Dietary carbohydrate restriction as the first approach in diabetes management: critical review and evidence base.

The inability of current recommendations to control the epidemic of diabetes, the specific failure of the prevailing low-fat diets to improve obesity, cardiovascular risk, or general health and the persistent reports of some serious side effects of commonly prescribed diabetic medications, in combination with the continued success of low-carbohydrate diets in the treatment of diabetes and metabolic syndrome without significant side effects, point to the need for a reappraisal of dietary guidelines. The benefits of carbohydrate restriction in diabetes are immediate and well documented. Concerns about the efficacy and safety are long term and conjectural rather than data driven. Dietary carbohydrate restriction reliably reduces high blood glucose, does not require weight loss (although is still best for weight loss), and leads to the reduction or elimination of medication. It has never shown side effects comparable with those seen in many drugs. Here we present 12 points of evidence supporting the use of low-carbohydrate diets as the first approach to treating type 2 diabetes and as the most effective adjunct to pharmacology in type 1. They represent the best-documented, least controversial results. The insistence on long-term randomized controlled trials as the only kind of data that will be accepted is without precedent in science. The seriousness of diabetes requires that we evaluate all of the evidence that is available. The 12 points are sufficiently compelling that we feel that the burden of proof rests with those who are opposed.

Effects of oral adenosine-5'-triphosphate supplementation on athletic performance, skeletal muscle hypertrophy and recovery in resistance-trained men.

BACKGROUND: Currently, there is a lack of studies examining the effects of adenosine-5'-triphosphate (ATP) supplementation utilizing a long-term, periodized resistance-training program (RT) in resistance-trained populations. Therefore, we investigated the effects of 12 weeks of 400 mg per day of oral ATP on muscular adaptations in trained individuals. We also sought to determine the effects of ATP on muscle protein breakdown, cortisol, and performance during an overreaching cycle. METHODS: The study was a 3-phase randomized, double-blind, and placebo- and diet-controlled intervention. Phase 1 was a periodized resistance-training program. Phase 2 consisted of a two week overreaching cycle in which volume and frequency were increased followed by a 2-week taper (Phase 3). Muscle mass, strength, and power were examined at weeks 0, 4, 8, and 12 to assess the chronic effects of ATP; assessment performance variables also occurred at the end of weeks 9 and 10, corresponding to the mid and endpoints of the overreaching cycle. RESULTS: There were time (p<0.001), and group x time effects for increased total body strength (+55.3 ± 6.0 kg ATP vs. + 22.4 ± 7.1 kg placebo, p<0.001); increased vertical jump power (+ 796 ± 75 ATP vs. 614 ± 52 watts placebo, p<0.001); and greater ultrasound determined muscle thickness (+4.9 ± 1.0 ATP vs. (2.5 ± 0.6 mm placebo, p<0.02) with ATP supplementation. During the overreaching cycle, there were group x time effects for strength and power, which decreased to a greater extent in the placebo group. Protein breakdown was also lower in the ATP group. CONCLUSIONS: Our results suggest oral ATP supplementation may enhance muscular adaptations following 12-weeks of resistance training, and prevent decrements in performance following overreaching. No statistically or clinically significant changes in blood chemistry or hematology were observed. TRIAL REGISTRATION: ClinicalTrials.gov NCT01508338.

Quality protein intake is inversely related with abdominal fat.

Dietary protein intake and specifically the quality of the protein in the diet has become an area of recent interest. This study determined the relationship between the amount of quality protein, carbohydrate, and dietary fat consumed and the amount of times the ~10 g essential amino acid (EAA) threshold was reached at a meal, with percent central abdominal fat (CAF). Quality protein was defined as the ratio of EAA to total dietary protein. Quality protein consumed in a 24-hour period and the amount of times reaching the EAA threshold per day was inversely related to percent CAF, but not for carbohydrate or dietary fat. In conclusion, moderate to strong correlations between variables indicate that quality and distribution of protein may play an important role in regulating CAF, which is a strong independent marker for disease and mortality.

Protein hydrolysates in sports nutrition.

It has been suggested that protein hydrolysates providing mainly di- and tripeptides are superior to intact (whole) proteins and free amino acids in terms of skeletal muscle protein anabolism. This review provides a critical examination of protein hydrolysate studies conducted in healthy humans with special reference to sports nutrition. The effects of protein hydrolysate ingestion on blood amino acid levels, muscle protein anabolism, body composition, exercise performance and muscle glycogen resynthesis are discussed.

Acute and timing effects of beta-hydroxy-beta-methylbutyrate (HMB) on indirect markers of skeletal muscle damage.

BACKGROUND: While chronic ß-Hydroxy ß-Methylbutyrate (HMB) supplementation (≥ 2 wk) lowers exercise induced muscle damage, its acute or timing effects have not been examined. The purpose of this study was to investigate the acute and timing effects of oral HMB supplementation on serum creatine kinase (CK), lactate dehydrogenase (LDH), muscle soreness, and maximal voluntary contraction (MVC). METHODS: Sixteen non-resistance trained men (22 ± 2 yrs) were assigned to HMB-Pre or HMB-Post groups. In a crossover design, all subjects performed 55 maximal eccentric knee extension/flexion contractions on 2 occasions on either the right or left leg. HMB-Pre (N = 8) randomly received 3 grams of either a placebo or HMB before and a placebo after exercise. HMB-Post (N = 8) received a placebo before and either 3 grams of HMB or a placebo after exercise. Muscle damage tests were recorded before, at 8, 24, 48, and 72 hrs post exercise. RESULTS: There was a reduction in MVC and an increase in soreness in the quadriceps and hamstrings following exercise (p < 0.001). Although HMB-Pre approached significance in attenuating soreness for the quadriceps (p = 0.07), there was no time x group effect. Serum indices of damage increased, peaking at 48 hrs for CK (773%) (p < 0.001) and 72 hrs for LDH (180%) (p < 0.001). While there were no time x group effects of HMB on CK and LDH, post hoc analysis revealed that only HMB-Pre showed no significant increase in LDH levels following exercise. CONCLUSION: Our findings suggest no clear acute or timing effects of HMB supplementation. However, consuming HMB before exercise appeared to prevent increases in LDH.

Dietary carbohydrate restriction in type 2 diabetes mellitus and metabolic syndrome: time for a critical appraisal.

Current nutritional approaches to metabolic syndrome and type 2 diabetes generally rely on reductions in dietary fat. The success of such approaches has been limited and therapy more generally relies on pharmacology. The argument is made that a re-evaluation of the role of carbohydrate restriction, the historical and intuitive approach to the problem, may provide an alternative and possibly superior dietary strategy. The rationale is that carbohydrate restriction improves glycemic control and reduces insulin fluctuations which are primary targets. Experiments are summarized showing that carbohydrate-restricted diets are at least as effective for weight loss as low-fat diets and that substitution of fat for carbohydrate is generally beneficial for risk of cardiovascular disease. These beneficial effects of carbohydrate restriction do not require weight loss. Finally, the point is reiterated that carbohydrate restriction improves all of the features of metabolic syndrome.

Effects of beta-hydroxy-beta-methylbutyrate (HMB) on exercise performance and body composition across varying levels of age, sex, and training experience: A review.

The leucine metabolite beta-hydroxy-beta-methylbutyrate (HMB) has been extensively used as an ergogenic aid; particularly among bodybuilders and strength/power athletes, who use it to promote exercise performance and skeletal muscle hypertrophy. While numerous studies have supported the efficacy of HMB in exercise and clinical conditions, there have been a number of conflicting results. Therefore, the first purpose of this paper will be to provide an in depth and objective analysis of HMB research. Special care is taken to present critical details of each study in an attempt to both examine the effectiveness of HMB as well as explain possible reasons for conflicting results seen in the literature. Within this analysis, moderator variables such as age, training experience, various states of muscle catabolism, and optimal dosages of HMB are discussed. The validity of dependent measurements, clustering of data, and a conflict of interest bias will also be analyzed. A second purpose of this paper is to provide a comprehensive discussion on possible mechanisms, which HMB may operate through. Currently, the most readily discussed mechanism has been attributed to HMB as a precursor to the rate limiting enzyme to cholesterol synthesis HMG-coenzyme A reductase. However, an increase in research has been directed towards possible proteolytic pathways HMB may operate through. Evidence from cachectic cancer studies suggests that HMB may inhibit the ubiquitin-proteasome proteolytic pathway responsible for the specific degradation of intracellular proteins. HMB may also directly stimulate protein synthesis, through an mTOR dependent mechanism. Finally, special care has been taken to provide future research implications.

Protein hydrolysates in sports and exercise: a brief review.

Protein can be hydrolyzed, producing small chains of amino acids called peptides. Several studies have shown that protein hydrolysates containing mostly di- and tripeptides are absorbed more rapidly than free form amino acids and much more rapidly than intact proteins. In addition, there is recent evidence that protein hydrolysate ingestion has strong insulinotropic effect. Thus, recovery sports drinks containing protein hydrolysates may be of great value. Key PointsProtein hydrolysates containing mostly di- and tripeptides are absorbed more rapidly than free form amino acids and much more rapidly than intact proteins.Oral intake of protein hydrolysates and amino acids in combination with carbohydrates can result in an insulinotropic effect as much as 100% greater than with the intake of carbohydrates only.Recovery sports drinks containing protein hydrolysates and insulinotropic amino acids may be of great value, but more research is needed before firm conclusions can be drawn.

A statement of the american heart association nutrition committee on dietary protein and weight reduction: a rigorous rebuttal.

Results of several recent studies show that high-protein, low-carbohydrate weight loss diets indeed have their benefits. However, there are always some concerns about high-protein diets. According to the American Heart Association (AHA) Nutrition Committee, highprotein diets may possess significant health risks. The purpose of this review is to evaluate the scientific validity of AHA Nutrition CommitteeA s statement on dietary protein and weight reduction (St. Jeor ST et al. Circulation 2001;104:1869-1874). Simply stated, there is little if any scientific evidence supporting above mentioned statement. Certainly, such public warnings should be based on a thorough analysis of the scientific literature, not unsubstantiated fears and misrepresentations. For individuals with normal renal function, the risks are minimal and must be balanced against the real and established risk of continued obesity.