Preliminary data about the influence of vitamin D status on the loss of body fat in young overweight/obese women following two types of hypocaloric diet.

Preliminary data about the influence of vitamin D status on the loss of body fat in young overweight/obese women following two types of hypocaloric diet.

Ortega RM, Aparicio A, Rodríguez-Rodríguez E, Bermejo LM, Perea JM, López-Sobaler AM, Ruiz-Roso B, Andrés P.

Departamento de Nutrición, Facultad de Farmacia, Universidad Complutense, Madrid 28040, Spain. rortega@farm.ucm.es

The loss of weight was analysed in a group of sixty overweight/obese women of childbearing age (20-35 years) according to their initial vitamin D status. Subjects were randomly assigned to one of two slightly hypocaloric diets: Diet V, in which the consumption of vegetables was increased, or Diet C, in which the relative consumption of cereals (especially breakfast cereals) was increased. Dietetic, anthropometric and biochemical data were collected at the start of the study and again at 2 weeks after dividing the women into groups depending on their having an initial serum 25-hydroxyvitamin D (25(OH)D) concentration of < 50 nmol/l (LD) or>or=50 nmol/l (HD). Dietary intervention led to a reduction in energy intake, body weight and BMI in all groups. The HD women showed greater body fat losses during the study than the LD women (1.7 (SD 1.8) kg compared to 0.5 (SD 0.8) kg). A better vitamin D status therefore aided the loss of body fat over the experimental period (OR 0.462; CI 0.271, 0.785; P < 0.001). However, when the dietary groups were analysed separately, this effect was only seen in the C subjects (OR 0.300; CI 0.121, 0.748; P < 0.001). The present results suggest that women with a better vitamin D status respond more positively to hypocaloric diets and lose more body fat; this was especially clear among the C subjects who had a greater vitamin D supply during the experimental period.

Vitamin D3 enhances mood in healthy subjects during winter.

Vitamin D3 enhances mood in healthy subjects during winter.

Lansdowne AT, Provost SC.

Department of Psychology, The University of Newcastle, Callaghan NSW, Australia.

Mood changes synchronised to the seasons exist on a continuum between individuals, with anxiety and depression increasing during the winter months. An extreme form of seasonality is manifested as the clinical syndrome of seasonal affective disorder (SAD) with carbohydrate craving, hypersomnia, lethargy, and changes in circadian rhythms also evident. It has been suggested that seasonality and the symptoms of SAD may be due to changing levels of vitamin D3, the hormone of sunlight, leading to changes in brain serotonin. Forty-four healthy subjects were given 400 IU, 800 IU, or no vitamin D3 for 5 days during late winter in a random double-blind study. Results on a self-report measure showed that vitamin D3 significantly enhanced positive affect and there was some evidence of a reduction in negative affect. Results are discussed in terms of their implications for seasonality, SAD, serotonin, food preference, sleep, and circadian rhythms.

Green tea: potential health benefits.

Green tea: potential health benefits.

Schneider C, Segre T.

Department of Family Medicine, Maine Medical Center, Portland, Maine 04102, USA.

Green tea has been used widely and in high doses for centuries as a health tonic in many societies. Evidence suggests that green tea is effective for treating genital warts. There is some supportive evidence for the use of green tea in cancer prevention. Drinking green tea is associated with a decrease in all-cause mortality, but not in cancer-related mortality. Small clinical studies have found that green tea may also be helpful in losing and managing weight, and lowering cholesterol. Epidemiologic evidence suggests that green tea may prevent stroke and cardiovascular disease. Green tea appears to be safe, although there have been case reports of hepatotoxicity possibly related to a specific extract in pill or beverage form. Green tea seems to be a low-risk complementary therapy for a number of conditions, but more studies are needed.

Effects of selenite and genistein on G2/M cell cycle arrest and apoptosis in human prostate cancer cells.

Effects of selenite and genistein on G2/M cell cycle arrest and apoptosis in human prostate cancer cells.

Zhao R, Xiang N, Domann FE, Zhong W.

Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792, USA.

Combination of chemopreventive agents with distinct molecular mechanisms is considered to offer a potential for enhancing cancer prevention efficacy while minimizing toxicity. Here we report two chemopreventive agents, selenite and genistein, that have synergistic effects on apoptosis, cell cycle arrest, and associated signaling pathways in p53-expressing LNCaP and p53-null PC3 prostate cancer cells. We show that selenite induced apoptosis only, whereas genistein induced both apoptosis and G2/M cell cycle arrest. Combination of these two agents exhibited enhanced effects, which were slightly greater in LNCaP than PC3 cells. Selenite or genistein alone upregulated protein levels of p53 in LNCaP cells only and p21(waf1) and Bax in both cell lines. Additionally, genistein inhibited AKT phosphorylation. Downregulation of AKT by siRNA caused apoptosis and G2/M cell cycle arrest and masked the effects of genistein. Treatment with insulin-like growth factor I (IGF-I) elevated levels of total and phosphorylated AKT and suppressed the effects of genistein. Neither downregulation of AKT nor IGF-I treatment altered the cellular effects of selenite. Our study demonstrates that selenium and genistein act via different molecular mechanisms and exhibit enhanced anticancer effects, suggesting that a combination of selenium and genistein may offer better efficacy and reduction of toxicity in prostate cancer prevention.

Fatty Fish Intake Decreases Lipids Related to Inflammation and Insulin Signaling—A Lipidomics Approach

Fatty Fish Intake Decreases Lipids Related to Inflammation and Insulin Signaling—A Lipidomics Approach

by Maria Lankinen et al.

Background

The evidence of the multiple beneficial health effects of fish consumption is strong, but physiological mechanisms behind these effects are not completely known. Little information is available on the effects of consumption of different type of fish. The aim of this study was to investigate how fatty fish or lean fish in a diet affect serum lipidomic profiles in subjects with coronary heart disease.

Methodology and Principal Findings

A pilot study was designed which included altogether 33 subjects with myocardial infarction or unstable ischemic attack in an 8-week parallel controlled intervention. The subjects were randomized to either fatty fish (n = 11), lean fish (n = 12) or control (n = 10) groups. Subjects in the fish groups had 4 fish meals per week and subjects in the control group consumed lean beef, pork and chicken. A fish meal was allowed once a week maximum. Lipidomics analyses were performed using ultra performance liquid chromatography coupled to electrospray ionization mass spectrometry and gas chromatography. Multiple bioactive lipid species, including ceramides, lysophosphatidylcholines and diacylglycerols, decreased significantly in the fatty fish group, whereas in the lean fish group cholesterol esters and specific long-chain triacylglycerols increased significantly (False Discovery Rate q-value <0.05).

Conclusions/Significance

The 8-week consumption of fatty fish decreased lipids which are potential mediators of lipid-induced insulin resistance and inflammation, and may be related to the protective effects of fatty fish on the progression of atherosclerotic vascular diseases or insulin resistance.

Consuming fructose-sweetened, not glucose-sweetened, beverages increases visceral adiposity and lipids and decreases insulin sensitivity in overweight/obese humans

Consuming fructose-sweetened, not glucose-sweetened, beverages increases visceral adiposity and lipids and decreases insulin sensitivity in overweight/obese humans

from Journal of Clinical Investigation

by Kimber L. Stanhope, Jean Marc Schwarz, Nancy L. Keim, Steven C. Griffen, Andrew A. Bremer, James L. Graham, Bonnie Hatcher, Chad L. Cox, Artem Dyachenko, Wei Zhang, John P. McGahan, Anthony Seibert, Ronald M. Krauss, Sally Chiu, Ernst J. Schaefer, Masumi Ai, Seiko Otokozawa, Katsuyuki Nakajima, Takamitsu Nakano, Carine Beysen, Marc K. Hellerstein, Lars Berglund, Peter J. Havel

Studies in animals have documented that, compared with glucose, dietary fructose induces dyslipidemia and insulin resistance. To assess the relative effects of these dietary sugars during sustained consumption in humans, overweight and obese subjects consumed glucose- or fructose-sweetened beverages providing 25% of energy requirements for 10 weeks. Although both groups exhibited similar weight gain during the intervention, visceral adipose volume was significantly increased only in subjects consuming fructose. Fasting plasma triglyceride concentrations increased by approximately 10% during 10 weeks of glucose consumption but not after fructose consumption. In contrast, hepatic de novo lipogenesis (DNL) and the 23-hour postprandial triglyceride AUC were increased specifically during fructose consumption. Similarly, markers of altered lipid metabolism and lipoprotein remodeling, including fasting apoB, LDL, small dense LDL, oxidized LDL, and postprandial concentrations of remnant-like particle–triglyceride and –cholesterol significantly increased during fructose but not glucose consumption. In addition, fasting plasma glucose and insulin levels increased and insulin sensitivity decreased in subjects consuming fructose but not in those consuming glucose. These data suggest that dietary fructose specifically increases DNL, promotes dyslipidemia, decreases insulin sensitivity, and increases visceral adiposity in overweight/obese adults.

Dietary sugars: a fat difference

Dietary sugars: a fat difference

from Journal of Clinical Investigation

by Susanna M. Hofmann, Matthias H. 

Coronary heart disease is a major cause of morbidity and mortality in Western societies. The metabolic syndrome, characterized by obesity, insulin resistance, elevated blood pressure, elevated triglycerides, and low levels of high-density lipoprotein cholesterol, confers substantial risk of coronary heart disease. Current pathogenetic models suggest that postprandial hyperlipidemia is one specific metabolic abnormality that is typically associated with increased morbidity. In this issue of the JCI, Stanhope and colleagues demonstrate that consumption of fructose-sweetened but not glucose-sweetened beverages for 10 weeks increases de novo lipid synthesis, promotes dyslipidemia, impairs insulin sensitivity, and increases visceral adiposity in overweight or obese adults 

Walnuts and fatty fish influence different serum lipid fractions in normal to mildly hyperlipidemic individuals: a randomized controlled study

Walnuts and fatty fish influence different serum lipid fractions in normal to mildly hyperlipidemic individuals: a randomized controlled study

from American Journal of Clinical Nutrition current issue by Rajaram, S., Haddad, E. H., Mejia, A., Sabate, J.

Background: Increased consumption of n–3 (omega-3) fatty acids decreases the incidence of coronary heart disease (CHD).

Objective: The objective was to determine whether walnuts (plant n–3 fatty acid) and fatty fish (marine n–3 fatty acid) have similar effects on serum lipid markers at intakes recommended for primary prevention of CHD.

Design: In a randomized crossover feeding trial, 25 normal to mildly hyperlipidemic adults consumed 3 isoenergetic diets (30% total fat and <10% saturated fat) for 4 wk each: a control diet (no nuts or fish), a walnut diet (42.5 g walnuts/10.1 mJ), or a fish diet (113 g salmon, twice/wk). Fasting blood was drawn at baseline and at the end of each diet period and analyzed for serum lipids.

Results: Serum total cholesterol and LDL cholesterol concentrations in adults who followed the walnut diet (4.87 ± 0.18 and 2.77 ± 0.15 mmol/L, respectively) were lower than in those who followed the control diet (5.14 ± 0.18 and 3.06 ± 0.15 mmol/L, respectively) and those who followed the fish diet (5.33 ± 0.18 and 3.2 ± 0.15 mmol/L, respectively; P < 0.0001). The fish diet resulted in decreased serum triglyceride and increased HDL-cholesterol concentrations (1.0 ± 0.11 and 1.23 ± 0.05 mmol/L, respectively) compared with the control diet (1.12 ± 0.11 and 1.19 ± 0.05 mmol/L, respectively) and the walnut diet (1.11 ± 0.11 mmol/L, P < 0.05, and 1.18 ± 0.05 mmol/L, P < 0.001, respectively). The ratios of total cholesterol:HDL cholesterol, LDL cholesterol:HDL cholesterol, and apolipoprotein B:apolipoprotein A-I were lower (P < 0.05) in those who followed the walnut diet compared with those who followed the control and fish diets.

Conclusion: Including walnuts and fatty fish in a healthy diet lowered serum cholesterol and triglyceride concentrations, respectively, which affects CHD risk favorably.

Should dairy be recommended as part of a healthy vegetarian diet? Point

Should dairy be recommended as part of a healthy vegetarian diet? Point

from American Journal of Clinical Nutrition current issue by Weaver, C. M

A benefit-risk evaluation of the evidence for including dairy foods in the diet is presented. For many persons dairy products provide a substantial portion of essential nutrients, but especially calcium, potassium, and magnesium. Dietary supplements and fortified foods can be alternative sources of these nutrients, although other components of dairy foods such as amino acid composition and conjugated linoleic acid may be instrumental in the benefits associated with dairy product consumption for bone health and reduced risk of stroke, metabolic syndrome, and some cancers. Newer evidence shows that protein-induced calciuria does not have a detrimental effect on net calcium retention, and the concentrations of hormones in milk are not outside of the range of endogenous concentrations. Increased dietary protein, including from milk, can elevate serum concentrations of insulin-like growth factor I, which has an unknown relation to cancer. The concern over consumption of milk leading to increased risk of prostate cancer through reduction of serum 1,25-dihydroxyvitamin D, a potent anti-prostate cancer hormone, has been resolved with new evidence that local production of this hormone is independent of diet. Overall, evidence suggests that being a lactovegetarian has greater health benefits and reduced health risks than being a vegan.

Fruit, vegetables, and colorectal cancer risk: the European Prospective Investigation into Cancer and Nutrition

Fruit, vegetables, and colorectal cancer risk: the European Prospective Investigation into Cancer and Nutrition

from American Journal of Clinical Nutrition current issue by van Duijnhoven, F. J., Bueno-De-Mesquita, H B., Ferrari, P., Jenab, M., Boshuizen, H. C, Ros, M. M, Casagrande, C., Tjonneland, A., Olsen, A., Overvad, K., Thorlacius-Ussing, O., Clavel-Chapelon, F., Boutron-Ruault, M.-C., Morois, S., Kaaks, R., Linseisen, J., Boeing, H., Nothlings, U., Trichopoulou, A., Trichopoulos, D., Misirli, G., Palli, D., Sieri, S., Panico, S., Tumino, R., Vineis, P., Peeters, P. H., van Gils, C. H, Ocke, M. C, Lund, E., Engeset, D., Skeie, G., Suarez, L. R., Gonzalez, C. A, Sanchez, M.-J., Dorronsoro, M., Navarro, C., Barricarte, A., Berglund, G., Manjer, J., Hallmans, G., Palmqvist, R., Bingham, S. A, Khaw, K.-T., Key, T. J, Allen, N. E, Boffetta, P., Slimani, N., Rinaldi, S., Gallo, V., Norat, T., Riboli, E.

Background: A high consumption of fruit and vegetables is possibly associated with a decreased risk of colorectal cancer (CRC). However, the findings to date are inconsistent.

Objective: We examined the relation between self-reported usual consumption of fruit and vegetables and the incidence of CRC.

Design: In the European Prospective Investigation into Cancer and Nutrition (EPIC), 452,755 subjects (131,985 men and 320,770 women) completed a dietary questionnaire in 1992–2000 and were followed up for cancer incidence and mortality until 2006. A multivariate Cox proportional hazard model was used to estimate adjusted hazard ratios (HRs) and 95% CIs.

Results: After an average follow-up of 8.8 y, 2,819 incident CRC cases were reported. Consumption of fruit and vegetables was inversely associated with CRC in a comparison of the highest with the lowest EPIC-wide quintile of consumption (HR: 0.86; 95% CI: 0.75, 1.00; P for trend = 0.04), particularly with colon cancer risk (HR: 0.76; 95% CI: 0.63, 0.91; P for trend < 0.01). Only after exclusion of the first 2 y of follow-up were these findings corroborated by calibrated continuous analyses for a 100-g increase in consumption: HRs of 0.95 (95% CI: 0.91, 1.00; P = 0.04) and 0.94 (95% CI: 0.89, 0.99; P = 0.02), respectively. The association between fruit and vegetable consumption and CRC risk was inverse in never and former smokers, but positive in current smokers. This modifying effect was found for fruit and vegetables combined and for vegetables alone (P for interaction < 0.01 for both).

Conclusions: These findings suggest that a high consumption of fruit and vegetables is associated with a reduced risk of CRC, especially of colon cancer. This effect may depend on smoking status.

Effect of age and frailty on ghrelin and cholecystokinin responses to a meal test

Effect of age and frailty on ghrelin and cholecystokinin responses to a meal test

from American Journal of Clinical Nutrition current issue by Serra-Prat, M., Palomera, E., Clave, P., Puig-Domingo, M.

Background: Ghrelin and cholecystokinin (CCK) are among the peripheral signals that regulate hunger and satiety.

Objective: The objective was to assess whether ghrelin and CCK responses to a standard nutritional load are related to age and frailty.

Design: Ghrelin, CCK, insulin, glucose, and 4-h visual analog hunger scale curves after a standard nutritional load test (380 kcal) were described and compared between 3 groups: old (>75 y) and frail persons (group A), old (>75 y) but nonfrail persons (group B), and young (25–65 y) adults (group C).

Results: Frail persons showed no postprandial ghrelin suppression, and old subjects, frail and nonfrail, showed no significant postprandial ghrelin recovery compared with young adults. Frailty was also associated with lower fasting ghrelin concentrations. No differences in fasting CCK were observed between young and old persons; however, postprandial CCK concentrations were enhanced in young persons, whereas no frailty effect on the CCK curve was observed in the old subjects. No correlations between mean ghrelin and hunger values over time were found, but strong negative correlations were shown between CCK and hunger (group A: rs = –0.88, P = 0.009; group B: rs = –0.86, P = 0.014; group C: rs = –0.71, P = 0.071) and insulin and hunger (group A: rs = –0.901, P = 0.006; group B: rs = –0.964, P < 0.001; group C: rs = –0.929, P = 0.003).

Conclusions: Advanced age determines a poorer ghrelin postprandial recuperation phase, a reduced CCK postprandial response, and an exaggerated postprandial insulin release. A loss of ghrelin prandial rhythm is present in old frail persons. The impaired response of these hunger regulatory hormones with age might contribute to the mechanisms of anorexia associated with aging.

Meta-analysis of animal fat or animal protein intake and colorectal cancer

Meta-analysis of animal fat or animal protein intake and colorectal cancer

from American Journal of Clinical Nutrition current issue by Alexander, D. D, Cushing, C. A, Lowe, K. A, Sceurman, B., Roberts, M. A

Background: In the recent World Cancer Research Fund/American Institute for Cancer Research report of diet and cancer, it was concluded that there is limited but suggestive evidence that animal fat intake increases the risk of colorectal cancer.

Objective: To clarify this potential relation, we conducted meta-analyses across a variety of subgroups, incorporating data from additional studies.

Design: Analyses of high compared with low animal fat intakes and categorical dose-response evaluations were conducted. Subgroup analyses, consisting of evaluations by study design, sex, and tumor site were also performed.

Results: Six prospective cohort studies with comprehensive dietary assessments, contributing 1070 cases of colorectal cancer and 1.5 million person-years of follow-up, were identified. The summary relative risk estimate (SRRE) for these studies was 1.04 (95% CI: 0.83, 1.31; P for heterogeneity = 0.221) on the basis of high compared with low intakes. When data from case-control studies were combined with the cohort data, the resulting SRRE was 1.15 (95% CI: 0.93, 1.42) with increased variability (P for heterogeneity = 0.015). In our dose-response analysis of the cohort studies, no association between a 20-g/d increment in animal fat intake and colorectal cancer was observed (SRRE: 1.02; 95% CI: 0.95, 1.09). In a separate analysis of 3 prospective cohort studies that reported data for animal protein or meat protein, no significant association with colorectal cancer was observed (SRRE: 0.90; 95% CI: 0.70, 1.15).

Conclusion: On the basis of the results of this quantitative assessment, the available epidemiologic evidence does not appear to support an independent association between animal fat intake or animal protein intake and colorectal cancer.

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

from American Journal of Clinical Nutrition current issue by Hunt, J. R, Johnson, L. K, Fariba Roughead, Z.

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 675 or 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 47Ca, 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.

Effects of dietary fatty acid composition on 24-h energy expenditure and chronic disease risk factors in men

Effects of dietary fatty acid composition on 24-h energy expenditure and chronic disease risk factors in men

from American Journal of Clinical Nutrition current issue by Cooper, J. A, Watras, A. C, Adams, A. K, Schoeller, D. A

Background: A high-fat (HF) diet and sedentary lifestyle are implicated in the development of obesity. Controlled feeding studies and measures of short-term resting energy expenditure (REE) have suggested that the type of dietary fat may alter energy expenditure (EE).

Objective: The objective was to examine the effects of an HF diet rich in either monounsaturated or saturated fatty acids (FAs) and of exercise on EE and chronic disease risk factors.

Design: Eight healthy men [age: 18–45 y; body mass index (in kg/m2): 22 ± 3] were randomly assigned in a 2 x 2 crossover design to 1 of 4 treatments: HF diet (50% of energy) with a high amount of saturated fat (22% of energy) plus exercise (SE) or a sedentary (SS) condition or a diet high in monounsaturated fat (30% of energy) plus exercise (UE) or a sedentary (US) condition. The subjects spent 5 d in a metabolic chamber and cycled at 45% of maximal oxygen uptake for 2 h each day during the exercise visits. Respiratory gases and urinary nitrogen were measured to determine 24-h EE. Resting metabolic rate was measured on days 2, 4, and 6.

Results: Average 24-h EE was not different with respect to dietary FA composition (3202 ± 146, 3208 ± 151, 2240 ± 82, and 2270 ± 104 for SE, UE, SS, and US, respectively). Total and LDL cholesterol and blood pressure were significantly greater after the SE and SS treatments than after the UE and US treatments.

Conclusion: Resting metabolic rate and 24-h EE were not significantly different after short-term exposure to an HF diet rich in monounsaturated FAs or after exposure to a diet rich in saturated FAs in healthy, nonobese men.

Vitamin D supplementation enhances the beneficial effects of weight loss on cardiovascular disease risk markers

Vitamin D supplementation enhances the beneficial effects of weight loss on cardiovascular disease risk markers

from American Journal of Clinical Nutrition current issue by Zittermann, A., Frisch, S., Berthold, H. K, Gotting, C., Kuhn, J., Kleesiek, K., Stehle, P., Koertke, H., Koerfer, R.

Background: High blood concentrations of parathyroid hormone and low concentrations of the vitamin D metabolites 25-hydroxyvitamin D [25(OH)D] and calcitriol are considered new cardiovascular disease risk markers. However, there is also evidence that calcitriol increases lipogenesis and decreases lipolysis.

Objective: We investigated the effect of vitamin D on weight loss and traditional and nontraditional cardiovascular disease risk markers in overweight subjects.

Design: Healthy overweight subjects (n = 200) with mean 25(OH)D concentrations of 30 nmol/L (12 ng/mL) received vitamin D (83 µg/d) or placebo in a double-blind manner for 12 mo while participating in a weight-reduction program.

Results: Weight loss was not affected significantly by vitamin D supplementation (–5.7 ± 5.8 kg) or placebo (–6.4 ± 5.6 kg). However, mean 25(OH)D and calcitriol concentrations increased by 55.5 nmol/L and 40.0 pmol/L, respectively, in the vitamin D group but by only 11.8 nmol/L and 9.3 pmol/L, respectively, in the placebo group (P < 0.001), whereas a more pronounced decrease occurred in the vitamin D group than in the placebo group in blood concentrations of parathyroid hormone (–26.5% compared with –18.7%; P = 0.014), triglycerides (–13.5% compared with +3.0%; P < 0.001), and the inflammation marker tumor necrosis factor- (–10.2% compared with –3.2%; P = 0.049). The beneficial biochemical effects were independent of the loss in body weight, fat mass, and sex. However, compared with placebo, vitamin D supplementation also increased LDL-cholesterol concentrations (+5.4% compared with –2.5%; P < 0.001).

Conclusions: The results indicate that a vitamin D supplement of 83 µg/d does not adversely affect weight loss and is able to significantly improve several cardiovascular disease risk markers in overweight subjects with inadequate vitamin D status participating in a weight-reduction program. This trial was registered at clinicaltrials.gov as NCT00493012.

Effect of a proprietary protein supplement on recovery indices following resistance exercise in strength/power athletes.

Amino Acids. 2009 Apr 4. [Epub ahead of print]Click here to read Links
Effect of a proprietary protein supplement on recovery indices following resistance exercise in strength/power athletes.
Hoffman JR, Ratamess NA, Tranchina CP, Rashti SL, Kang J, Faigenbaum AD.

Department of Health and Exercise Science, The College of New Jersey, PO Box 7718, Ewing, NJ, 08628-0718, USA, hoffmanj@tcnj.edu.

The effect of 42 g of protein ingested pre- and post-exercise on recovery from an acute resistance exercise session was examined in 15 male strength/power athletes who were randomly divided into a supplement (SUP) or placebo (PL) group. Subjects reported to the Human Performance Laboratory (HPL) on four separate occasions (T1-T4). Maximal strength [one repetition-maximum (1-RM)] testing was performed during T1. During T2 subjects performed four sets of ten repetitions at 80% of their 1-RM in the squat, dead lift and barbell lunge exercises with 90 s of rest between each set. Blood draws occurred at baseline (BL), immediate and 15 min post-exercise to determine testosterone, cortisol and creatine kinase (CK) concentrations. Subjects reported back to the HPL 24 (T3) and 48 h (T4) post-exercise for a BL blood draw and to perform four sets of ten repetitions with 80% of 1-RM for the squat exercise only. No differences in the number of repetitions performed in the squat exercise were seen between the groups at T2. Relative to T2, PL performed significantly (P < 0.05) fewer repetitions than SUP at T3 and T4 (-9.5 +/- 5.5 repetitions vs. -3.3 +/- 3.6 during T3, respectively, and -10.5 +/- 8.2 repetitions vs. -2.3 +/- 2.9 repetitions during T4, respectively). No differences in hormonal measures were seen between the groups. CK concentrations were significantly (P < 0.05) elevated at T3 for both groups, but continued to elevate (P < 0.05) at T4 for PL only. No significant group differences were noted for CK at any time point. Results indicate that a proprietary protein SUP consumed before and after a resistance training session significantly contributes to improvements in exercise recovery 24 and 48 h post-exercise.

Athletic Performance and Vitamin D.

Athletic Performance and Vitamin D.

Cannell JJ, Hollis BW, Sorenson MB, Taft TN, Anderson JJ.

PURPOSE:: Activated vitamin D (calcitriol) is a pluripotent pleiotropic secosteroid hormone. As a steroid hormone, which regulates more than 1000 vitamin D-responsive human genes, calcitriol may influence athletic performance. Recent research indicates that intracellular calcitriol levels in numerous human tissues, including nerve and muscle tissue, are increased when inputs of its substrate, the prehormone vitamin D, are increased. METHODS:: We reviewed the world's literature for evidence that vitamin D affects physical and athletic performance. RESULTS:: Numerous studies, particularly in the German literature in the 1950s, show vitamin D-producing ultraviolet light improves athletic performance. Furthermore, a consistent literature indicates physical and athletic performance is seasonal; it peaks when 25-hydroxy-vitamin D [25(OH)D] levels peak, declines as they decline, and reaches its nadir when 25(OH)D levels are at their lowest. Vitamin D also increases the size and number of Type II (fast twitch) muscle fibers. Most cross-sectional studies show that 25(OH)D levels are directly associated with musculoskeletal performance in older individuals. Most randomized controlled trials, again mostly in older individuals, show that vitamin D improves physical performance. CONCLUSIONS:: Vitamin D may improve athletic performance in vitamin D-deficient athletes. Peak athletic performance may occur when 25(OH)D levels approach those obtained by natural, full-body, summer sun exposure, which is at least 50 ng.mL. Such 25(OH)D levels may also protect the athlete from several acute and chronic medical conditions.

Fish consumption, omega 3 fatty acids and cardiovascular disease. The science and the clinical trials.

Fish consumption, omega 3 fatty acids and cardiovascular disease. The science and the clinical trials.

Galli C, Risé P.

Laboratory of Lipid Nutrition and Pharmacology, Department of Pharmacological Sciences, University of Milano, Via Balzaretti 9, 20133 Milano, Italy. claudio.galli@unimi.it

Fats in fish and marine animals are rich in highly unsaturated fatty acids (FA with 5 or more double bonds) of the Omega 3 series. These FA, present in aquatic animals as an adaptation to the environmental conditions, reached the human diet through the food chain, with a significant impact on nutrition, life style and cultural conditions. Studies in the 70's showed that high fish consumption is associated with better cardiovascular health and this observation was subsequently confirmed in many studies (epidemiological, cohort, case-control). The evidence is stronger for secondary prevention and when the intakes of fish or omega 3 FA are assessed, rather than just estimated. The major effects are reduction of cardiac, especially sudden, death. Underlying mechanisms concern the antiarrhythmic activities, reduction of thrombotic and inflammatory processes and of serum triacylglycerol levels. In conclusion consumption of fish and its components should be promoted on a global scale especially in the case of subjects with cardiovascular problems. Although still some issues need to be faced especially in large scale interventions (i.e. the assessment of the omega 3 fatty acid status, correlations between levels and cardiovascular indexes and bioavailability of different forms of administration), these recommendations are highly valuable.

Fish oil and the management of hypertriglyceridemia.

Fish oil and the management of hypertriglyceridemia.

Mattar M, Obeid O.

Department of Nutrition and Food Science, American University of Beirut.

Hypertriglyceridemia, regarded as one of the independent clinical markers of metabolic syndrome, is a frequently observed disorder that has been shown to be common in the Arab region. Epidemiologic and clinical trials demonstrated that omega-3 fatty acids have the potential to reduce the incidence of cardiovascular disease (CVD); one of the mechanisms by which this effect is achieved is through reducing plasma triglyceride levels. There is strong scientific evidence from human trials that omega-3 fatty acids from either fish or fish oil supplements significantly reduce blood triglyceride levels and these benefits appear to be dose-dependent. The active ingredients of fish oils include the long chain fatty acids EPA and DHA. The ideal amount of omega-3 fatty acid that should be incorporated into the diet without provoking detrimental effects on other lipid components such as decreasing HDL-C and/or increasing LDL-C has not yet been elucidated. Presently, a prescription form of omega-3 fatty acid has been approved by the United States Food and Drug Administration (USFDA) as an adjunct to the diet for the treatment of very high triglyceride levels (> or = 500 mg/dl) in adults. Patients with hypertriglyceridemia have been shown to respond well to the use of omega-3 fatty acids even when used in conjunction with statins where greater improvements in the lipid profile were found as compared to treatment with statins alone. A determinant of the responsiveness to fish oil could be attributed to the ApoE genotype of individuals.

Liquid carbohydrate/essential amino acid ingestion during a short-term bout of resistance exercise suppresses myofibrillar protein degradation.

Metabolism. 2006 May;55(5):570-7. 

Liquid carbohydrate/essential amino acid ingestion during a short-term bout of resistance exercise suppresses myofibrillar protein degradation.

Bird SP, Tarpenning KM, Marino FE.

School of Human Movement Studies, Charles Sturt University, Bathurst, NSW 2795, Australia. sbird@csu.edu.au

A number of physiological events including the level of contractile activity, nutrient status, and hormonal action influence the magnitude of exercise-induced skeletal muscle growth. However, it is not the independent action of a single mechanism, but the complex interaction between events that enhance the long-term adaptations to resistance training. The purpose of the present investigation was to examine the influence of liquid carbohydrate (CHO) and essential amino acid (EAA) ingestion during resistance exercise and modification of the immediate hormonal response on myofibrillar protein degradation as assessed by 3-methylhistidine (3-MH) excretion. After a 4-hour fast, 32 untrained young men (18-29 years) performed a single bout of resistance exercise (complete body; 3 setsx10 repetitions at 75% of 1-repetition maximum; 1-minute rest between sets), during which they consumed a 6% CHO (n=8) solution, a 6-g EAA (n=8) mixture, a combined CHO+EAA (n=8) supplement, or placebo (PLA; n=8) beverage. Resistance exercise performed in conjunction with CHO and CHO+EAA ingestion resulted in significantly elevated (P<.001) glucose and insulin concentrations above baseline, whereas EAA ingestion only increased the postexercise insulin response (P<.05). Time matched at 60 minutes, the PLA group exhibited a peak cortisol increase of 105% (P<.001) with no significant change in glucose or insulin concentrations. Conversely, the CHO and CHO+EAA groups displayed a decrease in cortisol levels of 11% and 7%, respectively. Coinciding with these hormonal response patterns were significant differences in myofibrillar protein degradation. Ingestion of the EAA and CHO treatments attenuated 3-MH excretion 48 hours after the exercise bout. Moreover, this response was synergistically potentiated when the 2 treatments were combined, with CHO+EAA ingestion resulting in a 27% reduction (P<.01) in 3-MH excretion. In contrast, the PLA group displayed a 56% increase (P<.01) in 3-MH excretion. These data demonstrate that not only does CHO and EAA ingestion during the exercise bout suppress exercise-induced cortisol release; the stimulatory effect of resistance exercise on myofibrillar protein degradation can be attenuated, most dramatically when the treatments are combined (CHO+EAA). Through an "anticatabolic effect," this altered balance may better favor the conservation of myofibrillar protein.

Upper limit of fat-free mass in humans: A study on Japanese Sumo wrestlers

Masakatsu Kondo, Takashi Abe, Ph.D, Shigeki Ikegawa, Yasuo Kawakami, Tetsuo Fukunaga

Upper limit of fat-free mass in humans: A study on Japanese Sumo wrestlers

American Journal of Human Biology, Volume 6 Issue 5, Pages 613 - 618

If limitations exist in skeletal dimensions, fat-free mass (FFM) might have an upper limit. To explore the upper limit to FFM, 37 professional Japanese Sumo wrestlers, 14 highly trained bodybuilders, and 26 untrained men were investigated for body composition (fat mass and FFM) and cross-sectional areas (CSA) of limb muscles, by hydrodensitometry and ultrasound, respectively. Mean % fat of Sumo wrestlers, bodybuilders, and untrained subjects were, respectively, 26.1%, 10.9%, and 12.1%. Sumo wrestlers had a significantly greater FFM than bodybuilders, who had a greater FFM than the untrained men. Six of the wrestlers had more than 100 kg of FFM, including the largest one of 121.3 kg (stature: 186 cm, mass: 181 kg, %fat: 33.0%). The FFM/stature ratio of elite Sumo wrestlers averaged at 0.61 kg/cm, with the highest 0.66 kg/cm. It is suggested that a FFM/stature ratio of 0.7 kg/cm may be an upper limit in humans.

Dietary Conjugated Linoleic Acid Induces Tissue-Specific Lipoprotein Lipase mRNA Modulation in High-Sucrose-Fed Mice

Dietary Conjugated Linoleic Acid Induces Tissue-Specific Lipoprotein Lipase mRNA Modulation in High-Sucrose-Fed Mice

Lyssia Castellanos-Tapiaa, Gloria Yepiz-Plasenciab, Silvia Y. Moya-Camarenaaa

Ann Nutr Metab 2009;54:131-137 (DOI: 10.1159/000210434)

  Abstract

Background/Aims: To delineate the hypotriglyceridemic effect of conjugated linoleic acid (CLA) in mice, the effect of this fatty acid on lipoprotein lipase (LPL) and apolipoprotein C-III (ApoCIII) mRNA accumulation in muscle, adipose and liver tissue was studied. Methods: CD-1 mice were housed in groups of 6 and randomized to one of three experimental diets for 3 weeks: SUC: 65% sucrose by weight; CLA: 1% CLA oil (34.4% c9,t11; 35.1% t10,c12 and 4.1% other conjugated isomers) and 65% sucrose, and DEX: 65% dextrose, as a control. Results: LPL mRNA levels in muscle tissue were increased in the DEX group and in the CLA group (240% increase) compared with the SUC group. In contrast, LPL mRNA levels were 81% lower in epididymal adipose tissue from the CLA group compared with the SUC group. There was no effect of dietary treatments on ApoCIII mRNA accumulation in the liver. Conclusions: These data suggest that dietary CLA may induce partitioning of circulating triglycerides to muscle tissue, preventing their accumulation in adipocytes

Coingestion of protein with carbohydrate during recovery from endurance exercise stimulates skeletal muscle protein synthesis in humans

Coingestion of protein with carbohydrate during recovery from endurance exercise stimulates skeletal muscle protein synthesis in humans

from Journal of Applied Physiology recent issues 

by Howarth, K. R., Moreau, N. A., Phillips, S. M., Gibala, M. J.

Coingestion of protein with carbohydrate (CHO) during recovery from exercise can affect muscle glycogen synthesis, particularly if CHO intake is suboptimal. Another potential benefit of protein feeding is an increased synthesis rate of muscle proteins, as is well documented after resistance exercise. In contrast, the effect of nutrient manipulation on muscle protein kinetics after aerobic exercise remains largely unexplored. We tested the hypothesis that ingesting protein with CHO after a standardized 2-h bout of cycle exercise would increase mixed muscle fractional synthetic rate (FSR) and whole body net protein balance (WBNB) vs. trials matched for total CHO or total energy intake. We also examined whether postexercise glycogen synthesis could be enhanced by adding protein or additional CHO to a feeding protocol that provided 1.2 g CHO·kg–1·h–1, which is the rate generally recommended to maximize this process. Six active men ingested drinks during the first 3 h of recovery that provided either 1.2 g CHO·kg–1·h–1 (L-CHO), 1.2 g CHO + 0.4 g protein·kg–1·h–1 (PRO-CHO), or 1.6 g CHO·kg–1·h–1 (H-CHO) in random order. Based on a primed constant infusion of l-[ring-2H5]phenylalanine, analysis of biopsies (vastus lateralis) obtained at 0 and 4 h of recovery showed that muscle FSR was higher (P < 0.05) in PRO-CHO (0.09 ± 0.01%/h) vs. both L-CHO (0.07 ± 0.01%/h) and H-CHO (0.06 ± 0.01%/h). WBNB assessed using [1-13C]leucine was positive only during PRO-CHO, and this was mainly attributable to a reduced rate of protein breakdown. Glycogen synthesis rate was not different between trials. We conclude that ingesting protein with CHO during recovery from aerobic exercise increased muscle FSR and improved WBNB, compared with feeding strategies that provided CHO only and were matched for total CHO or total energy intake. However, adding protein or additional CHO to a feeding strategy that provided 1.2 g CHO·kg–1·h–1 did not further enhance glycogen resynthesis during recovery.

Nutritional and contractile regulation of human skeletal muscle protein synthesis and mTORC1 signaling

Nutritional and contractile regulation of human skeletal muscle protein synthesis and mTORC1 signaling

from Journal of Applied Physiology recent issues 

by Drummond, M. J., Dreyer, H. C., Fry, C. S., Glynn, E. L., Rasmussen, B. B.

In this review we discuss current findings in the human skeletal muscle literature describing the acute influence of nutrients (leucine-enriched essential amino acids in particular) and resistance exercise on muscle protein synthesis and mammalian target of rapamycin complex 1 (mTORC1) signaling. We show that essential amino acids and an acute bout of resistance exercise independently stimulate human skeletal muscle protein synthesis. It also appears that ingestion of essential amino acids following resistance exercise leads to an even larger increase in the rate of muscle protein synthesis compared with the independent effects of nutrients or muscle contraction. Until recently the cellular mechanisms responsible for controlling the rate of muscle protein synthesis in humans were unknown. In this review, we highlight new studies in humans that have clearly shown the mTORC1 signaling pathway is playing an important regulatory role in controlling muscle protein synthesis in response to nutrients and/or muscle contraction. We propose that essential amino acid ingestion shortly following a bout of resistance exercise is beneficial in promoting skeletal muscle growth and may be useful in counteracting muscle wasting in a variety of conditions such as aging, cancer cachexia, physical inactivity, and perhaps during rehabilitation following trauma or surgery.