Endogenous acetone production is a by‐product of the fat metabolism process. Because of its small size, acetone appears in exhaled breath. Historically, endogenous acetone has been measured in exhaled breath to monitor ketosis in healthy and diabetic subjects. Recently, breath acetone concentration (BrAce) has been shown to correlate with the rate of fat loss in healthy individuals. In this review, the measurement of breath acetone in healthy subjects is evaluated for its utility in predicting fat loss and its sensitivity to changes in physiologic parameters.
BrAce can range from 1 ppm in healthy non‐dieting subjects to 1,250 ppm in diabetic ketoacidosis. A strong correlation exists between increased BrAce and the rate of fat loss. Multiple metabolic and respiratory factors affect the measurement of BrAce. BrAce is most affected by changes in the following factors (in descending order): dietary macronutrient composition, caloric restriction, exercise, pulmonary factors, and other assorted factors that increase fat metabolism or inhibit acetone metabolism. Pulmonary factors affecting acetone exchange in the lung should be controlled to optimize the breath sample for measurement.
When biologic factors are controlled, BrAce measurement provides a non‐invasive tool for monitoring the rate of fat loss in healthy subjects.
Acetone, a metabolite of fat catabolism, is produced in excessive amounts in subjects on restricted-calorie weight-loss programs. Breath acetone measurements are useful as a motivational tool during dieting and for monitoring the effectiveness of weight-loss programs. We have developed a simple, easy-to-read method that quantifies the amount of acetone in a defined volume of exhaled breath after trapping the sample in a gas-analyzer column. The concentration of acetone, as measured by the length of a blue color zone in the analyzer column, correlates with results obtained by gas chromatography. Using the breath acetone analyzer to quantify breath acetone concentrations of dieting subjects, we established a correlation between breath acetone concentration and rate of fat loss (slope 52.2 nmol/L per gram per day, intercept 15.3 nmol/L, n = 78, r = 0.81). We also discussed the possibility of using breath acetone in diabetes management.
Breath acetone is most promising as biomarker for tracking metabolic changes. It originates from lipolysis where fatty acids undergo hepatic β-oxidation to acetyl coenzyme A and acetoacetate, that is degraded into volatile acetone and β-hydroxybutyrate (BOHB).  Being volatile, acetone can be detected non-invasively, routinely and on-line  by breath analysis  (as established in clinics already for nitric oxide in detection of airway inflammation  ), with high user tolerance even in a non-diseased population. …
The ketone bodies β‐hydroxybutyrate and acetone are generated as a by‐product of the fat metabolism process. In healthy individuals, ketone body levels are ∼0.1 mM for blood β‐hydroxybutyrate (BOHB) and ∼1 ppm for breath acetone (BrAce). These levels can increase dramatically as a consequence of a disease process or when used therapeutically for disease treatment. For example, increased ketone body concentration during weight loss is an indication of elevated fat metabolism.
G Freund – Metabolism, 1965 – ElsevierAccording to the calorie deficiency hypothesis of ketogenesis, ketosis is due to calorie deficiency per se rather than to a specific lack of carbohydrates at the cellular level. The demonstration of adequate supplies of Krebs cycle intermediates in ketosis and the
alleviation of ketosis by ketogenic fat diets in calorically adequate amounts in rats have been considered to support the calorie deficiency hypothesis. In this study, acetone concentrations in alveolar air were determined by means of gas chromatography in four non …
R Passmore – The Lancet, 1961 – ElsevierKETOSIS is a well-known complication of uncontrolled diabetes; it develops during fasting (either voluntary, or secondary to severe disease of the alimentary tract) and also whenever the diet contains large quantities of fat. It arises in cattle and sheep, generally in association
with lactation, when it causes considerable economic loss to farmers. In all these circumstances there is a relative increase in fat metabolism or a decrease in carbohydrate metabolism. For many years medical students were taught that” fat burns in the flame.
G Rooth, S Östenson – The Lancet, 1966 – ElsevierTHERE are theoretical reasons for believing that a determination of the ketone bodies in
arterial blood would be a good indication of whether a case of diabetes is in good control or
not. The blood-glucose indicates the concentra-tion of the extracellular glucose but it is more
important to know if the muscle and fat-cells are obtaining enough carbohydrate for an
adequate metabolism of fats. If not, ketone bodies will be produced. The level of ketone
bodies in arterial blood has not been successfully used for assess-ing the degree of control
G Freund, RL Weinsier – Metabolism, 1966 – Elsevier
Ingestion of medium chain triglycerides (MCT) results in a quantitatively reproducible increase of acetone concentrations in end-expiratory air as measured by gas chromatography. Acetone concentrations rise rapidly, reach a maximum several hours after ingestion of MCT and gradually return to base-line values. Under standardized conditions,
ingestion of increasing amounts of MCT results in increasing acetone concentrations. Repeated tests in the same subject are reproducible within narrow limits. The acetone …