Increased intestinal permeability and inflammation, both fueled by dysbiosis, appear to contribute to rheumatoid arthritis (RA) pathogenesis. This single-center pilot study aimed to investigate zonulin, a marker of intestinal permeability, and calprotectin, a marker of intestinal inflammation, measured in serum and fecal samples of RA patients using commercially available kits. We also analyzed plasma lipopolysaccharide (LPS) levels, a marker of intestinal permeability and inflammation. Furthermore, univariate, and multivariate regression analyses were carried out to determine whether or not there were associations of zonulin and calprotectin with LPS, BMI, gender, age, RA-specific parameters, fiber intake, and short-chain fatty acids in the gut. Serum zonulin levels were more likely to be abnormal with a longer disease duration and fecal zonulin levels were inversely associated with age. A strong association between fecal and serum calprotectin and between fecal calprotectin and LPS were found in males, but not in females, independent of other biomarkers, suggesting that fecal calprotectin may be a more specific biomarker than serum calprotectin is of intestinal inflammation in RA. Since this was a proof-of-principle study without a healthy control group, further research is needed to validate fecal and serum zonulin as valid biomarkers of RA in comparison with other promising biomarkers.

MCTs are increasingly being used to promote ketogenesis by patients on ketogenic diet therapy, but also by people with other conditions and by the general public for the perceived potential benefits. However, consumption of carbohydrates with MCTs and untoward gastrointestinal side effects, especially at higher doses, could decrease the sustainability of the ketogenic response. This single-center study investigated the impact of consuming carbohydrate as glucose with MCT oil compared to MCT alone on the BHB response. The effects of MCT oil versus MCT oil plus glucose on blood glucose, insulin response, levels of C8, C10, BHB, and cognitive function were determined, and side effects were monitored. A significant plasma BHB increase with a peak at 60 min was observed in 19 healthy participants (24.4 ± 3.9 years) after consuming MCT oil alone, and a more delayed but slightly higher peak was observed after consuming MCT oil plus glucose. A significant increase in blood glucose and insulin levels occurred only after MCT oil plus glucose intake. The overall mean plasma levels of C8 and C10 were higher with the intake of MCT oil alone. MCT oil plus glucose consumption showed improved scores for the arithmetic and vocabulary subtests.

Fatty acids, such as medium-chain fatty acids (MCFAs) and short-chain fatty acids (SCFAs), both important components of a normal diet, have been reported to play a role in bone-related diseases such as rheumatoid arthritis (RA). However, the role of medium-chain triglycerides (MCTs) has not been investigated in RA to date. The aim of this study was to investigate the effect of supplementation of regular diet with MCT with and without fiber on disease activity as measured with the SDAI (Simplified Disease Activity Index) in RA patients. A total of 61 RA patients on stable drug treatment were randomly assigned to a twice-daily control regimen or to a twice-daily regimen of a formulation containing medium-chain triglycerides (MCTs) 30 g/day for 8 weeks followed by a second twice-daily regimen of combining MCT (30 g/day) plus fiber (30 g/day) for an additional 8 weeks. The control group received a formulation containing long-chain triglycerides (LCTs) instead of MCTs. The preliminary results showed a significant reduction in SDAI from baseline to week 16 in the test group and a significant increase in β-hydroxybutyrate (BHB) levels, while no improvement in SDAI was observed in the control group.

Dietary factors probably play a role in the pathogenesis and clinical course of rheumatoid arthritis (RA). There is a paucity of specific dietary guidelines for RA patients and little information on their implementation in daily life. Therefore, this study aimed to determine the nutritional status and provision of nutritional education among outpatients with RA. Here, 61 patients were included with a sex ratio of 2.03 (f/m). Based on BMI, 22% of women were overweight and 32% obese, whereas 50% of men were overweight and 30% obese. Fasting blood and a 3-day estimated dietary record were collected. Additionally, patients were asked whether they had already received information about a specific diet as part of their disease treatment plan. Elevated total cholesterol levels were found in 76% of women and in 60% of men caused by increased non-HDL-C levels. The dietary intake assessment showed a lower self-reported intake of energy, polyunsaturated fat, carbohydrates, fiber, and several micronutrients than recommended. Regarding healthy eating, all patients reported familiarity with dietary recommendations, but found it difficult to implement the recommendations into their diets. These findings suggested that RA patients need more specific recommendations and education in clinical practice to improve the quality of their diet.

Medium-chain triglycerides (MCTs, C6–C12 fatty acids) exhibit rapid absorption, preferential portal transport, efficient mitochondrial β-oxidation, promoting acetyl-CoA formation and ketogenesis. Under high lipid flux or impaired β-oxidation, MCTs undergo ω-oxidation, producing dicarboxylic acids further metabolized peroxisomally, preventing fatty acid accumulation. Industrially, MCTs are synthesized via chemical or enzymatic esterification of caprylic (C8) and capric (C10) acids, yielding high-purity triglycerides used in food and medical nutrition. In Germany and across the European Union, they are primarily used in Foods for Special Medical Purposes (FSMPs) for conditions such as fat malabsorption, ketogenic dietary therapy for refractory epilepsy, and inherited disorders of long-chain fatty-acid oxidation. In Japan, MCTs are additionally incorporated into functional food systems, including Foods for Specified Health Uses (FOSHU) and Foods with Function Claims (FFC), targeting generally healthy adults and older populations. In the United States, MCTs are widely marketed as food ingredients, dietary supplements, clinical nutrition products, and medical foods, reflecting their status as generally recognized as safe (GRAS). This review integrates knowledge on MCT metabolism, industrial production, clinical applications, and regulatory frameworks in Germany, Japan, and the United States, highlighting how regulatory environments influence the translation of MCTs from clinical nutrition toward broader preventive health strategies.

Mittelkettige Triglyceride (MCT) sind Glycerinester von gesättigten Fettsäuren mittlerer Kettenlänge (C6:0–C12:0). Sie unterscheiden sich grundlegend von den üblichen langkettigen Fettsäuren in Nahrungsfetten sowohl in ihren biochemischen und physikalischen Eigenschaften als auch hinsichtlich Resorption, Transportmechanismus und zellulärem Metabolismus. Aufgrund dieser Unterschiede haben MCT einen wichtigen Stellenwert in der Ernährungsmedizin. Trotz der hohen Bekanntheit von MCT im Bereich der klinischen Ernährungstherapie, existieren zahlreiche Forschungslücken. Zudem werden immer neue Indikationsgebiete für die Verwendung von MCT entdeckt. Der Artikel gibt eine breite Übersicht zu MCT, ausgewählten Anwendungsgebieten und aktuellen Forschungsthemen.