An Introduction To Nutrition And Metabolism

Book Cover......Page 1
Half-Title......Page 2
Title......Page 3
Copyright......Page 4
Contents......Page 5
Preface to the second edition......Page 8
1.1  The need for energy......Page 9
1.2.1  The need for carbohydrate and fat......Page 10
1.2.3  The need for minerals and vitamins......Page 11
1.3  Hunger and appetite......Page 12
1.3.2  Why do people eat what they do ?......Page 13
1.3.2.2  Religion, habit and tradition......Page 14
1.3.2.4  The social functions of food......Page 15
2.1  Problems of deficiency......Page 17
2.2  Diseases of affluence......Page 18
2.3.1  Food additives......Page 20
2.4.1  Energy intake......Page 21
2.4.2  Fat intake......Page 22
2.4.2.1  The type of fat in the diet......Page 25
2.4.3  Carbohydrate intake......Page 26
2.4.3.1  Sugars in the diet......Page 27
2.4.3.2  Undigested carbohydrates (dietary fibre)......Page 28
2.4.4  Salt......Page 29
2.4.6  Food labelling and nutritional information......Page 30
2.5.2  Tissue damage by oxygen radicals......Page 32
2.6  Is there any need for nutritional supplements?......Page 33
3.1  Elements and atoms......Page 36
3.1.1  Isotopes......Page 38
3.2  Compounds and molecules: the formation of chemical bonds......Page 39
3.2.2  Covalent bonding: the formation of molecules......Page 40
3.2.2.1  Unsaturated compounds: single, double and triple bonds......Page 42
3.2.2.2  Free radicals......Page 43
3.2.2.3  Molecular mass and moles......Page 44
3.3  The states of matter: solids, liquids and gases......Page 45
3.3.1.1  Solution in water: ions and electrolytes......Page 46
3.3.1.2  Solution of non-ionic compounds in water......Page 47
3.4  Complex ions, acids and bases......Page 48
3.4.1  Acids, bases and salts......Page 49
3.4.1.1  pH: a measure of acidity......Page 50
3.4.1.2  Buffers and the maintenance of pH......Page 51
3.5.1  Hydrogen bonding......Page 52
3.5.3  Hydrophobic interactions......Page 53
3.5.3.1  The arrangement of lipids to form cell membranes......Page 55
3.6.1  Hydrocarbons......Page 56
3.6.1.1  Aromatic compounds......Page 57
3.6.4  Sulphydryl groups......Page 58
3.6.5  Carbonyl groups: aldehydes and ketones......Page 59
3.6.6.1  Esters......Page 60
3.7  The naming of organic compounds......Page 61
3.7.1.1  Cis-trans isomerism around double bonds......Page 62
3.7.1.2  Asymmetric centres in molecules: DL-isomerism......Page 63
3.8  Biologically important molecules......Page 64
4.1  Chemical reactions: breaking and making covalent bonds......Page 65
4.1.1  Equilibrium......Page 66
4.2  Enzymes......Page 67
4.2.1.1  pH......Page 69
4.2.1.2  Temperature......Page 70
4.2.1.3  The concentration of substrate......Page 71
4.2.1.4  Inhibitors......Page 74
4.3.1  Coenzymes and metals in oxidation and reduction reactions......Page 75
4.3.1.2  Riboflavin and flavoproteins......Page 76
4.3.1.3  The nicotinamide nucleotide coenzymes: NAD and NADP......Page 78
4.5  Metabolic pathways......Page 80
4.5.1  Linear and branched pathways......Page 81
A note on metabolic pathways......Page 82
5.1  The adenosine nucleotides......Page 83
5.2.1  The role of ATP in endothermic reactions......Page 84
5.2.2  Transport of materials across cell membranes......Page 87
5.2.2.3  Ion pumps and active transport......Page 88
5.3  The phosphorylation of ADP to ATP......Page 90
5.3.1 Oxidative phosphorylation: the phosphorylation of ADP to ATP linked to the oxidation of metabolic fuels......Page 91
5.3.1.1  The mitochondrion......Page 92
5.3.1.2  The mitochondrial electron transport chain......Page 93
5.3.1.3  Phosphorylation of ADP linked to electron transport......Page 96
5.3.1.4  The coupling of electron transport, oxidative phosphorylation and fuel oxidation......Page 97
6.1  The gastrointestinal tract......Page 100
6.2.1  The classification of carbohydrates......Page 102
6.2.1.1  Monosaccharides......Page 104
6.2.1.2  Disaccharides......Page 105
6.2.1.3  Reducing and non-reducing sugars......Page 106
6.2.1.5  Non-starch polysaccharides (dietary fibre)......Page 107
6.2.2.1  Starch digestion......Page 108
6.2.2.3  The absorption of monosaccharides......Page 109
6.3.1.1  Fatty adds......Page 111
6.3.1.3  Cholesterol and the steroids......Page 114
6.3.2  Digestion and absorption of triacylglycerols......Page 116
6.3.2.1  Bile salts......Page 117
6.4.1  The amino acids......Page 118
6.4.2  Protein structure and denaturation......Page 121
6.4.3  Protein digestion......Page 123
6.6  The absorption of iron......Page 125
7.1  Estimation of energy expenditure......Page 127
7.1.1  Indirect calorimetry and the respiratory quotient......Page 128
7.1.3.1  Basal metabolic rate (BMR)......Page 129
7.1.3.2  Energy costs of physical activity......Page 130
7.2  Energy balance and changes in body weight......Page 132
7.3.1  The fed state......Page 133
7.3.2  The fasting state......Page 134
7.4.1  Glycolysis: the metabolism of glucose......Page 136
7.4.1.1  The pentose phosphate pathway: an alternative to glycolysis......Page 139
7.4.2.1  The reduction of pyruvate to lactate: anaerobic glycolysis......Page 141
7.4.2.2  The oxidation of pyruvate to acetyl CoA......Page 142
7.4.2.3  Complete oxidation of acetyl CoA: the citric acid cycle......Page 143
7.5  The metabolism of fats......Page 144
7.5.1  Carnitine and the transport of fatty acids into the mitochondrion......Page 146
7.5.2  The β-oxidation of fatty acids......Page 148
7.6  Tissue reserves of metabolic fuels......Page 149
7.6.1  Synthesis of fatty acids and triacylglycerols......Page 150
7.6.1.1  Unsaturated fatty adds......Page 152
7.6.2  Glycogen......Page 153
7.7  Gluconeogenesis: the synthesis of glucose from non-carbohydrate precursors......Page 156
8.1.1  Body mass index......Page 159
8.1.2  Measurement of body fat......Page 160
8.1.2.3  Imaging techniques......Page 162
8.2  The problem of overweight and obesity......Page 163
8.2.2  The health risks of obesity......Page 164
8.3  The causes and treatment of obesity......Page 166
8.3.2.1  Control of appetite......Page 167
8.3.3.1  How fast can excess weight be lost?......Page 168
8.3.3.3  Very low-energy diets......Page 169
8.3.3.5  Low carbohydrate diets......Page 170
8.3.3.7  ‘Diets’ that probably won’t work......Page 171
8.3.3.9  Appetite suppressants......Page 172
8.3.3.11  Help and support......Page 173
9.1  The classification of protein-energy malnutrition......Page 175
9.2  Marasmus......Page 176
9.2.1.1  Disorders of appetite: anorexia nervosa and bulimia......Page 177
9.2.1.2  Malabsorption......Page 178
9.2.1.4  Cachexia......Page 179
9.3  Kwashiorkor......Page 180
9.3.2  Rehabilitation of malnourished children......Page 181
10 Protein Nutrition and Metabolism......Page 182
10.1  Nitrogen balance and protein requirements......Page 183
10.1.1  Dynamic equilibrium......Page 184
10.1.2  Protein requirements......Page 185
10.1.2.2  Protein requirements in convalescence......Page 187
10.1.3  Essential amino acids......Page 188
10.1.3.1  Protein quality and complementation......Page 189
10.2  Protein synthesis......Page 190
10.2.1  The structure and information content of DNA......Page 191
10.2.1.2  The replication of DNA......Page 193
10.2.2.1  Transcription to form messenger RNA (mRNA)......Page 194
10.2.3  Translation of mRNA: the process of protein synthesis......Page 196
10.2.3.1  Transfer RNA (tRNA)......Page 197
10.2.3.2  Protein synthesis on the ribosome......Page 198
10.2.3.3  The energy cost of protein synthesis......Page 199
10.3  The metabolism of amino acids......Page 200
10.3.1.1  Deamination......Page 201
10.3.1.2  Transamination......Page 202
10.3.1.3  The metabolism of ammonia......Page 204
10.3.1.4  The synthesis of urea......Page 205
10.3.1.5  Incorporation of nitrogen in biosynthesis......Page 206
10.3.2  The metabolism of amino acid carbon skeletons......Page 208
11 The Integration and Control of Metabolism......Page 210
11.1.1  Allosteric modification of the activity of regulatory enzymes......Page 211
11.2  Responses to fast-acting hormones by covalent modification of enzyme proteins......Page 213
11.2.2  Cyclic AMP and cyclic GMP as second messengers......Page 215
11.2.3  Inositol trisphosphate and diacylglycerol as second messengers......Page 218
11.2.4  The insulin receptor......Page 219
11.3  Slow-acting hormones: changes in enzyme synthesis......Page 220
11.4  Hormonal control in the fed and fasting states......Page 221
11.4.1  Hormonal control of adipose tissue metabolism......Page 222
11.4.2  Control of fuel utilization in muscle......Page 223
11.5  Diabetes mellitus: a failure of hormonal regulation......Page 225
12.1  The determination of requirements and reference intakes......Page 227
12.1.1  Dietary reference values......Page 228
12.2  The vitamins......Page 233
12.2.1  Vitamin A......Page 236
12.2.1.2  Metabolic functions of carotene......Page 237
12.2.1.3  Vitamin A deficiency: night blindness and xerophthalmia......Page 238
12.2.1.5  Toxicity of preformed vitamin A......Page 239
12.2.2.1  Synthesis of vitamin D in the skin......Page 240
12.2.2.4  Vitamin D deficiency: rickets and osteomalacia......Page 241
12.2.2.6  Vitamin D toxicity......Page 243
12.2.3  Vitamin E......Page 244
12.2.3.1   Metabolic functions and deficiency of vitamin E......Page 245
12.2.4.1  Metabolic functions of vitamin K......Page 246
12.2.4.2  Vitamin K requirements......Page 248
12.2.5.1  Thiamin deficiency: beriberi and the Wernicke-Korsakoff syndrome......Page 249
12.2.6.2  Riboflavin requirements......Page 250
12.2.7  Niacin......Page 251
12.2.7.2  Niacin requirements......Page 252
12.2.8.1  Vitamin B6 deficiency......Page 253
12.2.8.2  Vitamin B6 requirements......Page 254
12.2.9  Vitamin B12......Page 255
12.2.9.1  Vitamin B12 deficiency: pernicious anaemia......Page 256
12.2.10.1  Folate deficiency: megaloblastic anaemia......Page 257
12.2.10.2  Folate requirements and pregnancy......Page 258
12.2.10.3  Folate toxicity......Page 259
12.2.12  Pantothenic acid......Page 260
12.2.13  Vitamin C (ascorbic acid)......Page 261
12.2.13.1  Vitamin C deficiency: scurvy......Page 262
12.2.13.3  High intakes of vitamin C......Page 263
12.3.1  Calcium......Page 264
12.3.1.1  Osteoporosis......Page 265
12.3.2.3  Iron......Page 266
12.3.2.6  Zinc......Page 267
12.3.3.3  Iodine......Page 268
12.3.4.1  Silicon......Page 270
12.3.5.2  Lithium......Page 271
12.3.5.3  Other minerals......Page 272
Appendix One......Page 273
Appendix Two......Page 275
Food composition tables......Page 294
Vitamins......Page 295
Sources of research reviews on nutritional topics......Page 296
Index......Page 297