Spontaneous ketonuria and risk of incident diabetes: a 12 year prospective study

Intact ketogenesis predicted reduced risk of moderate-severe metabolic-associated fatty liver disease assessed by liver transient elastography in newly diagnosed type 2 diabetes

Aim

Hepatic ketogenesis is a key metabolic pathway that regulates energy homeostasis. Some related controversies exist regarding the pathogenesis of metabolic-associated fatty liver disease (MAFLD). We aimed to investigate whether intact ketogenic capacity could reduce the risk of MAFLD based on transient electrography (TE) in patients with newly diagnosed type 2 diabetes (T2D).

Methods

A total of 361 subjects with newly diagnosed T2D were recruited and classified into two groups based on the median serum β-hydroxybutyrate (βHB) level, referred to as the intact and impaired ketogenesis groups. The glucometabolic relevance of ketogenic capacity and associations of the baseline serum β-HB and MAFLD assessed with TE were investigated.

Results

Compared to the impaired ketogenesis group, the intact ketogenesis group showed better insulin sensitivity, lower serum triglyceride levels, and higher glycated hemoglobin levels. The controlled attenuation parameter (CAP) was lower in the intact ketogenesis group without statistical significance (289.7 ± 52.1 vs. 294.5 ± 43.6; p=0.342) but the prevalence of moderate-severe steatosis defined by CAP ≥260 dB/m was significantly lower in the intact group. Moreover, intact ketogenesis was significantly associated with a lower risk of moderate-severe MAFLD after adjusting for potential confounders (adjusted odds ratio 0.55, 95% confidence interval 0.30-0.98; p=0.044).

Conclusion

In drug-naïve, newly diagnosed T2D patients, intact ketogenesis predicted a lower risk of moderate-severe MAFLD assessed by TE.

Association between Impaired Ketogenesis and Metabolic-Associated Fatty Liver Disease

Metabolic (dysfunction) associated fatty liver disease (MAFLD) is generally developed with excessive accumulation of lipids in the liver. Ketogenesis is an efficient pathway for the disposal of fatty acids in the liver and its metabolic benefits have been reported. In this review, we examined previous studies on the association between ketogenesis and MAFLD and reviewed the candidate mechanisms that can explain this association.

β-hydroxybutyrate as a biomarker of β-cell function in new-onset type 2 diabetes and its association with treatment response at 6 months

AIMS

Increasing attention has been paid to the potential metabolic benefits of ketone bodies, but the clinical relevance of ketone bodies in newly diagnosed type 2 diabetes mellitus (T2D) remains unclear. We investigated the clinical implications of ketone bodies at the time of diagnosis in patients with drug-naïve T2D.

METHODS

Clinical data including serum β-hydroxybutyrate (βHB) levels, were collected from 369 patients with newly diagnosed drug-naïve T2D from 2017 to 2021. Subjects were categorized into four βHB groups based on the level of initial serum βHB. The associations of initial serum βHB and urinary ketone levels with glucometabolic indices were analyzed.

RESULTS

Higher serum βHB group was associated with higher levels of glycemic parameters including glycated hemoglobin (HbA1c) with lower levels of indices for insulin secretory function at the point of initial diagnosis of T2D. Nevertheless, higher serum βHB group was an independent determinant of a greater relative improvement in HbA1c after 6 months of anti-diabetic treatment, regardless of the type of anti-diabetic drug. In addition, patients in higher serum βHB group were more likely to have well-controlled HbA1c levels (≤6.5%) after 6 months of anti-diabetic treatment.

CONCLUSION

In patients with newly diagnosed T2D, a higher initial βHB level was a significant predictive marker of greater glycemic improvement after antidiabetic treatment, despite its associations with hyperglycemia and decreased insulin secretion at baseline.

Impaired ketogenesis is associated with metabolic-associated fatty liver disease in subjects with type 2 diabetes

AIMS

The ketogenic pathway is an effective mechanism by which the liver disposes of fatty acids (FAs) to the peripheral tissues. Impaired ketogenesis is presumed to be related to the pathogenesis of metabolic-associated fatty liver disease (MAFLD), but the results of previous studies have been controversial. Therefore, we investigated the association between ketogenic capacity and MAFLD in subjects with type 2 diabetes (T2D).

METHODS

A total of 435 subjects with newly diagnosed T2D was recruited for the study. They were classified into two groups based on median serum β-hydroxybutyrate (β-HB) level: intact vs. impaired ketogenesis groups. The associations of baseline serum β-HB and MAFLD indices of hepatic steatosis index, NAFLD liver fat score (NLFS), Framingham Steatosis index (FSI), Zhejian University index, and Chinese NAFLD score were investigated.

RESULTS

Compared to the impaired ketogenesis group, the intact ketogenesis group showed better insulin sensitivity, lower serum triglyceride level, and higher low-density lipoprotein-cholesterol and glycated hemoglobin levels. Serum levels of liver enzymes were not different between the two groups. Of the hepatic steatosis indices, NLFS (0.8 vs. 0.9, p=0.045) and FSI (39.4 vs. 47.0: p=0.041) were significantly lower in the intact ketogenesis group. Moreover, intact ketogenesis was significantly associated with lower risk of MAFLD as calculated by FSI after adjusting for potential confounders (adjusted odds ratio 0.48, 95% confidence interval 0.25-0.91, p=0.025).

CONCLUSIONS

Our study suggests that intact ketogenesis might be associated with decreased risk of MAFLD in T2D.

Fasting Ketonuria and the Risk of Incident Nonalcoholic Fatty Liver Disease With and Without Liver Fibrosis in Nondiabetic Adults

INTRODUCTION

Dietary carbohydrate restriction or ketogenic diets are known to be beneficial in preventing liver fat accumulation. However, the effect of ketonemia on the risk of nonalcoholic fatty liver disease (NAFLD) in nondiabetic population is largely unknown. We investigated the association between fasting ketonuria and the risk of incident NAFLD in healthy adults.

METHODS

A cohort of 153,076 nondiabetic Koreans with no hepatic steatosis and low probability of fibrosis at baseline was followed for a median of 4.1 years. The outcome was incident hepatic steatosis with or without liver fibrosis, and it was assessed by liver ultrasound and noninvasive fibrosis indices, including fibrosis-4 and the NAFLD fibrosis score (NFS). Parametric proportional hazard models were used to estimate hazard ratios (HRs) for outcome according to ketonuria status.

RESULTS

Within 677,702.1 person-years of follow-up, 31,079 subjects developed hepatic steatosis. Compared with no ketonuria (reference), fasting ketonuria was significantly associated with a decreased risk of incident hepatic steatosis, with multivariable-adjusted HRs (95% confidence interval) of 0.81 (0.78-0.84). The corresponding HRs for incident hepatic steatosis with intermediate-to-high NFS were 0.79 (0.69-0.90). Similar associations were observed replacing NFS with fibrosis-4. In addition, the presence of persistent ketonuria at both baseline and subsequent visit was associated with the greatest decrease in the adjusted HR for incident NAFLD.

DISCUSSION

Ketonuria was associated with a reduced risk of developing incident hepatic steatosis with and without intermediate-to-high probability of advanced fibrosis in a large cohort of nondiabetic healthy individuals. The role of hyperketonemia in the prevention of NAFLD requires further exploration.

Association between Fasting Ketonuria and Advanced Liver Fibrosis in Non-Alcoholic Fatty Liver Disease Patients without Prediabetes and Diabetes Mellitus

Ketone body production, an alternative fuel upon low glucose availability, reduces hepatic fat accumulation. However, its clinical implications have not been established in patients with nonalcoholic fatty liver disease (NAFLD). We investigated the association between spontaneous fasting ketonuria and liver fibrosis in patients with NAFLD without prediabetes and diabetes mellitus (DM). A total of 6202 patients with ultrasound confirmed NAFLD without prediabetes and DM were enrolled in the study. Using low cut off values of NAFLD fibrosis score (NFS) and fibrosis-4, liver fibrosis was defined as an intermediate-high probability of advanced liver fibrosis. Of the 6202 NAFLD patients, 360 (5.8%) had ketonuria. Compared to the patients without ketonuria, patients with ketonuria were younger (41.1 vs. 44.6 years, p < 0.001), had lower levels of glucose (87.2 vs. 91.0 mg/dL, p < 0.001), and homeostatic model assessment for insulin resistance (1.0 vs. 1.5, p < 0.001). The presence of ketonuria had an inverse association with liver fibrosis, assessed using both NFS (final adjusted odds ratio [aOR], 0.67; 95% confidence interval [CI], 0.45-1.01) and fibrosis-4 (aOR, 0.58; 95% CI, 0.40-0.84). The presence of ketonuria in NAFLD patients without prediabetes and DM may have favorable metabolic effects compared to the absence of ketonuria, independent of traditional metabolic factors.

Free fatty acids, glicentin and glucose-dependent insulinotropic polypeptide as potential major determinants of fasting substrate oxidation

The selection of carbohydrates or fat to generate intracellular energy is thought to be crucial for long-term metabolic health. While most studies assess fuel selection after a metabolic challenge, the determinants of substrate oxidation in the fasted state remain largely unexplored. We therefore assessed the respiratory quotient by indirect calorimetry as a read-out for substrate oxidation following an overnight fast. This cross-sectional analysis consisted of 192 (92 women, 100 men) either lean or obese participants. Following an overnight fast, the respiratory quotient (RQ) was assessed, after which a 5-point 75-g oral glucose tolerance test was performed. Unlike glucose and insulin, fasting free fatty acids (FFA) correlated negatively with fasting RQ (p < 0.0001). Participants with high levels of the ketone body β-hydroxybutyric acid had significantly lower RQ values. Fasting levels of glucose-dependent insulinotropic polypeptide (GIP) and glicentin were positively associated with fasting RQ (all p ≤ 0.03), whereas GLP-1 showed no significant association. Neither BMI, nor total body fat, nor body fat distribution correlated with fasting RQ. No relationship between the RQ and diabetes or the metabolic syndrome could be observed. In the fasting state, FFA concentrations were strongly linked to the preferentially oxidized substrate. Our data did not indicate any relationship between fasting substrate oxidation and metabolic diseases, including obesity, diabetes, and the metabolic syndrome. Since glicentin and GIP are linked to fuel selection in the fasting state, novel therapeutic approaches that target these hormones may have the potential to modulate substrate oxidation.

Nutrition for Gestational Diabetes-Progress and Potential

Gestational diabetes (GDM), traditionally defined as any form of glucose intolerance first detected in pregnancy [...].

The Presence of Urinary Ketones according to Metabolic Status and Obesity

BACKGROUND

Recently, new concepts about obesity and normal weight subtypes with metabolic conditions are rising and ketone bodies are emerging as a significant indicator of metabolic health. This study aimed to find a relationship between ketonuria and those subtypes.

METHODS

The data of 19,036 subjects were analyzed in this cross-sectional study (2013-2017 Korea National Health and Nutrition Examination Survey, KNHANES). Based on body mass index and adult treatment panel III with modification of waist circumference, individuals were categorized into 4 groups: metabolically healthy normal weight (MHNW), metabolically healthy obese (MHO), metabolically unhealthy normal weight (MUNW), and metabolically unhealthy obese (MUO). Individuals were divided into 2 groups, positive and negative ketonuria groups, and the metabolic parameters were compared.

RESULTS

The metabolic indicators of the positive ketonuria group showed better results than those of the negative ketonuria group and the MHNW group showed the highest proportion of positive ketonuria. The MHNW group showed higher urinary ketones than the MUO group (odds ratio [OR], 0.391; 95% confidence interval [CI], 0.254-0.601) in men. In women, OR of having ketonuria was 0.698 (95% CI, 0.486-1.002) in the MHO group and 0.467 (95% CI, 0.226-0.966) in the MUNW group compared to the MHNW group, respectively.

CONCLUSION

Compared to the MHNW group, the MUO group showed lower presence of ketonuria in men, and tendency to have less ketonuria in women.

The mystery of the ketogenic diet: benevolent pseudo-diabetes

Designed a century ago to treat epilepsy, the ketogenic diet (KD) is also effective against obesity and diabetes. Paradoxically, some studies in rodents have found that the KD seemingly causes diabetes, contradicting solid clinical data in humans. This paradox can be resolved by applying the concept of starvation pseudo-diabetes, which was discovered in starved animals almost two centuries ago, and has also been observed in some rapamycin-treated rodents. Intriguingly, use of the KD and rapamycin is indicated for a similar spectrum of diseases, including Alzheimer's disease and cancer. Even more intriguingly, benevolent (starvation) pseudo-diabetes may counteract type 2 diabetes or its complications.