Teas, Cocoa and Coffee: Plant Secondary Metabolites and Health Book

Contributors ix

1 The Origins of Tea, Coffee and Cocoa as Beverages 1
Timothy J. Bond

1.1 Introduction 1

1.2 The beverages in question 1

1.3 Discoveries – myth and legend 2

1.3.1 Tea 3

1.3.2 Coffee 4

1.3.3 Cacao products 5

1.4 Global domination begins 8

1.4.1 Tea – overland and a race by sea 9

1.4.2 Coffee – from persecution to epitomising the protestant work ethic 13

1.4.3 Chocolate – from lying down . . . to sitting up 14

1.5 From foreign fancies to the drinks of the masses 15

1.6 Tea, coffee and chocolate ‘go public’ 18

1.7 Opinion is divided on the merits of the three beverages 19

1.8 Tea, coffee and chocolate – the future 22

References 22

2 Purine Alkaloids: A Focus on Caffeine and Related Compounds in Beverages 25
Michael E.J. Lean, Hiroshi Ashihara, Michael N. Clifford and Alan Crozier

2.1 Introduction 25

2.2 Occurrence of purine alkaloids 26

2.3 Biosynthesis of purine alkaloids 27

2.4 Degradation of purine alkaloids 27

2.5 Decaffeinated tea and coffee 29

2.6 Metabolism of caffeine by humans 31

2.7 Effects of caffeine consumption on human health 33

2.7.1 Biochemical and biological actions of caffeine 34

2.7.2 Mental performance enhancement 37

2.7.3 Physical performance enhancement 37

2.7.4 Caffeine toxicity 38

2.7.5 Tolerance, withdrawal and dependence 39

2.7.6 Caffeine in pregnancy 39

2.7.7 Toxicity in other species 40

2.8 Summary 40

References 40

3 Phytochemicals in Teas and Tisanes and Their Bioavailability 45
Michael N. Clifford and Alan Crozier

3.1 Introduction 45

3.2 Phytochemical content of teas and tisanes 45

3.2.1 Camellia teas 45

3.2.2 Yerba mat´e tea 54

3.2.3 Itadori tea 58

3.2.4 Rooibos tea 59

3.2.5 Honeybush tea 59

3.2.6 Chamomile tea 62

3.2.7 Hibiscus tea 62

3.2.8 Fennel tea 63

3.2.9 Anastatica tea 63

3.2.10 Ficus tea 66

3.3 Bioavailability – absorption, distribution, metabolism and excretion 66

3.3.1 Green tea 68

3.3.2 Black tea 77

3.3.3 Itadori tea 80

3.3.4 Rooibos tea 81

3.3.5 Honeybush tea 84

3.3.6 Hibiscus tea 85

3.3.7 Fennel tea 85

3.3.8 Other teas 87

3.4 Summary 87

References 88

4 Teas, Tisanes and Health 99
Diane L. McKay, Marshall G. Miller and Jeffrey B. Blumberg

4.1 Introduction 99

4.2 Black, oolong and green tea (C. sinensis) 100

4.2.1 Black tea 100

4.2.2 Oolong tea 107

4.2.3 Green tea 109

4.3 Other teas and tisanes 116

4.3.1 Yerba mat´e (Ilex paraguariensis) 116

4.3.2 Itadori (Polygonum cuspidatum) 118

4.3.3 Chamomile (Chamomilla recutita L.) 119

4.3.4 Hibiscus (Hibiscus sabdariffa L.) 120

4.3.5 Rooibos (Aspalathus linearis) 126

4.3.6 Honeybush (Cyclopia intermedia) 128

4.4 Summary and conclusions 130

References 131

5 Phytochemicals in Coffee and the Bioavailability of Chlorogenic Acids 143
Angelique Stalmach, Michael N. Clifford, Gary Williamson and Alan Crozier

5.1 Introduction 143

5.2 Harvesting coffee beans, roasting and blending 144

5.3 Phytochemicals in coffee 144

5.3.1 Effects of roasting on the phytochemical content of coffee beans 149

5.3.2 Chlorogenic acid intake and coffee consumption 154

5.4 Bioavailability of coffee chlorogenic acids in humans 155

5.4.1 Studies involving volunteers with and without a functioning colon 156

5.5 Conclusions 164

References 164

6 Coffee and Health 169
Gary Williamson

6.1 Introduction 169

6.2 Antioxidant status 170

6.2.1 Effect of coffee consumption on antioxidant status: epidemiological and cohort studies 179

6.2.2 Effect of coffee consumption on antioxidant status: intervention studies 179

6.3 Diabetes 180

6.3.1 Effect of coffee consumption on diabetes risk: epidemiological and cohort studies 180

6.3.2 Effect of coffee consumption on diabetes risk: intervention studies 182

6.4 Cardiovascular disease 183

6.4.1 Effect of coffee consumption on cardiovascular risk: epidemiological and cohort studies 183

6.4.2 Effect of coffee consumption on cardiovascular risk: intervention studies 184

6.5 Effect of coffee on inflammation 186

6.6 Effect of coffee consumption on cancer risk 186

6.6.1 Effect of coffee consumption on cancer risk: epidemiological and cohort studies 186

6.6.2 Effect of coffee consumption on cancer risk: intervention studies 188

6.7 Summary 188

References 188

7 Phytochemicals in Cocoa and Flavan-3-ol Bioavailability 193
Francisco Tomas-Barberan, Gina Borges and Alan Crozier

7.1 Introduction 193

7.2 Phytochemicals in cocoa 194

7.2.1 Purine alkaloids, theobromine and caffeine 194

7.2.2 Flavan-3-ols 194

7.2.3 Phenolic acid derivatives 196

7.2.4 Minor phytochemicals 197

7.3 Bioavailability of cocoa flavan-3-ols 198

7.3.1 Background 198

7.3.2 Flavan-3-ol monomers 200

7.3.3 Procyanidins 210

7.4 Conclusions 212

References 213

8 Cocoa and Health 219
Jennifer L. Donovan, Kelly A. Holes-Lewis, Kenneth D. Chavin and Brent M. Egan

8.1 Introduction 219

8.2 Composition of cocoa products 220

8.3 Worldwide consumption of cocoa and its contribution to flavonoid intake 222

8.4 Epidemiological and ecological studies of cocoa 222

8.5 Cocoa effects on vascular endothelial function and platelet activity 224

8.6 Cocoa and hypertension 227

8.7 Antioxidant and anti-inflammatory effects of cocoa 229

8.8 Effects of cocoa consumption on lipid and lipoprotein metabolism 232

8.9 Cocoa effects on insulin sensitivity 233

8.10 Cocoa effects on cerebral blood flow and neurocognitive functioning 234

8.11 Potential negative health effects of cocoa consumption 237

8.11.1 Obesity 237

8.11.2 Testicular health 237

8.11.3 Acne 238

8.11.4 Dental caries 238

8.12 Effects of consumption of cocoa with milk or other foods 238

8.13 Conclusions 239

References 240

Index 247

A color plate section falls between pages 6 and 7