Ketogenic diets, not for everyone

Low-density lipoprotein cholesterol elevation, ketogenic diets, body mass index, and heterozygous ABCG5 genetic variation: Review, case report, and large population analysis

BACKGROUND

Low-body mass index (BMI) has been associated with marked low-density-lipoprotein-cholesterol (LDL-C) elevations in response to very-low-carbohydrate diets (VLCD).

METHODS

We report a case (51-year-old woman, BMI 18.5 kg/m2) whose LDL-C was >500 mg/dL on a VLCD diet. We characterized her plasma lipoproteins and noncholesterol-sterols (gas chromatography/mass spectrometry) and the DNA sequences of her genes affecting lipid metabolism. We also carried out a large population analysis (224,126 subjects, 54% female, mean age 54 years) examining interrelationships between BMI and serum lathosterol/total cholesterol and β-sitosterol/total cholesterol ratios.

RESULTS

In this case, her LDL-C concentration increased from 142 mg/dL to 555 mg/dL on a VLCD, and her plasma β-sitosterol level was very high at 12.8 mg/L. DNA analysis revealed a heterozygous pathogenic ABCG5 exon 9 variant (c.1323_1324+2del at position g.44051049 TACAC>T). With dietary cholesterol restriction and ezetimibe therapy, her LDL-C and β-sitosterol levels decreased by 75% and 46% to 139 mg/dL and 7.1 mg/L, respectively. In the population analysis, we noted a significant inverse correlation between BMI and the plasma β-sitosterol/total cholesterol ratio (r = -0.573, P < .00001). Those with a BMI <20 kg/m2 had mean β-sitosterol/total cholesterol values that were significantly higher (+63%, P < .00001) than values in obese women. The converse was true for the plasma lathosterol/total cholesterol ratio. Similar findings were noted in men.

CONCLUSIONS

Our data are consistent with the concepts that low BMI predisposes to increased plasma β-sitosterol/total cholesterol ratios and an increased serum LDL-C when on high cholesterol VLCD diets, and that this response may be markedly enhanced in subjects with pathogenic heterozygous ABCG5 variants.

Dietary patterns to promote cardiometabolic health

Multiple professional societies recommend the Mediterranean and/or Dietary Approaches to Stop Hypertension dietary patterns in their cardiovascular disease prevention guidelines because these diets can improve cardiometabolic health and reduce the risk of cardiovascular events. Furthermore, low sodium intake can be particularly beneficial for patients with hypertension. Carbohydrate restriction, with an emphasis on including high-quality carbohydrates and limiting refined starches and foods and beverages with added sugars, can promote weight loss and cardiometabolic benefits in the short term, compared with higher carbohydrate intake. Evidence is lacking for sustained, long-term effects of low carbohydrate and very low carbohydrate intake on cardiometabolic risk and cardiovascular outcomes. Time-restricted eating, in the context of an overall healthy dietary pattern, can promote cardiometabolic health by aligning food intake with the circadian rhythm, although its effect on hard clinical outcomes remains to be proven. Although there is no one dietary pattern that is appropriate for all patients, engaging in shared decision-making with patients, utilizing behaviour-change principles and engaging members of the health-care team, such as registered dietitian nutritionists, can lead to substantial improvement in the lifestyle and overall health trajectory of a patient. Emphasizing the similarities, rather than differences, of recommended dietary patterns, which include an emphasis on vegetables, fruits, legumes, nuts, whole grains and minimally processed protein foods, such as fatty fish or plant-based proteins, can simplify the process for both patients and clinicians alike.

Ketogenic diet in clinical populations-a narrative review

Ketogenic diet (KD) is a high-fat, low-carbohydrate (CHO) diet, designed to induce a metabolic state of ketosis in which the body metabolizes primarily lipids for energy production. Various forms of KD are being promoted as promising treatments for numerous health conditions from chronic headaches to weight-loss and even different forms of cancer and are becoming increasingly more popular. KD appears to be an efficacious approach for weight-loss, and maintenance, improved glycemia, cognitive function and cancer prognosis. However, there is a controversy regarding the safety of KD, and the potential health risks that might be associated with long-term exposure to KD. There is a gap between the acceptance and utilization of KD in individuals with health conditions and the criticism and negative attitudes toward KD by some clinicians. Many individuals choose to follow KD and are encouraged by the positive results they experience. Although the medical establishment does not endorse KD as a first line of treatment, clinicians need to be informed about KD, and offer support and medical supervision for patients who self-select to follow KD. This can ensure that within the boundaries of KD, patients will make good and healthy dietary choices and prevent clinical disengagement in extreme cases. To that end, there is an urgent need for good quality research to address the issues of long-term safety of KD in different clinical populations and for standardization of KD both in research and in the clinic.

Dyslipidaemia in women with polycystic ovary syndrome referred to a teaching hospital in Cape Town, South Africa

The polycystic ovary syndrome (PCOS) imparts health risks including dyslipidaemia, diabetes and cardiovascular disease that are amenable to lifestyle adjustment and/or medication. We describe dyslipidaemia in women referred to a gynaecological endocrine clinic. Clinical data and endocrine and lipoprotein investigations comprising fasting triglyceride (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDLC) and calculated low density lipoprotein cholesterol (LDLC) were studied along with electrophoresis patterns of apolipoprotein B-containing lipoproteins. The 1721 participants comprised black, mixed ancestry, white and Indian individuals (9.8%, 83.2%, 5.8% and 1.2%, respectively). The mean ± standard deviation of the age, body mass index (BMI) and waist/hip ratio were 26.0 ± 5.9 years, 32.3 ± 8.3 kg/m2 and waist/hip ratio 0.88 ± 0.11, respectively. Overweight status (BMI 26-30 kg/m2) and obesity (BMI >30 kg/m2) involved 272 (15.8%) and 1010 (58.7%) individuals, respectively. Morbid obesity (BMI >40 kg/m2) was present in 309 (17.9%) individuals. The TG, TC, HDLC and LDLC concentrations were 1.22 ± 0.86, 4.77 ± 1.02, 1.3 ± 0.36, 2.94 ± 0.94 mmol/L, respectively. LDL hypercholesterolaemia occurred in 753 (43.7%) and exceeded 5 mmol/L in 39 (2.3%) women. Low HDLC (<0.9 mmol/L) affected 122 (7%), hypertriglyceridaemia (>1.7 mmol/L) affected 265 (15.4%) and exceeded 2.5 mmol/L in 91 (5.3%) women. Mixed hyperlipidaemia (TG >1.7, TC >5.0 mmol/L) occurred in 176 (10.2%). Electrophoresis revealed small LDL particles in 79 (4.6%) and dysbetalipoproteinaemia in 13 (0.76%) of the cohort. Small LDL associated with obesity, blood pressure, TG and glucose concentration and higher androgenic state. Many women with PCOS had unfavourable lipoprotein results: mostly moderate changes in TG, HDLC and LDLC. Small LDL is not rare, may aid risk assessment and is best determined directly. Incidental monogenic disorders of lipoprotein metabolism included dysbetalipoproteinaemia, familial hypercholesterolaemia and severe hypertriglyceridaemia. Dyslipidaemia in PCOS requires more careful diagnosis, individualised management and research.

Effect of ketogenic diets on lipid metabolism in adults: protocol for a systematic review

INTRODUCTION

The ketogenic diet is a very low carbohydrate diet known for its ability to reduce weight and counteract hyperglycaemia. However, ketogenic diets recommend an increased intake of fats, raising concerns about cardiometabolic risk in adults. Due to the higher intake of fats in the ketogenic diet, there is significant variability in outcomes of lipid metabolism in the population. Interventions have reported improvements in lipid profile while other studies did not find changes, and there are reports of increased low density lipoprotein (LDL) and triglyceride values. Hence, this is a protocol for a systematic review of the published literature and a summary of the effect of ketogenic diets on lipid metabolism in adults.

METHODS AND ANALYSIS

Five databases (PubMed, Embase, Scopus, Cochrane Library and Web of Science) will be searched for studies on ketogenic diets in adult populations. Studies will be included if they report results from ketogenic diet interventions among adults. Exclusion is populations with diagnosed neurological disorders. Two reviewers will independently screen retrieved citations, extract data and appraise the risk of bias. Quantitative estimates (eg, standardised mean difference) measuring the change in the total cholesterol, LDL and triglyceride concentration will be pooled using random effects meta-analysis to produce one summarised weighted estimate. Sources of heterogeneity will be explored using subgroup analysis. This protocol follows the Preferred Reporting Items for Systematic Review and Meta-Analysis for Protocols (PRISMA), and the final review will be reported following the PRISMA 2020 guidelines.

ETHICS AND DISSEMINATION

The present protocol and the systematic review to be carried out do not require ethics clearance. The data source will be published studies. This review will provide estimates to inform the public about the effect of ketogenic diets on lipid metabolism and the possible peril of increasing cardiometabolic risk. The results will be published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42022309665.

Obesity, dyslipidemia, and cardiovascular disease: A joint expert review from the Obesity Medicine Association and the National Lipid Association 2024

Background

This joint expert review by the Obesity Medicine Association (OMA) and National Lipid Association (NLA) provides clinicians an overview of the pathophysiologic and clinical considerations regarding obesity, dyslipidemia, and cardiovascular disease (CVD) risk.

Methods

This joint expert review is based upon scientific evidence, clinical perspectives of the authors, and peer review by the OMA and NLA leadership.

Results

Among individuals with obesity, adipose tissue may store over 50% of the total body free cholesterol. Triglycerides may represent up to 99% of lipid species in adipose tissue. The potential for adipose tissue expansion accounts for the greatest weight variance among most individuals, with percent body fat ranging from less than 5% to over 60%. While population studies suggest a modest increase in blood low-density lipoprotein cholesterol (LDL-C) levels with excess adiposity, the adiposopathic dyslipidemia pattern most often described with an increase in adiposity includes elevated triglycerides, reduced high density lipoprotein cholesterol (HDL-C), increased non-HDL-C, elevated apolipoprotein B, increased LDL particle concentration, and increased small, dense LDL particles.

Conclusions

Obesity increases CVD risk, at least partially due to promotion of an adiposopathic, atherogenic lipid profile. Obesity also worsens other cardiometabolic risk factors. Among patients with obesity, interventions that reduce body weight and improve CVD outcomes are generally associated with improved lipid levels. Given the modest improvement in blood LDL-C with weight reduction in patients with overweight or obesity, early interventions to treat both excess adiposity and elevated atherogenic cholesterol (LDL-C and/or non-HDL-C) levels represent priorities in reducing the risk of CVD.

Association of a Low-Carbohydrate High-Fat Diet With Plasma Lipid Levels and Cardiovascular Risk

Background

Low-carbohydrate high-fat (LCHF) diets have attracted interest for a variety of conditions. In some individuals, these diets trigger hypercholesterolemia. There are limited data on their effects on cardiovascular disease risk.

Objectives

The purpose of this study was to investigate the association between LCHF dietary patterns, lipid levels, and incident major adverse cardiovascular events (MACE).

Methods

In a cohort from the UK Biobank, participants with ≥1 24-hour dietary questionnaire were identified. A LCHF diet was defined as <100 g/day and/or <25% total daily energy from carbohydrates/day and >45% total daily energy from fat, with participants on a standard diet (SD) not meeting these criteria. Each LCHF case was age- and sex-matched 1:4 to SD individuals.

Results

Of the 2034 LCHF and 8136 SD identified participants, 305 LCHF and 1220 SD individuals completed an enrollment assessment concurrently with lipid collection. In this cohort, low-density lipoprotein-cholesterol (LDL-C) and apolipoprotein B levels were significantly increased in the LCHF vs SD group (P < 0.001). 11.1% of LCHF and 6.2% of SD individuals demonstrated severe hypercholesterolemia (LDL-C >5 mmol/L, P < 0.001). After 11.8 years, 9.8% of LCHF vs 4.3% of SD participants experienced a MACE (P < 0.001). This difference remained significant after adjustment for cardiovascular risk factors (HR: 2.18, 95% CI: 1.39-3.43, P < 0.001). Individuals with an elevated LDL-C polygenic risk score had the highest concentrations of LDL-C on a LCHF diet. Similar significant changes in lipid levels and MACE associations were confirmed in the entire cohort and in ≥2 dietary surveys.

Conclusions

Consumption of a LCHF diet was associated with increased LDL-C and apolipoprotein B levels, and an increased risk of incident MACE.

The Effects of Medium-Chain Triglyceride Oil and Butter on Lipid Profiles

Background and objective Butter coffee drinks, mainly a form of a saturated fat diet, are widely accepted as a "healthy energy-boosting drink", especially in the young and healthy military population. The objective of our study was to determine the effects of medium-chain triglyceride (MCT) oil and butter on lipid profile, especially apolipoprotein B (ApoB), low-density lipoprotein (LDL)-cholesterol (LDL-C), high-density lipoprotein (HDL)-cholesterol (HDL-C), and other risk factors for coronary heart disease, such as BMI, BP, fasting blood glucose, HbA1c, and high-sensitivity C-reactive protein (hs-CRP) levels in healthy adults. Materials and methods We conducted a prospective study of 60 subjects who were randomized to one of the two following regimens: (1) coffee or (2) coffee with butter plus MCT oil combination. The primary outcome was the effect on ApoB. Secondary outcomes were as follows: non-HDL-C, LDL-C, triglycerides, BP, waist circumference, fasting blood glucose, and HbA1c. These parameters were evaluated at the baseline and after 12 weeks. The Mann-Whitney U test was utilized for analysis of the results. Results While 60 subjects were recruited for the study, only 41 completed it, meeting the minimum required sample size (17 per group) necessary to achieve the desired effect size: 21 males (nine in the control group and 12 in the experimental group) and 20 females (10 in each group). Anthropometric measures were similar between the two groups at baseline, and so were age and BMI (average age: 33.00 ± 5.84 years among controls and 30.86 ± 6.14 years in the experimental group; BMI: 27.35 ± 4.63 kg/m2 vs. 25.74 ± 2.70 kg/m2). The pulse rate was 69.35 ± 10.98 in the control vs. 70.68 ± 10.32 bpm in the experimental group. The waist size was also similar in both groups. Baseline lab findings were as follows: ApoB: 89.85 ± 17.52 (control), 81.60 ± 12.84 mg/dL (experimental); hs-CRP: 0.18 ± 0.27 (control), 0.17 ± 0.27 mg/L (experimental); LDL-C 113.65 ±23.71 (control), 106.50 ± 18.99 mg/dL (experimental); HDL-C 57.35 ± 14.63 (control), 62.41 ± 16.15 mg/dL (experimental); and triglycerides: 76.00 ± 31.30 (control), 56.77 ± 14.77 mg/dL (experimental), and these values were similar. The values after 12 weeks of intervention were as follows: BMI: 27.37 ± 5.24 (control), 26.36 ± 3.55 (experimental); pulse rate: 78.88 ± 14.00 (control), 74.20 ± 11.90 bpm (experimental); ApoB 87.1 ± 17.38 (control), 85.7 ±20.59 mg/dL (experimental); hs-CRP 0.26 ± 0.22 (control), 0.15 ± 0.14 mg/L (experimental); LDL-C 111.59 ± 20.35 (control), 114.10 ± 26.99 mg/dL (experimental); HDL-C 57.71 ± 12.93 (control), 64.85 ± 13.32 mg/dL (experimental); and triglycerides: 74.71 ± 25.39 (control), 60.80 ± 15.77 mg/dL (experimental). Conclusion At a significance level of 5%, there was no difference between the two groups, either at the baseline or at 12 weeks of intervention. Based on our findings, adding MCT oil and butter to coffee may be safe. However, further studies with larger sample sizes and longer duration are needed to validate our findings.

Obesity, dyslipidemia, and cardiovascular disease: A joint expert review from the Obesity Medicine Association and the National Lipid Association 2024

BACKGROUND

This joint expert review by the Obesity Medicine Association (OMA) and National Lipid Association (NLA) provides clinicians an overview of the pathophysiologic and clinical considerations regarding obesity, dyslipidemia, and cardiovascular disease (CVD) risk.

METHODS

This joint expert review is based upon scientific evidence, clinical perspectives of the authors, and peer review by the OMA and NLA leadership.

RESULTS

Among individuals with obesity, adipose tissue may store over 50% of the total body free cholesterol. Triglycerides may represent up to 99% of lipid species in adipose tissue. The potential for adipose tissue expansion accounts for the greatest weight variance among most individuals, with percent body fat ranging from less than 5% to over 60%. While population studies suggest a modest increase in blood low-density lipoprotein cholesterol (LDL-C) levels with excess adiposity, the adiposopathic dyslipidemia pattern most often described with an increase in adiposity includes elevated triglycerides, reduced high-density lipoprotein cholesterol (HDL-C), increased non-HDL-C, elevated apolipoprotein B, increased LDL particle concentration, and increased small, dense LDL particles.

CONCLUSIONS

Obesity increases CVD risk, at least partially due to promotion of an adiposopathic, atherogenic lipid profile. Obesity also worsens other cardiometabolic risk factors. Among patients with obesity, interventions that reduce body weight and improve CVD outcomes are generally associated with improved lipid levels. Given the modest improvement in blood LDL-C with weight reduction in patients with overweight or obesity, early interventions to treat both excess adiposity and elevated atherogenic cholesterol (LDL-C and/or non-HDL-C) levels represent priorities in reducing the risk of CVD.

Common and divergent molecular mechanisms of fasting and ketogenic diets

Intermittent short-term fasting (ISTF) and ketogenic diets (KDs) exert overlapping but not identical effects on cell metabolism, function, and resilience. Whereas health benefits of KD are largely mediated by the ketone bodies (KBs), ISTF engages additional adaptive physiological responses. KDs act mainly through inhibition of histone deacetylases (HDACs), reduction of oxidative stress, improvement of mitochondria efficiency, and control of inflammation. Mechanisms of action of ISTF include stimulation of autophagy, increased insulin and leptin sensitivity, activation of AMP-activated protein kinase (AMPK), inhibition of the mechanistic target of rapamycin (mTOR) pathway, bolstering mitochondrial resilience, and suppression of oxidative stress and inflammation. Frequent switching between ketogenic and nonketogenic states may optimize health by increasing stress resistance, while also enhancing cell plasticity and functionality.

Does a Ketogenic Diet Have a Place Within Diabetes Clinical Practice? Review of Current Evidence and Controversies

Carbohydrate restriction has gained increasing popularity as an adjunctive nutritional therapy for diabetes management. However, controversy remains regarding the long-term suitability, safety, efficacy and potential superiority of a very low carbohydrate, ketogenic diet compared to current recommended nutritional approaches for diabetes management. Recommendations with respect to a ketogenic diet in clinical practice are often hindered by the lack of established definition, which prevents its capacity to be most appropriately prescribed as a therapeutic option for diabetes. Furthermore, with conflicted evidence, this has led to uncertainty amongst clinicians on how best to support and advise their patients. This review will explore whether a ketogenic diet has a place within clinical practice by reviewing current evidence and controversies.

Dietary Effects of Fasting on the Lipid Panel

INTRODUCTION

Dietary habits, such as the Mediterranean diet and the Dietary Approaches to Stop Hypertension (DASH), have been shown to improve cardiac health. Another more recent popular form of dieting incorporates periods of fasting known as intermittent fasting. The two main forms are alternate-day fasting and time-restricted eating.

METHODS

PubMed search and literature review was undertaken. This review evaluates the current literature regarding the effects of the fasting dietary model and other types of fasting upon the lipid panel.

RESULTS

There have been studies that have shown that intermittent fasting does provide a benefit in cardiovascular health, weight loss, and hypertension. However, the effect on cholesterol and triglyceride levels during intermittent fasting is in question.

CONCLUSION

The effect that fasting has on one's lipid panel is unclear, there are studies that show that different forms of fasting affect the lipid panel in various ways. There are studies that show that intermittent fasting does improve one's lipid profile and provides health benefits. Randomized controlled clinical trials with a large sample size are needed to evaluate the effects that intermittent fasting has based on race, ethnicity, gender, obesity, dyslipidemia, diabetic and healthy patients, and will lead to definitive evidence of lipid panel outcomes beyond current evidence based solely upon observational cohorts with numerous and multifactorial confounding factors and biases.

Extreme Hypercholesterolemia Following a Ketogenic Diet: Exaggerated Response to an Increasingly Popular Diet

A high-fat, very low-carbohydrate diet, often named the "ketogenic diet," is gaining popularity, particularly among patients with obesity and metabolic syndrome seeking rapid weight loss and improvement in glycemic control. A favorable reduction in triglycerides and an increase in high-density lipoprotein-cholesterol levels is often observed in the ketogenic diet. However, people vary significantly in their low-density lipoprotein-cholesterol (LDL-C) response to the dietary change. Here, we present the case of a 38-year-old normal-weight male with average cholesterol levels showing an extreme fourfold elevation in LDL-C levels, reaching 496 mg/dL after initiating a ketogenic diet. We highlight that a dramatic elevation in LDL-C may manifest following a ketogenic diet in normal-weight people without known genetic dyslipidemias before the dietary change; therefore, increased awareness and close monitoring of blood lipid profile is essential for all individuals following a ketogenic diet. We further discuss the potential mechanisms for the "lean mass hyper-responders" phenotype which has been recently gaining recognition, and suggest that these patients may benefit from ezetimibe therapy, decreasing the absorption of intestinal cholesterol to the liver.

Dietary recommendations for dysbetalipoproteinemia: A need for better evidence

The increased risk of cardiovascular disease in patients with dysbetalipoproteinemia (DBL) is well documented and is associated with the dysfunctional metabolism of remnant lipoproteins. Although these patients are known to respond well to lipid-lowering medication including statins and fibrates, the best dietary approach to lower remnant lipoprotein accumulation and to prevent cardiovascular outcomes remain unclear. Indeed, current evidence is based on studies published mainly in the 1970s, which comprise small sample sizes and methodological limitations. This review aims to summarize nutritional studies performed in DBL patients to date and to discuss potential avenues in this field and future areas of research.

Dramatic elevation of LDL cholesterol from ketogenic-dieting: A Case Series

High-fat, low carb dieting, also known as the "ketogenic diet," has increased in popularity as a rapid weight-loss tool. Previous studies describe a modest elevation in cholesterol in the average keto-diet participant without specific cardiovascular impact. We hypothesize that patients with a genetic predisposition to cholesterol metabolism dysregulation may have a disproportionate elevation in cholesterol in response to ketogenic dieting.

Low-carbohydrate diets in type 1 diabetes: balancing benefits and risks

PURPOSE OF REVIEW

Interest in the use of calorie restriction with low-carbohydrate diets for patients with type 1 diabetes appears to be increasing despite physicians' discomfort about its longer term outcomes. A divergence in opinion regarding the balance of benefits and safety may lead to patient disengagement from conventional medical supervision. This review describes the current evidence regarding the benefits and risks of these diets and suggests a way forward to addressing this potential misalignment between the aims of patients and their physicians.

RECENT FINDINGS

Benefits on glycaemia are observed in many studies, with improved HbA1c, time within target range and reduced glycaemic variability. A characteristic lipid profile with high LDL cholesterol is observed in many patients, but association with future cardiovascular events is undefined. A negative impact on growth has been identified in the paediatric population, and impact on mental health and disordered eating is of theoretical concern, without measurement in clinical studies.

SUMMARY

Patients will continue to trial and, with immediate glycaemic benefits, potentially remain on lower carbohydrate diets irrespective of concern by treating physicians about potential longer term risks. A supportive multidisciplinary approach with greater nutritional supervision and more research is required, to allow these patients to achieve their desired glycaemic outcomes without compromising longer term safety.

Severe Dyslipidemia Mimicking Familial Hypercholesterolemia Induced by High-Fat, Low-Carbohydrate Diets: A Critical Review

Emerging studies in the literature describe an association between high-fat, low-carbohydrate diets and severe hypercholesterolemia consistent with the levels observed in patients with (homozygous) familial hypercholesterolemia (FH). High levels of low-density lipoprotein cholesterol (LDL-C) may result from the reduced clearance of LDL particles from the circulation, the increased production of their precursor, or a combination of both. The increased intake of (saturated) fat and cholesterol, combined with limited to no intake of carbohydrates and fiber, are the main features of diets linked to hypercholesterolemia. However, several observations in previous studies, together with our observations from our lipid clinic, do not provide a definitive pathophysiological explanation for severe hypercholesterolemia. Therefore, we review these findings and possible pathophysiological explanations as well as opportunities for future research. Altogether, clinicians should rule out high-fat, low-carbohydrate diets as a possible cause for hypercholesterolemia in patients presenting with clinical FH in whom no mutation is found and discuss dietary modifications to durably reduce LDL-C levels and cardiovascular disease risk.

A Heart-Healthy Diet for Cardiovascular Disease Prevention: Where Are We Now?

Purpose of Review

The relationship between cardiovascular health and diet is evolving. Lifestyle modifications including diet changes are the primary approach in managing cardiometabolic risk factors. Thus, understanding different diets and their impact on cardiovascular health is important in guiding primary and secondary prevention of cardiovascular disease (CVD). Yet, there are many barriers and limitations to adopting a heart healthy diet.

Recent Findings

Diets rich in fruits, vegetables, legumes, whole grains, and lean protein sources, with minimization/avoidance of processed foods, trans-fats, and sugar sweetened beverages, are recommended by prevention guidelines. The Mediterranean, DASH, and plant-based diets have all proven cardioprotective in varying degrees and are endorsed by professional healthcare societies, while other emerging diets such as the ketogenic diet and intermittent fasting require more long-term study. The effects of diet on the gut microbiome and on cardiovascular health have opened a new path for precision medicine to improve cardiometabolic risk factors. The effects of certain dietary metabolites, such as trimethylamine N-oxide, on cardiometabolic risk factors, along with the changes in the gut microbiome diversity and gene pathways in relation to CVD management, are being explored.

Summary

In this review, we provide a comprehensive up-to-date overview on established and emerging diets in cardiovascular health. We discuss the effectiveness of various diets and most importantly the approaches to nutritional counseling where traditional and non-traditional approaches are being practiced, helping patients adopt heart healthy diets. We address the limitations to adopting a heart healthy diet regarding food insecurity, poor access, and socioeconomic burden. Lastly, we discuss the need for a multidisciplinary team-based approach, including the role of a nutrition specialist, in implementing culturally-tailored dietary recommendations. Understanding the limitations and finding ways to overcome the barriers in implementing heart-healthy diets will take us miles in the path to CVD prevention and management.

Dietary management of dyslipidemia and the impact of dietary patterns on lipid disorders

Dyslipidemia is a major risk factor for atherosclerotic cardiovascular disease and a healthy lifestyle is the first line of therapy for treatment. A healthy dietary pattern is a cornerstone for treating elevated low-density lipoprotein-cholesterol (LDL-C) and triglycerides (TG), both of which are hallmarks of dyslipidemia. Much research has been conducted evaluating the effect of different dietary patterns on LDL-C and TG, both eucalorically and with weight loss. Herein we review studies that have evaluated the effects of different dietary patterns on LDL-C and TG. Within the context of a healthy dietary pattern, constituent food and nutrient intakes impact LDL-C and TG lowering. Food- and nutrient-based recommendations for lowering both LDL-C and TG, will also be reviewed. Finally, the suitability of popular diets for patients with dyslipidemia will be discussed. Lifestyle interventions, including dietary intervention, should be individualized and customized to patient preferences to achieve clinically relevant lipid/lipoprotein improvements.

Obesity pillars roundtable: Phentermine - Past, present, and future

Background

Phentermine is a sympathomimetic amine, approved for "short-term"treatment of patients with obesity. Among phentermine contraindications include use in patients with cardiovascular disease or patients with uncontrolled hypertension.

Methods

This roundtable discussion includes perspectives from 3 obesity specialists with experience in the clinical use of phentermine. The questions asked of the panelists were derived from publications regarding phentermine safety and efficacy.

Results

While the panelists generally agreed upon core principles of phentermine use, each obesity specialist had their own priorities and style regarding the administration of phentermine. Among the variances in perceptions (based upon their individual "real world" clinical experiences) included the degree of efficacy and degree of clinical benefit of phentermine, degree of concern regarding phentermine use in patients with cardiovascular disease risk factors, the advisability of a screening electrocardiogram, and the role of telehealth in prescribing phentermine and monitoring for the efficacy and safety of phentermine.

Conclusions

Providing universal guidance regarding phentermine treatment for obesity is challenging because of the lack of long-term, prospective, randomized, placebo-controlled, health outcomes data. Such data is unlikely forthcoming any time soon. Also challenging are the substantial variances in governmental restrictions on phentermine use. Therefore, clinicians are left to rely on the best available evidence, their individual practical clinical experience, as well as the collective clinical experiences of others - as reflected by this roundtable.

Profound Elevation in LDL Cholesterol Level Following a Ketogenic Diet: A Case Series

The ketogenic diet (KD) is currently popular for the achievement of weight loss and improvement in glycemic variables. The diet allows consumption of foods high in fat and protein, with strict limitation of carbohydrates. We present a case series of substantial increases in total cholesterol and low-density lipoprotein cholesterol following the initiation of a KD, with improvements in cholesterol levels once the KD was stopped. Novel teaching points include the need for lipid monitoring in patients who choose to follow a KD and for raising awareness of the extreme lipid response that can occur in some patients, particularly lean individuals.

Keto is Trending: Implications for Body Weight and Lipid Management

PURPOSE OF REVIEW

Very-low-carbohydrate (VLC) and ketogenic diets (KDs) have been used for weight loss and more recently in patients with insulin resistance and type 2 diabetes. The impact of VLC and KDs on lipids/lipoproteins is a concern. The purpose of this review is to discuss the impact of KDs on body weight and lipids/lipoproteins.

RECENT FINDINGS

VLC/KDs contribute to greater weight loss in the short term (< 6 months) compared to higher carbohydrate diets, but there is typically no difference between the diets by 12 months. Triglyceride and high-density lipoprotein cholesterol levels generally improve, but there is a variable response in low-density lipoprotein cholesterol levels, with some individuals experiencing a dramatic increase, particularly those with latent genetic dyslipidemias. Healthcare professionals should educate patients on the risks and benefits of following VLC/KDs and encourage the consumption of carbohydrate-rich foods associated with positive health outcomes.

The Lipid Energy Model: Reimagining Lipoprotein Function in the Context of Carbohydrate-Restricted Diets

When lean people adopt carbohydrate-restricted diets (CRDs), they may develop a lipid profile consisting of elevated LDL-cholesterol (LDL-C) and HDL-cholesterol (HDL-C) with low triglycerides (TGs). The magnitude of this lipid profile correlates with BMI such that those with lower BMI exhibit larger increases in both LDL-C and HDL-C. The inverse association between BMI and LDL-C and HDL-C change on CRD contributed to the discovery of a subset of individuals—termed Lean Mass Hyper-Responders (LMHR)—who, despite normal pre-diet LDL-C, as compared to non-LMHR (mean levels of 148 and 145 mg/dL, respectively), exhibited a pronounced hyperlipidemic response to a CRD, with mean LDL-C and HDL-C levels increasing to 320 and 99 mg/dL, respectively, in the context of mean TG of 47 mg/dL. In some LMHR, LDL-C levels may be in excess of 500 mg/dL, again, with relatively normal pre-diet LDL-C and absent of genetic findings indicative of familial hypercholesterolemia in those who have been tested. The Lipid Energy Model (LEM) attempts to explain this metabolic phenomenon by positing that, with carbohydrate restriction in lean persons, the increased dependence on fat as a metabolic substrate drives increased hepatic secretion and peripheral uptake of TG contained within very low-density lipoproteins (VLDL) by lipoprotein lipase, resulting in marked elevations of LDL-C and HDL-C, and low TG. Herein, we review the core features of the LEM. We review several existing lines of evidence supporting the model and suggest ways to test the model’s predictions.

Approach to the Patient With Moderate Hypertriglyceridemia

Hypertriglyceridemia is a common lipid disorder encountered in clinical practice. Plasma triglycerides are a marker for the concentration of triglycerides carried in chylomicrons and very low-density lipoprotein particles. A fasting triglyceride level <150 mg/dL is accepted widely as the upper limit of normal range. Guidelines for hypertriglyceridemia are variable without a global consensus on classification and goals for triglyceride levels. A general classification of hypertriglyceridemia is mild < 200 mg/dL, moderate = 200 to 500 mg/dL, moderate to severe = 500 to 1000 mg/dL, and severe > 1000 mg/dL. Because moderate hypertriglyceridemia does increase atherosclerotic cardiovascular disease risk, it is important to determine the underlying etiology to guide appropriate and timely management. This article provides stepwise recommendations on the diagnosis and management of moderate hypertriglyceridemia, based on 3 common scenarios encountered in clinical practice. Initial steps in management include evaluating for secondary contributors, especially diabetes mellitus. Based on patient characteristics, appropriate management decisions include lifestyle adjustments aimed at weight loss and decreasing alcohol consumption and use of statin and nonstatin therapies.

Short-Chain Carbon Sources

Heart failure (HF) remains the leading cause of morbidity and mortality in the developed world, highlighting the urgent need for novel, effective therapeutics. Recent studies support the proposition that improved myocardial energetics as a result of ketone body (KB) oxidation may account for the intriguing beneficial effects of sodium-glucose cotransporter-2 inhibitors in patients with HF. Similar small molecules, short-chain fatty acids (SCFAs) are now realized to be preferentially oxidized over KBs in failing hearts, contradicting the notion of KBs as a rescue "superfuel." In addition to KBs and SCFAs being alternative fuels, both exert a wide array of nonmetabolic functions, including molecular signaling and epigenetics and as effectors of inflammation and immunity, blood pressure regulation, and oxidative stress. In this review, the authors present a perspective supported by new evidence that the metabolic and unique nonmetabolic activities of KBs and SCFAs hold promise for treatment of patients with HF with reduced ejection fraction and those with HF with preserved ejection fraction.

Case Report: Hypercholesterolemia "Lean Mass Hyper-Responder" Phenotype Presents in the Context of a Low Saturated Fat Carbohydrate-Restricted Diet

Emerging evidence suggests that "leanness" and good metabolic health markers may predict larger increases in LDL cholesterol (LDL-C) in response to carbohydrate restriction. Specifically, a recent cohort study demonstrated an inverse association between BMI and LDL-C change among individuals on carbohydrate-restricted diets and identified a subgroup of "Lean Mass Hyper-Responders" (LMHR) who exhibit exceptional increases in LDL-C, in the context of low triglycerides and high HDL-C. We present the case of one subject, LM, who adopted a ketogenic diet for management of ulcerative colitis. He subsequently experienced an increase in LDL-C from 95 to 545 mg/dl, at peak, in association with HDL-C >100 mg/dl and triglycerides ~40 mg/dl, typical of the emergent LMHR phenotype. Assessments of LM's dietary intake, lipid panels, and BMI are consistent with prior data and suggest that the LMHR phenomenon is not dependent on saturated fat intake but inversely associates with BMI changes. Finally, computed tomography angiography conducted on LM after over 2 years of hypercholesterolemia revealed no evidence of calcified or non-calcified plaque.

Nutrition and physical activity: An Obesity Medicine Association (OMA) Clinical Practice Statement 2022

Background

This Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) on Nutrition and Physical Activity provides clinicians an overview of nutrition and physical activity principles applicable to the care of patients with increased body fat, especially those with adverse fat mass and adiposopathic metabolic consequences.

Methods

The scientific information and clinical guidance is based upon referenced evidence and derived from the clinical perspectives of the authors.

Results

This OMA CPS on Nutrition and Physical Activity provides basic clinical information regarding carbohydrates, proteins, fats (including trans fats, saturated fats, polyunsaturated fats, and monounsaturated fats), general principles of healthful nutrition, nutritional factors associated with improved health outcomes, and food labels. Included are the clinical implications of isocaloric substitution of refined carbohydrates with saturated fats and vice-versa, as well as definitions of low-calorie, very low-calorie, carbohydrate-restricted, and fat-restricted dietary intakes. Specific dietary plans discussed include carbohydrate-restricted diets, fat-restricted diets, very low-calorie diets, the Mediterranean diet, Therapeutic Lifestyle diet, Dietary Approaches to Stop Hypertension (DASH), ketogenic (modified Atkins) diet, Ornish diet, Paleo diet, vegetarian or vegan diet (whole food/plant-based), intermittent fasting/time restricted feeding, and commercial diet programs. This clinical practice statement also examines the health benefits of physical activity and provides practical pre-exercise medical evaluation guidance as well as suggestions regarding types and recommended amounts of dynamic (aerobic) training, resistance (anaerobic) training, leisure time physical activity, and non-exercise activity thermogenesis (NEAT). Additional guidance is provided regarding muscle physiology, exercise prescription, metabolic equivalent tasks (METS), and methods to track physical activity progress.

Conclusion

This Obesity Medicine Association Clinical Practice Statement on Nutrition and Physical Activity provides clinicians an overview of nutrition and physical activity. Implementation of appropriate nutrition and physical activity in patients with pre-obesity and/or obesity may improve the health of patients, especially those with adverse fat mass and adiposopathic metabolic consequences.

Saturated fats and cardiovascular health: Current evidence and controversies

A diet high in saturated fatty acids (SFA) is a suspected contributor to atherosclerotic cardiovascular disease (ASCVD) risk, in large part because of an effect to raise the low-density lipoprotein cholesterol (LDL-C) concentration. Most dietary guidance from health authorities advocates limiting intake of SFA, particularly for people with clinical ASCVD, dyslipidemia, or diabetes mellitus. However, recent reviews have highlighted controversies regarding SFA intake and cardiovascular health. This brief editorial commentary includes a discussion of the evidence regarding SFA intake and cardiovascular health, outlines gaps in the available evidence, and proposes tentative conclusions based on what is known today about SFA consumption and ASCVD risk. Results from observational studies demonstrate that dietary patterns with lower average intakes of SFA are associated with favorable cardiovascular outcomes. Additionally, although the number of randomized controlled trials testing the effects of reducing SFA intake on ASCVD outcomes is limited, the available evidence supports the view that replacing SFA with unsaturated fatty acids, particularly polyunsaturated fatty acids, may reduce ASCVD risk. Beyond raising LDL-C and atherogenic lipoprotein particle concentrations, higher intakes of SFA may influence pathways affecting inflammation, cardiac rhythm, hemostasis, apolipoprotein CIII production, and high-density lipoprotein function. However, the impacts of these effects on ASCVD risk remain uncertain. In the authors' view, the totality of the evidence supports the current recommendation to limit SFA intake to <10% of total daily energy for the general healthy population and further (e.g., to 5-6% of total daily energy) for patients with hypercholesterolemia.

Effects of a low-carbohydrate diet on insulin-resistant dyslipoproteinemia-a randomized controlled feeding trial

BACKGROUND

Carbohydrate restriction shows promise for diabetes, but concerns regarding high saturated fat content of low-carbohydrate diets limit widespread adoption.

OBJECTIVES

This preplanned ancillary study aimed to determine how diets varying widely in carbohydrate and saturated fat affect cardiovascular disease (CVD) risk factors during weight-loss maintenance.

METHODS

After 10-14% weight loss on a run-in diet, 164 participants (70% female; BMI = 32.4 ± 4.8 kg/m2) were randomly assigned to 3 weight-loss maintenance diets for 20 wk. The prepared diets contained 20% protein and differed 3-fold in carbohydrate (Carb) and saturated fat as a proportion of energy (Low-Carb: 20% carbohydrate, 21% saturated fat; Moderate-Carb: 40%, 14%; High-Carb: 60%, 7%). Fasting plasma samples were collected prerandomization and at 20 wk. Lipoprotein insulin resistance (LPIR) score was calculated from triglyceride-rich, high-density, and low-density lipoprotein particle (TRL-P, HDL-P, LDL-P) sizes and subfraction concentrations (large/very large TRL-P, large HDL-P, small LDL-P). Other outcomes included lipoprotein(a), triglycerides, HDL cholesterol, LDL cholesterol, adiponectin, and inflammatory markers. Repeated measures ANOVA was used for intention-to-treat analysis.

RESULTS

Retention was 90%. Mean change in LPIR (scale 0-100) differed by diet in a dose-dependent fashion: Low-Carb (-5.3; 95% CI: -9.2, -1.5), Moderate-Carb (-0.02; 95% CI: -4.1, 4.1), High-Carb (3.6; 95% CI: -0.6, 7.7), P = 0.009. Low-Carb also favorably affected lipoprotein(a) [-14.7% (95% CI: -19.5, -9.5), -2.1 (95% CI: -8.2, 4.3), and 0.2 (95% CI: -6.0, 6.8), respectively; P = 0.0005], triglycerides, HDL cholesterol, large/very large TRL-P, large HDL-P, and adiponectin. LDL cholesterol, LDL-P, and inflammatory markers did not differ by diet.

CONCLUSIONS

A low-carbohydrate diet, high in saturated fat, improved insulin-resistant dyslipoproteinemia and lipoprotein(a), without adverse effect on LDL cholesterol. Carbohydrate restriction might lower CVD risk independently of body weight, a possibility that warrants study in major multicentered trials powered on hard outcomes. The registry is available through ClinicialTrials.gov: https://clinicaltrials.gov/ct2/show/NCT02068885.

Ketogenic diet impairs Mycobacterium ulcerans growth and toxin production, enhancing hosts' response to the infection in an experimental mouse model

Ketogenic diets have been used to treat diverse conditions, and there is growing evidence of their benefits for tissue repair and in inflammatory disease treatment. However, their role in infectious diseases has been little studied. Buruli ulcer (Mycobacterium ulcerans infection) is a chronic infectious disease characterized by large skin ulcerations caused by mycolactone, the major virulence factor of the bacillus. Here, we investigated the impact of ketogenic diet on this cutaneous disease in an experimental mouse model. This diet prevented ulceration, by modulating bacterial growth and host inflammatory response. β-hydroxybutyrate, the major ketone body produced during ketogenic diet and diffusing in tissues, impeded M. ulcerans growth and mycolactone production in vitro underlying its potential key role in infection. These results pave the way for the development of new patient management strategies involving shorter courses of treatment and improving wound healing, in line with the major objectives of the World Health Organization.

[Diet and Nutrition in the Prevention of Non-Communicable Diseases (NCD)]

Today, more than 50 % of adults in Germany are overweight, 20 million people are obese and 10 to 30 % suffer from non-communicable diseases (NCD). Unhealthy dietary patterns contribute to NCD, thus, NCD are at least partly avoidable. During the last decades nutrition research has changed from nutrients to foods identifying healthy food patterns characterizing healthy diets, e. g., Mediterranean diet, DASH diet and/or the New Nordic Diet. Scientifically, these diets have been shown to be effective strategies of primary and secondary prevention of NCD. Based on this evidence prevention of NCD is now urgently needed at the population level. However, effective public health strategies of prevention and health promotion go beyond daily medical practice and require re-thinking of our food system within a greater context of our environment and climate. To become sustainable, strategies and measures of behavior prevention addressing individuals have to be extended to measures against the obesogenic environment and its systemic drivers within our food system. Thus, social and political changes are needed for a better future health of the nation. Physicians may take the leadership to be prepared to add to a whole of society approach of prevention and health promotion.