Fat-soluble vitamins must be consumed together with dietary fat to be absorbed. The vitamins are first dissolved in the dietary fat. Then, bile released from the gall bladder acts like a detergent and allows the fat with the vitamins dissolved in it to be solubilized in micelles. Recall the discussion of detergents and micelles from the "Membranes, Proteins, and Dialysis" experiment. However, some newly-developed food products, unfortunately, have been found to disrupt this pathway for absorbing fat-soluble vitamins in the body.
In recent years, many types of "fat-free" foods have come into the marketplace. One such type of these foods contains artificial fats that are substituted for the natural fats and oils found in the foods. These artificial fats add no fat or calories to the diet, because they are not digested or absorbed by the body. Olestra is a fat substitute that has the properties of a fat in flavor and texture, but is indigestible - hence a fake fat. It does not add any calories as a normal fat would.
Olestra is part fatty acids from cottonseed or soybean oils and part sucrose rather than glycerol in triglycerides. The six to eight fatty acids are bonded to the hydroxyl or alcohol groups on the sucrose using an ester synthesis reaction. With olestra, you get the taste of the fat without any of the calories of the fat, because your body has no way to digest olestra.
So what makes a molecule of olestra indigestible? If you have read How Fats Work , you know that a typical fat molecule is essentially three long molecules made of carbon and hydrogen hooked together see How Fats Work for details. In olestra, there are six to eight chains instead of three.
These extra chains make olestra's molecular structure much different from that of the typical fat molecule. The reason that your body cannot digest olestra is similar to the reason that your body cannot digest wood see How Food Works for details. A cellulose molecule is too long for your stomach to process because your stomach lacks the right enzymes to handle it. Olestra is the same way. Olestra simply passes through your stomach and intestines unchanged.
Olestra chips have calories from the potatoes, corn or other foods they contain, but no calories from the olestra unlike a normal chip that contains 9 calories for every gram of fat. Here are the nutrition labels from a bag of regular full-fat potato chips and from a bag of chips made with olestra:.
Many scientists and doctors are worried about whether olestra is safe for people to consume. One big fear is that eating olestra may lead to nutritional deficiencies. Olestra's effect on vitamins D and E in humans can be offset by increasing dietary levels of these vitamins. Torri S. Olestra dose response on fat-soluble and water-soluble nutrients in humans. Webb D. Harrison G. Lee M. Huang M. Estimated consumption and eating frequency of olestra from savory snacks using menu census data.
Welsch R. Stepwise multiple comparison procedures. Winer , B. Published as a supplement to Journal of Nutrition. Guest editors for this supplement publication were John W. Ross, Pennsylvania State Universitiy, S. Henderson Bldg. Oxford University Press is a department of the University of Oxford. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide. Sign In or Create an Account. Sign In. Advanced Search. Search Menu. Article Navigation.
Close mobile search navigation Article Navigation. Volume Article Contents Abstract. Daher , George C. Oxford Academic. Dale A. John C. Cite Cite George C. Select Format Select format. Permissions Icon Permissions. Abstract A study was conducted in the domestic pig to determine 1 whether feeding olestra mixed in the diet exaggerated olestra effects on fat-soluble vitamin status compared with the effects of feeding it in a typical snack food, and 2 whether separating olestra consumption temporally from vitamin consumption affected the influence of olestra on vitamin status.
Table 1 Description of feeding patterns for pigs fed olestra mixed in the diet or in potato chips Olestra fed in. Feeding pattern. F 10 animals 5 males, 5 females per group. F Weight percentage of total daily diet, including the potato chips. Open in new tab. Table 2 Composition of the diets fed to the pigs.
Ingredient Composition of diet fed to. Group 1. Group 2. Groups 3, 4 and 5. F The vitamin-mineral mix is the same as that described by Cooper et al.
Table 3 Cumulative olestra consumption, energy consumption, body weight gain and digestible feed efficiency for pigs fed olestra mixed in the diet or in potato chips for 4 wk Group Feeding pattern. Olestra consumption. Energy consumption. Body weight gain. Digestible feed efficiency. Table 4 Liver and serum vitamin A concentrations for pigs fed olestra mixed in the diet or in potato chips Liver vitamin A concentration Serum vitamin A concentration.
Week 4. Week 0. F The liver concentration of vitamin A in the group killed at wk 0 was Table 5 Liver and serum vitamin E concentrations for pigs fed olestra mixed in the diet or in potato chips Liver vitamin E concentration Serum vitamin E concentration.
F The liver concentration of vitamin E in the group killed at wk 0 was 6. Table 6 Serum hydroxyergocalciferol [25 OH D 2 ] concentrations for pigs fed olestra mixed in the diet or in potato chips Serum 25 OH D 2 concentration.
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