Comparison Between Breath Acetone and Blood Beta-Hydroxybutyrate

The LEVL device (Medamonitor, Seattle, WA) provides users a method for assessing their own rate of fat metabolism. The LEVL device measures the concentration acetone in breath that the scientific literature has shown to correlate to the rate of fat metabolism.

Typically, the body uses glucose to meet its metabolic energy requirements. If needed, the body can shift from using glucose to using fat. Many different scenarios can cause this shift. Exercise can deplete accessible carbohydrate stores causing the body to use fats for energy production. Dietary changes that cause fat intake to increase and carbohydrate intake to decrease will alter metabolism to efficiently utilize the change in nutrients. In all of these scenarios, the body reduces it utilization of carbohydrates and, thus, shifts to using fats for energy production.

When the body uses fats as an energy substrate, some of these fat molecules are converted by the liver into acetoacetate, a ketone body. By enzymatic action, acetoacetate (AcAc) can be converted into beta-hydroxybutyrate (BOHB). The same enzyme can generate AcAc from BOHB. Additionally, acetoacetate can convert spontaneously into acetone which, due to its small size and highly water solubility, can readily appear in the breath.

Currently, measurement of BOHB in blood is the gold standard for assessing ketone body concentration, also known as ketosis. BOHB measurement requires an invasive finger puncture to obtain blood and a costly (\~$5 / test) assay. Because acetone (BrAce) is a sister ketone body to BOHB, breath acetone may be used to assess ketosis and replace the measurement of BOHB. Data in the scientific literature has shown BrAce to correlate with BOHB. Inferring BOHB concentrations from measurement of BrAce using LEVL is less invasive and is potentially less costly.

Reports have suggested that breath acetone is inversely correlated to blood sugar. However, others have suggested no relationship between the two species. If a relationship does exist, measurement of breath acetone could be used as a surrogate measure for blood sugar, a common assay used by individuals with diabetes.

In this study, subjects will provide blood and breath samples evaluate the relationship between breath acetone and two blood-bound species: BOHB and glucose. Subjects may be asked to provide breath and blood samples at two different times (i.e., visits) spaced approximately 3 hours apart. The second visit is not required for participation in the study (i.e., optional).