This case report is a retrospective review of ongoing clinical work, with the SIBO breath tests recorded between October 2018 to August 2020. All six subjects were regular patients at a functional medicine  clinic (FunMed) in Gothenburg, Sweden, and followed the structured process used by this clinic. The subjects consented to scientific publication of the collected data in writing. After a first visit to an M.D. (Dr Peter Martin) they all performed an extensive blood panel (Unilabs, Sweden), GI Effects comprehensive stool test (Genova Diagnostics, UK), Nutrient and Toxic Element Profile (NutrEval, Genova Diagnostics, UK), ImuPro IgG antibody screening for food intolerances (CTL & Ortholabor GmbH, Germany), and a SIBO lactulose hydrogen/methane breath test (Biolab, UK). The SIBO breath test was performed before and directly after (on the last day of) the dietary change. No antibiotic drugs or antimicrobial agents were used during the treatment period. There was no commercially available diagnostic tool for hydrogen sulphide SIBO when these patients were treated.
The therapeutic diet
All patients were instructed to follow a strict zero carbohydrate, zero fibre, carnivore diet for two to six weeks. The diet was exclusively composed of animal fats and proteins: all types of meat, organ meats, fish, poultry, tallow, lard, and eggs. No vegetables, vegetable oils or dairy products except for butter was included. Extra intake of table salt was recommended to compensate for sodium loss. The patients could drink coffee, tea, and water, but no sweetened beverages or diet sodas. No caloric limit or other restrictions were implied, the patients were encouraged to eat as much and as often as they wanted.
Lactulose Hydrogen and Methane Breath Test
Breath samples (n=10) were collected using glass vacuum vials with rubber tops that was pushed on a rubber-clad needle. Patients were instructed to, in the morning after a >12 hour overnight fast, breath into a standardized plastic bag connected to the needle and sample their breath at t=0 min, and then ingest a lactulose solution. Subsequent breath samples were collected at t= 20, 40, 60, 80, 100, 120, 140, 160 and 180 minutes. Preparation before the test is normally eating a zero carbohydrate, zero fibre diet the day before the test. The purpose for this is to starve the bacteria prior to the test to minimize ongoing gut fermentation. In our case, the strict diet was instead followed for two to six weeks.
The sample was sent to Biolab medical unit in England for analysis and measurement of hydrogen and methane levels. Since lactulose unlike glucose is poorly absorbed in the intestines, but readily digested by gas producing bacteria, this test makes it possible to detect bacterial overgrowth in the entire gastrointestinal tract. A positive lactulose breath test was
defined as an increase of hydrogen at least 20 ppm (parts per million) above baseline within the first 90 minutes, or if a hydrogen double peak was present, which is in line with our clinical experience reinforcing the SIBO diagnosis.
Urine samples were sent to Genova diagnostics laboratories to measure organic acids, which indicates cell functionality, nutrient balance, mitochondrial function, bacterial or fungus overgrowth and more. Blood samples were analysed for content of minerals, toxic elements, glutathione, CoQ10, vitamin D and fatty acids.
GI Effects Comprehensive stool test
Stool samples were sent to Genova diagnostics laboratories to analyse bacterial content in colon, digestion of macronutrients, parasites, inflammation, and more.
ImuPro IgG antibody test
Food intolerance test measuring IgG antibodies in blood for several foods. High levels of IgG antibodies indicate delayed allergic reaction to that specific kind of food. Blood samples were sent to CTL & Ortholabor GmbH in Germany.
A comprehensive blood panel including kidney, thyroid and liver status, nutrients, lipid panel, CRP, insulin, glucose and more. Unilabs test labs were used for these analyses.
The patients also filled out the FunMed clinic standard questionnaires about their lifestyle and current health status and went through the standard medical check-up. They all had individual health concerns that were taken into consideration as well as monitored and investigated.