Thyroid markers and body composition predict LDL-cholesterol change in lean healthy women on a ketogenic diet: experimental support for the lipid energy model

The impact of carbohydrate restriction-induced elevations in low-density lipoprotein cholesterol on progression of coronary atherosclerosis: the ketogenic diet trial study design

BACKGROUND

Despite innovations in pharmacotherapy to lower lipoprotein cholesterol and apolipoprotein B, risk factors for atherosclerotic cardiovascular disease (ASCVD), ASCVD persists as the leading global cause of mortality. Elevations in low-density lipoprotein cholesterol (LDL-C) are a well-known risk factor and have been a main target in the treatment of ASCVD. The latest research suggests that ketogenic diets are effective at improving most non-LDL-C/apolipoprotein B cardiometabolic risk factors. However, ketogenic diets can induce large increases in LDL-C to >190 mg/dl in some individuals. Interestingly, these individuals are often otherwise lean and healthy. The influence of increased levels of LDL-C resulting from a carbohydrate-restricted ketogenic diet on the progression of atherosclerosis in otherwise metabolically healthy individuals is poorly understood. This observational study aims to assess and describe the progression of coronary atherosclerosis in this population within 12 months.

METHODS

Hundred relatively lean individuals who adopted ketogenic diets and subsequently exhibited hypercholesterolemia with LDL-C to >190 mg/dl, in association with otherwise good metabolic health markers, were enrolled and observed over a period of 12 months. Participants underwent serial coronary computed tomography angiography scans to assess the progression of coronary atherosclerosis in a year.

RESULTS

Data analysis shall begin following the conclusion of the trial with results to follow.

CONCLUSION

Ketogenic diets have generated debate and raised concerns within the medical community, especially in the subset exhibiting immense elevations in LDL-C, who interestingly are lean and healthy. The relationship between elevated LDL-C and ASCVD progression in this population will provide better insight into the effects of diet-induced hypercholesterolemia.

Ketosis Suppression and Ageing (KetoSAge) Part 2: The Effect of Suppressing Ketosis on Biomarkers Associated with Ageing, HOMA-IR, Leptin, Osteocalcin, and GLP-1, in Healthy Females

Metabolic dysfunctions are among the best documented hallmarks of ageing. Cardiovascular disease, Alzheimer's disease, cancer, type 2 diabetes mellitus, metabolic-dysfunction-associated steatosis liver disease, and fragility fractures are diseases of hyperinsulinaemia that reduce life and healthspan. We studied the effect of suppressing ketosis in 10 lean (BMI 20.5 kg/m2 ± 1.4), metabolically healthy, pre-menopausal women (age 32.3 ± 8.9 years) maintaining nutritional ketosis (NK) for an average of 3.9 years (± 2.3) who underwent three 21-day phases: nutritional ketosis (NK; P1), suppressed ketosis (SuK; P2), and returned to NK (P3). Ketosis suppression significantly increased insulin, 1.83-fold (p = 0.0006); glucose, 1.17-fold (p = 0.0088); homeostasis model assessment for insulin resistance (HOMA-IR), 2.13-fold (p = 0.0008); leptin, 3.35-fold (p = 0.0010); total osteocalcin, 1.63-fold (p = 0.0138); and uncarboxylated osteocalcin, 1.98-fold (p = 0.0417) and significantly decreased beta-hydroxybutyrate, 13.50-fold (p = 0.0012) and glucagon-like peptide-1 (GLP-1), 2.40-fold (p = 0.0209). Sustained NK showed no adverse health effects and may mitigate hyperinsulinemia. All biomarkers returned to basal P1 levels after removing the intervention for SuK, indicating that metabolic flexibility was maintained with long-term euketonaemia.

Increased low-density lipoprotein cholesterol on a low-carbohydrate diet in adults with normal but not high body weight: A meta-analysis

BACKGROUND

Low-density lipoprotein (LDL) cholesterol change with consumption of a low-carbohydrate diet (LCD) is highly variable. Identifying the source of this heterogeneity could guide clinical decision-making.

OBJECTIVES

To evaluate LDL cholesterol change in randomized controlled trials involving LCDs, with a focus on body mass index (BMI) in kg/m2.

METHODS

Three electronic indexes (Pubmed, EBSCO, and Scielo) were searched for studies between 1 January, 2003 and 20 December, 2022. Two independent reviewers identified randomized controlled trials involving adults consuming <130 g/d carbohydrate and reporting BMI and LDL cholesterol change or equivalent data. Two investigators extracted relevant data, which were validated by other investigators. Data were analyzed using a random-effects model and contrasted with results of pooled individual participant data.

RESULTS

Forty-one trials with 1379 participants and a mean intervention duration of 19.4 wk were included. In a meta-regression accounting for 51.4% of the observed variability on LCDs, mean baseline BMI had a strong inverse association with LDL cholesterol change [β = -2.5 mg/dL/BMI unit, 95% confidence interval (CI): -3.7, -1.4], whereas saturated fat amount was not significantly associated with LDL cholesterol change. For trials with mean baseline BMI <25, LDL cholesterol increased by 41 mg/dL (95% CI: 19.6, 63.3) on the LCD. By contrast, for trials with a mean of BMI 25-<35, LDL cholesterol did not change, and for trials with a mean BMI ≥35, LDL cholesterol decreased by 7 mg/dL (95% CI: -12.1, -1.3). Using individual participant data, the relationship between BMI and LDL cholesterol change was not observed on higher-carbohydrate diets.

CONCLUSIONS

A substantial increase in LDL cholesterol is likely for individuals with low but not high BMI with consumption of an LCD, findings that may help guide individualized nutritional management of cardiovascular disease risk. As carbohydrate restriction tends to improve other lipid and nonlipid risk factors, the clinical significance of isolated LDL cholesterol elevation in this context warrants investigation. This trial was registered at PROSPERO as CRD42022299278.