issue of current interest. What is the justification for this? Are there potential benefits for the term infant? Riboflavin deficiency in the period around weaning may affect the normal structural and functional development of the gastrointestinal tract; some of these effects may be permanent. RESEARCH TO BE DONE: A greater understanding of the absorption and metabolism of vitamins during infancy is required in order to help establish dietary requirements. The relative bioavailability of vitamins in human milk and formulae needs to be investigated. Criteria for vitamin adequacy should be extended to include measures of function. Information regarding the conversion factor from tryptophan to niacin in infancy would allow us to set niacin requirements with greater confidence. There is a particular lack of information about concentrations of biotin and pantothenic acid in breast milk and the relative biochemical status of infants receiving breast milk and formulae. Benefits of including beta-carotene into infant formulae need to be evaluated. The role of individual micronutrients in the structural and functional development of the gastrointestinal tract should be explored.
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Affiliation(s)
- H J Powers
- University Department of Paediatrics, Sheffield Children's Hospital, Sheffield S10 2TH, UK
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Brouwer IA, van Dusseldorp M, West CE, Steegers-Theunissen RP. Bioavailability and bioefficacy of folate and folic acid in man. Nutr Res Rev 2009; 14:267-94. [DOI: 10.1079/nrr200126] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Melse-Boonstra A, Verhoef P, West CE, van Rhijn JA, van Breemen RB, Lasaroms JJP, Garbis SD, Katan MB, Kok FJ. A dual-isotope-labeling method of studying the bioavailability of hexaglutamyl folic acid relative to that of monoglutamyl folic acid in humans by using multiple orally administered low doses. Am J Clin Nutr 2006; 84:1128-33. [PMID: 17093166 DOI: 10.1093/ajcn/84.5.1128] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The bioavailability of dietary folate may be hampered by the need of the glutamate moieties to be deconjugated before absorption. Previous studies comparing the bioavailabilities of polyglutamyl and monoglutamyl folic acid had inconsistent results. OBJECTIVE The objective was to estimate the bioavailability of polyglutamyl relative to that of monoglutamyl folic acid by using a sensitive stable-isotope approach that allowed for the administration of multiple low doses in humans. DESIGN Twenty subjects aged 20-50 y ingested 2 capsules daily for 28 d; each capsule contained approximately 50 nmol [(13)C(6)]hexaglutamyl and approximately 50 nmol [(13)C(11)]monoglutamyl folic acid. Amounts of the isotopically labeled compounds in the capsules were verified by various methods. The degrees of isotopic enrichment of plasma 5-methyltetrahydrofolate with (13)C(6) and (13)C(11) were measured by using liquid chromatography tandem mass spectrometry, and the ratio of (13)C(6) to (13)C(11) ((13)C(6):(13)C(11)) in plasma on day 28 was used as a measure of their relative bioavailability. RESULTS The (13)C(11):(13)C(6) in plasma 5-methyltetrahydrofolate reached equilibrium on day 4 and was 0.66 (95% CI: 0.58, 0.74) on day 28. The (13)C(11):(13)C(6) content in the capsules varied between 1.18 and 1.96. After correction for this ratio, the estimated bioavailability of hexaglutamyl relative to that of monoglutamyl folic acid was >/=78%. CONCLUSION Multiple dosing of low amounts of labeled folic acid is a sensitive, accurate, and efficient method of measuring the relative bioavailability of folic acid compounds, provided that the administered doses can be reliably assessed.
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McKillop DJ, McNulty H, Scott JM, McPartlin JM, Strain JJ, Bradbury I, Girvan J, Hoey L, McCreedy R, Alexander J, Patterson BK, Hannon-Fletcher M, Pentieva K. The rate of intestinal absorption of natural food folates is not related to the extent of folate conjugation. Am J Clin Nutr 2006; 84:167-73. [PMID: 16825692 DOI: 10.1093/ajcn/84.1.167] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Evidence is conflicting as to whether the bioavailability of food folates is influenced by the extent of their conjugation. OBJECTIVE The objective was to compare the bioavailability of 3 representative food folate sources with various degrees of glutamylation-ie, egg yolk, spinach, and yeast, whose polyglutamyl folate content measured 0%, 50%, and 100%, respectively. DESIGN In a randomized crossover trial, 13 male subjects, after a prestudy folate saturation procedure, received in random order either placebo or 500 mug total folate, which was provided as concentrated freeze-dried extract removed from the normal food matrix of egg yolk, spinach, or yeast. Blood samples (n = 10) were collected before and up to 10 h after treatments, which were administered at weekly intervals. RESULTS A significant increase from baseline plasma folate concentrations was observed by 0.5 h after treatment with egg yolk folate or spinach folate and by 1 h after treatment with yeast folate, and the concentrations remained significantly elevated for 3-5 h; no plasma folate response was observed after placebo treatment. The overall responses, calculated as plasma folate area under the curve (AUC) for egg yolk, spinach, and yeast folate, were 122.6 +/- 23.6, 136.2 +/- 21.4, and 102.5 +/- 21.1 nmol . h/L, respectively. No significant differences in AUC were seen between monoglutamyl (egg yolk) folate and either of the polyglutamate-containing folates examined. CONCLUSION These results suggest that the ratio of monoglutamate to polyglutamate in natural folates is not a factor that limits the extent of intestinal absorption of food folate.
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Affiliation(s)
- Derek J McKillop
- Northern Ireland Centre for Food and Health, University of Ulster, Coleraine, United Kingdom
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Gregory JF, Quinlivan EP, Davis SR. Integrating the issues of folate bioavailability, intake and metabolism in the era of fortification. Trends Food Sci Technol 2005. [DOI: 10.1016/j.tifs.2005.03.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Melse-Boonstra A, Lievers KJA, Blom HJ, Verhoef P. Bioavailability of polyglutamyl folic acid relative to that of monoglutamyl folic acid in subjects with different genotypes of the glutamate carboxypeptidase II gene. Am J Clin Nutr 2004; 80:700-4. [PMID: 15321811 DOI: 10.1093/ajcn/80.3.700] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Before dietary folate is absorbed, polyglutamate folates are deconjugated to monoglutamates by folylpoly-gamma-glutamyl carboxypeptidase in the small intestine. The 1561T allele of the glutamate carboxypeptidase II gene (GCPII), which codes for folylpoly-gamma-glutamyl carboxypeptidase, may impair intestinal absorption of dietary folates. OBJECTIVE Our aim was to study the bioavailability of polyglutamyl folic acid relative to that of monoglutamyl folic acid across GCPII 1561 genotypes. DESIGN In a randomized study, 180 healthy adults aged 50-75 y received 323 nmol monoglutamyl folic acid/d (n = 59), 262 nmol heptaglutamyl folic acid/d (n = 61), or placebo (n = 60) for 12 wk. Genotypes were assessed after the intervention. The bioavailability of heptaglutamyl folic acid relative to that of monoglutamyl folic acid was calculated by using the changes in serum folate concentration in the treatment groups, after correction for changes in the placebo group and for the administered dose. RESULTS No subjects with the TT genotype were encountered. At baseline, serum and erythrocyte folate concentrations were higher (P < 0.05) in subjects with the CT genotype [16.3 nmol/L (geometric x; 95% CI: 13.7, 19.3 nmol/L) and 863 nmol/L (735, 1012 nmol/L), respectively; n = 19] than in subjects with the CC genotype [13.7 (13.1, 14.3) and 685 (652, 721) nmol/L, respectively; n = 161]. Baseline homocysteine concentrations were not significantly different between genotypes. The bioavailability of heptaglutamyl folic acid relative to that of monoglutamyl folic acid was not significantly different between subjects with the CC (64%; 52%, 76%) and CT genotypes (70%; 49%, 91%). CONCLUSIONS The 1561T allele of the GCPII gene does not impair the bioavailability of polyglutamyl folic acid. However, the allele is associated with higher folate status. This association may be explained by yet unidentified factors controlling the expression of the GCPII gene.
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Affiliation(s)
- Alida Melse-Boonstra
- Wageningen Centre for Food Sciences and the Division of Human Nutrition, Wageningen University, 6700 EV Wageningen, Netherlands
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Melse-Boonstra A, West CE, Katan MB, Kok FJ, Verhoef P. Bioavailability of heptaglutamyl relative to monoglutamyl folic acid in healthy adults. Am J Clin Nutr 2004; 79:424-9. [PMID: 14985217 DOI: 10.1093/ajcn/79.3.424] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND The bioavailability of dietary folate has been estimated to be approximately 50% of that of synthetic folic acid. Folate in the diet is linked to a polyglutamate chain that may restrict folate absorption. OBJECTIVE Our goal was to quantify the bioavailability and bioefficacy of low doses of polyglutamyl folic acid relative to that of monoglutamyl folic acid. DESIGN In total, 180 men and women aged 50-75 y ingested capsules containing 323 nmol heptaglutamyl folic acid/d or 262 nmol monoglutamyl folic acid/d or placebo in a randomized parallel trial. Serum and erythrocyte folate and plasma homocysteine concentrations were measured after an overnight fast at baseline and after 12 wk of intervention. RESULTS Mean serum and erythrocyte folate concentrations increased less in the polyglutamyl folic acid group [6.1 (95% CI: 5.3, 7.0) and 155 (122, 188) nmol/L, respectively] than in the monoglutamyl folic acid group [11.8 (10.3, 13.3) and 282 (246, 318) nmol/L, respectively]. Differences remained statistically significant (P < 0.05) after correction for the difference in the amount of folic acid administered. The decrease in plasma homocysteine concentrations did not differ significantly between treatment groups [polyglutamyl: -12.1% (-14.8%, -9.3%); monoglutamyl: -14.1% (-16.3%, -11.9%)]. The relative bioavailability of polyglutamyl folic acid was 64% (52%, 75%) on the basis of serum folate and was 68% (51%, 84%) on the basis of erythrocyte folate concentrations. Bioefficacy, determined by changes in plasma homocysteine concentrations, was 106% (77%, 134%). CONCLUSION The polyglutamate chain of folates in the diet reduces their bioavailability.
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Affiliation(s)
- Alida Melse-Boonstra
- Wageningen Centre for Food Sciences, Wageningen University, Wageningen, Netherlands
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Hjelt K, Krasilnikoff PA. The impact of gluten on haematological status, dietary intakes of haemopoietic nutrients and vitamin B12 and folic acid absorption in children with coeliac disease. ACTA PAEDIATRICA SCANDINAVICA 1990; 79:911-9. [PMID: 2264463 DOI: 10.1111/j.1651-2227.1990.tb11352.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The haematological status, as well as the fractional absorptions of folic acid-and of vitamin B12 (FAFol and FAB12) were studied longitudinally in 20 coelic children aged 1.2-16.6 yr (mean 7.5 yr) during periods of gluten-free and gluten containing diets. The absorption methods were specially adapted to use in children, and age-related reference limits were established. Also, dietary intakes of iron, folate and B12 were registered. The haemoglobin concentrations did not show any significant differences in relation to shifts in diet. A few had mild anaemia while the haemoglobin concentrations in the other patients remained within normal range. The iron status, as judged from mean corpuscular volume (MCV), serum (S)-iron, S-transferrin and saturation %, appeared to be generally insufficient. However, the only significant change related to shifts in diet was an increase of S-iron during the first period of gluten-free diet. Dietary intakes of iron proved to be insufficient, regardless of the type of diet. Plasma (P)-B12 concentrations demonstrated a wide range of values above the lower normal limit, whereas the level in a single patient was within the "intermediate range" of B12 insufficiency (150-200 pmol/l). The folate status (erythrocyte-folate) showed significant variations related to dietary changes. However, few patients were folate depleted. FAFol and FAB12 demonstrated rapidly occurring, and significant decreases and increases in relation to gluten challenge and gluten-free diet, respectively. Bacterial overgrowth of the small intestinal tract was not found to be a plausible cause of the B12 malabsorption in the case of 5 patients observed.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- K Hjelt
- Department of Paediatrics, University of Copenhagen, Gentofte Hospital, Hellerup, Denmark
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Abstract
Dietary folates exist as pteroylpolyglutamates (PteGlun) that undergo hydrolysis to pteroylmonoglutamate (PteGlu) forms during the process of intestinal absorption. Using the technique of jejunal perfusion of separately labeled folates, our laboratory has demonstrated that hydrolysis of PteGlun occurs on the surface of the jejunum and is a prerequisite for folate absorption. An intestinal brush border pteroylpolyglutamate hydrolase (BB-PPH) has been identified in human and pig jejunum with characteristics that are distinct from those of an intracellular hydrolase (IC-PPH). Functional parallels of BB-PPH with in vivo hydrolysis of PteGlun in human and pig intestine and the clinical responsiveness of BB-PPH to different disease states indicate that this enzyme plays the major physiological role in folate absorption. Folate malabsorption is found in diseases which affect the jejunal mucosa and in response to various drugs. In most of these clinical conditions, folate malabsorption results from suppression of both of the processes of hydrolysis of PteGlun and jejunal uptake of PteGlu. Ongoing studies in miniature pigs are aimed at definition of the sequence of development of folate malabsorption in chronic alcoholism.
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Affiliation(s)
- C H Halsted
- Department of Internal Medicine, University of California, Davis 95616
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Gregory JF. Chemical and nutritional aspects of folate research: analytical procedures, methods of folate synthesis, stability, and bioavailability of dietary folates. ADVANCES IN FOOD AND NUTRITION RESEARCH 1989; 33:1-101. [PMID: 2697230 DOI: 10.1016/s1043-4526(08)60126-6] [Citation(s) in RCA: 120] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- J F Gregory
- Food Science and Human Nutrition Department, University of Florida, Gainesville 32611
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