New Research & Science
Biomarkers of milk fat and the risk of myocardial infarction in men and women: a prospective, matched case-control study1,2,3
Eva Warensjö, Jan-Håkan Jansson, Tommy Cederholm, Kurt Boman, Mats Eliasson, Göran Hallmans, Ingegerd Johansson and Per Sjögren
ABSTRACT
Background: High intakes of saturated fat have been associated with cardiovascular disease, and milk fat is rich in saturated fat.
Objective: The objective of this study was to investigate the association between the serum milk fat biomarkers pentadecanoic acid (15:0), heptadecanoic acid (17:0), and their sum (15:0+17:0) and a first myocardial infarction (MI).
Design: The study design was a prospective case-control study nested within a large population-based cohort in Sweden. Included in the study were 444 cases (307 men) and 556 controls (308 men) matched on sex, age, date of examination, and geographic region. Clinical, anthropometric, biomarker fatty acid, physical activity, and dietary data were collected. The odds of a first MI were investigated by using conditional logistic regression.
Results: In women, proportions of milk fat biomarkers in plasma phospholipids were significantly higher (P < 0.05) in controls than in cases and were, in general, negatively, albeit weakly, correlated with risk factors for metabolic syndrome. The crude standardized odds ratios of becoming an MI case were 0.74 (95% CI: 0.58, 0.94) in women and 0.91 (95% CI: 0.77, 1.1) in men. After multivariable adjustment for confounders, the inverse association remained in both sexes and was significant in women. In agreement with biomarker data, quartiles of reported intake of cheese (men and women) and fermented milk products (men) were inversely related to a first MI (P for trend < 0.05 for all).
Conclusions: Milk fat biomarkers were associated with a lower risk of developing a first MI, especially in women. This was partly confirmed in analysis of fermented milk and cheese intake. Components of metabolic syndrome were observed as potential intermediates for the risk relations.
Lipids. 2010 Apr 16. [Epub ahead of print]
The Consumption of Milk and Dairy Foods and the Incidence of Vascular Disease and Diabetes: An Overview of the Evidence.
Elwood PC, Pickering JE, Givens DI, Gallacher JE.
Department of Primary Care and Public Health, Cardiff University, University Hospital of Wales, Cardiff, CF14 4YS, UK, pelwood@doctors.org.uk.
Abstract
The health effects of milk and dairy food consumption would best be determined in randomised controlled trials. No adequately powered trial has been reported and none is likely because of the numbers required. The best evidence comes, therefore, from prospective cohort studies with disease events and death as outcomes. Medline was searched for prospective studies of dairy food consumption and incident vascular disease and Type 2 diabetes, based on representative population samples. Reports in which evaluation was in incident disease or death were selected. Meta-analyses of the adjusted estimates of relative risk for disease outcomes in these reports were conducted. Relevant case-control retrospective studies were also identified and the results are summarised in this article. Meta-analyses suggest a reduction in risk in the subjects with the highest dairy consumption relative to those with the lowest intake: 0.87 (0.77, 0.98) for all-cause deaths, 0.92 (0.80, 0.99) for ischaemic heart disease, 0.79 (0.68, 0.91) for stroke and 0.85 (0.75, 0.96) for incident diabetes. The number of cohort studies which give evidence on individual dairy food items is very small, but, again, there is no convincing evidence of harm from consumption of the separate food items. In conclusion, there appears to be an enormous mis-match between the evidence from long-term prospective studies and perceptions of harm from the consumption of dairy food items.
Levels of vitamin D and cardiometabolic disorders: Systematic review and meta-analysis
Johanna Parkera, Omar Hashmia, David Duttonb, Angelique Mavrodarisa, Saverio Strangesa, Ngianga-Bakwin Kandalab, Aileen Clarkea, Oscar H. Francoa1
Received 8 December 2009; accepted 10 December 2009. published online 18 December 2009.
Abstract
Cardiometabolic disorders and vitamin D deficiency are becoming increasingly more prevalent across multiple populations. Different studies have suggested a potential association between abnormal vitamin D levels and multiple pathological conditions including cardiovascular diseases and diabetes.
We aimed to evaluate the association between vitamin D levels, using 25-hydroxy vitamin D (25OHD) as an indicator of vitamin D status, and the presence of cardiometabolic disorders including cardiovascular disease, diabetes and metabolic syndrome.
We performed a systematic review of the current literature on vitamin D and cardiometabolic disorders using the PubMed and Web of Knowledge databases in September 2009. Studies in adults looking at the effect of vitamin D levels on outcomes relating to cardiometabolic disorders were selected. We performed a meta-analysis to assess the risk of developing cardiometabolic disorders comparing the highest and lowest groups of serum 25OHD.
From 6130 references we identified 28 studies that met our inclusion criteria, including 99,745 participants. There was moderate variation between the studies in their grouping of 25OHD levels, design and analytical approach. We found that the highest levels of serum 25OHD were associated with a 43% reduction in cardiometabolic disorders [OR 0.57, 95% (CI 0.48–0.68)]. Similar levels were observed, irrespective of the individual cardiometabolic outcome evaluated or study design. High levels of vitamin D among middle-age and elderly populations are associated with a substantial decrease in cardiovascular disease, type 2 diabetes and metabolic syndrome. If the relationship proves to be causal, interventions targeting vitamin D deficiency in adult populations could potentially slow the current epidemics of cardiometabolic disorders.
Dietary Glycemic Load and Index and Risk of Coronary Heart Disease in a Large Italian Cohort
The EPICOR Study
Sabina Sieri, PhD; Vittorio Krogh, MD, MS; Franco Berrino, MD; Alberto Evangelista, BSc; Claudia Agnoli, PhD; Furio Brighenti, PhD; Nicoletta Pellegrini, PhD; Domenico Palli, MD; Giovanna Masala, MD; Carlotta Sacerdote, MD; Fabrizio Veglia, MD; Rosario Tumino, MD; Graziella Frasca, PhD; Sara Grioni, BSc; Valeria Pala, PhD; Amalia Mattiello, MD; Paolo Chiodini, PhD; Salvatore Panico, MD
Arch Intern Med. 2010;170(7):640-647.
Background Dietary glycemic load (GL) and glycemic index (GI) in relation to cardiovascular disease have been investigated in a few prospective studies with inconsistent results, particularly in men. The present EPICOR study investigated the association of GI and GL with coronary heart disease (CHD) in a large and heterogeneous cohort of Italian men and women originally recruited to the European Prospective Investigation into Cancer and Nutrition study.
Methods We studied 47 749 volunteers (15 171 men and 32 578 women) who completed a dietary questionnaire. Multivariate Cox proportional hazards modeling estimated adjusted relative risks (RRs) of CHD and 95% confidence intervals (CIs).
Results During a median of 7.9 years of follow-up, 463 CHD cases (158 women and 305 men) were identified. Women in the highest carbohydrate intake quartile had a significantly greater risk of CHD than did those in the lowest quartile (RR, 2.00; 95% CI, 1.16-3.43), with no association found in men (P = .04 for interaction). Increasing carbohydrate intake from high-GI foods was also significantly associated with greater risk of CHD in women (RR, 1.68; 95% CI, 1.02-2.75), whereas increasing the intake of low-GI carbohydrates was not. Women in the highest GL quartile had a significantly greater risk of CHD than did those in the lowest quartile (RR, 2.24; 95% CI, 1.26-3.98), with no significant association in men (P = .03 for interaction).
Conclusion In this Italian cohort, high dietary GL and carbohydrate intake from high-GI foods increase the overall risk of CHD in women but not men.
Intake of carbohydrates compared with intake of saturated fatty acids and risk of myocardial infarction: importance of the glycemic index
Marianne U Jakobsen, Claus Dethlefsen, Albert M Joensen, Jakob Stegger, Anne Tjønneland, Erik B Schmidt and Kim Overvad
ABSTRACT
Background: Studies have suggested that replacing saturated fatty acids (SFAs) with carbohydrates is modestly associated with a higher risk of ischemic heart disease, whereas replacing SFAs with polyunsaturated fatty acids is associated with a lower risk of ischemic heart disease. The effect of carbohydrates, however, may depend on the type consumed.
Objectives: By using substitution models, we aimed to investigate the risk of myocardial infarction (MI) associated with a higher energy intake from carbohydrates and a concomitant lower energy intake from SFAs. Carbohydrates with different glycemic index (GI) values were also investigated.
Design: Our prospective cohort study included 53,644 women and men free of MI at baseline.
Results: During a median of 12 y of follow-up, 1943 incident MI cases occurred. There was a nonsignificant inverse association between substitution of carbohydrates with low-GI values for SFAs and risk of MI [hazard ratio (HR) for MI per 5% increment of energy intake from carbohydrates: 0.88; 95% CI: 0.72, 1.07). In contrast, there was a statistically significant positive association between substitution of carbohydrates with high-GI values for SFAs and risk of MI (HR: 1.33; 95% CI: 1.08, 1.64). There was no association for carbohydrates with medium-GI values (HR: 0.98; 95% CI: 0.80, 1.21). No effect modification by sex was observed.
Conclusion: This study suggests that replacing SFAs with carbohydrates with low-GI values is associated with a lower risk of MI, whereas replacing SFAs with carbohydrates with high-GI values is associated with a higher risk of MI.
ISSN exercise & sport nutrition review: research & recommendations
ABSTRACT:
Sports nutrition is a constantly evolving field with hundreds of research papers published annually. For this reason, keeping up to date with the literature is often difficult. This paper is a five year update of the sports nutrition review article published as the lead paper to launch the JISSN in 2004 and presents a well-referenced overview of the current state of the science related to how to optimize training and athletic performance through nutrition. More specifically, this paper provides an overview of: 1.) The definitional category of ergogenic aids and dietary supplements; 2.) How dietary supplements are legally regulated; 3.) How to evaluate the scientific merit of nutritional supplements; 4.) General nutritional strategies to optimize performance and enhance recovery; and, 5.) An overview of our current understanding of the ergogenic value of nutrition and dietary supplementation in regards to weight gain, weight loss, and performance enhancement. Our hope is that ISSN members and individuals interested in sports nutrition find this review useful in their daily practice and consultation with their clients.
full text (93 pages) available here as PDF: http://www.jissn.com/content/pdf/1550-2783-7-7.pdf
Richard B. Kreider, Colin D. Wilborn, Lem Taylor, Bill Campbell, Anthony L. Almada, Rick Collins, Mathew Cooke, Conrad P. Earnest, Mike Greenwood, Douglas S. Kalman, Chad M. Kerksick, Susan M. Kleiner, Brian Leutholtz, Hector Lopez, Lonnie M. Lowery, Ron Mendel, Abbie Smith, Marie Spano, Robert Wildman, Darryn S. Willoughby, Tim N. Ziegenfuss, Jose Antonio. ISSN Exercise & sports nutrition review: research & Recommendations. J Int Soc Sports Nutr 2010, 7:7 doi: 10.1186/1550-2783-7-7
Professor Richard Kreider has put an enourmous effort on this study. Under his leadership over 500 original studies were estimated when putting together this review. What food should we eat to thrive as an athlete? What sports products, increase performance?
Nearly one hundred pages long, this publication provides a comprehensive overview of the following issues:
1) The definitional category of ergogenic aids and fietary supplements
2) How dietary supplements are legally regulated
3) How to evalueate the scientific merit of nutritional supplements
4) General nutritional strategies to optimize performance and enhance recovery
5) An overview of our current understanding of the ergogenic value of nutrition and dietary supplementation in regards to weight gain, weight loss, and performance enhancement
Ergogenic aid
Ergogenic aid is any training method, a mechanical instrument, nutritional counseling, a pharmacological method or a psychological tool that can improve an athlete's performance. In this we're find ways to improve the effectiveness and / or a variety of ways to increase the opportunities to return to exercise.
Nutritional supplements are legal and safety
Some sports organizations have banned the use of certain dietary supplements (eg prohormones, ephedrine and muscle growth-enhancing nutritional supplements). If a dietary supplement is specifically prohibited, then working in the area of sports nutrition professionals have to stay away from these substances and to actively work against their use.
Many dietary supplements are not for long term use. The use of nutritional supplements to consider for should remain very well-informed of possible side effects. Assessing the safety of the nutritional supplement supports the search for potential side effects of scientific and medical literature.
The classification of food supplements
Dietary supplements may contain carbohydrate, protein, fat, minerals, vitamins, herbs, enzymes, metabolic products, and / or different plant extracts. Dietary supplements, performance can be categorized as follows:
I. Apparently Effective. Nutritional supplements that help meet the energy needs of the public and / or in respect of which the majority of studies show that they are effective and safe
II. Possibly Effective. Dietary supplements, which calls for more studies of how these dietary supplements may increase performance.
III. Too early to tell. Nutritional supplements, whose efficacy there is a reasonable theory, but their efficacy has been confirmed too little data.
IV. Probably ineffective. Dietary supplements, which have been identified in studies to be ineffective.
General dietary guidelines for active people
Well-planned diet that will satisfy the energy needs and contain enough nutrients, it is the foundation, upon which a good workout program will be created. Surveys show that energy and macronutrient deficit may interfere with the athlete's adaptation to training compared to athletes who comply with the energy necessary for a satisfactory diet.
Energy deficient diet during training may lead to loss of muscle mass loss and degradation, increased susceptibility for sickness and risk of overtraining. Good dietary guidance inclusion into the training program is one way to optimize the integration of training and prevent overtraining.
Energy Consumption
One of the first tasks of training and performance through the optimization of nutrition, is to ensure the athlete receiving enough energy to replace the energy deficit.
General fitness program that is being practiced (eg, 30-40 minutes exercise per day, 3 times a week), can typically meet the nutritional needs by following the "normal" diet (1800-2400 kcal / day, or about 25-35 kcal / kg / day, if a man weighing 50-80 kg), because their exercise calorie consumption is not very significant (200-400 kcal / session).
Medium-level athletes who train intensively for 2-3 hours a day, 5-6 times a week, or top-level athletes (3-6 hours of exercise per day, 1-2 times a day and 5-6 days per week), can consume 600-1200 calories or more per hour during exercise. Therefore, their energy needs could increase 50-80 kcal / kg / day (2500-8000 kcal / day of 50-100kg press an athlete). Top-level athletes may be heavy demand for energy during exercise to be enormous.
For athletes who train at high intensity, it is often very difficult to eat enough food to meet calorie consumption.
Kreider RB. Physiological considerations of ultraendurance performance. Int J Sport Nutr 1 (1): 3-27, 1991
Brouns F, Saris WH, Beckers E, Adlercreutz H et al. Metabolic changes "induced by sustained exhaustive cycling and diet manipulation. Int J Sports Med 10 (Suppl 1): S49-62, 1989
Brouns F, Saris WH, Stroecken J et al. Eating, drinking, and cycling. A controlled Tour de France simulation study, Part I. Int J Sports Med 10 (Suppl 1): S32-40, 1989
Brouns F, Saris WH, Stroecken J et al. Eating, drinking, and cycling. A controlled Tour de France simulation study, Part II. Effect of diet manipulation. Int J Sports Med 10 (Suppl
1): S41-48, 1989
Energy deficient diet during training is the surest way to achieve weight loss, but the result are often unwanted: muscle mass loss and worse athletic preformance.
For sports nutrition professionals, it is important to work with athletes in order to ensure sufficient energy supply. It sounds so simple, but powerful practice that is often accompanied appendage such as the decrease in appetite.
Nutritional counselor should be particularly carefully refuted from inside to react to a situation where an athlete has no appetite. Energy-bar use offers athletes a way to meet the daily energy needs during exercise, athletes should be provided otherwise in danger of being deficient in energy intake.
Carbohydrate
Energy intake is also important to ensure the training and performance optimization of nutrition, to help athletes eat enough carbohydrate, protein and fat.
Sports enthusiasts can typically satisfy the needs for macronutrients by following the "normal" diet (45-55% carbohydrate, ie 3-5 g / kg / day, 10-15% protein, ie 0,8-1,0 g / kg / day and 25-35% fat, ie 0.5-1.5 g / kg / day).
Intermediate and high performance athletes need higher amounts of protein and carbohydrate to satisfy their macronutrient needs. For example, the average level of the athletes, who train 2-3 hours a day and 5-6 times a week, generally require a 55-65% carbohydrate (5-8 g / kg / day) or 250-1200 g / day for 50-150 kg in the case of athletes. Carbohydrate is needed to fil up liver and muscle glycogen stores.
Studies have shown that elite athletes (practicing 3-6 hours a day and 1-2 times a day, 5-6 days a week) may require 8-10 g / day, carbohydrate (400-1500 g / day for 50-150 kg athlete) to meet the muscle glycogen stores.
The majority of carbohydrates should be from foods with low glycemic index (eg, vegetables, fruits, whole grain cereals). Since it is difficult to get as much carbohydrate a day when an athlete to practice intensively, many sports nutrition professionals recommend the use of carbohydrate containing drinks during exercise.
Protein
Protein requirements of athletes is controversial. For "normal" people recommended protein intake is 0,8-1,0 g / kg / day. This amount is also sufficient for ordinary fitness.
Studies have shown that athletes who train intensively double the number of recommendations (1.5-2.0 g / kg / day).
Lemon PW, Tarnopolsky MA, MacDougall JD, Atkinson SA. Protein Requirements and muscle mass / strength changes "During intensive training in novice bodybuilders. J Appl Physiol 73 (2): 767-775, 1992
Tarnopolsky MA, MacDougall JD, Atkinson SA. Influence of protein intake and training status is nitrogen balance and lean body mass. J Appl Physiol 64 (1): 187-193, 1988
Tarnopolsky MA. Protein and physical performance. Curr learned Clin Nutr Metab Care 2 (6): 533-537, 1999
Kreider RB. Dietary Supplements and the promotion of muscle growth with Resistance Exercise. Sports Med 27 (2): 97-110, 1999
Chesley A, MacDougall JD, Tarnopolsky MA et al. Changes in human muscle protein synthesis on Resistance Exercise. J Appl Physiol 73 (4): 1383-1388, 1992
Too little protein intake slows down the recovery drills. Even older people can benefit from the higher than normal protein intake (1.0-1.2 g / kg / day). This slows down the sarcopenia, or old age-related muscle degeneration.
Intermediate athletes recommended quantity of protein is 1-1.5 g / kg / day (50-225 g / day 50-150 kg athlete). Top-level athletes need 1.5-2.0 g / kg / day of protein (75-300 g / day for 50-150 kg athlete).
Protein quality is very important, since all the proteins are not identical. There are differences in the availability of amino acids and peptides, which exhibit biological activity (alpha-lactalbumin, beta-lactoglobulin, glycomacropeptide, immunoglobulins, lactoperocsidases, lactoferrin was also shown, etc.).
Also the absorption of protein and metabolic activity are important factors.
Bucci L, Unlu L. Proteins and Amino Acid Supplements in Sports and Exercise. In: Driskell J, Wolinsky I, editors. Energy-Yielding Macronutrients and Energy Metabolism in Sports Nutrition. Boca Raton, FL: CRC Press, 2000. p. 191-212.
Protein absorption ratio should be taken into account, for example: casein and whey protein are absorbed at different speeds, which affects the whole body catabolism and anabolism.
Boirie Y, Dangin M, Gachon P et al. Slow and fast dietary Proteins differently modulate postprandial protein accretion. Proc Natl Acad Sci USA 94 (26): 14930-14935, 1997
Boirie Y, Beaufrere B, Ritz P. Energetic cost of protein turnover in Healthy Elderly Humans. Int J Obes relat Metab Disord 25 (5): 601-605, 2001
Boirie Y, Gachon P, Corny S et al. Acute postprandial changes "in leucine metabolism as assessed with an intrinsically Labeled milk protein. Am J Physiol 271 (6 Pt 1): E1083-1091, 1996
The athlete must therefore take into account that he eats a high-quality protein. The best protein sources include chicken, fish and egg protein (casein and whey protein). High quality protein supplements from the best sources are whey, casein, milk proteins, colostrum and egg protein.
Fat
Fat on the nutrition recommendations for athletes are consistent with or slightly larger than for normal people. Higher fat diets maintain testosterone production better than low-fat diet.
Dorgan JF, Judd JT, Longcope C et al. Effects of dietary fat and fiber is a plasma and urine androgens and estrogens in men: a controlled feeding study. Am J Clin Nutr 64 (6) :850-855, 1996
Hämäläinen EK, Adlercreutz H, Puska P, Pietinen P. Decrease of serum total and free testosterone During a low-fat diet highfibre. J Steroid Biochem 18 (3): 369-370, 1983
Reed MJ, Cheng RW, Simmonds M et al. Dietary Lipids: an Additional regulator of plasma levels when sex hormone binding of globuli. J Clin Endocrinol Metab 64 (5): 1083-1085, 1987
It is recommended for athletes to eat 30% of dietary fat during normal training season and up to 50% when training hard.
Venkatraman JT, Leddy, J, Pendergast D. Dietary fats and immune status in athletes: clinical implications ". Med Sci Sports Exerc 32 (7 Suppl): S389-395, 2000
For athletes who want to reduce body fat percentage, it is recommended of 0.5-1 g / kg / daily fat intake.
Eating and refueling
Studies have shown that the timing and composition of meals are important optimize performance, training adaptation and prevention of overtraining. Carbohydrate absorption and storage of muscle and liver glycogen takes about four hours. If an athlete to practice in the evening, breakfast is the most important meal in view of the liver and muscles glykogeenitasoja.
When exercise lasts longer than an hour, an athlete should drink glucose and electrolytes containing fluids to maintain blood glucose levels and prevent the body from drying out.
Nieman DC, Fagoaga OR, DE Butterworth et al. Carbohydrate supplementation affects blood granulocyte and monocyte trafficking vain Not Function on the 2.5 h of running. Am J Clin Nutr 66 (1): 153-159, 1997
Nieman DC. Influence of carbohydrate on the immune responses to intensive, prolonged Exercise. Exerc Immunol Rev 4:64-76, 1998
Nieman DC. Nutrition, exercise, and immune system function. Clin Sports Med 18 (3) :537-548, 1999
Burke LM. Nutritional Needs for Exercise in the heat. Comp Biochem Physiol A Mol Integra Physiol 128 (4): 735-748, 2001
Burke LM. Nutrition for post-exercise recovery. Aust J Sci Med Sport 29 (1): 3-10, 1997
Maughan RJ, Noakes TD. Fluid replacement and exercise stress. A brief review of studies is fluid replacement and some guidelines for the Athlete. Sports Med 12 (1): 16-31, 1991
After the session, an athlete must ensure that at least 30 minutes after that, he gets high quality carbohydrates (1 g / kg) and 0.5 g / kg protein. Carbohydrate containing meal should be consumed two hours after exercise. This nutritional practice has been exploited in most cases when you want to speed up the re-formation of glycogen and promote anabolism. This idea is supported following studies:
Zawadzki KM, Yaspelkis BB, 3rd, Ivy JL. Carbohydrate-protein complex increases the rate of muscle glycogen storage on Exercise. J Appl Physiol 72 (5): 1854-1859, 1992
Tarnopolsky MA, Bosman M, Macdonald JR et al. Post Exercise Protein-carbohydrate and carbohydrate Supplements Increase muscle glycogen in men and women. J Appl Physiol 83 (6): 1877-1883, 1997
Kraemer WJ, Volek JS, Bush et al AND. Responses to hormonal Consecutive days of heavyresistance Exercise with or without nutritional supplementation. J Appl Physiol 85 (4): 1544-1555, 1998
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Infectious Burden and Carotid Plaque Thickness. The Northern Manhattan Study
Mitchell S.V. Elkind MD, MS*;
Jorge M. Luna MPH; Yeseon Park Moon MS; Bernadette Boden-Albala DrPH; Khin M. Liu BS; Steven Spitalnik MD; Tanja Rundek MD, PhD; Ralph L. Sacco MD, MS; and Myunghee C. Paik PhDBackground and Purpose—The overall burden of prior infections may contribute to atherosclerosis and stroke risk. We hypothesized that serological evidence of common infections would be associated with carotid plaque thickness in a multiethnic cohort.
Methods—Antibody titers to 5 common infectious microorganisms (ie, Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus, and herpesvirus 1 and 2) were measured among stroke-free community participants and a weighted index of infectious burden was calculated based on Cox models previously derived for the association of each infection with stroke risk. High-resolution carotid duplex Doppler studies were used to assess maximum carotid plaque thickness. Weighted least squares regression was used to measure the association between infectious burden and maximum carotid plaque thickness after adjusting for other risk factors.
Results—Serological results for all 5 infectious organisms were available in 861 participants with maximum carotid plaque thickness measurements available (mean age, 67.2±9.6 years). Each individual infection was associated with stroke risk after adjusting for other risk factors. The infectious burden index (n=861) had a mean of 1.00±0.35 SD and a median of 1.08. Plaque was present in 52% of participants (mean, 0.90±1.04 mm). Infectious burden was associated with maximum carotid plaque thickness (adjusted increase in maximum carotid plaque thickness 0.09 mm; 95% CI, 0.03 to 0.15 mm per SD increase of infectious burden).
Conclusion—A quantitative weighted index of infectious burden, derived from the magnitude of association of individual infections with stroke, was associated with carotid plaque thickness in this multiethnic cohort. These results lend support to the notion that past or chronic exposure to common infections, perhaps by exacerbating inflammation, contributes to atherosclerosis. Future studies are needed to confirm this hypothesis and to define optimal measures of infectious burden as a vascular risk factor.
Epidemiology. 1997 Mar;8(2):144-9.
Margarine intake and subsequent coronary heart disease in men.
Gillman MW, Cupples LA, Gagnon D, Millen BE, Ellison RC, Castelli WP.
Department of Ambulatory Care and Prevention, Harvard Medical School, Boston, MA 02215, USA.
Comment in:
Margarine is a major source of trans fatty acids, the intake of which has risen since the early 20th century. Some data indicate that consumption of trans fatty acids increases the risk of coronary heart disease (CHD). In 1966-1969, 832 men from the Framingham Study, age 45-64 years and free of CHD, were administered a single 24-hour dietary recall, from which we estimated total daily margarine intake. We calculated CHD cumulative incidence rates and, using proportional hazards regression, CHD incidence rate ratios over 21 years of follow-up. Mean energy intake was 2,619 kcal; mean margarine intake was 1.8 (range 0-12) tsp per day. There were 267 incident cases of CHD. Age-adjusted CHD cumulative incidence rose over categories of margarine intake, but the increased risk was apparent only in the second half of the follow-up period. Adjusted for age and energy intake, the risk ratio for CHD for each increment of 1 teaspoon per day of margarine was 0.98 [95% confidence interval (CI) = 0.91-1.05] for the first 10 years of follow-up and 1.10 (95% CI = 1.04-1.17) for follow-up years 11-21. Adjustment for total fat intake and for cigarette smoking, glucose intolerance, left ventricular hypertrophy, body mass index, blood pressure, physical activity, and alcohol intake did not materially change the results. Butter intake did not predict CHD incidence. These data offer modest support to the hypothesis that margarine intake increases the risk of coronary heart disease.
Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease1,2,3,4,5
Patty W Siri-Tarino, Qi Sun, Frank B Hu and Ronald M Krauss
ABSTRACT
Background: A reduction in dietary saturated fat has generally been thought to improve cardiovascular health.
Objective: The objective of this meta-analysis was to summarize the evidence related to the association of dietary saturated fat with risk of coronary heart disease (CHD), stroke, and cardiovascular disease (CVD; CHD inclusive of stroke) in prospective epidemiologic studies.
Design: Twenty-one studies identified by searching MEDLINE and EMBASE databases and secondary referencing qualified for inclusion in this study. A random-effects model was used to derive composite relative risk estimates for CHD, stroke, and CVD.
Results: During 5–23 y of follow-up of 347,747 subjects, 11,006 developed CHD or stroke. Intake of saturated fat was not associated with an increased risk of CHD, stroke, or CVD. The pooled relative risk estimates that compared extreme quantiles of saturated fat intake were 1.07 (95% CI: 0.96, 1.19; P = 0.22) for CHD, 0.81 (95% CI: 0.62, 1.05; P = 0.11) for stroke, and 1.00 (95% CI: 0.89, 1.11; P = 0.95) for CVD. Consideration of age, sex, and study quality did not change the results.
Conclusions: A meta-analysis of prospective epidemiologic studies showed that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD. More data are needed to elucidate whether CVD risks are likely to be influenced by the specific nutrients used to replace saturated fat.
Received for publication March 6, 2009. Accepted for publication November 25, 2009.
Benefit-risk assessment of vitamin D supplementation.
Bischoff-Ferrari HA, Shao A, Dawson-Hughes B, Hathcock J, Giovannucci E, Willett WC.
Centre on Aging and Mobility, Department of Rheumatology and Institute of Physical Medicine, University Hospital Zurich, Gloriastrasse 25, 8091, Zurich, Switzerland, Heike.Bischoff@usz.ch.
Current intake recommendations of 200 to 600 IU vitamin D per day may be insufficient for important disease outcomes reduced by vitamin D. INTRODUCTION: This study assessed the benefit of higher-dose and higher achieved 25-hydroxyvitamin D levels [25(OH)D] versus any associated risk. METHODS AND RESULTS: Based on double-blind randomized control trials (RCTs), eight for falls (n = 2426) and 12 for non-vertebral fractures (n = 42,279), there was a significant dose-response relationship between higher-dose and higher achieved 25(OH)D and greater fall and fracture prevention. Optimal benefits were observed at the highest dose tested to date for 700 to 1000 IU vitamin D per day or mean 25(OH)D between 75 and 110 nmol/l (30-44 ng/ml). Prospective cohort data on cardiovascular health and colorectal cancer prevention suggested increased benefits with the highest categories of 25(OH)D evaluated (median between 75 and 110 nmol/l). In 25 RCTs, mean serum calcium levels were not related to oral vitamin D up to 100,000 IU per day or achieved 25(OH)D up to 643 nmol/l. Mean levels of 75 to 110 nmol/l were reached in most RCTs with 1,800 to 4,000 IU vitamin D per day without risk. CONCLUSION: Our analysis suggests that mean serum 25(OH)D levels of about 75 to 110 nmol/l provide optimal benefits for all investigated endpoints without increasing health risks. These levels can be best obtained with oral doses in the range of 1,800 to 4,000 IU vitamin D per day; further work is needed, including subject and environment factors, to better define the doses that will achieve optimal blood levels in the large majority of the population.
Med Sci Sports Exerc. 2009 Dec 4. [Epub ahead of print]
Timing Protein Intake Increases Energy Expenditure 24 Hours Post-Resistance Training.
Hackney KJ, Bruenger AJ, Lemmer JT.
1Department of Kinesiology, Michigan State University, East Lansing, MI 2Department of Kinesiology and Physical Education, University of Central Arkansas, Conway, AR 3Department of Movement Science, Grand Valley State University, Allendale, MI 4Department Exercise Science, Syracuse University, Syracuse, NY.
PURPOSE:: To determine if protein supplementation (PRO) prior to an acute bout of heavy resistance training (HRT) would influence post-exercise resting energy expenditure (REE) and the non-protein respiratory exchange ratio (RER). Hypothesis: REE would be increased and RER would be decreased up to 48 hours following timed PRO and HRT compared to carbohydrate supplementation (CHO) and HRT. METHODS:: Eight resistance-trained subjects (5M, 3W) participated in a double-blind, two trial crossover design, where REE and RER were measured (7:00am) on four consecutive days. On the second day of trial one, subjects consumed 376 KJ of either PRO (18g whey protein, 2g carbohydrate, 1.5g fat) or CHO (1g whey protein, 19g carbohydrate, 1g fat) 20 minutes prior to a single bout of HRT (9 exercises, 4 sets, 70-75% 1RM). REE and RER were measured 24 and 48 hours post-HRT. During trial two, the same protocol was followed except subjects consumed the second supplement prior to HRT. RESULTS:: Compared with baseline, REE was elevated significantly in both CHO and PRO at 24 and 48 hours post-HRT (p < 0.05). At 24 hours post-HRT, REE in response to PRO was significantly greater compared to CHO (p < 0.05). RER decreased significantly in both CHO and PRO at 24 hours post-HRT compared to baseline (p < 0.05). No differences were observed in total energy intake, macronutrient intake, or HRT volume (p > 0.05). CONCLUSION:: Timing PRO prior to HRT may be a simple and effective strategy to increase energy expenditure by elevating REE the day after HRT. Increasing REE could facilitate reductions in body fat mass and improve body composition if nutritional intake is stable.
New insight into factors that drive muscle-building stem cells
A report in the January issue of Cell Metabolism, a publication of Cell Press, provides new evidence explaining how stem cells known as satellite cells contribute to building muscles up in response to exercise. These findings could lead to treatments for reversing or improving the muscle loss that occurs in diseases such as cancer and AIDS as well as in the normal aging process, according to the researchers.
The researchers showed that a transient and local rise in an inflammatory signal, the cytokine known as interleukin-6 (IL-6), is essential for the growth of muscle fibers. The findings offer the first clear mechanism for the stem cells’ incorporation into muscle and the first evidence linking a cytokine to this process, said Pura Muñoz-Cánoves of Universitat Pompeu Fabra in Barcelona, Spain. “As we learn more about how muscles grow in adults, we may uncover new methods for restoring lost muscle mass in the elderly and ill,” she added.
Skeletal muscles are made up of individual myofibers, each with many nuclei containing genetic material. As muscles are made to work harder, they adapt by bulking up each of those individual fibers, the researchers explained, but the mechanisms responsible have largely remained elusive.
Mounting evidence has shown that the growth of myofibers is limited by the need to maintain an equilibrium between the number of nuclei and the fibers’ overall volume. Because mature myofibers are incapable of cell division, new nuclei must be supplied by satellite cells (muscle stem cells). Once activated, satellite cells follow an ordered set of events, including proliferation, migration, and incorporation into the myofiber, leading to its growth.
Now, the researchers have found that IL-6 is an essential regulator in that process. While IL-6 was virtually undetectable in the muscles of control mice, animals whose muscles were made to work harder showed an increase in IL-6 after one day. That cytokine rise was maintained for two weeks before it declined again.
Interestingly, systemically high levels of IL-6 had earlier been implicated in the muscle wasting process, Muñoz-Cánoves noted. “Having excess IL-6 is bad, but its local translation is required for muscle growth.”
The researchers further found that IL-6 was produced both within myofibers and in their associated satellite cells, leading to muscle growth. In contrast, the muscles of mice lacking IL-6 did not show any significant increase in size after several weeks of overloading. The researchers also showed that IL-6 exerts its effects by inducing the proliferation of satellite cells.
While Muñoz-Cánoves said that the findings are “just the beginning” of a new line of investigation into how adult muscle grows, she added that they might ultimately provide a new avenue for muscle-building therapies.
Source: Cell Press
“Treatments could be designed to compensate for or block the pathways leading to muscle loss,” she said. “In muscles that have already lost mass, you might also be able to stimulate muscle growth.”
Ann N Y Acad Sci. 2009 Aug;1172:54-62.
Yoga breathing, meditation, and longevity.
Columbia University College of Physicians and Surgeons, New York, New York, USA.
Yoga breathing is an important part of health and spiritual practices in Indo-Tibetan traditions. Considered fundamental for the development of physical well-being, meditation, awareness, and enlightenment, it is both a form of meditation in itself and a preparation for deep meditation. Yoga breathing (pranayama) can rapidly bring the mind to the present moment and reduce stress. In this paper, we review data indicating how breath work can affect longevity mechanisms in some ways that overlap with meditation and in other ways that are different from, but that synergistically enhance, the effects of meditation. We also provide clinical evidence for the use of yoga breathing in the treatment of depression, anxiety, post-traumatic stress disorder, and for victims of mass disasters. By inducing stress resilience, breath work enables us to rapidly and compassionately relieve many forms of suffering.
FULL TEXT HERE: http://www3.interscience.wiley.com/cgi-bin/fulltext/122580585/PDFSTART
Psychol Med. 2009 Nov 27:1-14. [Epub ahead of print]
A systematic review of neurobiological and clinical features of mindfulness meditations.
Institute of Psychiatry, University of Bologna, Italy.
BACKGROUND: Mindfulness meditation (MM) practices constitute an important group of meditative practices that have received growing attention. The aim of the present paper was to systematically review current evidence on the neurobiological changes and clinical benefits related to MM practice in psychiatric disorders, in physical illnesses and in healthy subjects.MethodA literature search was undertaken using Medline, ISI Web of Knowledge, the Cochrane collaboration database and references of retrieved articles. Controlled and cross-sectional studies with controls published in English up to November 2008 were included. RESULTS: Electroencephalographic (EEG) studies have revealed a significant increase in alpha and theta activity during meditation. Neuroimaging studies showed that MM practice activates the prefrontal cortex (PFC) and the anterior cingulate cortex (ACC) and that long-term meditation practice is associated with an enhancement of cerebral areas related to attention. From a clinical viewpoint, Mindfulness-Based Stress Reduction (MBSR) has shown efficacy for many psychiatric and physical conditions and also for healthy subjects, Mindfulness-Based Cognitive Therapy (MBCT) is mainly efficacious in reducing relapses of depression in patients with three or more episodes, Zen meditation significantly reduces blood pressure and Vipassana meditation shows efficacy in reducing alcohol and substance abuse in prisoners. However, given the low-quality designs of current studies it is difficult to establish whether clinical outcomes are due to specific or non-specific effects of MM.DiscussionDespite encouraging findings, several limitations affect current studies. Suggestions are given for future research based on better designed methodology and for future directions of investigation.
PMID: 19941676 [PubMed - as supplied by publisher]
Canada examines vitamin D for swine flu protection
By Lorraine Heller, 10-Aug-2009
Related topics: Research, Vitamins & premixes, Immune system
The Public Health Agency of Canada (PHAC) has confirmed that it will be investigating the role of vitamin D in protection against swine flu, NutraIngredients-USA.com has learned.
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The agency started a study last year on the role of vitamin D in severe seasonal influenza, which it said it will now adapt to the H1N1 swine flu virus.
“Researchers in PHAC are working with colleagues at McMaster University and with partners at other universities and hospitals to determine whether there is a correlation between severe disease and low vitamin D levels and/or a person’s genetic make up. This line of research in seasonal influenza will be adapted to H1N1,” wrote the agency in an e-mail to NutraIngredients-USA.com.
PHAC said it is testing serum samples to examine this possibility in collaboration with colleagues at the University of Toronto.
Preventing ‘severe outcomes’
Part of the researchers’ goal is to understand if vitamin D levels are in any way responsible for the fact that most people with seasonal influenza develop a mild illness but a small minority go on to develop severe symptoms.
According to PHAC, results from its study will indicate the extent and nature of the role of vitamin D in sever seasonal influenza. The agency said it would most likely take at least three influenza seasons to be able to recruit a sufficient sample size of individuals with severe disease and controls before the results can be “meaningfully” analyzed.
“If we find that there is a correlation between severe disease and vitamin D levels we shall, with our partners in the future, conduct randomized controlled studies to determine whether vitamin D can be used as a means to mitigate severe seasonal influenza,” it said.
“PHAC intends to adapt this strategy to H1N1 in order to prevent severe outcomes of infection.”
Experimental models
The agency stressed that the role of vitamin D in H1N1 is not well established. However, it added that early work in the 1940s, in experimental animal models, indicated that mice that receive diets low in vitamin D are more susceptible to experimental swine flu infection than those that receive adequate vitamin D (Young, 1946).
In addition, PHAC said that epidemiological evidence suggests a role for vitamin D in seasonal influenza in general.
“Influenza infection is correlated geographically and seasonally with levels of solar ultraviolet radiation (Cannell, 2006). Given that vitamin D is synthesisized in our skin on exposure to sunlight, low serum levels of 25(OH) vitamin D in winter months appear to correlate with the occurrence of seasonal influenza in the winter. However a direct causal relationship between low vitamin D levels and the risk of influenza remains to be proven.”
“How vitamin D might protect against influenza infection is not fully understood. However new research suggests that vitamin D induces the production of antimicrobial substances in the body that possess neutralizing activity against a variety of infectious agents including influenza virus (Doss, 2009).”
Resolvins: Current understanding and future potential in the control of inflammation.
Research on the formation of novel enzymatic oxygenation products derived from the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) has revealed the endogenous formation of several novel autacoids that have been termed resolvins and protectins. The elucidation of the chemical structures of resolvins and protectins, and the assessment of their endogenous functions, are providing a new understanding of the role of endogenous omega-3 fatty acid-derived lipid mediators in tissue protection, counteraction of inflammation and the activation of inflammation resolution. This review emphasizes the structural aspects of resolvin biosynthesis and metabolic inactivation, which are of central importance for understanding the current and future development of therapeutically relevant, stable analogs that may activate inflammation resolution.
Antioxidants prevent health-promoting effects of physical exercise in humans.
Exercise promotes longevity and ameliorates type 2 diabetes mellitus and insulin resistance. However, exercise also increases mitochondrial formation of presumably harmful reactive oxygen species (ROS). Antioxidants are widely used as supplements but whether they affect the health-promoting effects of exercise is unknown. We evaluated the effects of a combination of vitamin C (1000 mg/day) and vitamin E (400 IU/day) on insulin sensitivity as measured by glucose infusion rates (GIR) during a hyperinsulinemic, euglycemic clamp in previously untrained (n = 19) and pretrained (n = 20) healthy young men. Before and after a 4 week intervention of physical exercise, GIR was determined, and muscle biopsies for gene expression analyses as well as plasma samples were obtained to compare changes over baseline and potential influences of vitamins on exercise effects. Exercise increased parameters of insulin sensitivity (GIR and plasma adiponectin) only in the absence of antioxidants in both previously untrained (P < 0.001) and pretrained (P < 0.001) individuals. This was paralleled by increased expression of ROS-sensitive transcriptional regulators of insulin sensitivity and ROS defense capacity, peroxisome-proliferator-activated receptor gamma (PPARgamma), and PPARgamma coactivators PGC1alpha and PGC1beta only in the absence of antioxidants (P < 0.001 for all). Molecular mediators of endogenous ROS defense (superoxide dismutases 1 and 2; glutathione peroxidase) were also induced by exercise, and this effect too was blocked by antioxidant supplementation. Consistent with the concept of mitohormesis, exercise-induced oxidative stress ameliorates insulin resistance and causes an adaptive response promoting endogenous antioxidant defense capacity. Supplementation with antioxidants may preclude these health-promoting effects of exercise in humans.
http://www.pnas.org/content/early/2009/05/11/0903485106.short?rss=1
Tulkitsenko mä oikein (osittain lukeneena ja ymmärtäneenä), että jotkin antioksidandit saattaisivat estää liikunnan tuomia vaikutuksia. Liittyisikö tämä samaan mitä jostain kuulin, että keinotekoisesti tuotetut vitamiinit estäisivät kenties luonnosta ja harjoittelusta saatavia etuja.
Mikä neuvoksi, doc?:-)
Kyllä. Eli liiallinen c- ja e-vitskun nappailu käytännössä mitätöi liikunnasta saadun insuliiniherkistymisen tilan liiallisella antioksidanttivaikutuksellaan.
D-vitamiini on oikeastaan ainoa, jota ei saa ravinnosta tarpeeksi eli purkkiin täytyy turvautua ja mielellään annoskin yli 100mikrogrammaa. Muiden vitamiinien ja hivenaineiden osalta kannattaa suosia kaikkea värikästä sekä ehdottomasti ottaa joitakin “superfoodeja” mukaan ruokavalioon (itsellä mm. raaka kaakaopavut, goji-marjat, maca-jauhe sekä purple corn flour).