Molecular Nutrition

Vitamins

Vinood B. Patel, Vinood B. Patel

• Éditeur: Academic Press
• Année: 2019
• ISBN:
  9780128119365
• Sujet: Technologie et ingénierie
• Sous-sujet: Sciences de l'alimentation

Molecular Nutrition: Vitamins presents the nutritional and molecular aspects of vitamins with a specific focus on vitamins A, B1 (thiamine), B2 (riboflavin), B# (niacin), B5 (pantothenic acid), B6, (pyridoxine), B7 (biotin), B9 (folate), B12 (colbamin), C, D, E, and K. As part of the Molecular Nutrition series, this book discusses introductory aspects and general coverage of vitamins and nutrition, the molecular biology of the cell, including signaling, transporters, oxidative stress, receptors, uptake, immunity, proliferation, endoplasmic reticulum, differentiation, carcinogenesis and apoptosis. Final sections cover genetic machinery and its function, transcriptional processes, homeostasis genes, cancer, gene expression, mutations, and more.

Emerging fields of molecular biology and important discoveries related to diet and nutritional health are also covered, rounding out the book.

• Summarizes molecular nutrition in health as related to vitamins
• Includes material on signaling, transporters, oxidative stress, receptors, uptake, immunity, proliferation, endoplasmic reticulum, differentiation, carcinogenesis and apoptosis
• Presents transcriptional processes, homeostasis genes, cancer, gene expression, mutations, the sodium-dependent multivitamin transporter, p53, p21, microRNAs, one carbon metabolism, nucleic acids, DNA methylation and polymorphisms
• Addresses emerging fields of molecular biology and presents important discoveries related to diet and nutritional health
• Covers Vitamins A, B, C, D, E, and K
• Discusses their impact on health relating to cancer, diabetes, arthritis, and aging
• Includes key facts, a mini dictionary of terms, and summary points

Part I

General and Introductory Aspects

Outline

• Chapter 1 Reference dietary requirements of vitamins in different stages of life
• Chapter 2 Bioactive vitamin–metal compounds: other potential applications of vitamins
• Chapter 3 Vitamin E: an overview
• Chapter 4 Vitamin E: structure and forms
• Chapter 5 Riboflavin-enriched fermented soy milk for redox-mediated gut modulation: in the search of novel prebiotics
• Chapter 6 A review of vitamin B12
• Chapter 7 Nutrigenomic aspects of dietary pyridoxine (vitamin B₆) and selenium interaction and their implications in reproduction
• Chapter 8 Vitamin K2 is a key regulator of clinically relevant molecular processes
• Chapter 9 Biotin status screening

Chapter 1

Reference dietary requirements of vitamins in different stages of life

Mina Yamazaki Price¹ and Victor R. Preedy², ¹Division of Critical Care, Medicine and Surgery, Department of Therapies, Royal Free Hospital, Royal Free London NHS Foundation Trust, London, United Kingdom, ²Diabetes & Nutritional Sciences Division, School of Medicine, King’s College London, London, United Kingdom

Abstract

Vitamins are essential to life for their specific roles in maintaining normal physiological functions including growth and development. Deficiency and/or compromised vitamin status can result in a diversity of syndromes. Currently 13 vitamins are identified and commonly categorized as “fat-soluble” and “water-soluble” vitamins. Vitamins are not endogenously synthesized in humans to meet normal physiological needs. Therefore reference requirements are developed for individuals and populations to minimize risk of nutrient deficiency or excess in order to achieve optimal health and prevent disease. There are various factors and challenges for individuals and populations when meeting reference dietary requirements for vitamins. These include food availability, food choice, ethnicity, religion, age, season, climate, disposable income, food policies, public health strategies, and many other factors. These factors vary between different countries, populations, and communities. In this review we cover reference dietary requirements for the fat-soluble vitamins A, D, E, and K and the water-soluble vitamins thiamin (vitamin B1), riboflavin (vitamin B2), niacin (vitamin B3), vitamin B6 (pyridoxine), vitamin B12 (cobalamin), folate (vitamin B9), vitamin C, pantothenic acid, and biotin.

Keywords

Vitamins; health; disease; requirements; dietary requirements; fat-soluble vitamins; vitamin A; vitamin D; vitamin E; vitamin K; water-soluble vitamins; thiamin; vitamin B1; riboflavin; vitamin B2; niacin; vitamin B3; vitamin B6; pyridoxine; vitamin B12; cobalamin; folate; vitamin B9; vitamin C; pantothenic acid; biotin

Contents

• Key facts of vitamins 4
• Summary points 4
• Definitions of words and terms 4
• Abbreviations 5
• 1.1 Introduction 5
• 1.2 Reference dietary requirements 7
• 1.3 Fat-soluble vitamins 9
  • 1.3.1 Vitamin A 9
  • 1.3.2 Vitamin D 9
  • 1.3.3 Vitamin K 11
  • 1.3.4 Vitamin E 11
• 1.4 Water-soluble vitamins 15
  • 1.4.1 Thiamin (vitamin B1) 15
  • 1.4.2 Riboflavin (vitamin B2) 15
  • 1.4.3 Niacin (vitamin B3) 17
  • 1.4.4 Vitamin B6 (pyridoxine) 20
  • 1.4.5 Folate (vitamin B9) 20
  • 1.4.6 Vitamin B12 (cobalamin) 22
  • 1.4.7 Vitamin C (ascorbic acid) 25
  • 1.4.8 Pantothenic acid 25
  • 1.4.9 Biotin 27
• 1.5 Challenges of meeting requirements 29
• References 30
• Further reading 32

Key facts of vitamins

• • Vitamins are organic compounds and usually present naturally in food items in very small amounts.
• • Each vitamin has highly specific roles in normal physiological functions and metabolism including growth, development, and maintenance.
• • Humans require minute amounts of vitamins to meet physiological needs but are unable to endogenously synthesize adequate amounts. Therefore it is essential to obtain vitamins from food items.
• • A severe and prolonged insufficient dietary intake of specific vitamins can cause specific deficiency syndromes. For example, beriberi is a disorder caused by thiamin (vitamin B1) deficiency. Symptoms of beriberi include peripheral neuropathy, muscle pain, and weakness.
• • Vitamins are commonly classified under the umbrella of “micronutrients” in contrast to “macronutrients” (i.e., carbohydrate, protein, and fat).

Summary points

• • Currently 13 substances are recognized as vitamins. They can be categorized into two groups according to their solubilities, namely fat-soluble and water-soluble vitamins.
• • Fat-soluble vitamins are vitamins A, D, E, and K. Water-soluble vitamins are thiamin (vitamin B1), riboflavin (vitamin B2), niacin (vitamin B3), vitamin B6 (pyridoxine), vitamin B12 (cobalamin), folate (vitamin B9), vitamin C, pantothenic acid, and biotin.
• • For each vitamin, reference dietary requirements have been derived, though the amounts and age categories vary differ between countries.
• • Differences in dietary and nutrient patterns in different populations, even within the same country, influence overall vitamin intake and thus determine whether reference dietary requirements are met.
• • There are various challenges between different age groups for meeting vitamin B12 reference dietary requirements. On the other hand, it is less challenging to meet vitamin K reference dietary requirements across different populations.

Definitions of words and terms

• • Micronutrient: A chemical element required in very small amounts in living organisms to maintain normal physiological functions. It is often used in contrast to macronutrients (i.e., dietary carbohydrates, proteins, and fats).
• • Endogenously synthesized: Substances that are produced or synthesized within an organism rather than provided by nutrition.
• • Metabolic activation: The chemical reac...