Study Protocol for a Controlled Trial of Nutrition Education Intervention about Celiac Disease in Primary School: ZELIAKIDE Project.

The only treatment for celiac disease (CD) is a strict and lifelong gluten-free diet (GFD), which must be safe and nutritionally balanced. Avoiding gluten brings difficulties with following the diet and can affect the social life of people with CD. The Zeliakide Project is a nutrition education program aimed at increasing the knowledge of the general population about healthy diets, CD and GFD, and, therefore, to improve the social inclusion and quality of life of people with CD. It is a one-month intervention program, two-armed cluster, non-randomised and controlled trial, conducted among 10-12-year-old children. Pre- and post-intervention evaluation and 1 month follow-up will be carried out to assess the effectiveness of the program. It is based on competencies and their respective learning outcomes. The teaching methodology chosen is a STEAM methodology: inquiry-based learning (IBL). A teaching unit has been created to develop the project, which, in the future, will be useful for the self-application of the program. This study will provide a valid and useful tool to achieve changes in the diet at the school level and will help to promote the social inclusion of people with CD. Moreover, it will enforce the STEAM competences of children.

Uncovering the Concerns and Needs of Individuals with Celiac Disease: A Cross-Sectional Study.

The treatment for celiac disease (CD) involves a strict gluten-free diet, which can be challenging and lead to questions for patients. Pinpointing these uncertainties can enable the creation of efficient educational resources. In this study, a questionnaire was specifically designed to gain insights into the knowledge, concerns, and needs of individuals with CD and their supporters. The questionnaire was distributed through the Instagram social network and received adequate responses from 300 participants, 258 (86%) being female and 152 (50.7%) falling in the age range of 25-44 years. The concerns of individuals with celiac disease and celiac supporters were rated on a 1-4 scale, with a mean score of 3.5 indicating significant concern. A total of 255 (85%) of all participants expressed that their principal concern was the social limitations they faced, such as difficulties in eating out and sharing food with others. Every participant evaluated their overall disease knowledge, averaging at 2.92 out of 4, indicating a reasonable level of awareness. When asked if they believed that improving general knowledge about CD in the general population would enhance their quality of life, the vast majority responded affirmatively. This finding underscores the importance of not only educating individuals with CD but also reaching out to the wider population, especially those who have a direct impact on the daily lives of individuals with CD, such as family members, friends, and food service providers.

Melon/cowpea intercropping pattern influenced the N and C soil cycling and the abundance of soil rare bacterial taxa.

The high use of pesticides, herbicides, and unsustainable farming practices resulted in losses of soil quality. Sustainable farming practices such as intercropping could be a good alternative to traditional monocrop, especially using legumes such as cowpea (Vigna unguiculata L. Walp). In this study, different melon and cowpea intercropping patterns (melon mixed with cowpea in the same row (MC1); alternating one melon row and one cowpea row (MC2); alternating two melon rows and one cowpea row (MC3)) were assayed to study the intercropping effect on soil bacterial community through 16S rRNA region in a 3-year experiment. The results indicated that intercropping showed high content of total organic carbon, total nitrogen and ammonium, melon yield, and bacterial diversity as well as higher levels of beneficial soil microorganisms such a Pseudomonas, Aeromicrobium, Niastella, or Sphingomonas which can promote plant growth and plant defense against pathogens. Furthermore, intercropping showed a higher rare taxa diversity in two (MC1 and MC2) out of the three intercropping systems. In addition, N-cycling genes such as nirB, nosZ, and amoA were more abundant in MC1 and MC2 whereas the narG predicted gene was far more abundant in the intercropping systems than in the monocrop at the end of the 3-year experiment. This research fills a gap in knowledge about the importance of soil bacteria in an intercropping melon/cowpea pattern, showing the benefits to yield and soil quality with a decrease in N fertilization.

Perennial alley cropping contributes to decrease soil CO2 and N2O emissions and increase soil carbon sequestration in a Mediterranean almond orchard.

The implementation of alley cropping in orchards can be a sustainable strategy to increase farm productivity by crop diversification and contribute to climate change mitigation. In this research, we evaluated the short-term effect of alley cropping with reduced tillage on soil CO2 and N2O emissions and soil total organic carbon (TOC) in an almond orchard under Mediterranean rainfed conditions. We compared an almond monoculture with tillage in all plot surface (MC) with almond crop with reduced tillage and growth of Capparis spinosa (D1) and almond crop with reduced tillage and growth of Thymus hyemalis (D2). For two years, soil CO2 and N2O were measured, with soil sampling at the start and end of the experimental period. Results showed that CO2 emission rates followed the soil temperature pattern, while N2O emissions were not correlated with temperature nor moisture. Soil CO2 emissions were significantly higher in MC (87 mg m-2 h-1), with no significant differences between D1 and D2 (69 mg m-2 h-1). Some peaks in CO2 effluxes were observed after tillage operations during warm days. Soil N2O emission rates were not significantly different among treatments. Cumulative CO2 and CO2 equivalent (CO2e) emissions were significantly highest in MC. When CO2e emissions were expressed on a crop production basis, D2 showed the significantly lowest values (5080 g kg-1) compared to D1 (50,419 g kg-1) and MC (87,836 g kg-1), owing to the high thyme yield, additional to the almond yield. No production was obtained for C. spinosa, since at least two more years are required. TOC did not change with time in MC neither D1, but it significantly increased in D2 from 3.85 g kg-1 in 2019 to 4.62 g kg-1 in 2021. Thus, alley cropping can contribute to increase the agroecosystem productivity and reduce CO2 emissions. However, it is necessary to grow evergreen alley crops such as thyme to obtain short-term increases in soil organic matter. Thus, to estimate increases in TOC with alley cropping, the plantation density and the period required by the crop to cover most of the surface are essential factors at planning the cropping strategy.

Application of a Platform for Gluten-Free Diet Evaluation and Dietary Advice: From Theory to Practice.

The present work aimed to analyze, through the GlutenFreeDiet digital platform, the evolution over one year of the nutritional status, dietary profile and symptoms present among celiac people on a gluten-free diet (GFD) while receiving individualized dietary advice. Twenty-seven adults and thirty-one celiac children/adolescents participated in the study. This was then followed up by three visits, at diagnosis, and after 3 and 12 months (vt0, vt3 and vt12). Participants filled out dietary and gastrointestinal symptoms questionnaires. All patients received written personalized dietary advice from dietitians who interpreted data from the platform. Results obtained indicated that participants consumed proteins and lipids in excess and carbohydrates in defect. Low intakes of cereals, fruit and vegetables and high meat intakes were observed. However, gluten-free product (GFP) consumption and that of ultra-processed foods was reduced after 1 year in adults. Symptoms decreased after vt3 but recurred in vt12. Changes in ultra-processed foods and GFP intake, but lack of changes in the rest of the parameters suggested that the platform support was not effective enough. Even though the platform represents a useful tool for monitoring celiac patients and giving dietary advice, modules that require more continuous attention and nutritional education of patients should be provided for interventions to be more effective.

Nutritional Imbalances in Adult Celiac Patients Following a Gluten-Free Diet.

Celiac disease (CD) is a chronic autoimmune disorder of the small intestine, whose only effective treatment is a gluten-free diet (GFD). It is characterized by the atrophy of the intestinal villi that leads to altered nutrient absorption. This study describes the nutritional imbalances which may be found in adults with CD following a GFD. During the first year of treatment, deficiencies will overcome as the intestinal mucosa recovers. Thus, biochemical data will show this progression, together with the decrease in symptoms. In contrast, in the long term, when a strict GFD is followed and mucosal recovery is achieved, analyzing nutrient intake makes more sense. Macronutrient consumption is characterized by its low complex carbohydrate and fiber intakes, and high fat (especially SFA) and sugar intakes. This profile has been related to the consumption of GFP and their nutritional composition, in addition to unbalanced dietary habits. The most notable deficiencies in micronutrients are usually those of iron, calcium and magnesium and vitamin D, E and some of group B. It is necessary to follow up patients with CD and to promote nutritional education among them, since it could help not only to achieve a gluten free but also a balanced diet.

FODMAP Intake in Spanish Population: Open Approach for Risk Assessment.

Fermentable oligo-, di- and monosaccharides and polyols' (FODMAP) were related with intestinal complications. The present study aimed to determine the FODMAP consumption of Spanish children, adolescents and adults, analyzing the real FODMAP risk of foods, and to set an open methodology for the measurement of this intake in other regions as well as nutrient intake assurance. Total fructan analysis was performed analytically in eighty-seven food samples. Daily intake of FODMAPs, fiber and micronutrients was calculated by combining the food composition for selected fermentable carbohydrates with the national food consumption stratified by age in an open software. Spanish child and adolescent total FODMAP consumption was settled as 33.4 ± 92.4 and 27.3 ± 69.0 g/day, respectively. Both intakes were higher than that of the adult population (21.4 ± 56.7 g/day). The most important food sources of lactose, excess of fructose and total fructan, considering their content and dietary intake were different between age groups. The contribution of these foods to dietary calcium and fiber and the consequent risk of deficiency if they are withdrawn was highlighted. We demonstrated the relevance of stratifying the total FODMAP intake by age. An open approach for FODMAP intake quantification and nutrient control was provided.

Effect of analytically measured fiber and resistant starch from gluten-free products on the diets of individuals with celiac disease.

OBJECTIVE: The aim of the present work was to assess the content of fiber and resistant starch (RS) in several gluten-free products (GFPs), compare them with their gluten-containing analogs (GCP) analytically and with label data, and measure the contribution of these foodstuffs to the fiber content of a gluten-free diet. METHODS: Total dietary fiber and RS content in a large amount of GFP (n = 55) and their counterparts (n = 55) were measured by analytical techniques based on AOAC methods. Dietary assessment was carried out with a sample of 141 individuals (pediatric and adult patients with celiac disease) submitted to a food frequency questionnaire and a 24-h recall survey (three times on different days). RESULTS: In general terms, GFP and GCP showed similar fiber and RS content, with the exception of breads, which revealed a higher percentage of both in GFPs. This food group was the main contributor to fiber intake in both groups of patients. Even if GFPs were to be blamed for being nutritionally poorer than GCPs, this was not the case for fiber. CONCLUSIONS: The fiber and RS content were not different in the studied samples, except for the bread. It is noteworthy that label information can underestimate fiber consumption among those with celiac disease, and this must be considered for future database revision. Additionally, we demonstrated a significant effect on the fiber intake of children and adults due to GFPs, and especially to bread, a widely consumed basic product.

New Software for Gluten-Free Diet Evaluation and Nutritional Education.

Following a gluten-free diet (GFD) is the only treatment for celiac disease. This diet must ensure the absence of gluten but also needs to be nutritionally balanced. Dietitians working in this field cannot properly evaluate energy and nutrient intake of celiac people because dietary programs available on the market do not contain the nutritional composition of gluten-free products (GFP). Here we present a new GFD evaluation software that contains more than 700 gluten-free rendered foodstuffs and their macronutrient composition. Apart from diet evaluation and design, the software represents a tool for nutritional education as well, since it shows diet appropriacy and indicates how to promote balanced self-care. Moreover, anthropometric and biochemical data or symptoms presence and diet adherence can be recorded and evaluated. This open free software, can be downloaded in its app format for mobiles and tablets. Software evaluation indicated its correct functionality and the importance of assessing a GFD with GFP instead of with their gluten-containing analogues. Thus, this software represents an essential e-Health tool, not only for proper GFD evaluation, but also for improving life quality of celiac and gluten sensitive people.

Micronutrient Analysis of Gluten-Free Products: Their Low Content Is Not Involved in Gluten-Free Diet Imbalance in a Cohort of Celiac Children and Adolescent.

Data about the nutritional composition of gluten-free products (GFP) are still limited. Most studies are based on ingredient and nutrition information described on the food label. However, analytical determination is considered the gold standard for compositional analysis of food. Micronutrient analytical content differences were observed in a selection of GF breads, flakes and pasta, when compared with their respective gluten-containing counterparts. In general terms, lower iron, piridoxin, riboflavin, thiamin, niacin, folate, manganese and vitamin B5 can be underlined. Variations in biotin and vitamin E content differed among groups. In order to clarify the potential contribution of the GFP to the gluten-free diet's (GFD) micronutrient shortages, analytical data were used to evaluate GFD in a cohort of celiac children and adolescent. Participants did not reach recommendations for vitamin A, vitamin E, folic acid, vitamin D, biotin, iodine, and copper. It does not seem that the lower micronutrient content of the analyzed GFP groups contributed to the micronutrient deficits detected in GFD in this cohort, whose diet was not balanced. Nevertheless, GFP fortification for folate and biotin is proposed to prevent the deficiencies observed in GFD, at least in the case of pediatric celiac disease.

Celiac Male's Gluten-Free Diet Profile: Comparison to that of the Control Population and Celiac Women.

The aim of the present work was to analyze the body composition and dietary profile of Spanish celiac men and to compare them to control men and celiac women from our previous studies. Forty-two celiac men (31.5 ± 11.9 years) were recruited and anthropometric measurements were taken. Analysis of energy consumption, macro- and micronutrient intake and food frequency consumption was carried out. Celiac men were more overweight and obese than celiac women, but less than the control population, reporting the same energy intake and macronutrient distribution. Most micronutrient deficiencies in celiac men were not directly related to a gluten free diet; these were also observed for the entire population. The least adherence to Dietary Reference Intakes in women was reported for iron, iodine, potassium and selenium, whereas magnesium intake was higher than in men. Among celiac participants (both genders), cereal, vegetable and legume consumption was poor and meat intake was contrastingly excessive. In conclusion, the dietary profile of celiac men is as unbalanced as that of control men but slightly more than that of celiac women. General nutritional education should be given to both general and celiac populations, and specific advices to celiac men, in order to decrease the risk of celiac disease-related pathologies.

Consideraciones analíticas en la determinación de gluten en alimentos / No disponible

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Greenhouse gas emissions and soil organic matter dynamics in woody crop orchards with different irrigation regimes.

Water scarcity in arid, semiarid and dry regions is a limiting factor for the development of sustainable agriculture. As a consequence, the adoption of new strategies such as regulated deficit irrigation (RDI) to reduce water and energy consumption will be essential. Decreases in irrigation water content may also have positive effects on soil C cycle. Thus, an experiment was setup in three woody crop orchards during two years, with the objective of assessing if RDI can reduce soil CO2 and N2O emissions, modify soil inorganic C and organic C quality and stability and affect soil aggregation. Soil CO2 and N2O emissions were measured every two weeks while soil samplings were carried out every three months. Results indicated that decreases in soil moisture by RDI implementation were related to significant decreases in CO2 emissions in all crops. RDI contributed to an average decrease, compared with full irrigation, of 1088-1664 g CO2 m-2 in the experimental period. Furthermore, CO2 emission was negatively correlated with inorganic C, suggesting the protective effect of soil carbonates towards organic matter. RDI also contributed to significantly decrease soil N2O emissions. However, N2O emission patterns did not directly follow soil moisture patterns and were constant in the experimental period. RDI contributed to an average decrease, compared with full irrigation, of 90-409 mg N2O m-2. No physicochemical property was significantly affected by irrigation regime. Although microbial biomass was not significantly affected by RDI, ß-glucosidase activity was significantly higher under full irrigation during the warm seasons, with significant positive correlation with CO2 emissions. This seems to suggest that a significant fraction of CO2 emitted from soil derives from organic matter degradation, which is limited with low water content. So, RDI could contribute to promote soil C sequestration by reduced greenhouse gas emissions, with no negative effects on soil structure at short-term.

Evolution of Gluten Content in Cereal-Based Gluten-Free Products: An Overview from 1998 to 2016.

The treatment of Celiac disease consists in a strict lifelong gluten-free (GF) diet. As the ingestion of small amounts can have damaging complications, there has been an ongoing discussion regarding the safe threshold for dietary residual gluten. The aim was to analyze the evolution of gluten content in cereal-based GF foodstuffs (n = 3141) from 1998 to 2016 measured by the enzyme-linked immunosorbent assay (ELISA) technique. Eight categories were defined: flours, breakfast cereals/bars, bakery, pasta, breads, dough, snacks, and yeasts, and these were divided into GF labeled-foods (GF-L) or reportedly GF foodstuffs, but not certified (GF-NC). Gluten-detection was decreased over time in line with the evolving European regulations about food information and gluten content claims. This decline started sooner in GF-L products than in GF-NC. As a whole, gluten was detected in 371 samples, with breakfast cereals/bars being the most contaminated group. Snacks and yeasts changed from being high gluten-detected samples to being totally GF over the years. The downside is that, of contaminated samples, those in the low levels of gluten detection range have decreased while flour samples containing over 100 mg/kg gluten have risen in the 2013-2016 period. Obtained data confirm that GF cereal-based foods are becoming safer but gluten control must be maintained.

Resveratrol and piceid metabolites and their fat-reduction effects in zebrafish larvae.

Resveratrol, a polyphenolic phytoalexin found in many plants, has been reported to have antiobesogenic effects in several animal and in vitro models. Zebrafish present several technical advantages that place them at an interesting, halfway point between in vitro and rodent models. The aim of the present work was to evaluate the metabolization of resveratrol and its glucoside (piceid) in zebrafish and their ability to induce the consumption of fat reserve in zebrafish larvae. Resveratrol and piceid were both able to reduce yolk sac fat content depending on the dose tested. Furthermore, resveratrol showed a potent and rapid action, whereas piceid needed more time and higher doses to be as effective as resveratrol. In accordance with other animal models and humans, the principal metabolites found in zebrafish larvae were monoglucoronide and monosulfate forms of resveratrol. In conclusion, zebrafish are a potentially excellent animal model for polyphenol research as they present several advantageous characteristics for efficacy screening and metabolomic studies before rodents.

Prolyl hydroxylase-dependent modulation of eukaryotic elongation factor 2 activity and protein translation under acute hypoxia.

Early adaptive responses to hypoxia are essential for cell survival, but their nature and underlying mechanisms are poorly known. We have studied the post-transcriptional changes in the proteome of mammalian cells elicited by acute hypoxia and found that phosphorylation of eukaryotic elongation factor 2 (eEF2), a ribosomal translocase whose phosphorylation inhibits protein synthesis, is under the precise and reversible control of O(2) tension. Upon exposure to hypoxia, phosphorylation of eEF2 at Thr(56) occurred rapidly (<15 min) and resulted in modest translational arrest, a fundamental homeostatic response to hypoxia that spares ATP and thus facilitates cell survival. Acute inhibitory eEF2 phosphorylation occurred without ATP depletion or AMP kinase activation. Furthermore, eEF2 phosphorylation was mimicked by prolyl hydroxylase (PHD) inhibition with dimethyloxalylglycine or by selective PHD2 siRNA silencing but was independent of hypoxia-inducible factor α stabilization. Moreover, overexpression of PHD2 blocked hypoxic accumulation of phosphorylated eEF2. Therefore, our findings suggest that eEF2 phosphorylation status (and, as a consequence, translation rate) is controlled by PHD2 activity. They unravel a novel pathway for cell adaptation to hypoxia that could have pathophysiologic relevance in tissue ischemia and cancer.

A multi-gene analysis strategy identifies metabolic pathways targeted by trans-10, cis-12-conjugated linoleic acid in the liver of hamsters.

In mice, hepatic functions can be greatly affected by dietary trans-10, cis-12-conjugated linoleic acid (CLA). However, this phenomenon has been less documented in hamsters. In the present study, male hamsters were fed two doses of the trans-10, cis-12-CLA (0.5 and 1%, w/w diet) or linoleic acid (0.5%) for 6 weeks. The effects on the liver were examined by measuring the expression of thirty-six genes representing key metabolic pathways. CLA-responsive genes and their relationships with physiological outcomes were examined by a multivariate analysis procedure. Compared with control hamsters, those receiving either 0.5 or 1% CLA exhibited similar fat loss (15-24%; P < or = 0.05) and liver enlargement (21-28%; P < or = 0.05), with no signs of steatosis. We also observed a dose-dependent increase in the transcription of genes involved in lipid breakdown and lipid harvesting from blood, and in genes related to the oxidative stress and inflammatory responses. These responsive genes varied in parallel with cell membrane lipids (R2 0.31-0.42) and to a lesser extent with liver enlargement (R2 0.22) (all P < 0.05). We conclude that in hamsters, liver enlargement induced by trans-10, cis-12-CLA is accompanied by an increased metabolic potential to process fatty acids from mobilised adipose stores. This elevated metabolic activity, comprised of anabolic pathways and their catabolic counterparts, can trigger inflammation and the oxidant stress defence pathways in a dose-dependent manner. These results provide novel insights into the mechanisms by which trans-10, cis-12-CLA affects pathways related to liver function.

Effects of trans-10,cis-12 conjugated linoleic acid on cholesterol metabolism in hypercholesterolaemic hamsters.

BACKGROUND: Conjugated linoleic acid (CLA) has received great attention in recent years because of its pleiotropic biological activities, but considerably fewer studies have been published addressing its role in serum lipids and atherosclerosis compared to other topics covered. AIMS OF THE STUDY: The aim of the present study was to assess the effects of the trans-10,cis-12 isomer of CLA on cholesterolaemia and on several metabolic pathways involved in cholesterol metabolism in hamsters. METHODS: Animals were fed atherogenic diets supplemented with 0.5% linoleic acid, 0.5% trans-10,cis-12 CLA or 1.0% trans-10,cis-12 CLA, for 6 weeks. Serum lipoproteins were separated by FPLC. Cholesterol in serum and liver, as well as triacylglycerols and phospholipids in liver were assessed by spectrophotometry. 3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGCoAR), acyl-coenzyme A:cholesterol acyltransferase (ACAT) and cholesteryl ester hydrolase (CEH) activities were measured by radiometry, and LDL receptors were determined by Western blot. RESULTS: trans-10,cis-12 CLA feeding did not modify food intake nor final body weight. Although serum total cholesterol remained unchanged, when cholesterol fractions were analyzed a significant decrease in VLDL-cholesterol was observed in CLA-fed animals, without changes in HDL-cholesterol or LDL-cholesterol. trans-10,cis-12 CLA decreased cholesterol ester content and increased free cholesterol in liver. The activity of HMGCoAR was not modified. In contrast, ACAT activity was reduced by both CLA doses and CEH was increased by the high CLA dose. LDL receptors were significantly reduced by trans-10,cis-12 feeding when expressed as arbitrary units per mg of protein, however, the total receptor mass remained unchanged. CONCLUSIONS: These results suggest that, under the present experimental conditions, trans-10,cis-12 CLA feeding reduces cholesterol esterification in liver and decreases the minority serum VLDL-cholesterol fraction, but it does not show a hypocholesterolaemic effect. A dose-response effect was not observed.

Effects of conjugated linoleic acid on skeletal muscle triacylglycerol metabolism in hamsters.

OBJECTIVE: The present work evaluated the effects of conjugated linoleic acid (CLA) on various aspects of triacylglycerol metabolism in skeletal muscle to determine the potential involvement of this tissue in the effect of CLA to decrease body fat. METHODS: Animals were randomized to three groups that were fed atherogenic diets that provided different amounts of trans-10,cis-12 CLA (0%, 0.5%, or 1%) for 6 wk. Muscle triacylglycerol, protein, water, glycogen, and DNA contents and fatty acid profile in triacylglycerols were analyzed. Lipoprotein lipase and carnitine palmitoyltransferase-I (CPT-I) activities were assessed. Triacylglycerol, glucose, and insulin concentrations were evaluated in serum. RESULTS: The high dose of CLA increased food efficiency and gastrocnemius muscle weight. CLA feeding resulted in decreased muscle triacylglycerol content without changes in protein, water, glycogen, and DNA contents or in cell size (protein/DNA ratio) and produced decreased lipoprotein lipase activity and increased CPT-I activity. No differences were found between CLA doses. CLA feeding led to the saturation of stored triacylglycerols. CONCLUSIONS: Decreased fatty acid uptake and increased fatty acid oxidation can contribute to the decreased muscle triacylglycerol content observed in hamsters fed the CLA diets. The increase in muscle fatty acid beta-oxidation might ultimately prevent storage of triacylglycerols in adipose tissue. Nevertheless, the lack of matching of lipoprotein lipase and CPT-I modifications makes it difficult to ensure that skeletal muscle is responsible, at least in part, for the effect of CLA on decreasing body fat; thus, further research is needed.

Effects of conjugated linoleic acid on liver composition and fatty acid oxidation are isomer-dependent in hamster.

OBJECTIVE: The present work was designed to study the effects of the two main isomers of conjugated linoleic acid (CLA), cis-9,trans-11 and trans-10,cis-12, on liver composition and hepatic fatty acid oxidation in hamsters. METHODS: Animals were divided into three groups that were fed atherogenic diets supplemented with 0.5% linoleic acid, cis-9,trans-11 CLA, or trans-10,cis-12 CLA for 6 wk. Liver lipids, protein, water and DNA contents, and histologic structure were analyzed. Hepatic carnitine palmitoyltransferase-I and acyl coenzyme A oxidase activities were assessed. Triacylglycerol concentration, and aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltransferase, and alkaline phosphatase activities were evaluated in serum. CLA isomer contents were analyzed by gas chromatography in hepatic triacylglycerols. Peroxisome proliferator-activated receptor-alpha mRNA was determined by reverse transcriptase polymerase chain reaction. RESULTS: Trans-10,cis-12 CLA led to significantly greater weight, lower levels of triacylglycerol, cholesterol, and phospholipid, and larger total cell number in liver. Carnitine palmitoyltransferase-I and acyl coenzyme A oxidase activities were significantly increased by this isomer. No changes were induced by cis-9,trans-11 CLA. Trans-10,cis-12 CLA was recovered in significantly lower proportions than cis-9,trans-11 in liver triacylglycerols. Histopathologic analysis showed no abnormalities. No significant differences in serum aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltransferase, and alkaline phosphatase activities or in hepatic mRNA peroxisome proliferator-activated receptor-alpha expression were found among the three experimental groups. CONCLUSIONS: These results suggest that the addition of 0.5% of these CLA isomers to the diet do not induce toxic effects in liver after 6 wk of feeding. Intake of trans-10,cis-12 isomer but not of cis-9,trans-11 CLA increases liver fatty acid oxidation. This effect leads to decreased hepatic and serum triacylglycerols.