Search

We evaluated cardiac response to weight loss induced by a very-low-energy (VLE) diet similar to commer- cially available protein-sparing diets. Such diets have been im- plicated in sudden death, and whether organ and tissue responses to them are untoward is not known. Rapid weight loss was in- duced in rats with weights ranging from obese to normal, and cardiac mass and myocardial histomorphometry were assessed. Over 3 wk body weight dropped from 544 ± 12 to 417 ± 21 g (P < 0.001). Heart weight was less in the VLE group than in obese controls (1246 ± 115 vs 1625 ± 179 mg, P < 0.001), as were the weights of the left ventricle (805 ± 81 vs 1061 ± 134 mg, P < 0.001) and right ventricle (198 ± 27 vs 265 ± 40 mg, P < 0.002). Reduction in heart weight was commensurate with loss of body weight (r = 0.89). Myocyte cross-sectional area was reduced in the VLE group (452.6 ± 108.6 to 331.8 ± 41.5 j.�m2, P < 0.05), with no structural abnormalities. We conclude that weight loss in the weight range studied is accompanied by pro- portional reduction in cardiac mass and myocyte size. Myocar- dial regression is not accompanied by myocyte dropout or edema, and likely represents a simple adaptation to reduced body size. Am J Clin Nutr 1994;59:566-71.

The intake of a very-low-energy diet (VLED) complete in all essential nutrients decreases liver mass and total liver protein in dietary obese rats. To determine how these findings may affect hepatic drug metabolizing activity, the aminopyrine breath test was performed in nine male dietary obese Sprague-Dawley rats weighing 440-460 g. Animals were maintained on a VLED, and at 0, 14, and 21 d were injected with 9.25 k Bq (0.25 microCi) [dimethylamine-14C]aminopyrine and placed in airtight restraining cages; exhaled 14CO2 was collected for 120 min. VLED animals had an increased half-life of exhaled 14CO2 (P < 0.01) and a decreased rate constant of aminopyrine elimination (P < 0.01) consistent with decreased N-demethylation of aminopyrine. Decreased liver glutathione suggests reduced ability to detoxify drugs through this conjugation pathway. These studies suggest that animals on VLEDs have reduced capacity for demethylation of aminopyrine as measured by oxidative elimination of 14CO2, and may exhibit decreased metabolism of other drugs.

Hepatic effects of very-low-energy diets (VLEDs) and refeeding were studied in dietary obese rats. Rats weighing 490-530 g (ages 72-119 d) were randomly assigned to control (C) and VLED groups. Control animals consumed a complete diet ad libitum whereas VLED animals consumed 20% of the energy intake of C animals for 7, 14, or 21 d, and some VLED animals were refed the C diet for 7 d. Hepatic weights, lipid, DNA, and total protein decreased in VLED animals. Observed hepatocytic lipid was high in C and progressively decreased in VLED rats. Hepatocytes from VLED rats lost cytoplasmic organelles, contained myelin figures, and became smaller. Decreased protein-DNA ratios and lipids in these same animals is consistent with atrophy. Other biochemical findings included reductions in blood urea nitrogen, albumin, triglycerides, total protein, and glucose, all of which are synthesized or metabolized by the liver. These observations suggest that attenuation of hepatic function is likely.

Low molecular weight oligosaccharides of glucose may be utilized as a calorie source when given intravenously. Preliminary safety studies included the parenteral infusion of four healthy subjects with a solution of glucose oligosaccharides at a rate of 0.5 mg/kg/min for 1, 2, or 3 hours. Approximately 100% of the oligosaccharides was retained with only trace amounts of the glucose oligosaccharides recovered in the urine. In further studies, 12 healthy males, ages 22-31, were infused with a 10% solution of glucose oligosaccharides containing 25 μCi [U-14C]glucose oligosaccharides/liter at a rate of 2.5 or 5.0 mg/kg/min for 12 hours with or without insulin (0.12 unit/g oligosaccharides) given subcutaneously in 3 equi-divided doses. Four additional subjects received cold oligosaccharides at a rate of 1.75 mg/kg/min without insulin. Eighty percent of the glucose oligosaccharides consisted of 2 to 8 glucose chain lengths. Blood glucose and oligosaccharide glucose concentrations and 14CO2 were measured hourly. ...

Little is known about the specific effects of defined formula diets (DFD) on mucosal growth of the small intestine, pancreas, or liver. In the present study male Sprague Dawley rats weighing 220 to 250 g were fed isocaloric amounts of DFD (61 kcal/day) by continuous intragastric infusion. The diets fed were Vivonex, Vivonex-HN, Flexical, and Ensure. Oral chow- fed rats with intragastric water infusions served as reference. All groups gained weight: chow 50.50 g, Vivonex 27.17 g (P < 0.005), Vivonex-HN 25.40 g (P < 0.005), Flexical 30.5 g (P < 0.01), Ensure 39.29 g (NS). After 2 weeks rats were killed, the small bowel excised, rinsed, and divided into eight equal segments. Mucosal weight, DNA, and protein concentration per centimeter segment were measured. The pancreas was also removed, homogenized, and amylase activity assayed (units/g). Livers were excised, weighed, lipid content measured, and liver histology was examined by light microscopy. Mucosal weight, DNA, and protein concentrations per segment were decreased significantly in most bowel segments of DFD fed rats. Amyhase activity per gram pancreas was significantly reduced in rats fed Vivonex, Flexical, and Ensure. Serum amylase activity was also lowered in animals on DFD. There was significant accumulation of lipid in the liver of Vivonex and Flexical animals (P < 0.01). Liver histology confirmed the striking increase in fat in the Vivonex and Fhexical groups. These effects may result from differences in DFD absorption, mucosal metabolism, stimulation of enteric hormone release, and/or bile and pancreatic secre- tions. Am. J. Clin. Nutr. 33: 2106-2118, 1980.

The gastrointestinal response in rats nourished by continuous intragastric infusion of a variety of defined formula diets was compared with animals consuming the same diets orally. Two groups of rats were fed isocaloric amounts of DFD (73 kcal/day); group I : sham-operated, orally-fed: group 2: operated, intragastrically-fed. Diets included: Vivonex (V), Flexical (F), Vital, Vivonex high nitrogen, and a control casein rat liquid formula diet (C). After 2 wk rats were killed and the liver, pancreas, and small bowel removed. The bowel was divided into eight equal segments. Mucosal weight, DNA, and protein concentration per cm segment were measured. Pancreatic amylase activity (units/g), and liver weight and lipid content were measured. Weight gain was comparable in all oral-fed groups, but was decreased in all gastric-fed animals compared to the oral-fed group. Nitrogen retention was not influenced by route of feeding but was significantly lower for Vivonex and Flexical animals (p < 0.01) in both oral-fed and gastric-fed groups. There was significant accumulation of lipid in the liver of both oral-fed and gastric-fed animals sustained on Vivonex and Vivonex high nitrogen (p

A NNTIB prototype has been developed and implemented at the University of Alabama in Birmingham School of Medicine. The further development of the Bank as a shared national resource was considered at a workshop carried out in conjunction with the 1983 ASCN meeting. Through this forum it was confirmed that the concept of a NNTIB is both valid and viable, receiving the support of a variety of nutrition educators and the endorsement of the ASCN Committee on Nutrition Education. The general recommendations of the workshop participants were that a modification of the test-item bank prototype be used as the model for the development of a national bank. A key recommendation was the development of a committee to oversee the acceptance and review of test items included in the NNTIB. Recognizing that the major constraints in the development of a national bank are likely to be logistical, mechanical, and fiscal, it is our belief that each of the limitations could be overcome if the Bank were adopted by a parent society with a long-term commitment to its continued support and development. After such support has been identified and pilot trials have been carried out, the implications of the NNTIB for advances in the field of nutrition go well beyond improved quality of testing materials and extend into the critical area of the establishment of standards of nutrition education and certification of competency. The development of the NNTIB offers a challenge to nutrition educators, national nutrition organizations, and interested governmental agencies for their involvement and support.

Effects of low-calorie semistarvation diets on gastrointestinal and cardiac organ systems were studied. Male Sprague Dawley rats were divided into two groups, Group I, control (C) and Group II, semistarvation (SS), and maintained on a diet designed after low-calorie modified-fasting regimens in popular use. C animals consumed this diet ad libitum; SS animals received 23% of the total calories of C but the same ratio of calories from protein, carbohydrate, and fat and the same quantity and quality of all essential nutrients. Final weights of total body, heart, liver, and small intestine were lower in SS than in C animals. Protein depletion in SS compared with C animals was evident for heart, pancreas, and intestinal mucosa. Unless aggressively supplemented, low-calorie SS diets may deplete protein stores of the gastrointestinal organs of digestion and absorption and contribute to decrease in body nitrogen stores, specifically cardiac muscle.

A nationwide survey of core competencies of nutrition knowledge and skills that primary care physicians should know and/or be able to do has been completed. Nutrition competencies were synthesized from a review of clinical nutrition practices as reported in the medical literature and by medical school faculty group discussions. A nutrition competency questionnaire was sent to 445 practicing physicians and to 752 department chairpersons in every US medical school in the disciplines of family practice, medicine, obstetrics and gynecology, pediatrics, psychiatry, and surgery. The overall response rate for practitioners and faculty combined was 46.03%. Of the 55 nutrition competencies, 28 items received very strong support (greater than 90% of respondents marked agree or completely agree). Twenty-two competencies received strong support (80 to 89% of respondents marked agree or completely agree), and five items received mixed support (40 to 79% of respondents marked agree or completely agree). Statistical comparisons of the item responses between practitioners and faculty were significantly different (p less than 0.05) on 19 (35%) of the items. It is anticipated that the 50 nutrition competencies that have received strong or very strong agreement among the 551 physicians representing primary care disciplines across the US will serve as guidelines for continued development of medical school curriculum and continuing medical education in clinical nutrition.

The gastrointestinal response to oral alimentation of low residue commercial defined formula diets or a rat liquid formula was studied. Male Sprague-Dawley rats (220-250 g) were fed isocaloric amounts (73 kcal/day) of Vivonex (V), Vivonex HN (VHN), Flexical (F), Vital (Vit), or a control Casein diet 116EC (C). Nitrogen (N) retention was calculated from N intake minus N excretion/day. After 2 weeks, rats were killed and the liver, pancreas, and small bowel removed and weighed. Pancreatic amylase activity (U g) and liver lipid were measured. The bowel was divided into eight equal segments, and mucosal weight, DNA, and protein concentration per centimeter were measured. Despite isocaloric feeding, body weight gain was lower in V and VHN groups, and higher in F and Vit groups compared to the C. Amylase specific activity was increased in V, VHN, and F groups, while the liver lipid was increased in the V and VHN groups when compared to C animals. The most proximal intestinal segment weight, mucosal weight, protein and DNA of V, VHN, and Vit groups were less than C animals, while distal segments were similar. F animals showed greater intestinal mass than C rats. These studies indicate statistically significant differences in gastrointestinal response as a result of nutrient variation of defined formula diets.

A recent development in the treatment of obesity is the widespread use of very-low-calorie diets. This study assessed the response to refeeding (RF) after semistarvation (SS) in a rat model. Male Sprague-Dawley rats (440 g) were semistarved for 21 d, receiving a nutritionally complete defined formula diet at 23% of calories of control (C) rats fed ad libitum, and subsequently refed over 21 d (SS----RF). Organ weight, contents of protein and DNA, and the protein-DNA ratio were determined for the liver, pancreas, small intestine, and heart. Compared with C animals, SS----RF animals showed variable repletion of tissue protein but not of tissue DNA. The higher protein-DNA ratio shown in these organ systems suggests a cellular hypertrophic adaptive response to refeeding. A persistent reduced number of cells in ratio to protein concentration is evident despite refeeding over 21 d. Very-low-calorie diets as well as refeeding influence nitrogen economy of selected organ systems.

Inability to absorb lactose due to low intestinal lactase is common in many population groups. This study is the first to compare lactose tolerance in 282 Mexican-American (MA) children and 51 Anglo-American (AA) children 2 to 14 years of age with the dietary intake of selected nutrients found in milk. A lactose tolerance test and a 24-hr dietary recall were obtained for each child. Gastrointestinal symptoms were carefully recorded for a 24-hr period following the lactose load. Overall prevalence of lactose malabsorption was 37% in MA children and 8% in AA children, and it increased with age. Number of symptoms occurring in lactose malabsorbers of both ethnic groups also increased with age. Mean protein intake exceeded Recommended Dietary Allowances at all ages for both ethnic groups. Mean consumption of vitamin A, calcium, and energy was below the Recommended Dietary Allowance for MA children. There were no differences in calories, nutrient, or milk intakes between lactose absorbers and malabsorbers, but AA children drank more milk than MA children. Fifteen percent of lactose-absorbing MA, 23% of malabsorbing MA, but no AA children reported having symptoms after drinking milk. There was a significantly greater incidence of lactose intolerance in MA as compared to AA children. This suggests that Mexican-Americans share in the high incidence of primary lactose intolerance characteristic of the majority of the orld's peoples.