The efficacy of acetic acid for glycogen repletion in rat skeletal muscle after exercise

The improvement effect of apple cider vinegar as a functional food on anthropometric indices, blood glucose and lipid profile in diabetic patients: a randomized controlled clinical trial

Background

Numerous medical costs are spent each year on treating and preventing the progression of diabetes. The positive effect of apple cider vinegar (ACV) has been shown on post-prandial hyperglycemia. This study aimed to evaluate the effects of prolonged consumption of ACV on blood glucose indices and lipid profile in patients with type 2 diabetes.

Methods

This study was a randomized clinical trial and the participants were adults with type 2 diabetes. Participants were divided into two groups: ACV and control. The ACV group was treated with 30 ml of ACV per day. Both the intervention and control groups received the same recommendation for a healthy diet. Before and after eight weeks, fasting blood glucose, insulin, hemoglobin A1C, insulin resistance, total cholesterol (Chol), low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglyceride were measured.

Results

Fasting blood glucose decreased after intervention in both groups, which was only significant in the ACV group (p = 0.01). There was a significant difference in hemoglobin A1C levels between the two groups (p < 0.001) after eight weeks. LDL was decreased in the ACV group (p < 0.001). Total Chol, LDL/HDL and Chol/HDL ratio decreased after the intervention period in the ACV group compared to the control group (p = 0.003, p = 0.001 and p = 0.001, respectively).

Conclusion

Daily consumption of ACV may have beneficial effects in controlling blood glucose indices and lipid profile in patients with type 2 diabetes.

Clinical trial registration

http://www.irct.ir, identifier IRCT20140107016123N13.

Bioactivity and Pharmacological Potential of Date Palm (Phoenix dactylifera L.) Against Pandemic COVID-19: a Comprehensive Review

A novel coronavirus disease (COVID-19) or severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2), transmitted from person to person, has quickly emerged as the pandemic responsible for the current global health crisis. This infection has been declared a global pandemic, resulting in a concerning number of deaths as well as complications post-infection, primarily among vulnerable groups particularly older people and those with multiple comorbidities. In this article, we review the most recent research on the role of date palm (Phoenix dactylifera L.) fruits (DPFs) to prevent or treat COVID-19 infection. The mechanisms underlying this preventive or therapeutic effect are also discussed in terms of bioactivity potentials in date palm, e.g., antimicrobial, antioxidant, anticancer, anti-diabetic, anti-inflammatory, neuroprotective, and hemolytic potential, as well as prospect against COVID-19 disease and the potential product development. Therefore, it can be concluded that regular consumption of DPFs may be associated with a lower risk of some chronic diseases. Indeed, DPFs have been widely used in folk medicine since ancient times to treat a variety of health conditions, demonstrating the importance of DPFs as a nutraceutical and source of functional nourishment. This comprehensive review aims to summarize the majority of the research on DPFs in terms of nutrient content and biologically active components such as phenolic compounds, with an emphasis on their roles in improving overall health as well as the potential product development to ensure consumers’ satisfaction in a current pandemic situation. In conclusion, DPFs can be given to COVID-19 patients as a safe and effective add-on medication or supplement in addition to routine treatments.

Oligofructose-Enriched Inulin Intake, Gut Microbiome Characteristics, and the V̇O2 Peak Response to High-Intensity Interval Training in Healthy Inactive Adults

BACKGROUND

The gut microbiome has been associated with cardiorespiratory fitness.

OBJECTIVES

To assess the effects of oligofructose (FOS)-enriched inulin supplementation on the gut microbiome and the peak oxygen uptake (V̇O2peak) response to high-intensity interval training (HIIT).

METHODS

The study was a randomized controlled trial. Forty sedentary and apparently healthy adults [n = 31 women; aged 31.8 ± 9.8 y, BMI (in kg⋅m-2) 25.9 ± 4.3] were randomly allocated to 1) 6 wk of supervised HIIT (4 × 4-min bouts at 85-95% peak heart rate, interspersed with 3 min of active recovery, 3·wk-1) + 12 g·d-1 of FOS-enriched inulin (HIIT-I) or 2) 6 wk of supervised HIIT (3·wk-1, 4 × 4-min bouts) + 12 g·d-1 of maltodextrin/placebo (HIIT-P). Each participant completed an incremental treadmill test to assess V̇O2peak and ventilatory thresholds (VTs), provided a stool and blood sample, and completed a 24-h diet recall questionnaire and FFQ before and after the intervention. Gut microbiome analyses were performed using metagenomic sequencing. Fecal short-chain fatty acids were measured by mass spectrometry.

RESULTS

There were no differences in the mean change in V̇O2peak response between groups (P = 0.58). HIIT-I had a greater improvement in VTs than HIIT-P [VT1 (lactate accumulation): mean difference + 4.3% and VT2 (lactate threshold): +4.2%, P < 0.05]. HIIT-I had a greater increase in the abundance of Bifidobacterium taxa [false discovery rate (FDR) < 0.05] and several metabolic processes related to exercise capacity (FDR < 0.05). Exploratory analysis of merged data found participants with a greater response to HIIT (V̇O2peak ≥3.5 mL⋅kg-1⋅min-1) had a 2.2-fold greater mean abundance of gellan degradation pathways (FDR < 0.05) and a greater, but not significant, abundance of Bifidobacterium uniformis species (P < 0.00023, FDR = 0.08).

CONCLUSIONS

FOS-enriched inulin supplementation did not potentiate HIIT-induced improvements in V̇O2peak but led to gut microbiome changes possibly associated with greater ventilatory threshold improvements in healthy inactive adults. Gellan degradation pathways and B. uniformis spp. were associated with greater V̇O2peak responses to HIIT.

Potentials and Safety of Date Palm Fruit against Diabetes: A Critical Review

Diabetes is a chronic metabolic disorder triggered by disturbances in carbohydrate, protein, and lipid metabolisms, where either reduced secretion or sensitivity of insulin is observed coupled with poor glucose control. Date palm fruits are one of the fruits reported to have good potential in diabetes treatment due to its presence of polyphenols exerting strong antioxidant activities. Other possible mechanisms of action include the polyphenolic compounds, which can inhibit enzymes like α-amylase and α-glucosidase. Flavonoids in dates can stimulate β-cells by increasing the number of islets and β-cells, recovering endocrine pancreatic tissues, reducing β-cell apoptosis, activating insulin receptors following the increase in insulin secretion, in addition to improving diabetes-induced complications. In this review, the in vitro, in vivo, and human study-based evidence of date palm as an anti-diabetic fruit is summarised.

The Effect of Vinegar Supplementation on High-Intensity Cycling Performance within Recreationally Trained Individuals

Background and objectives: To investigate the effects of vinegar ingestion upon high-intensity cycle performance in recreationally trained individuals. Materials and methods: Twenty-two participants consumed one of the following in a randomized order on four separate visits: (1) 29 mL of vinegar along with 451 mL of water, (2) 39 g of sucrose along with 441 mL of water, (3) 29 mL of vinegar and 39 g of sucrose along with 412 mL of water, or (4) 480 mL of water alone. For each of the experimental testing sessions, all participants completed in order: (1) high-intensity cycle test 1, (2) fatiguing cycle test, (3) high-intensity cycle test 2, (4) supplement consumption, (5) 90 min rest period, and (6) high-intensity cycle test 3. Total time to exhaustion (TTE) and average heart rate (HR) for each set of sprints was used in analysis. Results: There was no supplement by time interaction or significant main treatment effect observed (p > 0.05) for either TTE or HR. However, there was a main time effect observed, with TTE (p = 0.0001) being lower for cycle test 2 than both cycle test 1 and cycle test 3, and cycle test 3 being lower than cycle test 1. HR (p = 0.0001) was lower for cycle test 3 than both cycle test 1 and cycle test 2, but HR for cycle test 1 did not differ significantly from HR for cycle test 2. Conclusions: The addition of vinegar or sucrose alone, or in combination, was ineffective in improving cycle sprinting TTE when performing three cycle tests.

Anti-Fatigue Effect of Prunus Mume Vinegar in High-Intensity Exercised Rats

Nowadays, new types of vinegar have been developed using various raw materials and biotechnological processes. The fruit of Prunus mume has been extensively distributed in East Asia and used as a folk medication for fatigue. In this study, the Prunus mume vinegar (PV) was produced by a two-step fermentation and was evaluated for its anti-fatigue activity by C2C12 myoblasts and high-intensity exercised rats. The administration of PV significantly improved running endurance and glycogen accumulation in the liver and muscle of PV supplemented rats compared to sedentary and exercised control groups. In addition, PV supplementation elicited lower fatigue-related serum biomarkers, for instance, ammonia, inorganic phosphate, and lactate. PV administered rats exhibited higher lactate dehydrogenase activity and glutathione peroxidase activity, and lower creatine kinase activity and malondialdehyde levels. Furthermore, phenolic compounds in PV were identified using HPLC analysis. The phenolic acids analyzed in PV were protocatechuic acid, syringic acid, chlorogenic acid, and its derivates. These results indicate that the administration of PV with antioxidative property contributes to the improvement of fatigue recovery in exhausted rats. The findings of this study suggest that the PV containing various bioactive constituents can be used as a functional material against fatigue caused by high-intensity exercise.

Effects of high-fiber diets enriched with carbohydrate, protein, or unsaturated fat on circulating short chain fatty acids: results from the OmniHeart randomized trial

BACKGROUND

Short chain fatty acids (SCFAs; e.g., acetate, propionate, and butyrate) are produced by microbial fermentation of fiber in the colon. Evidence is lacking on how high-fiber diets that differ in macronutrient composition affect circulating SCFAs.

OBJECTIVES

We aimed to compare the effects of 3 high-fiber isocaloric diets differing in %kcal of carbohydrate, protein, or unsaturated fat on circulating SCFAs. Based on previous literature, we hypothesized that serum acetate, the main SCFA in circulation, increases on all high-fiber diets, but differently by macronutrient composition of the diet.

METHODS

OmniHeart is a randomized crossover trial of 164 men and women (≥30 y old); 163 participants with SCFA data were included in this analysis. We provided participants 3 isocaloric high-fiber (∼30 g/2100 kcal) diets, each for 6 wk, in random order: a carbohydrate-rich (Carb) diet, a protein-rich (Prot) diet (protein predominantly from plant sources), and an unsaturated fat-rich (Unsat) diet. We used LC-MS to quantify SCFA concentrations in fasting serum, collected at baseline and the end of each diet period. We fitted linear regression models with generalized estimating equations to examine change in ln-transformed SCFAs from baseline to the end of each diet; differences between diets; and associations of changes in SCFAs with cardiometabolic parameters.

RESULTS

From baseline, serum acetate concentrations were increased by the Prot (β: 0.24; 95% CI: 0.12, 0.35), Unsat (β: 0.21; 95% CI: 0.10, 0.33), and Carb (β: 0.12; 95% CI: 0.01, 0.24) diets; between diets, only Prot compared with Carb was significant (P = 0.02). Propionate was decreased by the Carb (β: -0.10; 95% CI: -0.16, -0.03) and Unsat (β: -0.10; 95% CI: -0.16, -0.04) diets, not the Prot diet; between diet comparisons of Carb vs. Prot (P = 0.006) and Unsat vs. Prot (P = 0.002) were significant. The Prot diet increased butyrate (β: 0.05; 95% CI: 0.00, 0.09) compared with baseline, but not compared with the other diets. Increases in acetate were associated with decreases in insulin and glucose; increases in propionate with increases in leptin, LDL cholesterol, and blood pressure; and increases in butyrate with increases in insulin and glucose, and decreases in HDL cholesterol and ghrelin (Ps < 0.05).

CONCLUSIONS

Macronutrient composition of high-fiber diets affects circulating SCFAs, which are associated with measures of appetite and cardiometabolic health. This trial was registered at clinicaltrials.gov as NCT00051350.

Sodium Butyrate Improves Liver Glycogen Metabolism in Type 2 Diabetes Mellitus

Liver plays a central role in modulating blood glucose level. Our most recent findings suggested that supplementation with microbiota metabolite sodium butyrate (NaB) could ameliorate progression of type 2 diabetes mellitus (T2DM) and decrease blood HbA1c in db/db mice. To further investigate the role of butyrate in homeostasis of blood glucose and glycogen metabolism, we carried out the present study. In db/db mice, we found significant hypertrophy and steatosis in hepatic lobules accompanied by reduced glycogen storage, and expression of GPR43 was significantly decreased by 59.38 ± 3.33%; NaB administration significantly increased NaB receptor G-protein coupled receptor 43 (GPR43) level and increased glycogen storage in both mice and HepG2 cells. Glucose transporter 2 (GLUT2) and sodium-glucose cotransporter 1 (SGLT1) on cell membrane were upregulated by NaB. The activation of intracellular signaling Protein kinase B (PKB), also known as AKT, was inhibited while glycogen synthase kinase 3 (GSK3) was activated by NaB in both in vivo and in vitro studies. The present study demonstrated that microbiota metabolite NaB possessed beneficial effects on preserving blood glucose homeostasis by promoting glycogen metabolism in liver cells, and the GPR43-AKT-GSK3 signaling pathway should contribute to this effect.

The effect of apple vinegar consumption on glycemic indices, blood pressure, oxidative stress, and homocysteine in patients with type 2 diabetes and dyslipidemia: A randomized controlled clinical trial

BACKGROUND

Some foods and drinks contain special ingredients, causing impressive effects on human health. The aim of the current study was to assess the health effects of apple vinegar in patients with diabetes and dyslipidemia.

METHOD

Seventy participants with type 2 diabetes and hyperlipidemia were randomly assigned into an intervention and control group in order to assess the effect of 20 ml apple vinegar per day using an 8-week parallel study. Fasting blood sugar (FBS), homeostasis model assessment for insulin resistance (HOMA-IR), homeostasis model assessment for b-cell function (HOMA-B), quantitative insulin sensitivity checks index (QUICKI), insulin, malondialdehyde (MDA), 2,20-Diphenyl-1- picrylhydrazyl (DPPH), homocysteine, systolic blood pressure (SBP), and diastolic blood pressure (DBP) were measured at the beginning and end of the study.

RESULTS

The intervention with apple vinegar could significantly improve FBS (mean change: -10.16 ± 19.48 mg/dl, p = 0.006) and DPPH (mean change: 16.58 ± 11.56, p < 0.001) within intervention group and in comparison with control group (p < 0.001). Additionally, the significant increase of MDA in control group (p < 0.05) caused a considerable difference between two groups. Glycemic indices containing insulin, HOMA-IR, HOMA-B, and QUICKI decrease significantly in both groups (p < 0.05). No considerable effect was observed on blood pressure and homocysteine in intervention group as well as control group.

CONCLUSION

This trial provided some evidences that apple vinegar consumption may cause beneficial effects on glycemic indices and oxidative stress in individuals with diabetes and dyslipidemia. This randomized clinical trial was registered in the Iranian Registry of Clinical Trials (https://www.irct.ir/) as 2013070710826N5.

Vinegar (acetic acid) intake on glucose metabolism: A narrative review

Vinegar intake is considered a food item that improves blood glucose in humans. This review aimed to discuss studies that investigated the impact of vinegar intake on the glycemic profile in humans and the putative mechanistic cellular pathways in both human and animal models. A search of literature was performed on the Cochrane, MEDLINE and Web of Science databases for articles published between 1995 and 2018. There is considerable support for vinegar having a positive acute effect on blood glucose levels when combined with carbohydrate-rich meals. Conversely, there are few chronic interventions analyzing the impact of vinegar intake on blood glucose. Based on available evidence, we hypothesize three pathways by which vinegar may improve blood glucose: The inhibition of α-amylase action; increased glucose uptake; and mediation by transcription factors. When evaluating the current body of literature, daily vinegar intake in amounts of ∼10-30 mL (∼2-6 tablespoons) appear to improve the glycemic response to carbohydrate-rich meals; however, there is a paucity of studies investigating chronic effects of vinegar intake.

Daily red wine vinegar ingestion for eight weeks improves glucose homeostasis and affects the metabolome but does not reduce adiposity in adults

This is the first study to investigate the effects of vinegar on adiposity and glycemia using both anthropometrics and metabolomics.

Acetic acid enhances endurance capacity of exercise-trained mice by increasing skeletal muscle oxidative properties

Acetic acid has been shown to promote glycogen replenishment in skeletal muscle during exercise training. In this study, we investigated the effects of acetic acid on endurance capacity and muscle oxidative metabolism in the exercise training using in vivo mice model. In exercised mice, acetic acid induced a significant increase in endurance capacity accompanying a reduction in visceral adipose depots. Serum levels of non-esterified fatty acid and urea nitrogen were significantly lower in acetic acid-fed mice in the exercised mice. Importantly, in the mice, acetic acid significantly increased the muscle expression of key enzymes involved in fatty acid oxidation and glycolytic-to-oxidative fiber-type transformation. Taken together, these findings suggest that acetic acid improves endurance exercise capacity by promoting muscle oxidative properties, in part through the AMPK-mediated fatty acid oxidation and provide an important basis for the application of acetic acid as a major component of novel ergogenic aids.

Kibizu concentrated liquid suppresses the accumulation of lipid droplets in 3T3-L1 cells

Adipocyte size is closely related to the occurrence of diabetes, metabolic syndrome, and insulin resistance. Thus, researchers are searching for active substances that function to reduce adipocyte size. In the present study, we focused on sugar cane vinegar, Kibizu, and evaluated the function of Kibizu to reduce adipocyte size by using an in vitro model system, because people in Amami Oshima famous for longevity regularly consume Kibizu. Results showed that Kibizu treatment significantly reduced the size and number of lipid droplets in 3T3-L1 cells, relative to treatment with Kurozu, another traditional vinegar. Results of an extraction experiment suggest that the active components in Kibizu are lipophilic and hydrophobic. In addition, an in vivo experiment on rats treated with Kibizu showed that the active components were contained in large vein blood. Results of an additional in vivo experiment suggest that metabolites generated by Kibizu-treated rats are primarily contained or modified specifically in the large vein blood.

The role of acetic acid on glucose uptake and blood flow rates in the skeletal muscle in humans with impaired glucose tolerance

BACKGROUND/OBJECTIVES

Previous studies support the glucose-lowering effect of vinegar. However, the effect of vinegar on muscle glucose metabolism and endothelial function has not been studied in humans. This open, randomized, crossover, placebo-controlled study aims to investigate the effects of vinegar on muscle glucose metabolism, endothelial function and circulating lipid levels in subjects with impaired glucose tolerance (IGT) using the arteriovenous difference technique.

SUBJECTS/METHODS

Eight subjects with IGT (4 males, age 46±10 years, body mass index 30±5) were randomised to consume 0.50 mmol vinegar (6% acetic acid) or placebo before a mixed meal. Plasma samples were taken for 300 min from the radial artery and the forearm vein for measurements of glucose, insulin, triglycerides, non-esterified fatty acids (NEFAs) and glycerol. Muscle blood flow was measured with strain gauge plethysmography. Glucose flux was calculated as the arteriovenous difference of glucose multiplied by the blood flow rates.

RESULTS

Vinegar compared with placebo: (1) decreased arterial plasma insulin (Poverall<0.001; P75 min=0.014, β=-42), (2) increased forearm blood flow (Poverall<0.001; P240 min=0.011, β=1.53; P300 min=0.023, β=1.37), (3) increased muscle glucose uptake (Poverall<0.001; P60 min=0.029, β=2.78) and (4) decreased arterial plasma triglycerides (Poverall=0.005; P240 min<0.001, β=-344; P300 min<0.001, β=-373), without changing NEFA and glycerol.

CONCLUSIONS

In individuals with IGT, vinegar ingestion before a mixed meal results in an enhancement of muscle blood flow, an improvement of glucose uptake by the forearm muscle and a reduction of postprandial hyperinsulinaemia and hypertriglyceridaemia. From this point of view, vinegar may be considered beneficial for improving insulin resistance and metabolic abnormalities in the atherogenic prediabetic state.

Vinegar Consumption Increases Insulin-Stimulated Glucose Uptake by the Forearm Muscle in Humans with Type 2 Diabetes

BACKGROUND AND AIMS

Vinegar has been shown to have a glucose-lowering effect in patients with glucose abnormalities. However, the mechanisms of this effect are still obscure. The aim of this randomised, crossover study was to investigate the effect of vinegar on glucose metabolism in muscle which is the most important tissue for insulin-stimulated glucose disposal.

MATERIALS AND METHODS

Eleven subjects with DM2 consumed vinegar or placebo (at random order on two separate days, a week apart), before a mixed meal. Plasma glucose, insulin, triglycerides, nonesterified fatty acids (NEFA), and glycerol were measured preprandially and at 30-60 min for 300 min postprandially from the radial artery and from a forearm vein. Muscle blood flow was measured with strain-gauge plethysmography. Glucose uptake was calculated as the arteriovenous difference of glucose multiplied by blood flow.

RESULTS

Vinegar compared to placebo (1) increased forearm glucose uptake (p = 0.0357), (2) decreased plasma glucose (p = 0.0279), insulin (p = 0.0457), and triglycerides (p = 0.0439), and (3) did not change NEFA and glycerol.

CONCLUSIONS

In DM2 vinegar reduces postprandial hyperglycaemia, hyperinsulinaemia, and hypertriglyceridaemia without affecting lipolysis. Vinegar's effect on carbohydrate metabolism may be partly accounted for by an increase in glucose uptake, demonstrating an improvement in insulin action in skeletal muscle. This trial is registered with Clinicaltrials.gov NCT02309424.

Effect and mechanisms of action of vinegar on glucose metabolism, lipid profile, and body weight

The aim of this review is to summarize the effects of vinegar on glucose and lipid metabolism. Several studies have demonstrated that vinegar can help reduce hyperglycemia, hyperinsulinemia, hyperlipidemia, and obesity. Other studies, however, have shown no beneficial effect on metabolism. Several mechanisms have been proposed to explain these metabolic effects, including delayed gastric emptying and enteral absorption, suppression of hepatic glucose production, increased glucose utilization, upregulation of flow-mediated vasodilation, facilitation of insulin secretion, reduction in lipogenesis, increase in lipolysis, stimulation of fecal bile acid excretion, increased satiety, and enhanced energy expenditure. Although some evidence supports the use of vinegar as a complementary treatment in patients with glucose and lipid abnormalities, further large-scale long-term trials with impeccable methodology are warranted before definitive health claims can be made.

Effects of Kurozu concentrated liquid on adipocyte size in rats

Background

Kurozu concentrated liquid (KCL) is used as a health-promoting supplement for the treatment of disorders such as cancer, hyperlipidemia, and hypertension in Japan. We investigated the possible anti-obesity effects of KCL in rats.

Methods

Male Sprague Dawley rats were fed American Institute of Nutrition 76 formula diet and were orally administrated KCL or acetic acid at a dose of 100 mg/kg body weight or deionized water for 4 weeks. Adipocyte size, DNA content in subcutaneous adipose tissue, lipid levels in the serum and liver, and the rate of fatty acid excretion were determined. Effects of KCL on pancreatic lipase activity and 3T3-L1 preadipocyte differentiation were investigated in vitro.

Results

In the KCL group, the average adipocyte size in subcutaneous and perirenal adipose tissues was significantly reduced. The KCL-administered rats displayed greater numbers of small adipocytes in the subcutaneous, perirenal and mesenteric adipose tissues than did rats from the other groups. In the KCL group, the DNA content in subcutaneous adipose tissue was significantly increased. The rate of fatty acid excretion was significantly increased in the KCL group. Furthermore, KCL significantly inhibited pancreatic lipase activity in vitro, and also significantly inhibited fat accumulation and mRNA expression of fatty acid binding protein 2 (aP2) and peroxisome proliferator-activated γ (PPARγ) in 3T3-L1 preadipocyte. The levels of serum and liver lipids, the concentration of serum glucose, and the levels of adiponectin were similar among the 3 groups.

Conclusion

Oral administration of KCL decreases the adipocyte size via inhibition of dietary fat absorption and reductions of PPARγ and aP2 mRNA expression levels in adipocytes.

Nutritional aspects of post exercise skeletal muscle glycogen synthesis in horses: a comparative review

Carbohydrate (CHO) stored in the form of skeletal muscle glycogen is the main energy source for glycolytic and oxidative ATP production during vigorous exercise in mammals. In man, horse and dog both short-term high intensity and prolonged submaximal exercise deplete muscle glycogen. In horses, however, muscle glycogen synthesis is 2-3-fold slower than in man and rat, even when a diet high in soluble CHO is fed. There appear to be significant differences in CHO and glycogen metabolism between horses and other mammals, and it is becoming increasingly clear that many conclusions drawn from human exercise physiology do not apply to horses. This review aims to provide a comprehensive, comparative summary of the research on muscle glycogen synthesis in horse, man and rodent. Species differences in CHO uptake and utilisation are examined and the issues with feeding high soluble CHO diets to horses are discussed. Alternative feeding strategies, including protein and long and short chain fatty acid supplementation and the importance of rehydration, are explored.

Vinegar lacks antiglycemic action on enteral carbohydrate absorption in human subjects

The antiglycemic effects of vinegar have been known for more than a century and have been demonstrated in animal as well as human studies. Although the exact mechanism of vinegar action is not known, several possibilities have been proposed including suppression of disaccharidase activity, delayed gastric emptying, enhanced glucose uptake in the periphery and conversion to glycogen, and increased satiety. We hypothesized that by suppressing endogenous insulin secretion, we could estimate the glucose absorption rate from an oral carbohydrate load and determine the effects of vinegar ingestion on this rate. To do so, 5 subjects had 4 studies at 1-week intervals, randomly receiving placebo twice (60 mL water) and vinegar twice (20 mL apple cider vinegar, 40 mL water), followed 2 minutes later by a meal of mashed potatoes (0.75 g carbohydrate per kilogram body weight) that was consumed over 20 minutes. At the beginning of the meal, an oral octreotide/insulin suppression test (25-microg bolus octreotide; 180 minute infusion 5 mU/m(2) body surface area per minute regular human insulin, and 0.5 microg/min octreotide) was begun. Blood samples for insulin and glucose were drawn at 20-minute intervals. The oral octreotide/insulin suppression test suppressed endogenous insulin secretion for the first 100 minutes of the study. During this time, the rate of rise of glucose was modestly but significantly (P = .01) greater after vinegar ingestion compared to placebo, suggesting that vinegar does not act to decrease glycemia by interference with enteral carbohydrate absorption.

Oral acetate supplementation after prolonged moderate intensity exercise enhances early muscle glycogen resynthesis in horses

Oral acetate supplementation enhances glycogen synthesis in some mammals. However, while acetate is a significant energy source for skeletal muscle at rest in horses, its effects on glycogen resynthesis are unknown. We hypothesized that administration of an oral sodium acetate-acetic acid solution with a typical grain and hay meal after glycogen-depleting exercise would result in a rapid appearance of acetate in blood with rapid uptake by skeletal muscle. It was further hypothesized that acetate taken up by muscle would be converted to acetyl CoA (and acetylcarnitine), which would be metabolized to CO2 and water via the tricarboxylic acid cycle, generating ATP within the mitochondria and thereby allowing glucose taken up by muscle to be preferentially incorporated into glycogen. Gluteus medius biopsies and jugular venous blood were sampled from nine exercise-conditioned horses on two separate occasions, at rest and for 24 h following a competition exercise test (CET) designed to simulate the speed and endurance test of a 3 day event. After the CETs, horses were allowed water ad libitum and either 8 l of a hypertonic sodium acetate-acetic acid solution via nasogastric gavage followed by a typical hay-grain meal (acetate treatment) or a hay-grain meal alone (control treatment). The CET significantly decreased muscle glycogen concentration by 21 and 17% in the acetate and control treatments, respectively. Acetate supplementation resulted in a rapid and sustained increase in plasma [acetate]. Skeletal muscle [acetyl CoA] and [acetylcarnitine] were increased at 4 h of recovery in the acetate treatment, suggesting substantial tissue extraction of the supplemented acetate. Acetate supplementation also resulted in an enhanced rate of muscle glycogen resynthesis during the initial 4 h of the recovery period compared with the control treatment; however, by 24 h of recovery there was no difference in glycogen replenishment between trials. It is concluded that oral acetate could be an alternative energy source in the horse.

Preliminary evidence that regular vinegar ingestion favorably influences hemoglobin A1c values in individuals with type 2 diabetes mellitus

This report examined whether daily acetic acid ingestion as vinegar, dill pickle, or commercial vinegar pill influenced hemoglobin A1c in diabetic patients. Hemoglobin A1c values fell 0.16% with vinegar use but rose 0.06% and 0.22% for pill and pickle use respectively (p=0.018). Hence, regular vinegar use modestly improved glycemic control.

Dietary acetic acid reduces serum cholesterol and triacylglycerols in rats fed a cholesterol-rich diet

To investigate the efficacy of the intake of vinegar for prevention of hyperlipidaemia, we examined the effect of dietary acetic acid, the main component of vinegar, on serum lipid values in rats fed a diet containing 1% (w/w) cholesterol. Animals were allowed free access to a diet containing no cholesterol, a diet containing 1% cholesterol without acetic acid, or a diet containing 1% cholesterol with 0·3% (w/w) acetic acid for 19 d. Then, they were killed after food deprivation for 7 h. Cholesterol feeding increased serum total cholesterol and triacylglycerol levels. Compared with the cholesterol-fed group, the cholesterol and acetic acid-fed group had significantly lower values for serum total cholesterol and triacylglycerols, liver ATP citrate lyase (ATP-CL) activity, and liver 3-hydroxy-3-methylglutaryl-CoA content as well as liver mRNA levels of sterol regulatory element binding protein-1, ATP-CL and fatty acid synthase (P<,0·05). Further, the serum secretin level, liver acyl-CoA oxidase expression, and faecal bile acid content were significantly higher in the cholesterol and acetic acid-fed group than in the cholesterol-fed group (P<0·05). However, acetic acid feeding affected neither the mRNA level nor activity of cholesterol 7a-hydroxylase. In conclusion, dietary acetic acid reduced serum total cholesterol and triacylglycerol: first due to the inhibition of lipogenesis in liver; second due to the increment in faecal bile acid excretion in rats fed a diet containing cholesterol.

Effect of acetic acid feeding on the circadian changes in glycogen and metabolites of glucose and lipid in liver and skeletal muscle of rats

The aim of the present study is to investigate the effect of acetic acid feeding on the circadian changes in glycogen concentration in liver and skeletal muscle. Rats were provided meal once daily (09.00–13.00 hours) for 10d. On the 11th day, they were either killed immediately or given 9g diet containing either 0 (control) or 0·7g/kg-diet acetic acid beginning at 09.00 hours for 4h, as in the previous regimen. Rats in the fed group were killed at 4, 8 or 24h after the start of feeding. At 4h after the start of feeding, the acetic acid group had significantly greater liver and gastrocnemius muscle glycogen concentrations (P<0·05). Also, at this same point, liver xylulose-5-phosphate, a key stimulator of glycolysis, the ratio of fructose-1,6-bisphosphate to fructose-6-phosphate in skeletal muscle, which reflects phosphofructokinase-1 activity, and liver malonyl-CoA, an allosteric inhibitor of carnitine palmitoyl-transferase, were significantly lower in the acetic acid group than in the control group (P<0·05). In addition, the acetic acid group had a significantly lower serum lactate concentration and lower ratio of insulin to glucagon than the control group at the same point (P<0·05). We conclude that a diet containing acetic acid may enhance glycogen repletion but not induce supercompensation, a large increase in the glycogen level that is beneficial in improving performance, in liver and skeletal muscle by transitory inhibition of glycolysis. Further, we indicate the possibility of a transient enhancement of fatty acid oxidation in liver by acetic acid feeding.