Background Ketone body therapy and supplementation are of high interest for several medical and nutritional fields. The intake of ketone bodies is often discussed in relation to rare metabolic diseases, such as multiple acyl-CoA dehydrogenase deficiency (MADD), that have no alternatives for treatment. Case reports showed positive results of therapy using ketone bodies. The number of ketone body salts offered on the wellness market is increasing steadily. More information on the kinetics of intake, safety, and tolerance of these products is needed. Methods In a one-dose kinetic study, six healthy subjects received an intervention (0.5 g/kg bw) using a commercially available ketone body supplement. The supplement contained a mixture of sodium and calcium D-/L-β-hydroxybutyrate (βHB) as well as food additives. The blood samples drawn in the study were tested for concentrations of D-βHB, glucose, and electrolytes, and blood gas analyses were done. Data on sensory evaluation and observed side effects of the supplement were collected. The product also went through chemical food analysis. Results The supplement led to a significant increase of D-βHB concentration in blood 2.5 and 3 h after oral intake (p=0.033; p=0.043). The first significant effect was measured after 2 h with a mean value of 0.598 ± 0.300 mmol/L at the peak, which was recorded at 2.5 h. Changes in serum electrolytes and BGA were largely unremarkable. Taking the supplement was not without side effects. One subject dropped out due to gastrointestinal symptoms and two others reported similar but milder problems. Conclusions Intake of a combination of calcium and sodium D-/L-βHB salt shows a slow resorption with a moderate increase of D-βHB in serum levels. An influence of βHB salts on acid-base balance could not be excluded by this one-dose study. Excessive regular consumption without medical observation is not free of adverse effects. The tested product can therefore not be recommended unconditionally.

s u m m a r yBackground: Glycogen storage disease type IIIa (GSDIIIa) is a defect of the debranching enzyme (amylo-1,6-glucosidase) in glycogenolysis and has an effect on the muscles and the liver. The guidelines for diagnosis and management of GSDIIIa primarily recommend a nutritional therapy to avoid hypoglycaemia. For adolescents and adults, the recommendation is a diet high in protein (25 E%) and moderate or low in carbohydrates (<50 E%) while avoiding simple sugars and fasting. There are some indications that a ketogenic diet, such as the modified Atkins diet (MAD), could present a good approach to nutritional therapy for GSDIIIa. Methods: This report is a retrospective evaluation of the nutritional and clinical data of two adult patients with GSDIIIa. The effect of a diet according to the guidelines and a ketogenic diet (MAD) were compared in both cases. Patient compliance during the nutrition therapy is also described. Results: The MAD led to a reduction of CK and a stabilization of blood glucose as well as to an unwanted weight loss. The progression of the disease was decelerated, but existing complaints could not be improved. Compliance to the MAD decreased over time and re-training was necessary. Conclusions: The MAD presents a good option for nutritional therapy for glycogenosis with muscle involvement like in GSDIIIa.