Vinegar is made by fermenting alcohol in various ways to produce all the different varieties available. It has long been part of traditional medicine used for anything ranging from soothing minor burns, to easing arthritis to promoting restful sleep. While this may come as little surprise to those already in the know about the wealth of benefits vinegar has to offer, scientists in Japan have found it to be an excellent tool for controlling blood sugar levels, reducing blood pressure and preventing fat accumulation. Naturally bodybuilder’s are more concerned with glucose management and fat prevention, so these are the two main topics I’ll stick to.
The key component in vinegar is acetic acid. It makes up around 5% of the composition of typical vinegars, although some pickling vinegars can be up to 15-20%. The acetic acid upon ingestion, supplies an acetyl group which can then combine with Coenzyme A (CoA) to form acetyl-CoA which is central to the metabolism of carbohydrates and fat as part of the Krebs cycle. This also raises the production of adenosine monophosphate (AMP) in the liver, unbalancing the AMP:ATP (adenosine triphosphate – the energy “currency” of every cell) ratio and activating an enzyme called AMP-activated protein kinase (AMPk). AMPk has been referred to as the metabolic “master switch”, controlling many genes involved in glucose metabolism and lipogenesis, causing them to down regulate and thus prevent body fat accumulation.
Acetic acid can also increase the oxidation of fatty acids in the liver (i.e. reduce fat, not just prevent its accrual) by inhibiting the use of glucose as a fuel (a process called glycolysis). This occurs because acetic acid has a pH-buffering effect on the cell. Under homeostatic conditions, natural concentrations of acetic acid are usually kept quite low in order to avoid disrupting the control of the cellular pH. This metabolic regulation takes place because chief control of glycolysis is provided by the enzyme phosphofructokinase (PFK) which is extensively pH sensitive. Acidifying (lowering) pH acts to inhibit the actions of PFK, thereby promoting glycogen storage (if it cannot be used for fuel, it gets stored,). Incidentally, this can be a plus for bodybuilder’s in itself as it enhances glycogen synthesis and repletion in muscle tissue.
The researchers plan to perform further clinical studies into the effects of vinegar on fat mass as well as investigate the effect of acetic acid on fatty oxidative activation in other organs, particularly skeletal muscle. I especially look forward to the latter and will report back as soon as the data is published.
Source: Kondo T, Kishi M, Fushimi T, Kaga T. Acetic acid upregulates the expression of genes for fatty acid oxidation enzymes in liver to suppress body fat accumulation. J Agric Food Chem. 2009 Jul 8;57(13):5982-6.