When we say ketones, our company is referring to the key circulating fatty acid metabolites beta-hydroxybutyrate (OHB) and acetoacetate (AcAc). More about ketone basics here. Exogenous ketones (also referred to as ketone supplements) and well-formulated ketogenic diets share a minumum of one thing in common. Both of them result in increased circulating concentrations of beta-hydroxybutyrate (BOHB), but ultimately are related to very different patterns of ketosis, along with differing metabolic and physiologic outcomes. In a nutshell, they really should not be assumed to have equivalent effects simply because they achieve similar BOHB blood levels. Having said that, there are many reasons we must continue to study the different forms and potential applications of keto supplements.
Over the past few million years, the only way for humans to apply ketones for fuel was to restrict carbohydrates low enough and for enough time to induce the liver to make them. This is admittedly hard for most people to do in a world that also believes that dietary carbs are excellent and fats are bad. An emerging alternative would be to consume ketones as a dietary supplement. The study into how these function in your body and what benefits they are able to confer remains early stage, but we already have several such products on the market. In this particular section, we are going to discuss how exogenous ketones affect blood ketone levels, and just how they might influence health insurance and disease when compared with ketones produced in the human body.
Both predominant ketones produced by the liver are beta-hydroxybutyrate (BOHB) and acetoacetate (AcAc). Here’s a brief summary of basic info on these ketones:
It really is estimated which a keto-adapted adult will make 150 or more grams of ketones daily after adapting to a total fast (Fery 1985), and maybe 50-100 grams per day over a well-formulated ketogenic diet.
Some AcAc naturally breaks down to create acetone, which comes out with the lungs and kidneys, giving a chemical odor to the breath when ketones are high.
Most of the AcAc made in the liver is found by muscle and transformed into BOHB.
Within the keto-adaptation process, how muscles and kidneys handle BOHB and AcAc changes over the first weeks and months, and therefore the ratio of AcAc to BOHB within the blood changes considerably within the first couple of weeks.
While the ultimate fate of many ketones in the blood will be burned for fuel, BOHB and AcAc seem to have differing roles in regulating genes and cellular functions.
Particularly with gene regulation, BOHB seems to play a much more significant regulatory role than AcAc, but AcAc could have a particular role in signaling muscle regeneration .
Sources and Formulations of Exogenous Ketones – The two compounds typically called ‘ketone bodies’ (BOHB and AcAc) are made and used for multiple purposes across nature from algae to mammals, but seldom in concentrations helpful for extraction as human food. For that reason, the cause of the majority of exogenous ketones is chemical synthesis. Furthermore, most current research and make use of of ketone supplements targets BOHB. That is because AcAc is chemically unstable – it slowly fails to make acetone by releasing loejbp one molecule of CO2.
In a keto-adapted individual where ketone metabolism is brisk with as many as 100 grams or even more being oxidized (i.e., ‘burned for energy’) daily, the little amount lost in breath and urine as acetone is minor. But since this breakdown occurs spontaneously without the need for the help of enzymes, in addition, it transpires with AcAc in a stored beverage or food (even just in an aura-tight container), making the shelf-life of AcAc-containing products problematic. Thus all current ketone supplements include BOHB in some form as opposed to the naturally occurring mix of BOHB and AcAc produced by the liver.
Another essential difference between endogenous and exogenous BOHB is that most synthetic BOHB utilized in dietary supplements is a combination of the two ‘D’ and ‘L’ isomers, whereas endogenously produced BOHB consists of just the D-isomer. Metabolically, both isomers are very different, and current published information shows that the majority of the energy and signaling benefits of BOHB derive from your D-form. This is potentially problematic since the L-isomers are certainly not metabolized using the same chemical pathways since the D-forms (Lincoln 1987, Stubbs 2017), and it also remains unclear whether humans can convert the L-form towards the D-form.
Thus, as the L-isomers usually do not seem to be toxic, they are not very likely to impart the identical benefits as the D-forms. Furthermore, the current assays for blood ketones are specific to the D-isomer, so it will be difficult to track blood levels and clearance of the L-isomer taken in a supplement.