Hi, below are two articles on apple cider vinegar. I am now adding this VERY cheap and potentially quite effective supplement to my regimen. It seems to curb appetite, lower glycemic load, and may have anti-tumor and anti-inflammatory effects. Awesome!
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Vinegar Improves Insulin Sensitivity to a High-Carbohydrate Meal in Subjects With Insulin Resistance or Type 2 Diabetes
Carol S. Johnston, PHD, Cindy M. Kim, MS and Amanda J. Buller, MS
From the Department of Nutrition, Arizona State University, Mesa, Arizona
Address correspondence to Carol S. Johnston, Department of Nutrition, Arizona State University, East Campus, 7001 E. Williams Field Rd, Mesa, AZ 85212. E-mail: carol.johnston@asu.edu
The number of Americans with type 2 diabetes is expected to increase by 50% in the next 25 years; hence, the prevention of type 2 diabetes is an important objective. Recent large-scale trials (the Diabetes Prevention Program and STOP-NIDDM) have demonstrated that therapeutic agents used to improve insulin sensitivity in diabetes, metformin and acarbose, may also delay or prevent the onset of type 2 diabetes in high-risk populations. Interestingly, an early report showed that vinegar attenuated the glucose and insulin responses to a sucrose or starch load (1). In the present report, we assessed the effectiveness of vinegar in reducing postprandial glycemia and insulinemia in subjects with varying degrees of insulin sensitivity. These data indicate that vinegar can significantly improve postprandial insulin sensitivity in insulin-resistant subjects. Acetic acid has been shown to suppress disaccharidase activity (3) and to raise glucose-6-phosphate concentrations in skeletal muscle (4); thus, vinegar may possess physiological effects similar to acarbose or metformin. Further investigations to examine the efficacy of vinegar as an antidiabetic therapy are warranted.
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Vinegar: Medicinal Uses and Antiglycemic Effect
Carol S. Johnston, PhD, RD and Cindy A. Gaas, BS
Carol S. Johnston, Department of Nutrition, Arizona State University, Mesa, Arizona.
All author affiliations.
Disclosure: Carol S. Johnston, PhD, RD, has disclosed no relevant financial relationships.
Disclosure: Cindy A. Gaas, BS, has disclosed no relevant financial relationships.
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Cardiovascular Effects
Kondo and colleagues[30] reported a significant reduction in systolic blood pressure (approximately 20 mm Hg) in spontaneously hypertensive (SHR) rats fed a standard laboratory diet mixed with either vinegar or an acetic acid solution (approximately 0.86 mmol acetic acid/day for 6 weeks) as compared with SHR rats fed the same diet mixed with deionized water. These observed reductions in systolic blood pressure were associated with reductions in both plasma renin activity and plasma aldosterone concentrations (35% to 40% and 15% to 25% reductions in renin activity and aldosterone concentrations, respectively, in the experimental vs control SHR rats). Others have reported that vinegar administration (approximately 0.57 mmol acetic acid, orally) inhibited the renin-angiotensin system in nonhypertensive Sprague-Dawley rats.[31]
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Antitumor Activity
In vitro, sugar cane vinegar (Kibizu) induced apoptosis in human leukemia cells,[36] and a traditional Japanese rice vinegar (Kurosu) inhibited the proliferation of human cancer cells in a dose-dependent manner.[37] An ethyl acetate extract of Kurosu added to drinking water (0.05% to 0.1% w/v) significantly inhibited the incidence (−60%) and multiplicity (−50%) of azoxymethane-induced colon carcinogenesis in male F344 rats when compared with the same markers in control animals.[38] In a separate trial, mice fed a rice-shochu vinegar-fortified feed (0.3% to 1.5% w/w) or control diet were inoculated with sarcoma 180 (group 1) or colon 38 (group 2) tumor cells (2 × 106 cells subcutaneously).[39] At 40 days post-inoculation, vinegar-fed mice in both experimental groups had significantly smaller tumor volumes when compared with their control counterparts. A prolonged life span due to tumor regression was also noted in the mice ingesting rice-shochu vinegar as compared with controls, and in vitro, the rice-shochu vinegar stimulated natural killer cell cytotoxic activity.[39]
The antitumor factors in vinegar have not been identified. In the human colonic adenocarcinoma cell line Caco-2, acetate treatment, as well as treatment with the other short-chain fatty acids (SCFA) n-butyrate and propionate, significantly prolonged cell doubling time, promoted cell differentiation, and inhibited cell motility.[40] Because bacterial fermentation of dietary fiber in the colon yields the SCFA, the investigators concluded that the antineoplastic effects of dietary fiber may relate in part to the formation of SCFA. Others have also documented the antineoplastic effects of the SCFA in the colon, particularly n-butyrate.[41] Thus, because acetic acid in vinegar deprotonates in the stomach to form acetate ions, it may possess antitumor effects.
Vinegars are also a dietary source of polyphenols,[6] compounds synthesized by plants to defend against oxidative stress. Ingestion of polyphenols in humans enhances in vivo antioxidant protection and reduces cancer risk.[42] Kurosu vinegar is particularly rich in phenolic compounds, and the in-vitro antioxidant activity of an ethyl acetate extract of Kurosu vinegar was similar to the antioxidant activity of alpha-tocopherol (vitamin E) and significantly greater than the antioxidant activities of other vinegar extracts, including wine and apple vinegars.[43] Kurosu vinegar extracts also suppressed lipid peroxidation in mice treated topically with H2O2-generating chemicals.[43] Currently, much interest surrounds the role of dietary polyphenols, particularly from fruits, vegetables, wine, coffee, and chocolate, in the prevention of cancers as well as other conditions including cardiovascular disease[44]; perhaps vinegar can be added to this list of foods and its consumption evaluated for disease risk.
Epidemiologic data, however, is scarce and unequivocal. A case-control study conducted in Linzhou, China, demonstrated that vinegar ingestion was associated with a decreased risk for esophageal cancer (OR: 0.37).[45] However, vinegar ingestion was associated with a 4.4-fold greater risk for bladder cancer in a case-control investigation in Serbia.[46]
Blood Glucose Control
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In healthy subjects, Ostman and colleagues[58] demonstrated that acetic acid had a dose-response effect on postprandial glycemia and insulinemia. Subjects consumed white bread (50 g carbohydrate) alone or with 3 portions of vinegar containing 1.1, 1.4, or 1.7 g acetic acid. At 30 minutes post-meal, blood glucose concentrations were significantly reduced by all concentrations of acetic acid as compared with the control value, and a negative linear relationship was calculated between blood glucose concentrations and the acetic acid content of the meal (r = −0.47, P = .001). Subjects were also asked to rate feelings of hunger/satiety on a scale ranging from extreme hunger (−10) to extreme satiety (+10) before meal consumption and at 15-minute intervals after the meal. Bread consumption alone scored the lowest rating of satiety (calculated as area under the curve from time 0-120 minutes). Feelings of satiety increased when vinegar was ingested with the bread, and a linear relationship was observed between satiety and the acetic acid content of the test meals (r = 0.41, P = .004).[58]
In a separate trial, healthy adult women consumed fewer total calories on days that vinegar was ingested at the morning meal.[50] In this trial, which used a blinded, randomized, placebo-controlled, crossover design, fasting participants consumed a test drink (placebo or vinegar) followed by the test meal composed of a buttered bagel and orange juice (87 g carbohydrate). Blood samples were collected for 1 hour after the meal. At the end of testing, participants were allowed to follow their normal activities and eating patterns the remainder of the day, but they were instructed to record food and beverage consumption until bedtime. Vinegar ingestion, as compared with placebo, reduced the 60-minute glucose response to the test meal (−54%, P < .05) and weakly affected later energy consumption (−200 kilocalories, P = .111). Regression analyses indicated that 60-minute glucose responses to test meals explained 11% to 16% of the variance in later energy consumption (P < .05).[50] Thus, vinegar may affect satiety by reducing the meal-time glycemic load. Of 20 studies published between 1977 and 1999, 16 demonstrated that low-glycemic index foods promoted postmeal satiety and/or reduced subsequent hunger.[59]
It is not known how vinegar alters meal-induced glycemia, but several mechanisms have been proposed. Ogawa and colleagues examined the effects of acetic acid and other organic acids on disaccharidase activity in Caco-2 cells.[60] Acetic acid (5 mmol/L) suppressed sucrase, lactase, and maltase activities in concentration- and time-dependent manners as compared with control values, but the other organic acids (eg, citric, succinic, L-maric, and L-lactic acids) did not suppress enzyme activities. Because acetic acid treatment did not affect the de-novo synthesis of the sucrase-isomaltase complex at either the transcriptional or translational levels, the investigators concluded that the suppressive effect of acetic acid likely occurs during the posttranslational processing of the enzyme complex.[60] Of note, the lay literature has long proclaimed that vinegar interferes with starch digestion and should be avoided at meal times.[61]
Several investigations examined whether delayed gastric emptying contributed to the antiglycemic effect of vinegar. Using noninvasive ultrasonography, Brighenti and colleagues[50] did not observe a difference in gastric emptying rates in healthy subjects consuming bread (50 g carbohydrate) in association with acetic acid (ie, vinegar) vs sodium acetate (ie, vinegar neutralized by the addition of sodium bicarbonate); however, a significant difference in post-meal glycemia was noted between treatments with the acetic acid treatment lowering glycemia by 31.4%. In a later study, Liljeberg and Bjorck[62] added paracetamol to the bread test meal to permit indirect measurement of the gastric emptying rate. Compared with reference values, postmeal serum glucose and paracetamol concentrations were reduced significantly when the test meal was consumed with vinegar. The results of this study should be carefully considered, however, because paracetamol levels in blood may be affected by food factors and other gastrointestinal events. In rats fed experimental diets containing the indigestible marker polyethylenglycol and varying concentrations of acetic acid (0, 4, 8, 16 g acetic acid/100 g diet), dietary acetic acid did not alter gastric emptying, the rate of food intake, or glucose absorption.[63]
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Edited by efosse, 29 July 2007 - 04:49 AM.
