& Joannie Dobbs Saturday
April 21, 2007
Jack Sprat missed out on essential acids
Many people eat too much fat. But, could some of us actually be eating too little fat? People who attempt to eat a nearly fat-free diet or limited amounts of certain types of fat may not be meeting their essential fatty acid requirements.
Fats and the essential fatty acid components of fat are required for numerous important functions in the body.
Question: What are the functions of dietary fats?
Answer: The components of fats and oils have many important functions in the body. Fats are sources of energy and essential fatty acids that the body can't make.
As part of a meal, fats promote the intestinal absorption of both essential fat-soluble vitamins and many phytochemicals that are beneficial to health. Vitamins A, D, E, and K, as well as many phytochemicals such as lycopene and lutein, are poorly absorbed by the intestine when the meal lacks fat.
Fats play extremely important roles in the structures of cells, chemical reactions in the body, the synthesis and regulation of various hormones, the integrity of blood vessels, the conduction of nerve impulses, blood pressure regulation, blood clotting, and even memory storage.
Q: How much fat is needed in the diet to meet these needs?
A: The Institute of Medicine recommends that people consuming about 2,000 calories a day consume a minimum of 45 grams of dietary fat.
However, when fat intake is this low, it can be difficult to get an adequate amount of dietary essential fatty acids unless fat sources are selected carefully.
Q: Which foods provide essential fatty acids?
A: The two basic types of essential fatty acids, omega-3 and omega-6, are found in some common plant oils like soybean and canola oils.
However, many plant oils only provide one of these fatty acids in significant amounts and some plant oils are low in both.
Olive oil is low in both essential fatty acids, despite its other positive attributes. To meet recommended levels of essential fatty acid intake solely with olive oil, an adult would need to consume about 2,000 calories of olive oil every day.
Most cultures that rely heavily on olive oil obtain their omega-3 fatty acids from fish oils. The types of omega-3 fatty acids in fish oils are used by the body much more efficiently than are those found in plant oils.
Consuming a variety of food sources of fats and oils in moderate amounts increases the odds of meeting the body's needs for these important components of fats
Alan Titchenal, Ph.D., C.N.S. and Joannie Dobbs, Ph.D., C.N.S.
are nutritionists in the Department of Human Nutrition, Food and Animal Sciences,
College of Tropical Agriculture and Human Resources, UH-Manoa.
Dr. Dobbs also works with the University Health Service
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