Journal of Nutrition current issue

[Commentary] Lessons from the Bovine Genome: Implications for Human Nutrition and Research

Lemay, D. G., Rijnkels, M., German, J. B. — 2009-06-19

[Biochemical, Molecular, and Genetic Mechanisms] Telomere Length in Peripheral Blood Mononuclear Cells Is Associated with Folate Status in Men

2009-06-19

Human chromosomes are capped by telomeres, which consist of tandem repeats of DNA and associated proteins. The length of the telomeres is reduced with increasing cell divisions except when the enzyme telomerase is active, as in stem cells and germ cells. Telomere dysfunction has been associated with development of age-related pathologies, including cancer, cardiovascular disease, Alzheimer's disease, and Parkinson's disease. DNA damage in the telomeric region causes attrition of telomeres. Because folate provides precursors for nucleotide synthesis and thus affects the integrity of DNA, including that of the telomeric region, folate status has the potential to influence telomere length. Telomere length is epigenetically regulated by DNA methylation, which in turn could be modulated by folate status. In this study, we determined whether folate status and the 677C > T polymorphism of the methylene tetrahydrofolate reductase (MTHFR) gene are associated with the telomere length of peripheral blood mononuclear cells in healthy men. The results of our study showed that plasma concentration of folate was associated with telomere length of peripheral blood mononuclear cells in a nonlinear manner. When plasma folate concentration was above the median, there was a positive relationship between folate and telomere length. In contrast, there was an inverse relationship between folate and telomere length when plasma folate concentration was below the median. The MTHFR 677C > T polymorphism was weakly associated (P = 0.065) with increased telomere length at below-median folate status. We propose that folate status influences telomere length by affecting DNA integrity and the epigenetic regulation of telomere length through DNA methylation.

[Nutrient Physiology, Metabolism, and Nutrient-Nutrient Interactions] Dietary Supplementation of L-Arginine and Conjugated Linoleic Acid Reduces Retroperitoneal Fat Mass and Increases Lean Body Mass in Rats

Nall, J. L., Wu, G., Kim, K. H., Choi, C. W., Smith, S. B. — 2009-06-19

We hypothesized that l-arginine and conjugated linoleic acid (CLA) would have additive effects in decreasing adiposity. Sprague Dawley rats were assigned to the following dietary groups (n = 6/group; 5 wk total): 1) control (2.55% l-alanine plus 1.5% canola oil); 2) arginine (1.25% l-arginine plus 1.5% canola oil); 3) CLA (2.55% l-alanine plus 1.5% CLA); and 4) arginine plus CLA (1.25% l-arginine plus 1.5% CLA). Supplemental amino acids were provided in drinking water and CLA was incorporated into the food pellets. Daily weight gain, food intake, arginine intake, and final body and eviscerated body weights were greater in rats fed supplemental CLA then in rats fed canola oil. The retroperitoneal adipose tissue:body weight ratio was less in rats fed supplemental CLA than in rats fed canola oil, but epididymal adipose tissue, liver, and soleus and extensor digitorum longus muscle weights were unaffected by arginine or CLA. CLA decreased epididymal adipose tissue concentrations of palmitoleic, oleic, and cis-vaccenic acid. CLA and arginine increased palmitate oxidation to CO₂ in epididymal adipose tissue in vitro relative to control rats. Glucose and palmitate incorporation into total lipids in epididymal adipose tissue was lower in rats fed supplemental arginine than in alanine-fed rats. Arginine increased plasma glycerol relative to alanine-fed rats and CLA and arginine independently decreased most serum essential amino acids and alanine, glutamate, glutamine, and ornithine. We conclude that CLA and arginine modulated adipose tissue metabolism by separate, but not additive, effects. Also, CLA and arginine may have depressed muscle protein turnover.

[Nutrient Physiology, Metabolism, and Nutrient-Nutrient Interactions] Impaired Ghrelin Response after High-Fat Meals Is Associated with Decreased Satiety in Obese and Lean Chinese Young Adults

Yang, N., Liu, X., Ding, E. L., Xu, M., Wu, S., Liu, L., Sun, X., Hu, F. B. — 2009-06-19

Ghrelin and peptide tyrosine tyrosine (PYY) are known to affect appetite and body weight, but the acute effects of fat-rich and carbohydrate-rich meals on plasma ghrelin, PYY response, and appetite remain unclear. We hypothesized that obese individuals had impaired postprandial ghrelin and PYY response based on macronutrient content of meals, affecting appetite and energy intake. We conducted a randomized crossover trail comparing fasting ghrelin and PYY concentrations, postprandial ghrelin and PYY responses, and subjective appetite in 15 obese and 12 lean Chinese young adults after they consumed isocaloric high-carbohydrate [HC; 88% energy carbohydrate, 4% energy fat, 8% energy protein] and high-fat (HF; 25% energy carbohydrate, 71% energy fat, 4% energy protein) meals. Ghrelin concentrations over time differed between HC and HF meals (P < 0.01) via repeated measures of ANOVA, with lower postprandial ghrelin suppression after HF meals, especially among obese participants. PYY response differed between meals among lean participants, with a delayed and higher postprandial PYY peak after the HF meal (P < 0.01); however, PYY response did not differ among obese participants. The incremental area under the curve of PYY was higher in lean than in obese participants after the HF meal (P < 0.01). These results suggest that impaired ghrelin response after HF meals may contribute to reduced satiety and overeating, especially among obese individuals. Whether an attenuated response of PYY in obese participants after a HF meal bears any physiological consequences warrants further study.

[Nutrient Physiology, Metabolism, and Nutrient-Nutrient Interactions] Creatine Synthesis Is a Major Metabolic Process in Neonatal Piglets and Has Important Implications for Amino Acid Metabolism and Methyl Balance

2009-06-19

Our objectives in this study were as follows: 1) to determine the rate of creatine accretion by the neonatal piglet; 2) identify the sources of this creatine; 3) measure the activities of the enzymes of creatine synthesis; and 4) to estimate the burden that endogenous creatine synthesis places on the metabolism of the 3 amino acids required for this synthesis: glycine, arginine, and methionine. We found that piglets acquire 12.5 mmol of total creatine (creatine plus creatine phosphate) between 4 and 11 d of age. As much as one-quarter of creatine accretion in neonatal piglets may be provided by sow milk and three-quarters by de novo synthesis by piglets. This rate of creatine synthesis makes very large demands on arginine and methionine metabolism, although the magnitude of the demand depends on the rate of remethylation of homocysteine and of reamidination of ornithine. Of the 2 enzymes of creatine synthesis, we found high activity of l-arginine:glycine amidinotransferase in piglet kidneys and pancreas and of guanidinoacetate methyltransferase in piglet livers. Piglet livers also had appreciable activities of methionine adenosyltransferase, which synthesizes S-adenosylmethionine, and of betaine:homocysteine methyltransferase, methionine synthase, and methylene tetrahydrofolate reductase, which are required for the remethylation of homocysteine to methionine. Creatine synthesis is a quantitatively major metabolic process in piglets.

[Nutrient Physiology, Metabolism, and Nutrient-Nutrient Interactions] Dietary L-Homoserine Spares Threonine in Chicks

Bryant, K. I., Dilger, R. N., Parsons, C. M., Baker, D. H. — 2009-06-19

Four chick bioassays were conducted to evaluate the threonine (Thr) replacement value of l-homoserine (HS). Growth rate was increased (P < 0.05) by dietary addition of 800 mg l-HS/kg diet to a purified diet severely deficient in Thr or by the addition of 800 or 1000 mg of l-HS/kg diet to a corn-peanut meal diet distinctly deficient in Thr. The addition of an isomolar level of -ketobutyrate, a catabolic product of both Thr and HS, did not elicit a response. Standard-curve methodology predicted a Thr replacement value of 38 ± 9% for HS. Interactions (P < 0.01) were observed in assays 2 and 4 between dietary Thr adequacy and 800 or 1000 mg l-HS/kg supplementation. Thus, HS improved growth performance when added to a Thr-deficient diet (0.46 g Thr/100 g diet), but it decreased growth performance when added to the same diet containing surfeit Thr (0.80 g Thr/100 g diet). The results indicate that low levels of HS elicit a growth response in young chicks fed Thr-deficient diets.

[Nutrient Physiology, Metabolism, and Nutrient-Nutrient Interactions] Intestinal Physiology and Peptidase Activity in Male Pigs Are Modulated by Consumption of Corn Culture Extracts Containing Fumonisins

Lessard, M., Boudry, G., Seve, B., Oswald, I. P., Lalles, J.-P. — 2009-06-19

Fumonisin B₁ (FB1) alters intestinal epithelial cell cycle and absorptive, secretory, and barrier properties in vitro, but in vivo data are lacking. Therefore, we tested the hypothesis that repeated intake of a corn culture extract rich in fumonisins, mainly in FB1, alters indices of intestinal absorptive and secretory physiology and barrier function in vivo. Intra-litter pairs of pigs (n = 36) weaned at 28 d, were fed the vehicle (control) or the extract (providing 1.5 mg FB1/kg body weight) daily for 9 d starting 7 d postweaning. After slaughter, the jejunal mucosa of pigs was mounted in Ussing chambers (UC). Extract consumption for 9 d decreased the gain:feed ratio (P = 0.04) and increased liver weight (P = 0.01). Basal net ion secretion (P = 0.02), sodium-dependent glucose absorption (P = 0.02), and theophylline-induced secretion (P < 0.01) of the jejunal mucosa determined in UC were higher in pigs fed the extract than in controls. By contrast, jejunal permeability to the horseradish peroxidase model protein in UC was not influenced by extract consumption. Ileal villi tended to be longer (P = 0.07) and jejunal aminopeptidase N activity was lower (P < 0.01) in pigs fed the extract. In conclusion, consumption of an extract rich in fumonisins for 9 d has the potential to alter intestinal physiology, villous architecture, and enzyme activities. Underlying mechanisms remain to be investigated.

[Nutrient Physiology, Metabolism, and Nutrient-Nutrient Interactions] Diet Calcium Level but Not Calcium Supplement Particle Size Affects Bone Density and Mechanical Properties in Ovariectomized Rats

2009-06-19

Calcium (Ca) supplements, especially Ca carbonate (CaCO₃), are the main alternative sources of dietary Ca and an important part of a treatment regimen for osteoporosis, the most common metabolic bone disorder of aging and menopause. In a female ovariectomized (OVX) rat model for studying postmenopausal osteoporosis, we tested the hypothesis that a small compared with a large particle size of CaCO₃ (13.0- vs. 18.5-µm geometric diameter) would result in increased Ca balance and subsequently bone mass and that this would be affected by dietary Ca level. We used 6-mo-old rats that were OVX either at 6 or 3 mo of age as models of early or stable menopausal status, respectively. The rats received semipurified diets that contained either 0.4 or 0.2% dietary Ca provided from CaCO₃ of 2 particle sizes. A group of Sham-operated rats with intact ovaries served as control and were fed 0.4% dietary Ca from large particles. Estrogen deficiency as a result of ovariectomy had an adverse effect on bone density, mineral content, and bone mechanical properties (P < 0.001). Reducing dietary Ca from 0.4 to 0.2% resulted in significant adverse effects on bone density and mechanical properties (P < 0.001). The particle size of CaCO₃ did not affect total Ca balance, bone dual energy X-ray absorptiometry and peripheral quantitative computed tomography indices, bone ash and Ca content, or the mechanical determinants of bone strength. We conclude that a decrease in particle size of CaCO₃ to 70% of that typically found in Ca supplements does not provide a benefit to overall Ca metabolism or bone characteristics and that the amount of Ca consumed is of greater influence in enhancing Ca nutrition and skeletal strength.

[Nutrient Physiology, Metabolism, and Nutrient-Nutrient Interactions] The Bone Morphogenetic Protein Signaling Pathway Is Upregulated in a Mouse Model of Total Parenteral Nutrition

Zhang, C., Feng, Y., Yang, H., Koga, H., Teitelbaum, D. H. — 2009-06-19

Total parenteral nutrition (TPN) results in intestinal mucosal atrophic changes due to an absence of enteral nutrition; however, the mechanisms responsible for this are not fully understood. It has been shown that bone morphogenetic protein (BMP) activation inhibits intestinal epithelial cell (EC) proliferation. Therefore, we hypothesized that the BMP pathway could be upregulated by TPN. To address this, we randomly assigned mice to receive TPN or to be enterally fed (control) for 7 d. Mucosal EC isolates were harvested from the entire length of small intestine for RNA and protein measurements. Full-thickness, mid-small bowel was processed for histological examination. TPN increased the abundance of BMP2, BMP4, and BMP type II receptor at the RNA and protein levels. Phosphorylation of Smad1, Smad5, and Smad8 also was greater in the TPN group than in the control, which helped to confirm activation of this pathway. Interestingly, the TPN and control groups did not differ in the mRNA expression of the extracellular soluble bmp antagonists, noggin, gremlin, chordin, or follistatin. Compared to the control group, the expression of c-Myc (cellular myelocytomatosis) mRNA was lower, whereas the level of p21^WAF1/CIP1 was greater, in the TPN group. Because the BMP family may function through suppression of Wnt-β-catenin signaling, this pathway was also examined. mRNA expression of Wnt 3, Wnt5a, and the Wnt receptor Lrp5 were lower in the TPN group compared to controls. The results suggest that the BMP signaling pathway may be involved in the development of intestinal mucosal atrophy due to TPN administration.

[Nutrient Physiology, Metabolism, and Nutrient-Nutrient Interactions] {alpha}-Lactalbumin Hydrolysate Stimulates Glucagon-Like Peptide-2 Secretion and Small Intestinal Growth in Suckling Rats

2009-06-19

We investigated whether bovine milk constituents influenced glucagon-like peptide (GLP)-2 secretion and intestinal growth in suckling rats. Male Sprague-Dawley rats (14 d old) received i.g. infusions of a milk protein fraction, a lactose solution, or the cream fraction of milk. The serum concentration of GLP-2, but not GLP-1, markedly increased in rats administered milk protein compared with those given the lactose solution or the cream fraction from 60 to 120 min after administration. In another experiment, both casein (CN) and whey protein isolate stimulated GLP-2 secretion at 120 min after administration, but soy protein and ovalbumin did not. Stimulation of GLP-2 secretion by several milk proteins was similar, including -CN, -lactalbumin (-La), and β-lactoglobulin, in a separate experiment. A hydrolysate of -La obtained by incubation with protease A extracted from Aspergillus oryzae (LaHPA) caused almost twice the GLP-2 release due to intact -La and other -La hydrolysates. Free amino acid concentrations and molecular size distributions did not differ among -La hydrolysates, including LaHPA. In rat pups reared with milk formulae containing -La or LaHPA, LaHPA significantly promoted small intestinal elongation and increased the number of crypt epithelial cells compared with a formula containing intact -La. LaHPA administration also increased the maltase:lactase activity ratio, a marker of maturation of the intestinal mucosa. In conclusion, milk proteins stimulate GLP-2 secretion and contribute to growth and maturation of the small intestine in suckling rats.

[Nutrition and Disease] Proapoptotic Effects of Dietary (n-3) Fatty Acids Are Enhanced in Colonocytes of Manganese-Dependent Superoxide Dismutase Knockout Mice

2009-06-19

We recently demonstrated that (n-3) PUFA trigger the induction of apoptosis in the colon by enhancing phospholipid oxidation and mitochondrial Ca²⁺ accumulation. To further elucidate the mechanisms regulating oxidative stress-induced apoptosis in vivo, a 2 x 2 experiment was designed using both wild type (control) and manganese-dependent superoxide dismutase (SOD2) heterozygous knockout mice (SOD2^+/–), which exhibit increased mitochondrial oxidative stress. Mice were fed diets differing only in the type of fat [corn oil or fish oil containing (n-3) PUFA] at 15% by weight for 4 wk. Dietary (n-3) PUFA treatment enhanced (22%) apoptosis in colonic crypts. In addition, SOD2 haploinsufficiency enhanced (20%) apoptosis, which was further increased (36%) by (n-3) PUFA feeding. Dietary lipid source and genotype interactively modulated nitrotyrosine levels (P = 0.027) and inflammation (P = 0.032). These findings demonstrate that the proapoptotic effects of (n-3) PUFA are enhanced in oxidatively stressed SOD2^+/– mice. Thus, (n-3) PUFA appear to promote an oxidation-reduction imbalance in the intestine, which may directly or indirectly trigger apoptosis and thereby reduce colon cancer risk.

[Nutrition and Disease] Regular Consumption of Nuts Is Associated with a Lower Risk of Cardiovascular Disease in Women with Type 2 Diabetes

Li, T. Y., Brennan, A. M., Wedick, N. M., Mantzoros, C., Rifai, N., Hu, F. B. — 2009-06-19

Higher nut consumption has been associated with lower risk of coronary heart disease (CHD) events in several epidemiologic studies. The study examined the association between intake of nuts and incident cardiovascular disease (CVD) in a cohort of women with type 2 diabetes. For the primary analysis, there were 6309 women with type 2 diabetes who completed a validated FFQ every 2–4 y between 1980 and 2002 and were without CVD or cancer at study entry. Major CVD events included incident myocardial infarction (MI), revascularization, and stroke. During 54,656 person-years of follow-up, there were 452 CHD events (including MI and revascularization) and 182 incident stroke cases. Frequent nut and peanut butter consumption was inversely associated with total CVD risk in age-adjusted analyses. After adjustment for conventional CVD risk factors, consumption of at least 5 servings/wk of nuts or peanut butter [serving size, 28 g (1 ounce) for nuts and 16 g (1 tablespoon) for peanut butter] was significantly associated with a lower risk of CVD (relative risk = 0.56; 95% CI: 0.36–0.89). Furthermore, when we evaluated plasma lipid and inflammatory biomarkers, we observed that increasing nut consumption was significantly associated with a more favorable plasma lipid profile, including lower LDL cholesterol, non-HDL cholesterol, total cholesterol, and apolipoprotein-B-100 concentrations. However, we did not observe significant associations for HDL cholesterol or inflammatory markers. These data suggest that frequent nut and peanut butter consumption is associated with a significantly lower CVD risk in women with type 2 diabetes.

[Nutrition and Disease] Quercetin Administration Ameliorates Pulmonary Complications of Cirrhosis in Rats

2009-06-19

In the hepatopulmonary syndrome (HPS), a common complication of liver cirrhosis, pulmonary endothelial endothelin B (ETB) receptor overexpression, enhanced endothelial nitric oxide (NO) synthase (eNOS)-derived NO production, and increases in pulmonary inducible NO synthase (iNOS) and heme oxygenase (HO-1) are important factors in the development of vasodilatation. These changes may be influenced by redox-sensitive signaling pathways, including nuclear factor-B (NF-B). In this study, our aim was to evaluate the effects of the flavonoid antioxidant quercetin on the development of HPS in rats with common bile duct ligation (CBDL). Rats were divided into the following 4 groups: rats subjected to CBDL, Sham (rats subjected to simulated CBDL), quercetin-treated sham, and quercetin-treated CBDL. Quercetin (50 mg/kg) was administered for 2 wk starting on d 14 after surgery. Increased NO production, overexpression of iNOS, eNOS, HO-1, and ETB-receptor and activation of NF-B were observed in lung of CBDL rats. Quercetin inhibited oxidative stress, NF-B activation, and the expression of different pulmonary mediators involved in HPS. Quercetin also ameliorated liver injury and reduced the expression of hepatic endothelin-1 and HO-1 in untreated cirrhotic rats. Our findings suggest that quercetin administered after the onset of hepatic injury significantly ameliorates pulmonary complications in CBDL rats and that limitation of cirrhotic evolution contributes to this effect.

[Nutrition and Disease] Conjugated Linoleic Acids Reduce Body Fat in Healthy Postmenopausal Women

2009-06-19

Isomers of conjugated linoleic acids (CLA) reduce fat mass (FM) and increase insulin sensitivity in some, but not all, murine studies. In humans, this effect is still debatable. In this study, we compared the effect of 2 CLA supplements on total and regional FM assessed by dual energy X-ray absorptiometry, changes in serum insulin and glucose concentrations, and adipose tissue (AT) gene expression in humans. In a double-blind, parallel, 16-wk intervention, we randomized 81 healthy postmenopausal women to 1) 5.5 g/d of 40/40% of cis9,trans11-CLA (c9,t11-CLA) and trans10,cis12-CLA (t10,c12-CLA) (CLA-mix); 2) cis9, trans11-CLA (c9,t11-CLA); or 3) control (olive oil). We assessed all variables before and after the intervention. The CLA-mix group had less total FM (4%) and lower-body FM (7%) than the control (P = 0.02 and < 0.001, respectively). Post hoc analyses showed that serum insulin concentrations were greater in the CLA-mix group (34%) than the control group (P = 0.02) in the highest waist circumference tertile only. AT mRNA expression of glucose transporter 4, leptin, and lipoprotein lipase was lower, whereas expression of tumor necrosis factor- was higher in the CLA-mix group than in the control group (P < 0.04). In conclusion, a 50:50 mixture of c9,t11- and t10,c12-CLA isomers resulted in less total and lower-body FM in postmenopausal women and greater serum insulin concentrations in the highest waist circumference tertile. Future research is needed to confirm the insulin desensitizing effect of the CLA mixture and the effect on the mRNA expression of adipocyte-specific genes in humans.

[Nutrient Requirements and Optimal Nutrition] Dietary Echium Oil Increases Tissue (n-3) Long-Chain Polyunsaturated Fatty Acids without Elevating Hepatic Lipid Concentrations in Premature Neonatal Rats

Yang, Q., O'Shea, T. M. — 2009-06-19

Echium oil (EO) contains notable quantities of both (n-6) and (n-3) PUFA and has not, to our knowledge, been studied in neonates. We compared growth, tissue PUFA concentrations, and liver lipid profiles in premature neonatal Sprague-Dawley rats that were fed an EO diet with those that were dam-fed (DF) or fed rat milk substitute (RMS) or a fish oil (FO) diet. EO or FO comprised 10% of dietary fat. Rats were delivered prematurely at d 21 of gestation by caesarean section and then DF or fed one of the diets for 6 d. Rats were killed and the fatty acid (FA) concentrations in brain, liver, ileum, and serum and liver lipid profiles were analyzed. All diet-fed rats had similar weight gain and tissue protein concentrations. Compared with DF rats, EO-fed rats had similar brain docosahexaenoic acid (DHA) levels, similar brain and liver arachidonic acid (ARA) levels, higher liver and ileal eicosapentaenoic acid (EPA) levels (P < 0.05), and similar ARA:(EPA+DHA) ratios in brain, liver, and serum. Compared with RMS-fed rats, EO-fed rats had lower liver triglyceride FA and cholesterol ester concentrations (P < 0.05), higher EPA and DHA levels in liver, ileum, and serum, a higher DHA level in brain, and lower tissue and serum ratios of total (n-6):(n-3) PUFA and ARA:(EPA + DHA) (P < 0.05). Compared with FO-fed rats, EO-fed rats had higher ARA levels in brain, liver, ileum, and serum. In conclusion, dietary EO increases tissue EPA and DHA without reducing ARA in brain and liver and without elevating hepatic lipid concentrations of premature neonatal rats.

[Nutritional Epidemiology] A Traditional Rice and Beans Pattern Is Associated with Metabolic Syndrome in Puerto Rican Older Adults

Noel, S. E., Newby, P. K., Ordovas, J. M., Tucker, K. L. — 2009-06-19

The prevalence of metabolic syndrome was ~50% for Puerto Rican elders living in Massachusetts. Diet is known to be associated with metabolic syndrome. Little information exists regarding the dietary intakes of Puerto Ricans. We aimed to characterize the dietary patterns of 1167 Puerto Ricans (45–75 y) using principal components analysis and to further examine associations with metabolic syndrome. Factor solutions were examined for robustness using a random split sample. Adjusted means for metabolic syndrome components were calculated for factor quintiles. Logistic regression models examined associations between factors, metabolic syndrome, and its components. Analyses were also performed excluding subjects with diabetes. "Meat and French fries," "traditional," and "sweets" patterns emerged as most meaningful. A meat and French fries pattern was associated with higher blood pressure (systolic P-trend = 0.03 and diastolic < 0.001) and waist circumference (P-trend = 0.04). The traditional pattern was associated with lower HDL concentrations (P-trend = 0.007) and a higher likelihood of metabolic syndrome [odds ratio (OR): 1.7, 95% CI: 1.04, 2.7]). The sweets pattern was associated with lower HDL concentrations (P-trend < 0.001) and higher waist circumference (P-trend < 0.05). After excluding individuals with diabetes, the sweets pattern was no longer associated with fasting serum glucose and was associated with metabolic syndrome (OR: 1.8, 95% CI: 1.03, 3.3). Dietary patterns were significantly associated with metabolic syndrome and its components. More research is needed to make appropriate nutritional recommendations for this high-risk population.

[Nutritional Epidemiology] Consuming Functional Foods Enriched with Plant Sterol or Stanol Esters for 85 Weeks Does Not Affect Neurocognitive Functioning or Mood in Statin-Treated Hypercholesterolemic Individuals

2009-06-19

Recent animal and human studies have shown that plant sterols and stanols, which are used as functional food ingredients to lower increased LDL cholesterol concentrations, pass the blood-brain barrier. Whether this affects neurocognitive functioning and mental well-being in humans has, to our knowledge, never been investigated. The aim of the present study was therefore to examine the effects of long-term plant sterol or stanol consumption on neurocognitive functioning and mood in a randomized, double-blind, placebo-controlled dietary intervention trial. To this end, hypercholesterolemic individuals, aged 43–69 y, receiving stable statin treatment were randomly assigned to an 85-wk supplementation with margarines enriched with plant sterol esters (2.5 g/d), plant stanol esters (2.5 g/d), or placebo. At baseline and at the end of the intervention period, all participants underwent a cognitive assessment. In addition, subjective cognitive functioning and mood were assessed by means of questionnaires (Cognitive Failure Questionnaire and depression subscale of the Symptom Checklist 90, respectively). Long-term supplementation with plant sterol or stanol esters did not affect cognitive performance (memory, simple information processing speed, complex information processing speed, Letter-Digit Substitution test performance), subjective cognitive functioning, or mood. In conclusion, the present results indicate that long-term use of plant sterols or stanols at recommended intakes of 2.5 g/d does not affect neurocognitive functioning or mood in hypercholesterolemic individuals receiving statin treatment.

[Nutritional Epidemiology] Patterns of Recommended Dietary Behaviors Predict Subsequent Risk of Mortality in a Large Cohort of Men and Women in the United States

Kant, A. K., Leitzmann, M. F., Park, Y., Hollenbeck, A., Schatzkin, A. — 2009-06-19

Recommendations for intake of fruits and vegetables, whole grains, lean meats, and low-fat dairy form the underpinning of dietary guidance for health promotion. We examined the association of a summary index of food consumption behaviors compatible with the spirit of prevailing dietary guidance and mortality. We used data from the NIH-American Association of Retired Persons cohort (n = 350,886), aged 50–71 y and disease free at baseline in 1995–1996, to examine the association of a dietary behavior score (DBS) with mortality after 10.5 y of follow-up (deaths, n = 29,838). The DBS included 6 equally weighted components derived from responses to questions on usual dietary behaviors related to consumption of fruits, vegetables, low-fat dairy, whole grains, lean meat and poultry, and discretionary fat. The covariate-adjusted association of DBS and mortality from all causes, cancer, and coronary heart disease was examined using Cox proportional hazards regression methods. Compared with those in the lowest one-fifth of DBS, the multivariate-adjusted relative risk of mortality in the highest one-fifth of the DBS was 0.75 (95% CI, 0.70–0.80) in women and 0.79 (95% CI, 0.75–0.83) in men (P-trend < 0.0001). The inverse association of DBS and mortality was significant in both genders in nearly all categories of covariates. Similar trends were observed for DBS associations with mortality from cancer and heart disease. Nearly 12% of the covariate-adjusted population risk of mortality was attributable to nonconformity with dietary recommendations. Adoption of recommended dietary behaviors was associated with lower mortality in both men and women independent of other lifestyle risk factors.

[Nutritional Epidemiology] Decreasing Trends in Malnutrition Prevalence Rates Explained by Regular Audits and Feedback

2009-06-19

To our knowledge, no studies have analyzed the influence of annual audit and feedback on the prevalence rates of malnutrition. This study analyzes the trend of malnutrition prevalence rates between 2004 and 2007 and the effects of previous audits and feedback from the annual Dutch National Prevalence Measurement of Care Problems (LPZ) and the effect of the participation in Dutch national improvement programs. From 2004 to 2007, an annual multicenter study was performed in Dutch hospitals, nursing homes, and home care organizations using a standardized questionnaire involving measurements at institutional, ward, and patient levels. The data were analyzed by logistic multilevel analysis. Nutritional status was assessed by BMI, undesired weight loss, and nutritional intake. In total, 80 hospitals, 141 nursing homes, and 48 home care organizations participated. The prevalence of malnutrition tended to decrease in hospitals and home care over the years. In nursing homes, prevalence rates were stable. Furthermore, the more often hospitals and home care organizations participated in the annual LPZ audits, the lower the prevalence rate of malnutrition (P < 0.001). Participation in national improvement programs also resulted in lower prevalence rates (P = 0.027). In conclusion, malnutrition prevalence rates have decreased over the last 4 y in hospitals and home care in The Netherlands. Participation in the LPZ and involvement in national improvement programs positively influenced these malnutrition prevalence rates, possibly indicating that increasing awareness and actively working toward improvement could be important in lowering these rates.

[Community and International Nutrition] Caregiver Verbal Encouragement Increases Food Acceptance among Vietnamese Toddlers

2009-06-19

Responsive feeding, defined as the positive environment and caregiving behaviors that encourage children to eat, is critical to their physical, mental, and social development. However, research and programs designed to foster responsive feeding have been limited. This research tested the hypothesis that caregiver encouragement, caregiver and child behaviors, and other feeding characteristics were associated with acceptance of food. A total of 91 mother/child pairs in rural, northern Vietnam were videotaped during 2 2-h feeding episodes. Children were 12 and 17 mo of age at the time of study. Caregiver and child behaviors were coded at the level of the "intended bite" (7135 bites total). Feeding episodes were marked by few physical actions and minimal verbal encouragement by caregivers. Results from generalized linear mixed models suggest that when caregivers provided children with positive comments, children were 2.4 times as likely to accept bites compared with when no comments were given. Twelve-mo-olds who were in the caregiver's arms [odds ratio (OR) = 0.5] or lap (OR = 0.5) were significantly less likely than those who stood to accept bites. The 17-mo-olds who played were less likely than those with no physical action to accept bites. Play appeared to distract boys more than girls. In Vietnam, programs should help caregivers provide positive verbal encouragement to eat. Program planners and implementers may want to encourage caregivers to avoid force feeding and other forms of physical pressure. Further, mealtime should be seen as an opportunity to develop long-term feeding skills and encourage a healthy appetite.

[Nutritional Immunology] Zinc Supplementation Increases Zinc Status and Thymopoiesis in Aged Mice

Wong, C. P., Song, Y., Elias, V. D., Magnusson, K. R., Ho, E. — 2009-06-19

The age-related decline in lymphocyte development and function coincides with impaired zinc status in the elderly. Thymic involution and reduced immune responsiveness are classic hallmarks of both aging and zinc deficiency, resulting in decreased host defense and an increased susceptibility to infections. Thus, compromised zinc status associated with aging may be an important contributing factor in reduced thymopoiesis and impaired immune functions. Our goal in this study was to understand how dietary zinc supplementation affects thymopoiesis in aged mice. We hypothesized that impaired zinc status associated with aging would mediate the decline in thymic function and output and that restoring plasma zinc concentrations via zinc supplementation would improve thymopoiesis and thymic functions. In this study, groups of young (8 wk) and aged (22 mo) mice were fed a zinc-adequate (30 mg/kg zinc) or zinc-supplemented diet (300 mg/kg) for 25 d. Aged mice had impaired zinc status, with zinc supplementation restoring plasma zinc to a concentration not different from those of young male C57Bl/6 mice. Zinc supplementation in aged mice improved thymopoiesis, as assessed by increased total thymocyte numbers. In addition, improved thymic output was mediated in part by reducing the age-related accumulation of immature CD4^–CD8^–CD44⁺CD25^– thymocytes, as well as by decreasing the expression of stem cell factor, a thymosuppressive cytokine. Taken together, our results showed that in mice, zinc supplementation can reverse some age-related thymic defects and may be of considerable benefit in improving immune function and overall health in elderly populations.

[Nutritional Immunology] Cow Milk Allergy Symptoms Are Reduced in Mice Fed Dietary Synbiotics during Oral Sensitization with Whey

2009-06-19

Cow milk allergy is the most common food allergy in children. So far, no effective treatment is available to prevent or cure food allergy. The purpose of this study was to compare effects of dietary supplementation with a prebiotic mixture (Immunofortis), a probiotic strain [Bifidobacterium breve M-16V], or a synbiotic diet combining both on the outcome of the allergic response when provided during oral sensitization with whey in mice. Mice were fed diets containing 2% (wt:wt) Immunofortis and/or the B. breve M-16V (n = 6/group). The acute allergic skin response was determined by measuring ear swelling. Antigen-induced anaphylaxis was scored. Furthermore, whey-specific serum immunoglobulins and mouse mast cell protease-1 (mMCP-1) were determined. In mice fed the synbiotic mixture, the allergic skin response and the anaphylactic reaction were strongly reduced compared with whey-sensitized mice fed the control diet (P < 0.01). Immunofortis or B. breve M-16V alone were significantly less effective in reducing the allergic skin response than the synbiotic diet and did not reduce the anaphylactic reaction. The whey-specific IgE and IgG₁ responses were not affected; however, IgG_2a was greater in all treated groups than in the control group (P < 0.05). Serum mMCP-1 concentrations, reflecting mucosal mast cell degranulation, were lower in mice fed synbiotics compared with those fed the control diet (P < 0.01). Dietary supplementation with Immunofortis, B. breve M-16V, and particularly the synbiotic mixture, provided during sensitization, reduces the allergic effector response in a murine model of IgE-mediated hypersensitivity that mimics the human route of sensitization. This model shows the potential for dietary intervention with synbiotics in reducing the allergic response to food allergens.

[Nutritional Immunology] Prebiotics Modulate Immune Responses in the Gut-Associated Lymphoid Tissue of Chickens

2009-06-19

The recent European Union ban on the prophylactic use of in-feed antibiotics has escalated the search for alternatives for use within the poultry industry. When evaluating the efficacy of potential antibiotic alternatives on bird health and productivity, it is important to analyze the competence of the immune cells in the gut-associated lymphoid tissue (GALT), because it is routinely involved in the surveillance of colonizing microbes as well as in interacting with the ingested feed antigens. Therefore, we studied the effect of the prebiotics mannan-oligosaccharide (MOS) and fructo-oligosaccharide (FOS) on the phenotypic and functional competence of immune cells in cecal tonsil (CT), which is a major GALT. Day-old Cobb 500 male broilers were randomized to 4 groups. Control chickens were fed the basal diet only. Chickens in experimental groups received 0.05 g/kg zinc bacitracin or 5 g/kg of either FOS or MOS in addition to basal diet. At the end of 25 d, our comparison of the experimental groups with controls revealed that the addition of prebiotics to diet resulted in a significant reduction in the proportion of B cells and in mitogen responsiveness of lymphocytes in CT. Furthermore, FOS treatment significantly enhanced the IgM and IgG antibody titers in plasma. These findings emphasize the need for the analyses of the gut immune function following treatment with novel feed additives. The knowledge obtained from such analyses may aid in understanding the mechanisms underlying the immune competence of the birds, which needs consideration when selecting and optimizing new feed additives instead of antibiotics for poultry production.

[Nutritional Immunology] Reduced ex Vivo Interleukin-6 Production by Dietary Fish Oil Is Not Modified by Linoleic Acid Intake in Healthy Men

Damsgaard, C. T., Lauritzen, L., Calder, P. C., Kjaer, T. R., Frokiaer, H. — 2009-06-19

Fish oil (FO) is considered antiinflammatory, but evidence regarding its effect on human cytokine production is conflicting. High linoleic acid (LA) intake may impair any effects of FO. The aim of this study was to investigate how FO combined with high or low LA intake affected ex vivo cytokine production from cultures of whole blood, peripheral blood mononuclear cells (PBMC), and monocytes in healthy men. The study was a double-blinded, controlled, 2 x 2 factorial 8-wk intervention. Sixty-four healthy men were randomized to 5 mL/d FO or olive oil (OO) provided in capsules and to spreads and oils with high or low LA content, resulting in LA intakes of 7 ± 2% and 4 ± 1% energy, respectively. We measured eicosapentaenoic acid (EPA) in PBMC and stimulated cytokine production in whole blood and PBMC 24-h cultures before and immediately after intervention and after an 8-wk wash-out period, and in monocyte cultures immediately after intervention. PBMC-EPA was markedly increased by FO (P < 0.001). LA intake did not modify the incorporation of FO and tended to have only a slight effect on PBMC-EPA by itself (P = 0.06). Lipopolysaccharide (LPS)-stimulated whole-blood interleukin (IL)-6 production immediately after intervention was lower with FO than OO (P = 0.02) but did not correlate with PBMC-EPA in the FO groups (r = –0.12; P = 0.53; n = 31). The LA intake did not modify IL-6 production or the effect of FO. Neither FO nor LA intake affected the production of tumor necrosis factor-, IL-10, or interferon- in any of the cultures. In conclusion, FO intake reduced IL-6 production from LPS-stimulated whole blood in healthy men compared with OO, but the effect was not modified by the LA intake.

[Methodology and Mathematical Modeling] Analytical Recovery of Folate Degradation Products Formed in Human Serum and Plasma at Room Temperature

Hannisdal, R., Ueland, P. M., Eussen, S. J. P. M., Svardal, A., Hustad, S. — 2009-06-19

Folate is not stable in serum and plasma. This may impair laboratory diagnostics and distort the outcome of epidemiological studies on folate and chronic diseases. The present study was designed to determine the kinetics of folate loss in human serum and plasma (collected into tubes containing EDTA, heparin, or citrate) at room temperature and the recovery of folate as 4--hydroxy-5-methyltetrahydrofolate (hmTHF) or p-aminobenzoylglutamate (pABG) equivalents. Different folate species and pABG were determined by liquid chromatography-tandem MS and microbiologically active folate was measured by a Lactobacillus rhamnosus assay. Concentrations of 5mTHF and microbiologically active folate had a parallel and rapid decrease in EDTA plasma to ~60% of the initial concentration after 24 h. In serum, heparin plasma, and citrate plasma, folate decreased more slowly to ~50% after 192 h. The loss of 5mTHF that occurred within 48 h was totally recovered as hmTHF. Folate measured as pABG equivalents decreased slowly to ~80% in 192 h and the decline was essentially matrix independent. In conclusion, the degradation of 5mTHF and microbiologically active folate in serum and plasma at room temperature can largely be corrected for by determining hmTHF or measuring folate as pABG equivalents. Moreover, results obtained using conventional folate assays may be biased by improper sample handling or if samples contained high concentrations of hmTHF.

[Methodology and Mathematical Modeling] Simulation Model Accurately Estimates Total Dietary Iodine Intake

Verkaik-Kloosterman, J., van 't Veer, P., Ocke, M. C. — 2009-06-19

One problem with estimating iodine intake is the lack of detailed data about the discretionary use of iodized kitchen salt and iodization of industrially processed foods. To be able to take into account these uncertainties in estimating iodine intake, a simulation model combining deterministic and probabilistic techniques was developed. Data from the Dutch National Food Consumption Survey (1997–1998) and an update of the Food Composition database were used to simulate 3 different scenarios: Dutch iodine legislation until July 2008, Dutch iodine legislation after July 2008, and a potential future situation. Results from studies measuring iodine excretion during the former legislation are comparable with the iodine intakes estimated with our model. For both former and current legislation, iodine intake was adequate for a large part of the Dutch population, but some young children (<5%) were at risk of intakes that were too low. In the scenario of a potential future situation using lower salt iodine levels, the percentage of the Dutch population with intakes that were too low increased (almost 10% of young children). To keep iodine intakes adequate, salt iodine levels should not be decreased, unless many more foods will contain iodized salt. Our model should be useful in predicting the effects of food reformulation or fortification on habitual nutrient intakes.

[American Society for Nutrition Awards] Invitation for Nominations for 2010

2009-06-19

[Announcements] Announcements

2009-06-19