Thought I’d post this here also to see if we can get a discussion going.
Anyone using this post workout?
It is supposed to enhance glycogen repletion in muscle cells after exercise by retarding glycolysis (aerobic glycolysis I think) by means of the inhibition of an enzime called phosphofructokinase.
There have been many people in other forums reporting changes in body composition while having higher carbs intakes, inclusively losing fat without that flat muscle look you tend to get with lower carb diets.
The active substance is acetic acid, and citric acid has been used in other studies with similar effects.
To investigate the efficacy of the ingestion of vinegar in aiding recovery from fatigue, we examined the effect of dietary acetic acid, the main component of vinegar, on glycogen repletion in rats. Rats were allowed access to a commercial diet twice daily for 6 d. After 15 h of food deprivation, they were either killed immediately or given 2 g of a diet containing 0 (control), 0.1, 0.2 or 0.4 g acetic acid/100 g diet for 2 h. The 0.2 g acetic acid group had significantly greater liver and gastrocnemius muscle glycogen concentration than the control group (P < 0.05). The concentrations of citrate in this group in both the liver and skeletal muscles were >1.3-fold greater than in the control group (P > 0.1). In liver, the concentration of xylulose-5-phosphate in the control group was significantly higher than in the 0.2 and 0.4 g acetic acid groups (P < 0.01). In gastrocnemius muscle, the concentration of glucose-6-phosphate in the control group was significantly lower and the ratio of fructose-1,6-bisphosphate/fructose-6-phosphate was significantly higher than in the 0.2 g acetic acid group (P < 0.05). This ratio in the soleus muscle of the acetic acid fed groups was <0.8-fold that of the control group (P > 0.1). In liver, acetic acid may activate gluconeogenesis and inactivate glycolysis through inactivation of fructose-2,6-bisphosphate synthesis due to suppression of xylulose-5-phosphate accumulation. In skeletal muscle, acetic acid may inhibit glycolysis by suppression of phosphofructokinase-1 activity. We conclude that a diet containing acetic acid may enhance glycogen repletion in liver and skeletal muscle.
I’ve been using it for a while now to lower the GI of starchy meals–via slowing down gastric emptying. I use it in the first whole food meal P-W. I’m hesitating to have it with the P-W shake, since I don’t know whether it will slow the digestion of the whey hydrolysate.
Something else to think about: distilled vinegar increases pH but apple cider vinegar decreases it.
P-dog, it does contain acetic acid. All vinegar does.
From the Vinegar Information Center:
“Vinegar (Fr. Vinaigre) is a thin, sour liquid used for thousands of years as a preservative, cooking ingredient, condiment and cleaning solution. Vinegar is obtained through the fermentation of wine or other alcoholic liquid. Bacteria attacks the alcohol in the solution, turning it into acetic acid. No alcohol will retain when the transformation is complete. The quality of vinegar depends upon the quality of the wine or other liquid on which it is based. Vinegar flavors are as varied as the liquids from which they are made.”
Vinegar has been advocated in several camps for a number of years now for it’s various health related effects. I’ve used vinegar with positive results off and on for several years and have come to understand vinegar can have a variety of effects on the body. Remember that vinegar will have a slightly different effect if taken with food vs taken before meals. Vinegar taken with meals will slow gastric emptying, thus lowering or slowing down the glycemic response of a meal where as vinegar taken 1/2 hour before meals won’t have the delayed gastric emptying effect or corresponding lowered glycemic effect but will increase insulin sensitivity. So the take home message is take your vinegar 1/2 hour before carb meals to increase insulin sensitivity (use much like ALA) where as take vinegar with meals to slow digestion and glycemic response. Both effects can be accomplished with dual doses but if used POW, the delayed gastric emptying effect may not be beneficial, where as on non WO days, the lowered glycemic response is beneficial.
have you seen the research I posted, the full text? I would say that the extra glycogen repletion should make up for any downsides there might be from the delayed gastric emptying effect when used post workout.
According to this study (I could only find the abstract) vinegar added to white bread lowered its glycemic index from 100 to 64. It's possible that the benefit of PFK inhibition (if acetic acid inhibits PFK in humans)offsets the lowering of the GI. Maybe JMB will look into that while he's testing it.
Eur J Clin Nutr. 1998 May;52(5):368-71.
Delayed gastric emptying rate may explain improved glycaemia in healthy subjects to a starchy meal with added vinegar.
Liljeberg H, Bjorck I.
Department of Applied Nutrition and Food Chemistry, Chemical Center, Lund University, Sweden.
OBJECTIVES: The aim of the study was to evaluate the possible influence of acetic acid (administered as vinegar) on the postprandial glucose and insulin responses, and the potential involvement of a modified gastric emptying rate was studied by use of paracetamol as a marker. DESIGN: The white bread reference meal as well as the corresponding meal supplemented with vinegar had the same content of starch, protein and fat. The meals were served in the morning after an over-night fast and in random order. Capillary blood samples for analysis of glucose, insulin and paracetamol were collected postprandially. SETTING: The study was performed at the Department of Applied Nutrition and Food Chemistry, Lund University, Sweden. SUBJECTS: Ten healthy volunteers, seven women and three men, aged 22-51 y, with normal body mass indices were recruited. RESULTS: The presence of acetic acid, given as vinegar, significantly reduced the postprandial glucose (GI=64) and insulin responses (II=65) to a starchy meal. As judged from lowered paracetamol levels after the test meal with vinegar, the mechanism is probably a delayed gastric emptying rate. CONCLUSIONS: Fermented foods or food products with added organic acids should preferably be included in the diet in order to reduce glycaemia and insulin demand.