Resistance exercise with whey protein ingestion affects mTOR signaling pathway and myostatin in men.

Resistance exercise with whey protein ingestion affects mTOR signaling pathway and myostatin in men.

Hulmi JJ, Tannerstedt J, Selanne H, Kainulainen H, Kovanen V, Mero AA.

University of Jyväskylä

Signaling pathways sense local and systemic signals and regulate muscle hypertrophy. The effects of whey protein ingestion on acute and long-term signaling responses of resistance exercise are not well known. Previously untrained young men were randomized into protein (n=9), placebo (n=9) and control (n=11) groups. Vastus lateralis (VL) muscle biopsies were taken before, and 1h and 48h after a leg press of 5x10 repetitions (RE) and after 21-wk (2x/wk) resistance training (RT). Protein (15g of whey) or non-energetic placebo was ingested before and after a single RE bout and each RE workout throughout the RT. Protein group increased its body mass and VL muscle thickness (measured by ultrasonography) already at week 10.5 (P<0.05). At week 21, protein and placebo groups had similarly increased their myofiber size. No changes were observed in the non-exercised controls. However, the phosphorylation of p70S6K and rpS6 were increased at 1h post-RE measured by western blotting, the former being the greatest with protein ingestion. mTOR phosphorylation was increased after the RE bout and RT only in the protein group whereas the protein ingestion prevented the post-RE decrease in p-4E-BP1. Akt phosphorylation decreased after RT whereas no change was observed in p-eEF2. A post-RE decrease in muscle myostatin protein occurred only in the placebo group. The results indicate that resistance exercise rapidly increases mTOR signaling and may decrease myostatin protein expression in muscle, and that whey protein increases and prolongs the mTOR signaling response. Key words: hypertrophy, training, nutrition, S6K1.

Does creatine supplementation hinder exercise heat tolerance or hydration status? A systematic review with meta-analyses.

J Athl Train. 2009 Mar-Apr;44(2):215-23.

Does creatine supplementation hinder exercise heat tolerance or hydration status? A systematic review with meta-analyses.

Lopez RM, Casa DJ, McDermott BP, Ganio MS, Armstrong LE, Maresh CM.

University of Connecticut, Storrs, CT 06269, USA. Rebecca.Lopez@uconn.edu

OBJECTIVE: To critically assess original research addressing the effect of creatine supplementation on exercise heat tolerance and hydration status. DATA SOURCES: We searched the electronic databases PubMed, Scopus, Web of Science, SPORTDiscus, and Rehabilitation & Physical Medicine, without date limitations, for the following key words: creatine, exercise, thermoregulation, dehydration, hyperthermia, heat tolerance, exertional heat illnesses, and renal function. Our goal was to identify randomized clinical trials investigating the effect of creatine supplementation on hydration status and thermoregulation. Citations from related articles also were identified and retrieved. DATA SYNTHESIS: Original research was reviewed using the Physiotherapy Evidence Database (PEDro) Scale. One author initially screened all articles. Fifteen of 95 articles examined the effects of creatine on thermoregulation or hydration status (or both). Two independent reviewers then reviewed these articles. Ten studies were selected on the basis of inclusion and exclusion criteria. The PEDro scores for the 10 studies ranged from 7 to 10 points (maximum possible score = 10 points). CONCLUSIONS: No evidence supports the concept that creatine supplementation either hinders the body's ability to dissipate heat or negatively affects the athlete's body fluid balance. Controlled experimental trials of athletes exercising in the heat resulted in no adverse effects from creatine supplementation at recommended dosages.

Different forms of obesity as a function of diet composition.

Different forms of obesity as a function of diet composition.

Dourmashkin JT, Chang GQ, Gayles EC, Hill JO, Fried SK, Julien C, Leibowitz SF.

The Rockefeller University, New York, NY 10021, USA.

OBJECTIVE: To characterize the phenotype of obesity on a high-carbohydrate diet (HCD) as compared to a high-fat diet (HFD) or moderate-fat diet (MFD).

METHODS AND PROCEDURES: In four experiments, adult Sprague-Dawley rats (275-300 g) were maintained for several weeks on a: (1) HFD with 50% fat; (2) balanced MFD with 25% fat; or (3) HCD with 10% fat/65% carbohydrate. Then, based on the amount of body fat accumulated in four dissected fat pads, the animals were subgrouped as lean (lowest tertile) or obese (highest tertile) and characterized with multiple measures.

RESULTS: The obese rats of these diet groups, with 70-80% greater body fat than the lean animals, exhibited elevated levels of leptin and insulin and increased activity of lipoprotein lipase in adipose tissue (aLPL), with no change in muscle LPL. Characteristics common to the obese rats on the HFD or MFD, but not seen on the HCD, were hyperphagia, elevated circulating levels of triglycerides (TG), nonesterified fatty acids (NEFA) and glucose, and a significant increase in beta-hydroxyacyl-CoA dehydrogenase (HADH) activity in muscle, reflecting its greater capacity to metabolize fat. This was accompanied by a significant increase in expression of the peptide, galanin (GAL), in the paraventricular nucleus (PVN), as measured by in situ hybridization and real-time quantitative PCR, and also in GAL peptide immunoreactivity. These measures of GAL were consistently, positively correlated with circulating TG levels and also with HADH activity in muscle. In contrast to these fat-associated changes, rats that became obese on an HCD maintained normal caloric intake and levels of TG, NEFA, and glucose. They also showed no change in PVN GAL mRNA or peptide. Instead, they exhibited a significant reduction in HADH activity compared to the lean animals, along with increased activity of phosphofructokinase in muscle, a key enzyme in glycolysis.

CONCLUSION: Specific characteristics of obesity, including expression of hypothalamic peptides, are dependent upon diet composition. Whereas obesity on an HFD is associated with hyperphagia and elevated lipids, fat metabolism in muscle, and fat-stimulated peptides such as GAL, obesity on an HCD with a similar increase in body fat shows none of these characteristics and instead exhibits a metabolic pattern in muscle that favors carbohydrate over fat oxidation. These results suggest the existence of multiple forms of obesity with different underlying mechanisms that are diet dependent.

Urinary Potassium Is a Clinically Useful Test to Detect a Poor Quality Diet

Urinary Potassium Is a Clinically Useful Test to Detect a Poor Quality Diet

from Journal of Nutrition current issue by Mente, A., Irvine, E. J., Honey, R. J. DA., Logan, A. G.

Poor eating habits, a strong predictor of health outcomes, are not objectively assessed in routine clinical practice. In this study, we evaluated the use of urinary potassium (K+) as a means to identify people consuming a poor quality diet. Consecutive patients with kidney stones (n = 220), aged 18–50 y, from a population-based lithotripsy unit, collected a single 24-h urine sample to assess urinary K+. They also completed a FFQ to derive the recommended foods score (RFS), an index of overall diet quality, and had their blood pressure, heart rate, weight, and height measured. Urinary K+ was related positively with the intake of recommended food items, including vegetables, fruit, whole grains, low-fat dairy products, fish and poultry, and wine and negatively to those not recommended by current dietary guidelines, including red meat, fast food, and high-energy drinks. Urinary K+ was also correlated with the RFS (r = 0.226; P < 0.001). Using a receiver operating characteristic curve, K+ excretion values below the gender-specific median (men, 60 mmol/d; women, 41 mmol/d) were identified as the optimal cutoff values for a poor quality diet, indicated by the RFS. Higher urinary K+ was inversely related to adjusted BMI (P-trend = 0.03), diastolic blood pressure (P-trend = 0.04) and heart rate (P-trend = 0.006), after controlling for potential confounders. Urinary K+ provides a summary measure of diet quality, is significantly related to BMI, blood pressure, and heart rate, and may be useful clinically to detect poor dietary habits and monitor response to dietary interventions.

Effects of beer, wine, and liquor intakes on bone mineral density in older men and women

Effects of beer, wine, and liquor intakes on bone mineral density in older men and women

from American Journal of Clinical Nutrition current issue by Tucker, K. L, Jugdaohsingh, R., Powell, J. J, Qiao, N., Hannan, M. T, Sripanyakorn, S., Cupples, L A., Kiel, D. P

Background: Moderate intake of alcohol has been reported to have beneficial effects on bone. However, different classes of alcoholic beverages have not been investigated.

Objective: Our aim was to determine the association between intake of total alcohol or individual alcoholic beverages and bone mineral density (BMD).

Design: Adjusting for potential confounding factors, we examined alcohol intakes and BMD at 3 hip sites and the lumbar spine in 1182 men and in 1289 postmenopausal and 248 premenopausal women in the population-based Framingham Offspring cohort (age: 29–86 y).

Results: Men were predominantly beer drinkers, and women were predominantly wine drinkers. Compared with nondrinkers, hip BMD was greater (3.4–4.5%) in men consuming 1–2 drinks/d of total alcohol or beer, whereas hip and spine BMD were significantly greater (5.0–8.3%) in postmenopausal women consuming >2 drinks/d of total alcohol or wine. Intake of >2 drinks/d of liquor in men was associated with significantly lower (3.0–5.2%) hip and spine BMD than was intake of 1–2 drinks/d of liquor in men. After adjustment for silicon intake, all intergroup differences for beer were no longer significant; differences for other alcohol sources remained significant. Power was low for premenopausal women, and the associations were not significant.

Conclusions: Moderate consumption of alcohol may be beneficial to bone in men and postmenopausal women. However, in men, high liquor intakes (>2 drinks/d) were associated with significantly lower BMD. The tendency toward stronger associations between BMD and beer or wine, relative to liquor, suggests that constituents other than ethanol may contribute to bone health. Silicon appears to mediate the association of beer, but not that of wine or liquor, with BMD. Other components need further investigation.

Soy consumption and prostate cancer risk in men: a revisit of a meta-analysis

Soy consumption and prostate cancer risk in men: a revisit of a meta-analysis

from American Journal of Clinical Nutrition current issue by Yan, L., Spitznagel, E. L

Background: Epidemiologic studies have shown that the consumption of soy foods may be associated with a reduction in cancer risk in humans.

Objective: The purpose of this study was to conduct a meta-analysis on the association between soy consumption and prostate cancer risk in men.

Design: We systematically reviewed studies obtained through a thorough Medline literature search and identified 15 epidemiologic publications on soy consumption and 9 on isoflavones in association with prostate cancer risk. We extracted the most adjusted relative risks (RRs) and odds ratios (ORs) of the highest and the lowest reported categories of intake from each study and conducted this analysis using a random-effects model in which studies with smaller SEEs are given greater weight in the summary measure.

Results: Our analysis of studies on soy intake yielded a combined RR/OR of 0.74 (95% CI: 0.63, 0.89; P = 0.01). When separately analyzed, studies on nonfermented soy foods yielded a combined RR/OR of 0.70 (95% CI: 0.56, 0.88; P = 0.01) and those on fermented soy foods yielded a combined RR/OR of 1.02 (95% CI: 0.73, 1.42; P = 0.92). The analysis of studies on isoflavones yielded a combined RR/OR of 0.88 (95% CI: 0.76, 1.02; P = 0.09). Further separate analyses showed a combined RR/OR of 0.52 (95% CI: 0.34, 0.81; P = 0.01) from studies with Asian populations and 0.99 (95% CI: 0.85, 1.16; P = 0.91) from studies with Western populations.

Conclusions: The results of this analysis suggest that consumption of soy foods is associated with a reduction in prostate cancer risk in men. This protection may be associated with the type and quantity of soy foods consumed.

Dietary calcium and magnesium intakes and the risk of type 2 diabetes: the Shanghai Women's Health Study

Dietary calcium and magnesium intakes and the risk of type 2 diabetes: the Shanghai Women's Health Study

from American Journal of Clinical Nutrition current issue by Villegas, R., Gao, Y.-T., Dai, Q., Yang, G., Cai, H., Li, H., Zheng, W., Shu, X. O.

Background: Diet plays a key role in the development of type 2 diabetes (T2D), but little is known about the contributions of specific nutrients in populations in which dietary patterns differ from Western populations.

Objective: We examined associations between calcium and magnesium intakes and the risk of T2D in a Chinese population.

Design: We used data from a population-based, prospective study of 64,191 women who were free of T2D or other chronic diseases at study recruitment and were living in urban Shanghai, China. Dietary intake, physical activity, and anthropometric measurements were assessed through in-person interviews. A Cox regression model was used to evaluate the association of the exposures under study with the risk of T2D.

Results: An inverse association between calcium and magnesium intakes and T2D risk was observed. The relative risks for the lowest to the highest quintiles of calcium intake were 1.00, 0.82, 0.73, 0.67, and 0.74 (P for trend < 0.001), and for magnesium they were 1.00, 0.84, 0.84, 0.79, and 0.86 (P for trend < 0.001). Milk intake was also inversely associated with the risk of T2D.

Conclusion: Our data suggest that calcium and magnesium intakes may protect against the development of T2D in this population.

Effect of exercise intensity on abdominal fat loss during calorie restriction in overweight and obese postmenopausal women: a randomized, controlled trial

Effect of exercise intensity on abdominal fat loss during calorie restriction in overweight and obese postmenopausal women: a randomized, controlled trial

from American Journal of Clinical Nutrition current issue by Nicklas, B. J, Wang, X., You, T., Lyles, M. F, Demons, J., Easter, L., Berry, M. J, Lenchik, L., Carr, J J.

Background: Exercise intensity may affect the selective loss of abdominal adipose tissue.

Objective: This study showed whether aerobic exercise intensity affects the loss of abdominal fat and improvement in cardiovascular disease risk factors under conditions of equal energy deficit in women with abdominal obesity.

Design: This was a randomized trial in 112 overweight and obese [body mass index (in kg/m2): 25–40; waist circumference >88 cm], postmenopausal women assigned to one of three 20-wk interventions of equal energy deficit: calorie restriction (CR only), CR plus moderate-intensity aerobic exercise (CR + moderate-intensity), or CR plus vigorous-intensity exercise (CR + vigorous-intensity). The diet was a controlled program of underfeeding during which meals were provided at individual calorie levels (400 kcal/d). Exercise (3 d/wk) involved treadmill walking at an intensity of 45–50% (moderate-intensity) or 70–75% (vigorous-intensity) of heart rate reserve. The primary outcome was abdominal visceral fat volume.

Results: Average weight loss for the 95 women who completed the study was 12.1 kg (±4.5 kg) and was not significantly different across groups. Maximal oxygen uptake ( O2max) increased more in the CR + vigorous-intensity group than in either of the other groups (P < 0.05). The CR-only group lost relatively more lean mass than did either exercise group (P < 0.05). All groups showed similar decreases in abdominal visceral fat (25%; P < 0.001 for all). However, changes in visceral fat were inversely related to increases in O2max (P < 0.01). Changes in lipids, fasting glucose or insulin, and 2-h glucose and insulin areas during the oral-glucose-tolerance test were similar across treatment groups.

Conclusion: With a similar amount of total weight loss, lean mass is preserved, but there is not a preferential loss of abdominal fat when either moderate- or vigorous-intensity aerobic exercise is performed during caloric restriction. This trial was registered at clinicaltrials.gov as NCT00664729.

Sweetened beverage consumption and risk of coronary heart disease in women

Sweetened beverage consumption and risk of coronary heart disease in women

from American Journal of Clinical Nutrition current issue by Fung, T. T, Malik, V., Rexrode, K. M, Manson, J. E, Willett, W. C, Hu, F. B

Background: Previous studies have linked full-calorie sugar-sweetened beverages (SSBs) with greater weight gain and an increased risk of type 2 diabetes.

Objective: We prospectively examined the association between consumption of SSBs and the risk of coronary heart disease (CHD) in women.

Design: Women (n = 88,520) from the Nurses' Health Study aged 34–59 y, without previously diagnosed coronary heart disease (CHD), stroke, or diabetes in 1980, were followed from 1980 to 2004. Consumption of SSBs was derived from 7 repeated food-frequency questionnaires administered between 1980 and 2002. Relative risks (RRs) for CHD were calculated by using Cox proportional hazards models and adjusted for known cardiovascular disease risk factors.

Results: During 24 y of follow-up, we ascertained 3105 incident cases of CHD (nonfatal myocardial infarction and fatal CHD). After standard and dietary risk factors were adjusted for, the RRs (and 95% CIs) of CHD according to categories of cumulative average of SSB consumption (<1/mo, 1–4/mo, 2–6/wk, 1/d, and ?2 servings/d) were 1.0, 0.96 (0.87, 1.06), 1.04 (0.95, 1.14), 1.23 (1.06, 1.43), and 1.35 (1.07, 1.69) (P for trend < 0.001). Additional adjustment for body mass index, energy intake, and incident diabetes attenuated the associations, but they remained significant. Artificially sweetened beverages were not associated with CHD.

Conclusion: Regular consumption of SSBs is associated with a higher risk of CHD in women, even after other unhealthful lifestyle or dietary factors are accounted for.

Increased television viewing is associated with elevated body fatness but not with lower total energy expenditure in children

Increased television viewing is associated with elevated body fatness but not with lower total energy expenditure in children

from American Journal of Clinical Nutrition current issue by Jackson, D. M, Djafarian, K., Stewart, J., Speakman, J. R

Background: Television (TV) viewing in children is associated with a higher body mass index, but it is unknown whether this reflects body fatness, and, if it does, why.

Objective: The objective was to investigate whether TV viewing is associated with body fatness, physical activity, and total energy expenditure in preschool children.

Design: Eighty-nine children were recruited into a cross-sectional study. Total daily energy expenditure (TEE) was measured by doubly labeled water, body composition by dual-energy X-ray absorptiometry, and physical activity by accelerometry.

Results: There was a significant positive association between fat mass (corrected for fat-free body mass) and TV viewing (F = 9.05, P = 0.004). Each extra hour of watching TV was associated with an extra 1 kg of body fat. Children who watched more TV were also significantly less physically active (F = 5.16, P = 0.026). Independent of body composition and sex, children with greater physical activity levels had higher TEE (F = 5.15, P = 0.029); however, physical activity did not mediate the relation between TV viewing and adiposity (P > 0.05).

Conclusions: Preschool children who watch more TV are fatter and are less active, and activity influences TEE. However, despite TV viewing being linked to lower physical activity, the relation between TV viewing and fatness is not mediated by physical activity. The results suggest that a relation between TV viewing and fatness is more likely to be due to an effect on food intake.

Amino Acid Supplementation Increases Lean Body Mass, Basal Muscle Protein Synthesis, and IGF-1 Expression in Older Women

Amino Acid Supplementation Increases Lean Body Mass, Basal Muscle Protein Synthesis, and IGF-1 Expression in Older Women.

Dillon EL, Sheffield-Moore M, Paddon-Jones D, Gilkison C, Sanford AP, Casperson SL, Jiang J, Chinkes DL, Urban RJ.

Department of Internal Medicine (M.S.-M., D.P.J., C.G., S.L.C., J.J., E.L.D., R.J.U.), Department of Surgery (A.P.S., D.L.C.), Department of Physical Therapy and Rehabilitation Sciences (D.P.J.), University of Texas Medical Branch at Galveston, Texas 77555-1060.

Context: Inadequate dietary protein intake has been implicated in sarcopenia. Objective and Design: The objective of this study was to determine 1) if chronic essential amino acid (EAA) supplementation improves post-absorptive muscle protein fractional synthesis rate (FSR), lean body mass (LBM) and 1 repetition maximum (1RM) muscle strength, and androgen receptor (AR) and IGF-1 muscle protein expression, and 2) if the acute anabolic response to EAA ingestion is preserved following a 3 month supplementation period. Using a randomized, double-blinded, placebo controlled design, older women (68 +/- 2 yr) were assigned to receive either placebo (Placebo, n=7), or 15g EAA/day (SUP, n=7) for three months. Metabolic outcomes were assessed in association with stable isotope studies conducted at 0 and 3 months. Setting: The study was performed at the UTMB General Clinical Research Center (GCRC). Results: Ingestion of 7.5g EAA acutely stimulated FSR in both groups at 0 months (P<0.05). Basal FSR at three months was increased in SUP only. The magnitude of the acute response to EAA was unaltered after 3 months in SUP. LBM increased in SUP only (P<0.05). 1RM strength remained unchanged in both groups. Basal IGF-1 protein expression increased in SUP after 3 months (P=0.05), with no changes in AR or total and phosphorylated Akt, mTOR, S6K1 and 4E-BP1. Conclusion: EAA improved lean body mass and basal muscle protein synthesis in older individuals. The acute anabolic response to EAA supplementation is maintained over time and can improve lean body mass, possibly offsetting the debilitating effects of sarcopenia.

Greater satiety response with resistant starch and corn bran in human subjects

Greater satiety response with resistant starch and corn bran in human subjects

from Nutrition Research by Holly J. Willis, Alison L. Eldridge, Jeannemarie Beiseigel, William Thomas, Joanne L. Slavin

Abstract: Some studies suggest high-fiber foods are more satiating than foods with little or no fiber. However, we hypothesized that certain types of dietary fiber may enhance satiety more than others. Healthy men and women (N = 20) participated in this acute, randomized double-blind, crossover study comparing the effects of 4 fibers and a low-fiber (LF) treatment on satiety. On 5 separate visits, fasting subjects consumed either a LF muffin (1.6 g fiber) or 1 of 4 high-fiber muffins (8.0-9.6 g fiber) for breakfast. The subjects used 4 questions on 100 mm visual analogue scales to rate satiety at baseline and at regular intervals for 180 minutes after muffin consumption. Responses were analyzed as area under the curve and significant differences from baseline. Satiety differed among treatments. Resistant starch and corn bran had the most impact on satiety, whereas polydextrose had little effect and behaved like the LF treatment. Results from this study indicate that not all fibers influence satiety equally.

Cocoa and Cardiovascular Health

Cocoa and Cardiovascular Health

Roberto Corti, MD^*; Andreas J. Flammer, MD^*; Norman K. Hollenberg, MD, PhD; Thomas F. Lüscher, MD

From the Cardiovascular Center, Cardiology University Hospital, Zurich, Switzerland (R.C., A.J.F., T.F.L.), and Department of Medicine and Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass (N.K.H.).

Correspondence to Roberto Corti, MD, Cardiovascular Center, Cardiology, University Hospital, Raemistrasse 100, CH-8091 Zurich, Switzerland. E-mail roberto.corti@usz.ch

Epidemiological data demonstrate that regular dietary intake of plant-derived foods and beverages reduces the risk of coronary heart disease and stroke. Among many ingredients, cocoa might be an important mediator. Indeed, recent research demonstrates a beneficial effect of cocoa on blood pressure, insulin resistance,and vascular and platelet function. Although still debated, a range of potential mechanisms through which cocoa might exert its benefits on cardiovascular health have been proposed, including activation of nitric oxide and antioxidant and antiinflammatory effects. This review summarizes the available data on the cardiovascular effects of cocoa, outlines potential mechanisms involved in the response to cocoa, and highlights the potential clinical implications associated with its consumption.

Negative effects of alcohol consumption and tobacco use on bone formation markers in young Korean adult males

Negative effects of alcohol consumption and tobacco use on bone formation markers in young Korean adult males

Auteur(s) / Author(s)

KIM Mi-Hyun (1) ; CHUNG Yoon-Sok (2) ; SUNG Chung-Ja (3) ;

Résumé / Abstract

The purpose of this study was to investigate the effects of alcohol drinking and tobacco smoking on bone mineral density and bone metabolism in young Korean adult males. A total of 463 healthy adult males 20 to 26 years of age participated in the study. The subjects were evaluated for anthropometric characteristics, amount of alcohol consumption, smoking status, and nutrient intake using a 3-day 24-hour recall method. Bone mineral density of the calcaneus was measured using quantitative ultrasound. Bone formation biomarkers including blood total alkaline phosphatase activity (ALP) and N-mid osteocalcin concentration were determined. The subjects were divided into 3 groups: alcohol-only drinking group (n = 254), combined alcohol drinking and smoking group (n = 125), and nondrinking/nonsmoking control group (n = 84). There were no significant differences in height, weight, body mass index, energy and calcium intake, and bone mineral density of the calcaneus among the 3 groups. However, blood total ALP was significantly lower in the combined drinking and smoking group than in the control group (P <.05). Duration of alcohol consumption was noted to have a negative correlation relationship with ALP levels (P <.001) and N-mid osteocalcin (P <.001). Daily cigarette use and smoking duration showed a significantly negative correlation with ALP (P <.001). Our findings show that smoking and alcohol consumption may have negative effects on bone metabolism by reducing bone formation during the period of young adulthood in men.

Alpha-Linolenic acid supplementation and conversion to n-3 long-chain polyunsaturated fatty acids in humans.

Alpha-Linolenic acid supplementation and conversion to n-3 long-chain polyunsaturated fatty acids in humans.
Brenna JT, Salem N Jr, Sinclair AJ, Cunnane SC; for the International Society for the Study of Fatty Acids and Lipids, ISSFAL.

Division of Nutritional Sciences, Cornell University, Savage Hall, Ithaca, NY 14853, USA.

Blood levels of polyunsaturated fatty acids (PUFA) are considered biomarkers of status. Alpha-linolenic acid, ALA, the plant omega-3, is the dietary precursor for the long-chain omega-3 PUFA eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA). Studies in normal healthy adults consuming western diets, which are rich in linoleic acid (LA), show that supplemental ALA raises EPA and DPA status in the blood and in breast milk. However, ALA or EPA dietary supplements have little effect on blood or breast milk DHA levels, whereas consumption of preformed DHA is effective in raising blood DHA levels. Addition of ALA to the diets of formula-fed infants does raise DHA, but no level of ALA tested raises DHA to levels achievable with preformed DHA at intakes similar to typical human milk DHA supply. The DHA status of infants and adults consuming preformed DHA in their diets is, on average, greater than that of people who do not consume DHA. With no other changes in diet, improvement of blood DHA status can be achieved with dietary supplements of preformed DHA, but not with supplementation of ALA, EPA, or other precursors.

Dietary protein and calcium interact to influence calcium retention: a controlled feeding study.

Dietary protein and calcium interact to influence calcium retention: a controlled feeding study.

Hunt JR, Johnson LK, Roughead ZF.

US Department of Agriculture, Agricultural Research Service, Grand Forks Human Nutrition Research Center, Grand Forks, ND, and the University of North Dakota, Grand Forks, ND.

BACKGROUND: The effect of meat protein on calcium retention at different calcium intakes is unresolved. OBJECTIVE: The objective was to test the effect of dietary protein on calcium retention at low and high intakes of calcium. DESIGN: In a randomized, controlled feeding study with a 2 x 2 factorial crossover design, healthy postmenopausal women (n = 27) consumed either approximately 675 or approximately 1510 mg Ca/d, with both low and high protein (providing 10% and 20% energy) for 7 wk each, separated by a 3-wk washout period. After 3 wk, the entire diet was extrinsically labeled with (47)Ca, and isotope retention was monitored by whole-body scintillation counting. Clinical markers of calcium and bone metabolism were measured. RESULTS: High compared with low dietary protein significantly increased calcium retention from the low-calcium (29.5% compared with 26.0% absorbed) but not the high-calcium diet (18% absorbed). For the low-calcium diet, this effect nearly balanced a protein-related 0.5 mmol/d greater urinary calcium excretion. Protein-related calciuretic effects were independent of dietary calcium. Testing at 1, 2, 3, 5, and 7 wk showed no long-term adaptation in urinary acidity or urinary calcium excretion. High compared with low dietary protein decreased urinary deoxypyridinoline and increased serum insulin-like growth factor I without affecting parathyroid hormone, osteocalcin, bone-specific alkaline phosphatase, or tartrate-resistant acid phosphatase. CONCLUSIONS: In healthy postmenopausal women, a moderate increase in dietary protein, from 10% to 20% of energy, slightly improved calcium absorption from a low-calcium diet, nearly compensating for a slight increase in urinary calcium excretion. Under practical dietary conditions, increased dietary protein from animal sources was not detrimental to calcium balance or short-term indicators of bone health.

Beta-Alanine Improves Sprint Performance in Endurance Cycling.

beta-Alanine Improves Sprint Performance in Endurance Cycling.

VAN Thienen R, VAN Proeyen K, Eynde BV, Puype J, Lefere T, Hespel P.

Department of Biomedical Kinesiology, Research Centre for Exercise and Health, Katholieke Universiteit Leuven, Leuven, BELGIUM.

PURPOSE:: Recent research has shown that chronic dietary beta-alanine (betaALA) supplementation increases muscle carnosine content, which is associated with better performance in short (1-2 min) maximal exercise. Success in endurance competitions often depends on a final sprint. However, whether betaALA can be ergogenic in sprint performance at the end of an endurance competition is at present unknown. Therefore, we investigated the effect of 8-wk betaALA administration in moderately to well-trained cyclists on sprint performance at the end of a simulated endurance cycling race. METHODS:: A double-blind study was performed, which consisted of two experimental test sessions interspersed by an 8-wk betaALA (2-4 g.d; n = 9) or matched placebo (PL; n = 8) supplementation period. In the pretesting and the posttesting, subjects performed a 10-min time trial and a 30-s isokinetic sprint (100 rpm) after a 110-min simulated cycling race. Capillary blood samples were collected for determination of blood lactate concentration and pH. RESULTS:: Mean power output during the time trial was approximately 300 W and was similar between PL and betaALA during either the pretesting or the posttesting. However, compared with PL, during the final sprint after the time trial, betaALA on average increased peak power output by 11.4% (95% confidence interval = +7.8 to +14.9%, P = 0.0001), whereas mean power output increased by 5.0% (95% confidence interval = +2.0 to +8.1%, P = 0.005). Blood lactate and pH values were similar between groups at any time. CONCLUSION:: Oral betaALA supplementation can significantly enhance sprint performance at the end of an exhaustive endurance exercise bout.

Towards Establishing Dietary Reference Intakes for Eicosapentaenoic and Docosahexaenoic Acids.

Towards Establishing Dietary Reference Intakes for Eicosapentaenoic and Docosahexaenoic Acids.

Harris WS, Mozaffarian D, Lefevre M, Toner CD, Colombo J, Cunnane SC, Holden JM, Klurfeld DM, Morris MC, Whelan J.

Cardiovascular Health Research Center, Sanford Research/USD and Sanford School of Medicine at University of South Dakota, Sioux Falls, SD 57105.

There is considerable interest in the impact of (n-3) long-chain PUFA in mitigating the morbidity and mortality caused by chronic diseases. In 2002, the Institute of Medicine concluded that insufficient data were available to define Dietary Reference Intakes (DRI) for eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA), noting only that EPA and DHA could contribute up to 10% toward meeting the Adequate Intake for alpha-linolenic acid. Since then, substantial new evidence has emerged supporting the need to reassess this recommendation. Therefore, the Technical Committee on Dietary Lipids of the International Life Sciences Institute North America sponsored a workshop on 4-5 June 2008 to consider whether the body of evidence specific to the major chronic diseases in the United States-coronary heart disease (CHD), cancer, and cognitive decline-had evolved sufficiently to justify reconsideration of DRI for EPA+DHA. The workshop participants arrived at these conclusions: 1) consistent evidence from multiple research paradigms demonstrates a clear, inverse relation between EPA+DHA intake and risk of fatal (and possibly nonfatal) CHD, providing evidence that supports a nutritionally achievable DRI for EPA+DHA between 250 and 500 mg/d 2) because of the demonstrated low conversion from dietary ALA, protective tissue levels of EPA+DHA can be achieved only through direct consumption of these fatty acids 3) evidence of beneficial effects of EPA+DHA on cognitive decline are emerging but are not yet sufficient to support an intake level different from that needed to achieve CHD risk reduction; 4) EPA+DHA do not appear to reduce risk for cancer; and 5) there is no evidence that intakes of EPA+DHA in these recommended ranges are harmful.

Yacon syrup: Beneficial effects on obesity and insulin resistance in humans.

Yacon syrup: Beneficial effects on obesity and insulin resistance in humans.

Genta S, Cabrera W, Habib N, Pons J, Carillo IM, Grau A, Sánchez S.

Instituto Superior de Investigaciones Biológicas (INSIBIO), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Tucumán (UNT), Chacabuco 461, 4000-San Miguel de Tucumán, Tucumán, Argentina.

BACKGROUND & AIMS: Syrup obtained from yacon roots could be well positioned as a nutraceutical product due to its high fructooligosaccharides content. We examined the beneficial effects and tolerance of yacon syrup on human health. METHODS: Obese and slightly dyslipidemic pre-menopausal women were studied over a 120-day period in a double-blind placebo-controlled experiment. We used two doses of yacon syrup, 0.29g and 0.14g fructooligosaccharides/kg/day. At the start and end of the study, anthropometric measurements, blood glucose, calcium, lipid and insulin concentrations and Homeostasis Model Assessment index were determined. RESULTS: The recommended daily consumption of yacon syrup with no undesirable gastrointestinal effects is 0.14g fructooligosaccharides/kg. Daily intake of yacon syrup produced a significant decrease in body weight, waist circumference and body mass index. Additionally, decrease in fasting serum insulin and Homeostasis Model Assessment index was observed. The consumption of yacon syrup increased defecation frequency and satiety sensation. Fasting glucose and serum lipids were not affected by syrup treatment and the only positive effect was found in serum LDL-cholesterol levels. CONCLUSIONS: Yacon syrup is a good source of fructooligosaccharides and its long-term consumption produced beneficial health effects on obese pre-menopausal women with insulin resistance.

Effects of Growth Hormone on Glucose, Lipid and Protein Metabolism in Human Subjects.

Effects of Growth Hormone on Glucose, Lipid and Protein Metabolism in Human Subjects.

Moller N, Otto Lunde Jorgensen J.

Medical Department M, Aarhus University Hospital; and Clinical Institute Aarhus University, Aarhus, Denmark.

In evolutionary terms growth hormone (GH) and intracellular STAT 5 signaling is a very old regulatory system. Whereas insulin dominates peri-prandially, GH may be viewed as the primary anabolic hormone during stress and fasting. GH exerts anabolic effects directly and through stimulation of IGF-I, insulin, and free fatty acids (FFA). When well nourished the GH-induced stimulation of IGF-I and insulin is important for anabolic storage and growth of lean body mass (LBM), adipose tissue and glycogen reserves. During fasting and other catabolic states GH predominantly stimulates the release and oxidation of FFA which leads to decreased glucose and protein oxidation and preservation of LBM and glycogen stores. The most prominent metabolic effect of GH is a marked increase in lipolysis and FFA levels. In the basal state the effects of GH on protein metabolism are modest and include increased protein synthesis and decreased breakdown at the whole body level and in muscle together with decreased amino acid degradation/oxidation and decreased hepatic urea formation. During fasting and stress the effects of GH on protein metabolism become more pronounced; lack of GH during fasting increases protein loss and urea production rates by approximately 50% with a similar increase in muscle protein breakdown. GH is a counter-regulatory hormone, which antagonizes the hepatic and peripheral effects of insulin on glucose metabolism via mechanisms involving the concomitant increase in FFA flux and uptake This ability of GH to induce insulin resistance is significant for the defense against hypoglycemia, for the development of "stress" diabetes during fasting and inflammatory illness and perhaps for the "Dawn" phenomenon (the increase in insulin requirements in the early morning hours). Adult patients with GH-deficiency are insulin resistant-probably related to increased adiposity, reduced LBM, and impaired physical performance-which temporarily worsens when GH treatment is initiated. Conversely, despite increased LBM and decreased fat mass patients with acromegaly are consistently insulin resistant and become more sensitive after appropriate treatment.

Exploring the therapeutic role of creatine supplementation.

Exploring the therapeutic role of creatine supplementation.

Gualano B, Artioli GG, Poortmans JR, Lancha Junior AH.

Laboratory of Applied Nutrition and Metabolism, School of Physical Education and Sport, University of Sao Paulo, Sao Paulo, Brazil, gualano@usp.br.

Creatine (Cr) plays a central role in energy provision through a reaction catalyzed by phosphorylcreatine kinase. Furthermore, this amine enhances both gene expression and satellite cell activation involved in hypertrophic response. Recent findings have indicated that Cr supplementation has a therapeutic role in several diseases characterized by atrophic conditions, weakness, and metabolic disturbances (i.e., in the muscle, bone, lung, and brain). Accordingly, there has been an evidence indicating that Cr supplementation is capable of attenuating the degenerative state in some muscle disorders (i.e., Duchenne and inflammatory myopathies), central nervous diseases (i.e., Parkinson's, Huntington's, and Alzheimer's), and bone and metabolic disturbances (i.e., osteoporosis and type II diabetes). In light of this, Cr supplementation could be used as a therapeutic tool for the elderly. The aim of this review is to summarize the main studies conducted in this field and to highlight the scientific and clinical perspectives of this promising therapeutic supplement.

A novel seed extract of the West African plant Irvingia gabonensis, significantly reduces body weight and improves metabolic parameters in overweigh

from Lipids in Health and Disease - Latest articles by Judith L Ngondi, Blanche C Etoundi, Christine B Nyangono, Carl MF Mbofung and Julius E Oben

Background: A recent in vitro study indicates that IGOB131, a novel seed extract of the traditional West African food plant Irvingia gabonensis, favorably impacts adipogenesis through a variety of critical metabolic pathways including PPAR gamma, leptin, adiponectin, and glycerol-3 phosphate dehydrogenase. This study was therefore aimed at evaluating the effects of IGOB131, an extract of Irvingia gabonensis, on body weight and associated metabolic parameters in overweight human volunteers. Methods: The study participants comprised of 102 healthy, overweight and/ or obese volunteers (defined as BMI > 25 kg/m2) randomly divided into two groups. The groups received on a daily basis, either 150mg of IGOB131 or matching placebo in a double blinded fashion, 30-60 minutes before lunch and dinner. At baseline, 4, 8 and 10 weeks of the study, subjects were evaluated for changes in anthropometrics and metabolic parameters to include fasting lipids, blood glucose, C-reactive protein, adiponectin, and leptin. Results: Significant improvements in body weight, body fat, and waist circumference as well as plasma total cholesterol, LDL cholesterol, blood glucose, C-reactive protein, adiponectin and leptin levels were observed in the IGOB131 group compared with the placebo group.

Conclusion: Irvingia gabonensis administered 150 mg twice daily before meals to overweight and/ or obese human volunteers favorably impacts body weight and a variety of parameters characteristic of the metabolic syndrome. This is the first double blind randomized placebo controlled clinical trial regarding the anti-obesity and lipid profile modulating effects of an Irvingia gabonensis extract. The positive clinical results, together with our previously published mechanisms of gene expression modulation related to key metabolic pathways in lipid metabolism, provide impetus for much larger clinical studies. Irvingia gabonensis extract may prove to be a useful tool in dealing with the emerging global epidemics of obesity, hyperlipidemia, insulin resistance, and their co-morbid conditions. Trial registration: ClinicalTrials.gov NCT00645775

Coffee Consumption and Risk of Stroke in Women

from Circulation current issue by Lopez-Garcia, E., Rodriguez-Artalejo, F., Rexrode, K. M., Logroscino, G., Hu, F. B., van Dam, R. M.
Background— Data on the association between coffee consumption and risk of stroke are sparse. We assessed the association between coffee consumption and the risk of stroke over 24 years of follow-up in women.

Methods and Results— We analyzed data from a prospective cohort of 83 076 women in the Nurses’ Health Study without history of stroke, coronary heart disease, diabetes, or cancer at baseline. Coffee consumption was assessed first in 1980 and then repeatedly every 2 to 4 years, with follow-up through 2004. We documented 2280 strokes, of which 426 were hemorrhagic, 1224 were ischemic, and 630 were undetermined. In multivariable Cox regression models with adjustment for age, smoking status, body mass index, physical activity, alcohol intake, menopausal status, hormone replacement therapy, aspirin use, and dietary factors, the relative risks (RRs) of stroke across categories of coffee consumption (<1 trend="0.003)." trend="0.05).">

Conclusions— Long-term coffee consumption was not associated with an increased risk of stroke in women. In contrast, our data suggest that coffee consumption may modestly reduce risk of stroke.

Mediterranean Diet and Incidence of and Mortality From Coronary Heart Disease and Stroke in Women

from Circulation current issue by Fung, T. T., Rexrode, K. M., Mantzoros, C. S., Manson, J. E., Willett, W. C., Hu, F. B.

Background— Several studies have documented an inverse association between adherence to the Mediterranean diet and risk of coronary heart disease (CHD), but few data are available on the relationship between Mediterranean diet and risk of stroke.

Methods and Results— For the present study, 74 886 women 38 to 63 years of age in the Nurses’ Health Study, a cohort study of female nurses, without a history of cardiovascular disease and diabetes were followed up from 1984 to 2004. We computed an Alternate Mediterranean Diet Score from self-reported dietary data collected through validated food frequency questionnaires administered 6 times between 1984 and 2002. Relative risks for incident CHD, stroke, and combined fatal cardiovascular disease were estimated with Cox proportional-hazards models adjusted for cardiovascular risk factors. During 20 years of follow-up, 2391 incident cases of CHD, 1763 incident cases of stroke, and 1077 cardiovascular disease deaths (fatal CHD and strokes combined) were ascertained. Women in the top Alternate Mediterranean Diet Score quintile were at lower risk for both CHD and stroke compared with those in the bottom quintile (relative risk [RR], 0.71; 95% CI, 0.62 to 0.82; P for trend<0.0001 trend="0.03">

Conclusion— A greater adherence to the Mediterranean diet, as reflected by a higher Alternate Mediterranean Diet Score, was associated with a lower risk of incident CHD and stroke in women.

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