Very-low-calorie ketogenic diet: An alternative to a pharmacological approach to improve glycometabolic and gonadal profile in men with obesity

The Effects of Different Types of Diets on Steroid Hormone Concentrations

The great popularity of various diets in recent years has led us to reflect on their suitability for our health. The aim of this communication is to review current knowledge on the influence of the most well-known diets on the concentrations of the main steroids and to consider possible mechanisms. The influence of diet on hormone concentrations is expected, but the literature data on this topic are inconsistent and yield conflicting results. The main problem in evaluating these influences is the change in weight that a change in diet induces. This effect needs to be filtered out in order to discover interesting associations between diet and steroid hormones. This is illustrated by the example of the effects of ketogenic diets on testosterone levels in men, where the direct effect of the diet is to reduce testosterone levels, but a number of papers have described increases that are due to diet-related weight loss and the modification of obesity-induced changes. A second major driver is the change in circadian rhythm, and it is necessary to assess hormonal changes induced by changing the time of day of the diet. Such shifts within the circadian rhythm rather than due to a particular type of diet itself are documented by changes in the circadian rhythm of cortisol.

Low carbohydrate intake correlates with trends of insulin resistance and metabolic acidosis in healthy lean individuals

Introduction

Both obesity and a poor diet are considered major risk factors for triggering insulin resistance syndrome (IRS) and the development of type 2 diabetes mellitus (T2DM). Owing to the impact of low-carbohydrate diets, such as the keto diet and the Atkins diet, on weight loss in individuals with obesity, these diets have become an effective strategy for a healthy lifestyle. However, the impact of the ketogenic diet on IRS in healthy individuals of a normal weight has been less well researched. This study presents a cross-sectional observational study that aimed to investigate the effect of low carbohydrate intake in healthy individuals of a normal weight with regard to glucose homeostasis, inflammatory, and metabolic parameters.

Methods

The study included 120 participants who were healthy, had a normal weight (BMI 25 kg/m2), and had no history of a major medical condition. Self-reported dietary intake and objective physical activity measured by accelerometry were tracked for 7 days. The participants were divided into three groups according to their dietary intake of carbohydrates: the low-carbohydrate (LC) group (those consuming <45% of their daily energy intake from carbohydrates), the recommended range of carbohydrate (RC) group (those consuming 45-65% of their daily energy intake from carbohydrates), and the high-carbohydrate (HC) group (those consuming more than 65% of their daily energy intake from carbohydrates). Blood samples were collected for the analysis of metabolic markers. HOMA of insulin resistance (HOMA-IR) and HOMA of β-cell function (HOMA-β), as well as C-peptide levels, were used for the evaluation of glucose homeostasis.

Results

Low carbohydrate intake (<45% of total energy) was found to significantly correlate with dysregulated glucose homeostasis as measured by elevations in HOMA-IR, HOMA-β% assessment, and C-peptide levels. Low carbohydrate intake was also found to be coupled with lower serum bicarbonate and serum albumin levels, with an increased anion gap indicating metabolic acidosis. The elevation in C-peptide under low carbohydrate intake was found to be positively correlated with the secretion of IRS-related inflammatory markers, including FGF2, IP-10, IL-6, IL-17A, and MDC, but negatively correlated with IL-3.

Discussion

Overall, the findings of the study showed that, for the first time, low-carbohydrate intake in healthy individuals of a normal weight might lead to dysfunctional glucose homeostasis, increased metabolic acidosis, and the possibility of triggering inflammation by C-peptide elevation in plasma.

A bibliometric analysis of the global trends and hotspots for the ketogenic diet based on CiteSpace

The ketogenic diet (KD) is a potential nutritional therapy that is frequently utilized in various conditions. More and more studies are being done on KD in recent years. However, as far as we know, few studies have made an effort to offer a thorough synthesis and assessment of this topic. This paper aims to do a rigorous and thorough evaluation of the knowledge structure, development trend, and research hotspot of scientific outputs connected to KD. The bibliographic records connected to KD from January 1, 2001 to April 22, 2022 were collected using the core collection database of Web of Science. The complex data input, that consisted of the amount of publications, journals, authors, institutions, countries, keywords and cited references, was generated and analyzed visually using CiteSpace. A total of 2676 literatures on the KD were published between 2001 and 2022. The most KD-related publications were found in Epilepsia and Epilepsia Research. The authors with the most KD-related papers are Kossoff EH and Rho J. The United States is the country with the most publications, and Johns Hopkins University, Johns Hopkins University Hospital, and Johns Hopkins Medical Institutions are the institutions with the most articles. The high frequency keywords are "KD," "ketone body," "children," "efficacy," "weight loss," "low carbohydrate diet," "metabolism," "epilepsy," "beta hydroxybutyrate," and "modified atkins diet." The 2018 study by Kossoff EH on epilepsia and the 2017 study by Puchalska P on ketone body metabolism earned 127 and 114 citations, respectively. The results of this bibliometric analysis provide information on the state and trends in KD and may be used by researchers to pinpoint hot issues and discover new areas of study.

Italian Ketogenic Mediterranean Diet in Overweight and Obese Patients with Prediabetes or Type 2 Diabetes

Obesity is a multifactorial disease strongly associated with insulin resistance and/or type 2 diabetes mellitus. Correct nutrition represents a valid strategy to fight these dysmetabolic pathologies responsible for numerous diseases, including inflammatory and cardiovascular ones. Medical nutrition therapy, including a Mediterranean diet (MD) and a very low-calorie ketogenic diet (VLKCD), is the first-line treatment for prediabetes/diabetes and overweight/obesity. Eighty patients (forty women and forty men) affected by overweight/obesity and type 2 diabetes mellitus or impaired glucose tolerance or impaired fasting glucose (51 (ys) ± 1.75; BMI (kg/m2) 33.08 ± 1.93; HA1c (%): 6.8% ± 0.25) were enrolled at the University Service of Diet Therapy, Diabetology and Metabolic Diseases, Policlinico Riuniti Hospital of Foggia, and subjected to a very-low-calorie Mediterranean diet and a very-low-calorie ketogenic Mediterranean diet for thirty days. Both diets result in a marked decrease in body weight (kg) and BMI (kg/m2). At the same time, only the very-low-calories ketogenic Mediterranean diet reduced waist and hip circumferences. Both diets helped reduce fat mass, but a major loss was achieved in a very low-calorie ketogenic Mediterranean diet. Among gluco-metabolic parameters, only the very-low-calorie ketogenic Mediterranean diet group showed a significant decrease in fasting blood glucose and HbA1c, insulin, C-peptide total cholesterol, LDL, and triglycerides. The results of our study seem to show that the very-low-calorie ketogenic Mediterranean diet is a good strategy to improve rapidly metabolic, anthropometric, and body composition parameters in patients with prediabetes or diabetes and overweight/obesity.

Adipose Tissue Dysfunction and Obesity-Related Male Hypogonadism

Obesity is a chronic illness associated with several metabolic derangements and comorbidities (i.e., insulin resistance, leptin resistance, diabetes, etc.) and often leads to impaired testicular function and male subfertility. Several mechanisms may indeed negatively affect the hypothalamic–pituitary–gonadal health, such as higher testosterone conversion to estradiol by aromatase activity in the adipose tissue, increased ROS production, and the release of several endocrine molecules affecting the hypothalamus–pituitary–testis axis by both direct and indirect mechanisms. In addition, androgen deficiency could further accelerate adipose tissue expansion and therefore exacerbate obesity, which in turn enhances hypogonadism, thus inducing a vicious cycle. Based on these considerations, we propose an overview on the relationship of adipose tissue dysfunction and male hypogonadism, highlighting the main biological pathways involved and the current therapeutic options to counteract this condition.

Obesity and Male Reproduction: Do Sirtuins Play a Role?

Obesity is a major current public health problem of global significance. A progressive sperm quality decline, and a decline in male fertility, have been reported in recent decades. Several studies have reported a strict relationship between obesity and male reproductive dysfunction. Among the many mechanisms by which obesity impairs male gonadal function, sirtuins (SIRTs) have an emerging role. SIRTs are highly conserved nicotinamide adenine dinucleotide (NAD+)-dependent deacetylases that play a role in gene regulation, metabolism, aging, and cancer. SIRTs regulate the energy balance, the lipid balance, glucose metabolism, and adipogenesis, but current evidence also indicates a role for SIRTs in male reproduction. However, the majority of the studies have been conducted in animal models and very few have been conducted with humans. This review shows that SIRTs play an important role among the molecular mechanisms by which obesity interferes with male fertility. This highlights the need to deepen this relationship. It will be of particular interest to evaluate whether synthetic and/or natural compounds capable of modifying the activity of SIRTs may also be useful for the treatment of obesity and its effects on gonadal function. Although few studies have explored the role of SIRT activators in obesity-induced male infertility, some molecules, such as resveratrol, appear to be effective in modulating SIRT activity, as well as counteracting the negative effects of obesity on male fertility. The search for strategies to improve male reproductive function in overweight/obese patients is a challenge and understanding the role of SIRTs and their activators may open new interesting scenarios in the coming years.