National Academies Press: OpenBook

Dietary Fat and Human Health; a Report (1966)

Chapter: NUTRITIONAL ROLE OF FOOD FATS

« Previous: FAT METABOLISM
Suggested Citation:"NUTRITIONAL ROLE OF FOOD FATS." National Research Council. 1966. Dietary Fat and Human Health; a Report. Washington, DC: The National Academies Press. doi: 10.17226/18643.
×
Page 21
Suggested Citation:"NUTRITIONAL ROLE OF FOOD FATS." National Research Council. 1966. Dietary Fat and Human Health; a Report. Washington, DC: The National Academies Press. doi: 10.17226/18643.
×
Page 22

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

NUTRITIONAL ROLE OF FOOD FATS Energy and Storage Fat is the most concentrated energy source in the diet. One gram of fat provides approximately 9 calories, compared with 4 calories from 1 gm of protein or carbohydrate. Fat is the only form of energy that the body can store in quantity. For this purpose, both carbohydrate and protein are converted to fat. Adipose tis- sue insulates the body from rapid changes in environmental temperature and cushions organs and the body as a whole against external forces. Palatability of Diets Dietary fat has a palatability role difficult to measure but impor- tant to proper nutrition. An appreciable content of fat is requisite to a diet generally acceptable in our society. Observations of fat-craving are quite common among peoples deprived of their accustomed intake of fat. Satiety from fats in the diet may be in part traceable to the slower emptying of the stomach when a high-fat meal has been ingested. Many of the substances respon- sible for the flavors and aromas of foods are dissolved in fat and associated with the fat in the diet. The distinctiveness and attrac- tiveness of a foodstuff often can be attributed to desirable flavor and texture qualities provided by the fatty constituents. Nutrient Carriers Fats in the diet act as carriers of certain nonfat nutrients. Some fats, such as butterfat and the fats of marine animals, eggs, and margarine (through fortification), provide important amounts of vitamins A and D. Many fats contain vitamin E and some are sources of vitamin K. 21

Dietary Fat and Human Health Essential Fatty Acids The essentiality of certain polyunsaturated fatty acids in the diet was demonstrated first in experiments with rats (27). The essential fatty acids are required by animals for growth, re- production, membrane integrity, and the proper utilization and metabolism of fat. Linoleic and arachidonic acids will cure essential fatty acid deficiency, but linolenic acid and its related polyunsaturated acids are not fully effective (147). The amount of dietary linoleate required by experimental animals to prevent deficiency symptoms and for maintenance of the usual pattern of polyunsaturated acids has been determined to lie between 1 and 2 percent of total calories for rats (98) and swine (36). At lower levels of dietary linoleate, the content of linoleate and arachidonate of tissue and plasma lipids decreases, and eicosotrienoic acid increases. Infantile eczema (32) may sometimes be an expression of essential fatty acid deficiency (83) and the linoleate requirement of infants has been estimated to be between 1 and 3 percent of total calories. Human milk normally is at least three times richer in essential fatty acids than cow's milk. Dietary cholesterol affects essential fatty acid deficiency in the rat (163) and the polyunsaturated acid pattern in the tissues. As essential fatty acids account for a substantial proportion of the fatty acids of cholesterol esters and phospholipids in plasma lipoproteins and of mitochondrial lipoproteins, these acids pre- sumably may have critical roles in membrane structures and in transport processes. 22

Next: ATHEROSCLEROSIS (ARTERIOSCLEROSIS) »
Dietary Fat and Human Health; a Report Get This Book
×
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF
  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!