Hepatorenal Tyrosinaemia: Impact of a Simplified Diet on Metabolic Control and Clinical Outcome.

Background: Tyrosinaemia type 1 is a rare inherited metabolic disease caused by an enzyme defect in the tyrosine degradation pathway. It is treated using nitisinone and a low-protein diet. In a workshop in 2013, a group of nutritional specialists from Germany, Switzerland and Austria agreed to advocate a simplified low-protein diet and to allow more natural protein intake in patients with tyrosinaemia type 1. This retrospective study evaluates the recommendations made at different treatment centers and their impact on clinical symptoms and metabolic control. Methods: For this multicenter study, questionnaires were sent to nine participating treatment centers to collect data on the general therapeutic approach and data of 47 individual patients treated by those centers. Results: Dietary simplification allocating food to 3 categories led to increased tyrosine and phenylalanine blood concentrations without weighing food. Phenylalanine levels were significantly higher in comparison to a strict dietary regimen whereas tyrosine levels in plasma did not change. Non-inferiority was shown for the simplification and liberalization of the diet. Compliance with dietary recommendations was higher using the simplified diet in comparison to the stricter approach. Age correlates negatively with compliance. Conclusions: Simplification of the diet with increased natural protein intake based on three categories of food may be implemented in the diet of patients with tyrosinaemia type 1 without significantly altering metabolic control. Patient compliance is strongly influencing tyrosine blood concentrations. A subsequent prospective study with a larger sample size is necessary to get a better insight into the effect of dietary recommendations on metabolic control.

Low-protein diet-induced hyperphagia and adiposity are modulated through interactions involving thermoregulation, motor activity, and protein quality in mice.

Low protein (LP)-containing diets can induce overeating in rodents and possibly in humans in an effort to meet protein requirement, but the effects on energy expenditure (EE) are unclear. The present study evaluated the changes induced by reducing dietary protein from 20% to 6%-using either soy protein or casein-on energy intake, body composition, and EE in mice housed at 22°C or at 30°C (thermal neutrality). LP feeding increased energy intake and adiposity, more in soy-fed than in casein-fed mice, but also increased EE, thus limiting fat accumulation. The increase in EE was due mainly to an increase in spontaneous motor activity related to EE and not to thermoregulation. However, the high cost of thermoregulation at 22°C and the subsequent heat exchanges between nonshivering thermogenesis, motor activity, and feeding induced large differences in adaptation between mice housed at 22°C and at 30°C.

[Celiac disease: evaluation of compliance to gluten-free diet and knowledge of disease in patients registered at the Brazilian Celiac Association (ACA)]. / Doença celíaca: avaliação da obediência à dieta isenta de glúten e do conhecimento da doença pelos pacientes cadastrados na Associação dos Celíacos do Brasil (ACELBRA).

BACKGROUND: The compliance to a gluten-free diet may prevent the development of both non-malignant and malignant complications. AIM: To evaluate compliance to a gluten-free diet and knowledge of the disease in celiac patients registered at the Brazilian Celiac Association (BCA). METHODS: A structured questionnaire was designed to assess compliance to a gluten-free diet as well as knowledge of the celiac disease. It was mailed to 584 members of BCA. RESULTS: Five hundred and twenty nine (90.6%) of a total of 534 (91.4%) answered questionnaires were analyzed; 69.4% were classified as compliant patients whereas 29.5% were classified as noncompliant. The proportion of patients age 21 or older who consume gluten frequently or without any restriction is larger (17.7%) than those who were younger than 21 years (9.9%). Frequency of dietary compliance was higher when the diagnosis had taken less than 5 years to be established; 82% of the patients replied that the small intestine was the part of the body affected by the disease. The most common symptoms of the disease according to the answers were diarrhea (96.6%), weight loss (93.4%), protuberant abdomen (90.4%), anemia (68.1%) and vomiting (59.6%). Only 59.0% agreed with the existence of genetic predisposition; 90.4% answered that the disease is permanent and 96.2% stated that the diet should exclude gluten absolutely; 67.1% answered that the gluten is a protein and according to 92.1% questionnaires this protein is present in wheat, rye, barley and oat. Greater compliance was observed when there was an understanding of the disease and diet. The small intestine biopsy was considered necessary for just 67.5% of the patients, and greater compliance was observed in patients who had undergone at least one small intestine biopsy. CONCLUSION: Our findings indicate that the more the patients know and understand about the disease, the better able they are to comply with the diet.

mRNA levels of the calpain system in longissimus muscle of young pigs during prolonged feeding of a protein-free diet.

This experiment was conducted to investigate the effects of feeding a protein-free diet on mRNA levels of the calpain system in skeletal muscle of growing pigs during a 15-d feeding trial. Twenty crossbred barrows were divided into two dietary treatments: control or protein-free diet (mean initial weight for both groups: 38.3 kg). Daily diets were provided at 2.5 times energy for maintenance (twice a day). On d 0, 3, and 14, biopsies were taken from longissimus muscle between the third and fourth ribs (d 0 and 3) and between the fourth and fifth rib (d 14). On d 15, animals were slaughtered and longissimus muscles were dissected and analyzed for calpastatin, and mu- and m-calpain activity. From biopsies, mRNA level of skeletal muscle calpain, mu- and m-calpain, and calpastatin were measured using reversed transcription PCR. Subsequently, PCR products were quantified using ELISA. Feeding the protein-free diet lowered growth rate to almost zero. Only total level of mRNA of mu-calpain on d 14 was influenced by dietary treatments, being lower for the protein-free group than for the control group (P < .05). However, proteolytic activities were not different between treatments. Total RNA concentration in longissimus muscle decreased during the experiment for both treatments, but on d 14 this was more pronounced for the protein-free than for the control group (P < .05). If mRNA levels were corrected for this change, specific mRNA level on d 14 of skeletal muscle calpain and mu-calpain were lower (P < .05) for the protein-free than for the control group. These data suggest that activity of the components of the calpain system are differentially regulated.

Crystalline lysine and threonine supplementation of soft red winter wheat or triticale, low-protein diets for growing-finishing swine.

Five trials, with five treatments each, involving a total of 240 pigs were conducted to evaluate the effectiveness of supplementation of soft red winter wheat- or triticale-based diets with crystalline lysine and threonine for growing and finishing pigs (25 to 110 kg). Within each trial, wheat- or triticale-based diets were supplemented with soybean meal to meet the requirement of the first- (lysine) or third- (isoleucine/methionine + cystine) limiting amino acid. Diets formulated to the third-limiting amino acid also were supplemented with feed grade L-lysine. HCl and L-threonine to meet the requirements of the first- and second-limiting amino acids. A cornsoybean meal diet was included in each trial as a positive control treatment resulting in the five dietary treatments. Three different crop years of soft red winter wheat and triticale were utilized. Three of the trials, conducted in successive years with each using a different crop year of grain, were done at Marianna, and the other two, conducted in successive years using yr 1 and 2 crops, respectively, were done at Gainesville. In all trials, growing diets (.82% lysine) were fed from 29 (Marianna) or 25 kg (Gainesville) to 55 kg average BW and finishing diets (.64% lysine) to 110 or 100 kg. Over the three crop years, the wheat and triticale averaged 11.3 and 11.0% crude protein, .36 and .38% lysine, and .36 and .37% threonine, respectively. Overall, at either location, growth rate and carcass lean content were not affected by grain source (P > .10). At Marianna, gain:feed was 2 to 3% lower for pigs fed the triticale diets than for pigs fed wheat (P = .15) or corn (P < .10); gain:feed was not affected by grain source at Gainesville (P > .10). At both locations, substantial replacement of soybean meal protein with crystalline lysine and threonine did not affect pig growth or carcass lean content (P > .10), even when the diet contained very little or no soybean meal as occurred for finishing pigs (55 to 110 kg) fed diets containing triticale.

Comparison between 3-methylhistidine production and proteinase activity as measures of skeletal muscle breakdown in protein-deficient growing barrows.

This experiment was conducted to determine the relationship between 3-methylhistidine (3MH) production and proteinase activity in skeletal muscles of growing barrows. Barrows at 13 wk of age were randomly assigned to either control diet available on an ad libitum basis (21% of ME consisted of protein; control group), control diet fed restricted (pair-fed with barrows in protein-free group; intake-restricted group), or protein-free diet available on an ad libitum basis (protein-free group) for 14 d. During the last 3 d, blood samples were collected for determination of 3MH production rate, which is a measure of myofibrillar protein breakdown. At slaughter, two muscles were taken: masseter (M) and longissimus (L) muscles. The muscle samples were analyzed for calpastatin, mu-calpain, m-calpain, multicatalytic proteinase (MCP), cathepsin B, cathepsins B+L, and cystatins activities. Both muscles were also analyzed for amounts of DNA, RNA, total protein, and myofibrillar and sarcoplasmic proteins. Growth rate (kilograms/day) was influenced by dietary treatments (P < .05). Fractional breakdown rate (FBR, percentage/day) of skeletal muscle, as calculated from 3MH production rate (micromoles.kilogram-1.day-1), was 27% higher for the protein-free group than for the control group. However, no differences in proteinase activities were observed, except for lower MCP activity in the M muscle of the protein-free group than in that of the other groups (P < .05). In the present study, no direct relation was observed between myofibrillar protein degradation rate and proteinase activities in skeletal muscle during a protein-free feeding strategy.

Effects of moderate changes in protein intake on urinary albumin excretion in type I diabetic patients.

We investigated the short-term effects of moderate increments or decrements of protein intake on albumin excretion rates of type I diabetic patients. Ten normotensive patients with either normal albumin excretion rates (< 20 micrograms/min, group I, n = 5) or persistent mu-albuminuria (20-200 micrograms/min, group II, n = 5) were fed successively three test diets providing different protein intakes. Each patient was randomly allocated to 3-wk sequences of the following diets: low-protein diet (LPD; median 0.84, range 0.76-0.94 g.kg-1.day-1), medium-protein diet (MPD; median 1.33, range 0.98-2.00 g.kg-1.day-1), and high-protein diet (HPD; median 2.05, range 1.54-2.61 g.kg-1.day-1). The three diets were isoenergetic and isoglucidic. In group I patients, no consistent change was found in mu-albuminuria. In group II patients, LPD resulted in a reduction in mu-albuminuria compared with MPD and HPD. Changes in albumin excretion rates were positively correlated to relative changes in protein intake. This suggests that moderately protein-restricted diets can reduce mu-albuminuria in diabetic patients suffering from incipient nephropathy, the degree of reduction depending on the degree of restriction. Because of poor patient compliance with protein intakes < 0.8 g.kg-1.day-1, we conclude that moderately rather than severely protein-restricted diets should be recommended for long-term prescriptions.