Assessment of the nutritional effects of olestra

The minipig as nonrodent species in toxicology--where are we now?

Over the past 3 decades minipigs have moved from being an obscure alternative to dogs and nonhuman primates to being a standard animal model in regulatory toxicity studies. This article covers the use of minipigs as a model in the context of nonclinical drug safety and provides an overview of the minipig's developmental history and relates minipigs to other animal species commonly used in toxicology; and the minipig's translational power is supported by 43 case studies of marketed drug products covered. Special focus is given to criteria for selecting minipigs in nonclinical programs supporting the development of new medicines; the use of swine in the assessment of food additives, agrochemicals, and pesticides; as well as a regulatory perspective on the use of minipigs in Food and Drug Administration (FDA)-regulated products. This article presents the main points conveyed at a symposium held at the 2010 American College of Toxicology meeting in Baltimore, Maryland.

Daily intake of multivitamins during long-term intake of olestra in men prevents declines in serum vitamins A and E but not carotenoids

The objective of this study was to determine whether vitamin supplementation during long-term (36 wk) ingestion of olestra supplemented with vitamin E could prevent decreases in vitamin E, vitamin A, and carotenoids. This was a 36-wk study of 37 healthy males randomly assigned to consume a control diet composed of 33% energy from fat, a similar diet in which one third of the energy from fat had been replaced with olestra, or a fat-reduced (25% of energy from fat) diet. Subjects also ingested a daily multivitamin (Centrum). Serum concentrations of alpha-tocopherol, retinol, beta-carotene, lycopene, and lutein + zeaxanthin were analyzed by HPLC. Subjects eating the olestra-containing diet had substantial decreases in serum beta-carotene, lycopene, and lutein + zeaxanthin, which occurred by 12 wk; these changes were found despite correcting for serum total cholesterol or BMI. Serum beta-carotene and lycopene concentrations were below the lower limit of the reference range (<0.186 and <0.298 mumol/L, respectively) at one or more time points. The slight decline in serum alpha-tocopherol concentration, significant at 24 wk, was caused by the decline in serum cholesterol. Retinol concentrations decreased with time in all 3 groups, but were not affected by olestra. We conclude that supplementation with a multivitamin containing vitamins A and E was adequate to prevent olestra-induced decrease in serum alpha-tocopherol and retinol. Olestra-induced decreases in serum beta-carotene, lycopene, and lutein + zeaxanthin were not prevented by the vitamin supplement used in this study.

Authors' financial relationships with the food and beverage industry and their published positions on the fat substitute olestra

OBJECTIVES

This study examined the association between authors' published positions on the safety and efficacy in assisting with weight loss of the Procter & Gamble (P&G) fat substitute olestra and their financial relationships with the food and beverage industry.

METHODS

Journal articles about olestra, and their authors, were classified as supportive, critical, or neutral with respect to its use. Authors not known to have industry affiliations were surveyed about their financial relationships.

RESULTS

Supportive authors were significantly more likely than critical or neutral authors to have financial relationships with P&G (80% vs 11% and 21%, respectively; P <.0001). All authors disclosing an affiliation with P&G were supportive.

CONCLUSIONS

Because authors' published opinions were associated with their financial relationships, obtaining noncommercial funding may be more essential to maintaining objectivity than disclosing personal financial interests.

A 9-mo randomized clinical trial comparing fat-substituted and fat-reduced diets in healthy obese men: the Ole Study

BACKGROUND

Dietary fat has been implicated as a risk factor for cardiovascular disease and obesity.

OBJECTIVE

We evaluated the effect on body weight, body fat, lipids, glucose, and insulin of replacing dietary fat with olestra in moderately obese men.

DESIGN

Forty-five healthy overweight men were randomly assigned to 1 of 3 diets: control diet (33% fat), fat-reduced diet (25% fat), or fat-substituted diet (one-third of dietary fat replaced by olestra to achieve a diet containing 25% metabolizable fat). Body fat was measured by dual-energy X-ray absorptiometry and visceral and subcutaneous abdominal fat by computed tomography.

RESULTS

Thirty-six men completed the 9-mo study. Body weight and body fat in the fat-substituted group declined by a mean (+/- SEM) of 6.27 +/- 1.66 and 5.85 +/- 1.34 kg, respectively, over 9 mo compared with 3.8 +/- 1.34 and 3.45 +/- 1.0 kg in the control group and 1.79 +/- 0.81 and 1.68 +/- 0.75 kg in the fat-reduced diet group. At 9 mo, the mean difference in body fat between the fat-reduced and fat-substituted groups was -4.19 +/- 1.19 kg (95% CI: -6.57, -1.81), that between the control and fat-substituted groups was -2.55 +/- 1.21 kg (-0.13, -4.97), and that between the control and fat-reduced groups was 1.63 +/- 1.18 kg (3.96, -0.70). The men eating the fat-reduced diet asked for almost no extra foods, in contrast with the significantly higher requests (P < 0.05) from both of the other 2 groups.

CONCLUSION

Replacement of dietary fat with olestra reduces body weight and total body fat when compared with a 25%-fat diet or a control diet containing 33% fat.

Obesidade e a substituição de macronutrientes da dieta

Os fatores envolvidos na gênese da obesidade não são conclusivos, incluindo o papel dos macronutrientes da dieta na suscetibilidade ao ganho de peso. O carboidrato pode ser considerado um componente importante na saciedade. Sua substituição pelo adoçante, reduz o valor energético da dieta, reduzindo a massa corporal. Os efeitos dos adoçantes sobre o apetite dependem da natureza e da densidade dos nutrientes consumidos simultaneamente. Não existem evidencias suficientes que mostrem que os adoçantes causam ganho de peso, mas seu uso pode resultar em compensação energética com alimentos ricos em lipídios. Os lipídios tendem a aumentar a densidade energética da dieta promovendo o superconsumo passivo de energia, além de apresentar baixa prioridade oxidativa, estando associado à baixa saciedade. Sua substituição tem sido relacionada à compensação da ingestão energética, principalmente por carboidratos. Um plano alimentar disciplinado deve incluir alimentos que reduzam a densidade energética da dieta, sem promoção do consumo alimentar.

Early adopters of olestra-containing foods: who are they?

OBJECTIVE

To identify the characteristics of people consuming olestra-containing foods when first introduced at a test-marketing site.

DESIGN

Data are from the Olestra Postmarketing Surveillance Study (OPMSS). After the introduction of olestra into a large test-marketing site, study participants received 3 follow-up telephone calls, at 3-month intervals, in which they were questioned about their diets during the previous month.

SUBJECTS/SETTING

1,007 adults in Indianapolis, Ind, who participated in a baseline clinic visit (before introduction of olestra into the food market) and completed at least 2 of 3 follow-up telephone calls (after the introduction of olestra into the market).

STATISTICAL ANALYSES PERFORMED

Logistic regression was used to examine associations between olestra consumption and sociodemographic characteristics, health conditions, attitudes toward health and diet, and health-related behaviors.

RESULTS

Olestra consumption on at least 1 of the follow-up telephone calls was reported by 41.5% of the study sample, and consumption on 2 or more telephone calls was reported by 20.0% of the sample. Factors associated with early adoption of olestra-containing foods included white ethnicity, higher education, overweight, absence of diabetes, attitudes indicative of diet and health concerns (e.g.; perceptions that there is a strong relationship between diet and disease), and a lower fat intake.

APPLICATIONS/CONCLUSIONS

In spite of the controversy surrounding the introduction of olestra into the food market persons with attitudes indicative of diet and health concerns were likely to be early adopters of olestra-containing foods. Dietitians and other health care providers should inquire about intake levels of foods with fat substitutes and ensure that these foods are not being consumed in excessive amounts or being consumed instead of nutrient-dense foods that are naturally low in fat.

Review article: olestra and its gastrointestinal safety

Olestra is a fat substitute made from sucrose and vegetable oil. Olestra is neither digested nor absorbed, and therefore adds no calories or fat to the diet. Because the gut is the only organ that is exposed to olestra, the potential for olestra to affect gastrointestinal structure and function, and the absorption of nutrients from the gut, has been investigated. Histological evaluations performed after long-term feeding studies have shown no indications that olestra causes injury to the gastrointestinal mucosa. Olestra is not metabolized by the colonic microflora, and has no meaningful effects on the metabolic function of these organisms. Studies of gastrointestinal transit have shown that the consumption of olestra with food does not affect gastric emptying, or small or large bowel transit times. Olestra does not affect the absorption of macronutrients, water-soluble vitamins or minerals. It causes a dose-responsive decrease in the availability of the fat-soluble vitamins A, D, E and K; however, this potentially adverse effect is offset by the addition of vitamins to olestra-containing foods. Olestra has no consistent effect on the amount of total bile acids excreted in the faeces, and therefore probably has no significant effect on bile acid absorption. The occurrence of gastrointestinal symptoms, including diarrhoea, loose stools, gas and abdominal cramping, after consumption of olestra under ordinary snacking conditions is comparable to that following consumption of triglyceride-containing snacks.