Mindfulness vs psychoeducation in adult ADHD: a randomized controlled trial.

BACKGROUND: Mindfulness training is a promising treatment approach in adult ADHD. However, there has not yet been a randomized controlled trial comparing mindfulness to an active control condition. In this study, we assessed the efficacy of a mindfulness training program (MAP) compared to structured psychoeducation (PE). METHODS: After randomization 81 medication-free adult ADHD patients participated either in an 8-week MAP or PE group program. At baseline (T1), after 8 weeks (T2) and after 8 months (T3), severity of ADHD and associated symptoms (depression, general psychopathology, quality of life) were measured with the Conner's ADHD Rating Scales (CAARS), the Beck Depression Inventory (BDI), the Brief Symptom Inventory (BSI) and the SF-36 by self and blind observer ratings. RESULTS: Both groups showed significant pre-post improvements in observer-rated Inattention scale (p < .001, partial η2 = 0.18) and in associated symptomatology, which persisted through 6 months of follow-up. There were no significant differences regarding symptom reduction between the treatment groups. Women benefited more compared to men irrespective of treatment group. Men showed the most pronounced changes under MAP. CONCLUSIONS: In the current study, MAP was not superior to PE regarding symptom reduction in adult ADHD. Both interventions, mindfulness meditation and PE, were efficacious in reducing symptom load in adult ADHD. Furthermore in exploratory post hoc tests the study provides evidence for a potential gender-specific treatment response in adult ADHD.

A meta-analysis to assess the effect of the composition of dietary fat on α-tocopherol blood and tissue concentration in pigs.

A meta-analysis based on the results from 13 selected publications was performed to assess the effect of dietary fat supplementation (quantity and fatty acid composition) on α-tocopherol (TOL) concentration in 4 pig tissues (blood, liver, muscle, and adipose tissue). Dietary fat supplementation was defined by the quantity of fat added to the basal diet and its fatty acid profile. After standardization of tissue TOL concentration (as the dependent variable), statistical analyses were performed using multiple nonlinear regression, data partitioning, and partial least squares regression with 7 predictor variables including added vitamin E (VE), added fat, PUFA (% fat), MUFA (% fat), SFA (% fat), omega-3 fatty acids (-3; % fat), and omega-6 fatty acids (-6; % fat). The statistical analyses first showed that the VE level in the diet was the main factor that modulates tissue TOL concentration. The dose-response relationship followed a logarithmic curve, with a saturation of tissue TOL concentration in all the studied tissues. Moreover, the amount of dietary fat, at least up to 20%, was not linearly correlated with tissue TOL concentration, considering that the main fatty acid classes, MUFA and, to a lesser extent, SFA, were positively associated with tissue TOL concentrations. Finally, this study suggests that the inclusion of -3 fatty acids in the diet may decrease tissue and, more precisely, blood TOL concentration.

Vitamin D bioavailability: state of the art.

There has been renewed interest in vitamin D since numerous recent studies have suggested that besides its well-established roles in bone metabolism and immunity, vitamin D status is inversely associated with the incidence of several diseases, e.g., cancers, cardio-vascular diseases, and neurodegenerative diseases. Surprisingly, there is very little data on factors that affect absorption of this fat-soluble vitamin, although it is acknowledged that dietary vitamin D could help to fight against the subdeficient vitamin D status that is common in several populations. This review describes the state of the art concerning the fate of vitamin D in the human upper gastrointestinal tract and on the factors assumed to affect its absorption efficiency. The main conclusions are: (i) ergocalciferol (vitamin D2), the form mostly used in supplements and fortified foods, is apparently absorbed with similar efficiency to cholecalciferol (vitamin D3, the main dietary form), (ii) 25-hydroxyvitamin D (25OHD), the metabolite produced in the liver, and which can be found in foods, is better absorbed than the nonhydroxy vitamin D forms cholecalciferol and ergocalciferol, (iii) the amount of fat with which vitamin D is ingested does not seem to significantly modify the bioavailability of vitamin D3, (iv) the food matrix has apparently little effect on vitamin D bioavailability, (v) sucrose polyesters (Olestra) and tetrahydrolipstatin (orlistat) probably diminish vitamin D absorption, and (vi) there is apparently no effect of aging on vitamin D absorption efficiency. We also find that there is insufficient, or even no data on the following factors suspected of affecting vitamin D bioavailability: (i) effect of type and amount of dietary fiber, (ii) effect of vitamin D status, and (iii) effect of genetic variation in proteins involved in its intestinal absorption. In conclusion, further studies are needed to improve our knowledge of factors affecting vitamin D absorption efficiency. Clinical studies with labeled vitamin D, e.g., deuterated or (13)C, are needed to accurately and definitively assess the effect of various factors on its bioavailability.

Dietary fat modulates dl-α-tocopheryl acetate (vitamin E) bioavailability in adult cockerels.

1. A trial was designed to assess the effect of fat supplementation (amount and type of fatty acids) on vitamin E bioavailability in adult cockerels. 2. A total of 60 birds were force-fed three different diets: a semi-purified diet without added fat (Control diet) or supplemented with 3% fat as linseed (Linseed diet) or hydrogenated coconut oil (Coconut diet). The three experimental diets were also supplemented with dl-α-tocopheryl acetate to provide 40 mg vitamin E per bird. 3. After one week of depletion, blood was collected from the wing vein before (baseline) and 6, 12, 24 and 96 h after the gavage. Plasma samples were analysed for their α-tocopherol, cholesterol and triglycerides concentrations. 4. Results showed that the addition of 3% fat in the experimental diet increased post-gavage plasma α-tocopherol response by 153% for Linseed diet and by 75% for Coconut diet (P < 0.0001) compared to the Control group. Furthermore, the plasma α-tocopherol response observed with the Linseed diet was 44% greater than that observed with the Coconut diet (P < 0.0001). There was no effect of treatments on either plasma triglycerides (P = 0.91) or cholesterol (P = 0.45) responses. 5. In conclusion, this study shows that the addition of 3% fat to the diet significantly increases dl-α-tocopheryl acetate bioavailability in adult cockerels. Supplementation of fat rich in unsaturated fatty acids also leads to a higher dl-α-tocopheryl acetate bioavailability than fat rich in saturated fatty acids.

Effect of the type of dietary triacylglycerol fatty acids on α-tocopherol concentration in plasma and tissues of growing pigs.

A study was performed in growing pigs to evaluate the efficacy of α-tocopherol (Tol) concentration in plasma, muscle, liver, and adipose tissue following dietary supplementation with vitamin E (VE) and various sources of fat. The trial involved 96 piglets weaned at an average of 28 d of age. Piglets were fed for 2 wk a semipurified diet not supplemented with VE. Piglets were then randomly assigned to 5 isoenergetic semipurified diets with 100 IU/kg VE as dl-α-tocopheryl acetate: a control (CTRL) diet (with no added fat) and 4 other diets containing either 3% linseed oil (LIN), 3% hydrogenated coconut oil (COC), 3% olive oil (OLI), or 3% safflower oil (SAF) representing diets rich in n-3 PUFA, SFA, MUFA, and n-6 PUFA, respectively. After 49 d of treatment, pigs were killed and blood, muscle (longissimus dorsi), adipose tissue, and whole liver (without gallbladder) were collected and analyzed for their Tol concentrations. For all tissues, LIN and SAF diets led to lower (P < 0.02) Tol concentrations as compared to the CTRL diet: -63 and -67%, respectively. α-Tocopherol concentrations in plasma, liver, and adipose tissue were greater (P < 0.001) in the COC group as compared to the CTRL group. The OLI diet led to greater (P < 0.01) liver Tol concentration (+92%) as compared to the CTRL diet but had no significant effect on plasma, muscle, and adipose tissue Tol concentrations. There were significant correlations (P < 0.001) between plasma, muscle, and liver Tol concentrations (r > 0.78). These results show that supplementation with PUFA markedly decreases Tol concentration in blood and tissues of growing pigs, whereas SFA increase Tol content in blood, liver, and adipose tissue. Monounsaturated fatty acids only increase liver Tol concentrations. Therefore, increasing the amount of fat in the diet (from <0.1 to approximately 3.5%) and the type of dietary fatty acids supplemented with VE are key factors with regards to VE concentration in plasma and tissue. The Tol:PUFA needs to be carefully considered to meet the VE pigs requirement and to ensure an optimal Tol meat enrichment.

The bioavailability of alpha- and beta-carotene is affected by gut microflora in the rat.

The present study examined whether the intestinal microflora could affect the bioavailability and vitamin A activity of dietary alpha- and beta-carotene in the rat. In the first set of experiments, we used conventional, germ-free (axenic), and human-flora-associated (heteroxenic) rats. In a second series, conventional rats were treated with either an antibiotic mixture or a potent inhibitor of gastric secretion (Omeprazole). All animals were first depleted of vitamin A over 4 weeks and then were fed on a sterilized diet supplemented with 14 mg beta-carotene and 3 mg alpha-carotene/kg for 2 weeks. In both experiments, a reduction in the intestinal microflora resulted in an increased storage of beta-carotene, alpha-carotene and vitamin A in the liver. Neither the nature of the metabolism of the intestinal microflora (aerobic or anaerobic) nor treatment with omeprazole, to modify intestinal pH, induced a significant effect on the measured variables. When incubated with 15 mumol beta-carotene/l for 72 h, neither the anaerobic nor the aerobic sub-fractions obtained from rat or human faeces contributed to beta-carotene degradation or to vitamin A synthesis. These findings suggest that reduction in gut microflora results in a better utilization of alpha- and beta-carotene by rats, although bacteria do not have a direct effect on the bioavailability of these pigments.

In vitro and in vivo inhibition of beta-carotene dioxygenase activity by canthaxanthin in rat intestine.

beta-Carotene dioxygenase catalyzes the conversion of provitamin A carotenoids to vitamin A in mammalian tissues. Whether the enzyme can also cleave non-provitamin A carotenoids to retinoid analogs with biological activities is still unclear. We investigated (i) substrate specificities of beta-carotene dioxygenase toward provitamin A and non-provitamin A carotenoids and (ii) potential antagonistic effects of non-provitamin A carotenoids on beta-carotene conversion to vitamin A. Provitamin A substrates were 8 to 23% as active as beta-carotene. No polar metabolites were detected with canthaxanthin or zeaxanthin as substrates; these compounds efficiently inhibited the beta-carotene cleavage reaction by 71 and 40%, respectively. Kinetic studies indicated mixed inhibition for canthaxanthin (Ki = 1.6 microM) and non-competitive for zeaxanthin (Ki = 7.8 microM), suggesting that both compounds do not interact significantly with the active site of the enzyme. In vivo, dietary combinations of canthaxanthin and beta-carotene resulted in lower liver levels of both carotenoids and vitamin A and in a higher beta-carotene/vitamin A ratio as compared to groups supplemented with the compounds separately. This supports the view that canthaxanthin at high doses competes with beta-carotene for intestinal absorption and inhibits the conversion of beta-carotene to vitamin A. Thus, we suggest that although canthaxanthin is not a substrate for beta-carotene dioxygenase, it is likely to affect the activity of provitamin A carotenoids by direct interaction with the enzyme.

Emulsification and lipolysis of triacylglycerols are altered by viscous soluble dietary fibres in acidic gastric medium in vitro.

This in vitro study was designed to test the hypothesis that soluble dietary fibres can alter the process of intragastric lipid emulsification and possibly subsequent triacylglycerol lipolysis. Three guar gums, two pectins and gum arabic were dissolved in acidic gastric medium in the concentration range 0.3-2.0% (w/v). Viscosities of fibre solutions were measured and apparent viscosities varied over a wide range (0.7-77 mPa/s). Emulsification of a lipid mixture (triolein/phosphatidylcholine/cholesterol) was performed under mild conditions in the presence of increasing concentrations of soluble fibres. The amount of emulsified lipid was not affected whereas the size of the emulsified droplets was increased by raising the concentration of viscous fibres only. The droplet size (r=0.75, P=0.006) and overall droplet surface area (r=-0.69, P=0.009) were strongly correlated with the medium viscosity in the range 0-20 mPa/s. The addition of solutions of viscous fibres to a preformed standard emulsion did not change the initial velocity of human gastric lipase reaction. Conversely, when emulsions prepared in the presence of fibres (i.e. with different droplet sizes) were incubated with excess gastric enzyme for 2 h, the high-viscosity guar gum significantly reduced the extent of triacylglycerol lipolysis, as compared with control and low- or medium-viscosity fibres. In conclusion, the data obtained show that reducing emulsification of dietary lipids in the mildly acid medium found in the stomach is a mechanism by which soluble viscous fibres can alter lipid assimilation.

Effects of pea and soybean fibre on postprandial lipaemia and lipoproteins in healthy adults.

To evaluate some possible mechanisms whereby total dietary fibre (TDF) may affect lipid metabolism in humans, six normolipidaemic males ingested on separate days a low-fibre test meal (2.8 g TDF) containing 70 g fat and 756 mg cholesterol, enriched with 10 g TDF in the form of either pea fibre or soybean fibre. Fasting and post-meal blood samples were obtained for 7 h and chylomicrons (CM) were isolated. Lipoproteins (VLDL+CM remnants, LDL, HDL) were isolated from the baseline samples and the samples of the 2-3 h triglyceride peaks. As compared to the postprandial response given by the control low-fibre test meal, adding fibre induced no change in serum glucose, insulin or Apo A1 and Apo B variations. The serum triglyceride response was not altered by adding fibres but the 2-3 h chylomicron triglyceride rise was increased (P < or = 0.05) by soybean fibre. VLDL+CM remnants, LDL and HDL triglyceride variations were unchanged with fibres. Cholesterolaemia decreased postprandially for 6 h, and was further lowered in the presence of pea fibre. This resulted from a marked decrease in serum esterified cholesterol. The chylomicron cholesterol and phospholipid rise was lowered in the presence of either fibre. The postprandial changes in the free cholesterol concentrations of the various lipoprotein classes were not altered by fibre whereas changes from baseline in esterified cholesterol concentrations were reduced by soybean fibre in LDL and amplified by soybean and pea fibres in HDL. The results obtained show that dietary fibre present in legumes may alter postprandial lipaemia and lipoproteins in humans to a variable extent. These effects could be related to some long-term metabolic effects.

Carboxyl terminus structural requirements for glycosyl-phosphatidylinositol anchor addition to cell surface proteins.

Glycosyl phosphatidylinositol (GPI)-anchored proteins contain in their COOH-terminal region a peptide segment that is thought to direct glycolipid addition. This signal has been shown to require a pair of small amino acids positioned 10-12 residues upstream of an hydrophobic C-terminal domain. We analysed the contribution of the region separating the anchor acceptor site and the C-terminal hydrophobic segment by introducing amino acid deletions and substitutions in the spacer element of the GPI-anchored Thy-1 glycoprotein. Deletions of 7 amino acids in this region, as well as the introduction of 2 charged residues, prevented the glycolipid addition to Thy-1, suggesting that the length and the primary sequence of the spacer domain are important determinants in the signal directing GPI anchor transfer onto a newly synthesized polypeptide. Furthermore, we tested these rules by creating a truncated form of the normally transmembranous Herpes simplex virus I glycoprotein D (gDI) and demonstrating that when its C-terminal region displays all the features of a GPI-anchored protein, it is able to direct glycolipid addition onto another cell surface molecule.

Effect of pectin, wheat bran and cellulose on serum lipids and lipoproteins in rats fed on a low- or high-fat diet.

1. Four groups of adult male Sprague-Dawley rats were fed for 6 weeks on a diet with a low-fat content (50 g/kg) and another four groups were given a diet rich in fat (250 g/kg) and cholesterol (12 g/kg). In both cases, the basal diets were either fibre-depleted or supplemented with cellulose (60 g/kg), wheat bran (100 g/kg) or low-methoxyl pectin (100 g/kg). 2. Low-methoxyl pectin displayed the most hypocholesterolaemic effect and decreased the cholesterol content of the very-low-density lipoproteins (VLDL) and low-density lipoproteins (LDL), when the low-fat diet was given. When rats were fed on the high-fat diet, pectin no longer had a hypocholesterolaemic effect but still decreased the VLDL-cholesterol content. Pectin lowered serum triglyceride and VLDL-triglyceride levels only when the low-fat diet was given. 3. Wheat bran exerted no hypocholesterolaemic effect in rats fed on the low- and high-fat diets, but decreased the cholesterol content of VLDL and lowered serum triglycerides and VLDL-triglycerides when the high-fat diet was given. 4. Purified cellulose had no significant effect on plasma lipids. 5. As shown by multivariance analysis, low-methoxyl pectin and wheat bran both beneficially modified the serum triglyceride and cholesterol variables except VLDL-triglycerides. However, the magnitude of the effect of each individual type of fibre was dependent on the fat and cholesterol content of the diet, suggesting the existence of different mechanisms of action.