The Domestic Pig as a Model for Evaluating Olestra's Nutritional Effects , ,

Abstract

Experimental conditions for measuring the effect of the noncaloric fat substitute olestra on the availability of dietary nutrients were established in the weanling domestic pig. To evaluate the tolerance of the pig for dietary fat levels similar to those in the human diet, groups were fed a standard corn-soy-based swine feed with and without 14% (30% of energy) added fat for 4 wk. To evaluate the adequacy of a purified diet to produce good growth, groups of pigs were fed purified diets providing 30% of energy from fat and micronutrients at 1, 1.3 or 1.6 times the NRC's requirements for 5- to 10-kg swine. Cumulative body weight gain, digestible feed efficiency and a lack of adverse effects showed that the pig can tolerate diets providing 30% of energy from fat and that a purified diet providing the NRC's requirements for micronutrients produces growth comparable to a nutritionally complete swine feed. To determine whether tissue concentrations of vitamins A, D, E and K in the pig respond to olestra and dietary concentrations of the vitamins, two groups were fed purified diet providing 1 or 1.6 times the NRC's requirements for micronutrients and 4.8% olestra. Significant increases occurred in the serum concentration of 25-hydroxyergocalciferol and liver concentrations of retinol and alpha-tocopherol with increasing dietary concentrations of the vitamins. Olestra reduced the tissue concentrations of vitamins A, D and E. Prothrombin time was not affected by dietary concentration of either phylloquinone or olestra. To determine the amount of UV light exposure required to produce 50-80% of vitamin D status from vitamin D3, a range typical of humans, two groups of pigs were fed the NRC requirement for vitamin D and exposed to 15 or 45 min/d of UV light. Serum concentration of 25-hydroxycholecalciferol increased with increased exposure time. UV exposure of 1-2 min/d was calculated to be sufficient to produce 50-80% of total vitamin D status from vitamin D3. No antemortem observations indicated an adverse olestra effect.

Behaviour influences cholesterol plasma levels in a pig model

“…Pigs have been used extensively in human nutrition research because they are similar in several key areas (Cooper et al, 1997;Darragh and Hodgkinson, 2000). They are monogastric, meal-eating, omnivorous mammals.…”

Olestra is associated with slight reductions in serum carotenoids but does not markedly influence serum fat-soluble vitamin concentrations

“…4 Additionally adjusted for total serum cholesterol, percentage of energy from fat, smoking, dietary supplement use, physical activity, and season. 5 Additionally adjusted for serum triacylglycerol, BMI, alcohol use, smoking, and season. 6 No tests for trend were significant.…”

“…This blinding was considered the optimal way to conduct an unbiased surveillance study to assess population-level olestra consumption and its association with serum fat-soluble nutrients in free-living persons for the following reason. Randomized controlled trials in both humans and animals were conducted before the FDA approval of olestra to investigate general safety, doseresponse effects, and adverse events (2,4,5,15), but these experimental studies were not designed to answer questions about who would adopt foods made with a macronutrient substitute or olestra's effect on nutritional status when consumed in a manner consistent with the customary snack habits of free-living persons. The Institutional Review Boards of the Fred Hutchinson Cancer Research Center, Johns Hopkins University, the University of Minnesota, and the University of California, San Diego, approved all study procedures.…”

“…4 Additionally adjusted for fruit and vegetable intake, BMI, and smoking. 5 Additionally adjusted for percentage of energy from fat, BMI, smoking, alcohol use, and season. 6 Additionally adjusted for fruit and vegetable intake, BMI, smoking, alcohol use, and season.…”

“…Because olestra is neither hydrolyzed by gastrointestinal enzymes nor absorbed, however, it has the capability to interfere with the absorption of fat-soluble nutrients. Animal model and human experimental studies published before the FDA's approval of olestra consistently showed that olestra could sequester carotenoids and fatsoluble vitamins (2)(3)(4)(5). For these reasons, FDA approval required that all olestra-containing products include the addition of vitamins A, D, E, and K and a label statement indicating that the extra vitamins were intended to compensate for any olestrainduced nutritional losses (6,7).…”