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Understanding Dietary Fats and Oils:
A Scientific Guide to their Health EffectsDr. Steve Blake, ScD
New in April 2010
Updated October 2010
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Please see below for a detailed table of contents and a list of charts, figures, and graphs, with some samples.
Table of contents
Part I: From Seeds To Cells
Chapter 1, What happened to our fats and oils? 18
Chapter 2, Three Kinds of Fat: Triglycerides, Phospholipids, and Cholesterol 32
Chapter 3, Digestion and transport of food fats 46
Part II: Four Kinds of Fat
Chapter 4, Saturated fats: the hard fats 59
Chapter 5, Monounsaturated fats 80
Chapter 6, Essential fats 92
Chapter 7, Trans fatty acids: the bread and butter of disease 107
Part III: Best Oils, Worst Fats
Chapter 8, Comparing fats and oils 129
Chapter 9, Comparing less common oils 148
Chapter 10, Comparing the oils in food 162
Part IV: Powerful balances
Chapter 11, Eicosanoid precursors: how EPA is made 177
Chapter 12, Eicosanoids: cellular activists 193
Detailed Table of Contents
Introduction 2
Table of contents 3
Detailed table of contents 4
List of Charts 14
List of Figures 15
List of Graphs 16
Part I: From Seeds To Cells
Chapter 1
What happened to our fats and oils? 18
Summary 18
The uses of fats and oils 18
How oil used to be made 18
Modern oil processing 19
Changing the seeds 20
Seeds that have not been genetically mutated 20
Some genetically engineered oils 21
Cold pressed oils 21
Preparing the seeds, beans, or grains for processing 21
Expeller pressed oils 21
Hexane extraction of oils 22
Oils not normally extracted with the solvent hexane 22
Oils routinely extracted with the solvent hexane 23
The loss of lecithin: degumming 24
Caustic refining 24
Bleaching of edible oils 25
Nutrients eliminated during bleaching of oils 26
Dewaxing 26
Hydrogenation 26
Winterization 28
Deodorization or physical refining 28
Vitamin E lost in oil processing 29
Chemicals leaching into oils from bottles 30
References 30
Chapter 2
Three Kinds of Fat: Triglycerides, Phospholipids, and Cholesterol 32
Summary 32
Triglycerides in food, in fat cells, and in blood 32
Uses of triglycerides in the body 33
The shape of triglycerides 33
Digestion of triglycerides 36
Health effects of excess triglycerides 37
Phospholipids 37
Phosphatidlinositol 40
Phosphatidylserine 40
Phosphatidylcholine 41
Phosphatidylethanolamine 41
Sphingolipids 41
Cholesterol and other sterols 42
Plant sterols 44
References 45
Chapter 3
Digestion and Transport of Food Fats 46
Summary 46
Digestion of fats and oils 46
Digestion of fats in the mouth and stomach 47
Bile emulsifies fat 47
Bitter tonics 48
Digestion of fats and oils in the intestine 49
Absorption of lipids 50
Micelles 50
Chylomicrons 50
Lipoproteins: transport of lipids through the bloodstream 51
Chylomicrons 51
Very low density lipoproteins 52
Vitamin E and lipoproteins 52
VLDL becomes LDL 53
LDL: Low density lipoproteins 53
High density lipoproteins 54
The ratio of total cholesterol to HDL 55
Measuring total serum cholesterol 55
Ratios of lipoproteins 56
Metabolism of fats and oils 56
References 58
Part II: Four Kinds of Fat
Chapter 4
Saturated fats, the hard fats 59
Summary 59
Uses of saturated fats in our bodies 60
How excess saturated fats increase blood cholesterol 60-61
Saturated fats and disease 61
Saturated fats and diabetes 62
Saturated fats and blood cholesterol 62
How much saturated fat is too much? 63
Saturated fats made in the body 64
Saturated fats in food 64
Saturated fats in diets 68
Atkin's diet 69
American diet 70
Mediterranean diet 71
Vegetarian diet 72
Whole food vegan diet 73
Raw food diet high in fats from nuts and seeds 74
Heart attack recovery diet 75
Structure of saturated fats 75
Length of saturated fatty acids 76
Chart of saturated fatty acids 76
The acid delta end and the methyl omega end 76
References 78
Chapter 5
Monounsaturated Fats 80
Summary 80
Oleic acid 80
Oleic acid in nuts and seeds graph 81
Oleic acid in nuts in common oils graph 82
Double bonds 82
Omega-9 fatty acid 84
Double bonds and oxidation 85
Cis and trans configurations 85
Biological importance of cis and trans bonds 86
Common monounsaturated fatty acids 87
Shorthand notation 88
Other monounsaturated fatty acids 88
Palmitoleic acid 88
Petroselinic acid 88
Gadoleic acid 89
Cetoleic acid 89
Erucic acid 89
Nervonic acid 90
Common and uncommon monounsaturated fatty acids (with chart) 90
References 91
Chapter 6
Essential Fats 92
Summary 92
The meaning of essential 92
Activation of essential fatty acids 93
ALA and LA are needed inside our bodies 93
Other long-chain polyunsaturated fatty acids 95
Linoleic acid, the easy essential fatty acid 95
Food sources of linoleic acid 96
Linoleic acid in common diets 98
The structure of linoleic acid 98
Alpha-Linolenic acid, the hard-to-get essential fatty acid 99
Food sources of ALA 100
ALA in oils and fats 101
ALA in some common diets 102
Structure of ALA 103
Why ALA and LA cannot be made in the body 104
References 106
Chapter 7
Trans Fatty Acids: The Bread and Butter of Disease 107
Summary 107
Introduction 107
Dietary sources of trans fatty acids 108
Alternatives to partially hydrogenated oils 109
Frying 109
Snack foods 110
Bakery products 110
The risks of reducing trans fats 110
Palm and other tropical oils 111
Animal fats to replace hydrogenated oils 111
Designer oils 111
Choosing food low in trans fatty acids 111
Worldwide variation in trans fatty acid intake 112
Trans fats in food in America 113
Labeling deceit 114
Absorption and metabolism of trans fatty acids 114
Heart disease and trans fatty acids 115
Trans fats and blood lipids 115
Diabetes and trans fatty acids 116
Trans fatty acids in infants and children 117
Trans fatty acids from dairy products and beef 117
Structure of trans fatty acids 118
Trans fatty acids in animal vs. vegetable fats 122
Conjugated linoleic acid 123
References 126
Part III: Best Oils, Worst Fats
Chapter 8
Comparing fats and oils 129
Summary 129
What makes an oil or fat healthy? 129
A nice balance of the essential fatty acids 130
Oils need the protection of vitamin E 130
Avoid trans fats 130
Saturated fats 131
Organic oils are healthier 132
Processing can ruin a good oil 132
Comparing fats and oils 132
Butter 132
Canola oil 133
Cocoa butter 135
Coconut oil 135
Palm kernel oil 136
Monolaurin and monocaprin 136
Corn oil 137
Cottonseed oil 138
Flax oil 138
Lard 139
Olive oil 139
Palm oil 140
Peanut oil 141
Safflower oil 142
Sesame oil 142
Soybean oil 143
Sunflower oil 143
Vegetable shortening 144
Genetic alteration of oil seeds 145
Mutagenic breeding 145
Genetic engineering 146
References 147
Chapter 9
Comparing Less Common Oils 148
Summary 148
Uncommon oils 148
Almond oil 148
Amaranth oil 149
Apricot kernel oil 149
Avocado oil 149
Black currant oil 150
Borage oil 150
Candlenut oil 151
Caraway oil 151
Cashew oil 151
Cherry oil 152
Chia oil 152
Evening primrose oil 153
Gold of pleasure oil 153
Grapeseed oil 154
Hazelnut oil 154
Hemp oil 155
Honesty seed oil 155
Macadamia nut oil 155
Mango oil 155
Marigold oil 155
Nigella oil 156
Niger oil 156
Nutmeg butter 157
Oat oil 157
Passionfruit seed oil 158
Perilla seed oil 158
Pistachio nut oil 158
Poppy seed oil 158
Purslane seed oil 159
Rice bran oil 159
Shea butter 159
Walnut oil 159
Wheatgerm oil 160
References 160
Chapter 10
Comparing the Oils in Food 162
Summary 162
Fats in food 162
Nuts and Seeds 162
Oleic acid in nuts and seeds 163
Saturated fats in nuts and seeds 163
Vitamin E in nuts and seeds 164
Alpha-linolenic acid in nuts and seeds 165
Linoleic acid in nuts and seeds 166
Fatty acids in commonly selected food choices 167
Total fat in food 168
Saturated fat in food 169
Cholesterol in common food selections 170
Trans fats in selected foods 171
Monounsaturated fats in selected food 172
Linoleic acid in selected food sources 173
Alpha-linolenic acid in selected food sources 174
EPA and DHA in selected food sources 174
Vitamin E in selected food sources 175
References 176
Part IV: Powerful balances
Chapter 11
Eicosanoid precursors: how EPA is made 177
Summary 177
How the essential fatty acids are elongated and desaturated 178
Can our bodies make enough EPA or do we need to eat fish or fish oils? 179
Dietary guidelines and intakes for EPA and ALA 180
Competition for the desaturation enzymes 181
The ratio of LA to ALA 182
Hormones affect desaturation 184
Nutrition and desaturation 185
Other factors that affect desaturation 187
Conversion of ALA to EPA, step by step 187
Blood levels of EPA and arachidonic acid 190
References 191
Chapter 12
Eicosanoids: cellular activists 193
Summary 193
Eicosanoid precursors 194
Eicosanoids 194
Eicosanoids in inflammation 195
The eicosanoids 196
Thromboxanes 196
The Balance between series 2 and series 3 thromboxanes 197
The biosynthesis of thromboxanes 198
Leukotrienes 198
Biosynthesis of Leukotrienes 199
Asthma and leukotrienes 199
Inflammation and leukotrienes 200
Prostacyclins 201
Blood clotting and prostacyclins 202
Kidneys and prostacyclin 202
Aspirin, Prostacyclin, and Thromboxane 203
Prostaglandins 205
Biosynthesis of prostaglandins 206
Dietary fatty acids and prostaglandins 207
Regulation of prostaglandins 207
Prostaglandin E, PGE 208
Inflammation and PGE 208
Blood clotting and PGE 209
Immune response and PGE 209
Lungs and PGE 209
Digestion and PGE 209
Other effects of PGE 210
Chart of eicosanoids 210
Prostaglandin D, PGD 211
Prostaglandin F, PGF2α 211
Prostaglandin J, PGJ 212
PGJ and tumors 212
References 212
Charts
Some oils have not been genetically engineered or mutated 20
Some genetically engineered oils 21
Oils not normally extracted with the solvent hexane 22
Oils routinely extracted with the solvent hexane 23
Nutrients eliminated during bleaching of oils 26
Hydrogenation changes melting temperatures 27
Bitter tonics can stimulate bile after fatty meals 48
The ratio of total cholesterol to HDL 55
How Excess Saturated Fats Raise Blood Cholesterol 60
Saturated fat chart 76
Chart of monounsaturated fatty acids 91
The importance of essential fatty acids and their derivatives 94
Food sources of ALA 100
Essential fatty acids in common diets, including added flaxseed 102
Trans fat consumption from hydrogenation and ruminant sources 108
Trans fatty acids in animal vs. vegetable fats 122
Balancing the essential fatty acids in cooking oils 135
Which is the best oil? 141
Food serving size for comparison 168
Essential fatty acids in common diets, including added flaxseed 184
Types of eicosanoids 195
Inflammation triggered by leukotrienes 200
Prostacyclin functions 202
Eicosanoid chart 210
Figures
Triglyceride 3D 34
Trans-oleic acid, Stearic acid, and Oleic acid 3D 35
Comparing triglycerides with saturated and unsaturated fats 35
Triglycerides and phospholipids are similar 38
The four types of phospholipids 39
Phospholipids in cell membranes 40
Sphingomyelin structure 42
Cholesterol structure 43
Stigmasterol structure 44
Triglyceride 3D 47
Triglyceride hydrolysis structure 49
VLDL and LDL 53
Metabolism of fat 57
Stearic acid structure 77
The structure of four common saturated fats 78
Unsaturated and saturated bonds 83
Oleic acid compared to stearic acid, 2D structures 84
Oleic acid compared to stearic acid, 3D structures 85
Structural differences between cis-oleic and trans-oleic acids 86
Oleic acid compared to stearic acid and trans-oleic, 3D structures 85
Petroselenic acid, a positional isomer of oleic acid 88
Linoleic acid structure 2D 99
ALA structure, 2D 104
Delta-5 desaturase diagram in the last step of EPA biosynthesis 105
Major sources of trans fats for American adults 113
The structure of trans and cis bonds compared, 2D 120
Elaidic and vaccenic trans fatty acid structures compared, 2D 121
Oleic acid compared to stearic acid and trans-oleic, 3D structures 122
Conjugated trans linoleic acid structure, 2D 124
Omega-3 and omega-6 eicosanoid precursors 179
Biosynthesis of eicosanoid precursors, simplified 181
Effects of hormones on the desaturation of ALA 185
Effects of nutrition on the desaturation of ALA 187
The first step in creating EPA from ALA 188
The second step in creating EPA from ALA 189
The third step in creating EPA from ALA 190
Biosynthesis of eicosanoids 197
Biosynthesis of thromboxanes 198
Biosynthesis of prostacyclin 201
Aspirin, Prostacyclin, and Thromboxane 203
Biosynthesis of prostaglandins 205
Series 1, 2, and 3 prostaglandins 206
Graphs
Saturated fatty acid content of one serving of various foods 65
The amount and variation of saturated fats in some common nuts and seeds 66
Saturated fats in one serving of various common livestock products 67
Saturated fats in one serving of common fats and oils 68
Atkin's diet saturated fats 69
Standard American diet saturated fats 70
Mediterranean diet saturated fats 71
Transition vegetarian diet saturated fats 72
Whole food vegan diet saturated fats 73
Raw food vegan diet saturated fats 74
Heart attack recovery diet saturated fats 75
Oleic acid in nuts and seeds 81
Oleic acid in common oils 82
Food sources of linoleic acid 96
Linoleic acid in common oils 97
ALA in common oils with LA/ALA ratios 101
Saturated fats in common fats and oils 131
ALA in common oils 134
Vitamin E in common oils 137
Oleic acid in some common oils 144
Vitamin E in less common oils 150
GLA in four oils 151
Oleic acid in less common oils 153
Linoleic acid in less common oils 154
Saturated fatty acids in less common oils 157
Percent of ALA in less common oils 158
Oleic acid in nuts and seeds 163
Saturated fat in one serving of nuts and seeds 164
Vitamin E compared to daily need in nuts and seeds 165
ALA in nuts and seeds 166
Linoleic acid in nuts and seeds 167
Total fat in one serving of selected food 169
Saturated fat in one serving of selected food 170
Dietary cholesterol in selected food 171
Trans fatty acids in selected food 172
Monounsaturated fats in selected food 172
Linoleic acid in selected food 173
ALA in selected food 174
EPA and DHA in selected food 175
Vitamin E in selected food 176
ALA in common oils with LA/ALA ratios 183
