Understanding Dietary Fats and Oils
A Scientific Guide to their Health
Effects
Dr.
Steve Blake, ScD
2010
LifeLong
Press
College
of World Health
Permission
granted for everyone to download and read this book ©2009 Steve Blake
This book provides a comprehensive overview of the role that fats and oils play in human health. Both fats in foods and added fats are investigated. There is now clear evidence that certain dietary fats and oils affect the incidence of heart and artery disease, diabetes, and obesity.
Our choices of fats and oils are crucial in attaining excellent health and preventing disease. Alterations in dietary fats can also sometimes reverse certain diseases, such as atherosclerosis, the very common clogging of arteries.
My goal is to provide reliable and accurate information to help guide you in your quest for better health. I will introduce you to triglycerides, which are the most common form of fat in food and in the human body. Each triglyceride is made up of three fatty acids. These fatty acids are the key to understanding fats.
Our cell membranes are vitally important for health. These cell membranes are largely composed of two important fatty substances: phospholipids and cholesterol. Phospholipids each contain two fatty acids. The specific fatty acids in the phospholipids and the amount of cholesterol determine the fluidity of the cell membranes. Excessive amounts of saturated fatty acids in cell membranes reduce the number of receptors needed for removal of excess sugars and fats from the bloodstream. Phospholipids also act as storehouses for the longer chain fatty acids. Cholesterol has many uses in our bodies, especially as a raw material for the creation of hormones and vitamin D.
There are only two fatty acids needed by human beings. Both of these essential fatty acids provide the raw materials for eicosanoids. Eicosanoids are powerful tissue hormones. On a cellular level, these tissue hormones determine our response to injury. They control certain aspects of inflammation, blood clotting, and arterial contractions. This makes them important in heart disease and arthritis and many other states of disease and health. Our response to inflammation and blood clotting can be altered by dietary changes that affect the balance between the essential fatty acids.
I look forward to your comments and suggestions,
Steve Blake, October, 2009
A special thanks to Dr. William Harris for his generous support of this book project.
Part I: From Seeds To Cells
Chapter 1, What happened to our fats and oils? 14
Chapter 2, Three Kinds of Fat: Triglycerides, Phospholipids, and Cholesterol 30
Chapter 3, Digestion and transport of food fats 44
Part II: Four Kinds of Fat
Chapter 4, Saturated fats: the hard fats 57
Chapter 5, Monounsaturated fats 78
Chapter 6, Essential fats 90
Chapter 7, Trans fatty acids: the bread and butter of disease 106
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 163
Part IV: Powerful balances
Chapter 11, Eicosanoid precursors: how EPA is made 180
Chapter 12, Eicosanoids: cellular activists 197
Chapter
1: What happened to our fats and oils?.
Preparing
the seeds, beans, or grains for processing
The
loss of lecithin: degumming
Deodorization
or physical refining
Vitamin
E lost in oil processing
Chemicals
leaching into oils from bottles
Fat
mimetics and fat substitutes
Chapter
2: Three Kinds of Fat, Triglycerides, Phospholipids, and Cholesterol
Triglycerides in food, in
fat cells, and in blood
Uses
of triglycerides in the body
Health effects of excess
triglycerides
Chapter
3: Digestion and Transport of Food Fats
Digestion
of fats in the mouth and stomach
Digestion
of fats and oils in the intestine
Lipoproteins: transport of
lipids through the bloodstream
Measuring
blood LDL and HDL levels
Measuring
total serum cholesterol
Chapter
4: Saturated fats, the hard fats
Uses of saturated fats in
our bodies
How
excess saturated fats increase blood cholesterol
Saturated fats and blood
cholesterol
How much saturated fat is
too much?
Saturated fats made in the
body
Length
of saturated fatty acids
The
acid delta end and the methyl omega end
Chapter
5: Monounsaturated Fats
Biological importance of
cis and trans bonds
Common monounsaturated
fatty acids
Other monounsaturated
fatty acids
Common and uncommon
monounsaturated fatty acids
Activation of essential
fatty acids
ALA and LA are needed
inside our bodies
Other long-chain
polyunsaturated fatty acids
Linoleic acid, the easy
essential fatty acid
The
structure of linoleic acid
Alpha-Linolenic acid, the
hard-to-get essential fatty acid
Why ALA and LA cannot be
made in the body
Chapter
7: Trans Fatty Acids, The Bread and Butter of Disease
Dietary sources of trans
fatty acids
Alternatives to partially
hydrogenated oils
The risks of reducing
trans fats
Animal
fats to replace hydrogenated oils
Choosing food low in trans
fatty acids
Worldwide
variation in trans fatty acid intake
Absorption and metabolism
of trans fatty acids
Heart disease and trans fatty
acids
Diabetes and trans fatty
acids
Trans fatty acids in
infants and children
Trans fatty acids from
dairy products and beef
Structure of trans fatty
acids
Part
III: Best Oils, Worst Fats
Chapter
8: Comparing fats and oils
What makes an oil or fat
healthy?
A
nice balance of the essential fatty acids
Oils
need the protection of vitamin E
Processing
can ruin a good oil
Genetic alteration of oil
seeds