Short- and long-term effects of very low- and low-calorie ketogenic diets on metabolism and cardiometabolic risk factors: a narrative review.

Worldwide obesity and cardiovascular diseases have encouraged the adoption of new and efficient dietary strategies. Among various proposed diets, ketogenic diets, both the very-low-calorie ketogenic diet (VLCKD) and the low-calorie ketogenic diet (LCKD), have been suggested in recent years as an effective nutritional approach for obesity management. The VLCKD and the LCKD are characterized by a low carbohydrate content (<50 g/day), 1-1.5 g of protein/kg of ideal body weight, less than 20-30 g of lipids, and a daily intake of about 800 calories for VLCKD and about 1200-1400 calories for LCKD. The purpose of our narrative review is to offer an overview of the most impactful studies in the scientific literature regarding VLCKD and LCKD to discuss their short- and long-term effects (less than 12 months and more than 12 months respectively) on weight loss, metabolic and cardiovascular aspects. Articles we focused on were cohort studies, case-control studies, cross-sectional studies, randomized controlled trials, and meta-analyses. Results indicate that VLCKD and LCKD could be helpful to ameliorate metabolic and cardiovascular risk factors such as weight loss, glucose, and cholesterol levels, both in the short and long term. Further research in this area may include more randomized controlled trials to gather more data.

Mediterranean Diet versus Very Low-Calorie Ketogenic Diet: Effects of Reaching 5% Body Weight Loss on Body Composition in Subjects with Overweight and with Obesity-A Cohort Study.

The best nutritional strategy to fight the rise in obesity remains a debated issue. The Mediterranean diet (MD) and the Very Low-Calorie Ketogenic diet (VLCKD) are effective at helping people lose body weight (BW) and fat mass (FM) while preserving fat-free mass (FFM). This study aimed to evaluate the time these two diets took to reach a loss of 5% of the initial BW and how body composition was affected. We randomized 268 subjects with obesity or overweight in two arms, MD and VLCKD, for a maximum of 3 months or until they reached 5% BW loss. This result was achieved after one month of VLCKD and 3 months of MD. Both diets were effective in terms of BW (p < 0.0001) and FM loss (p < 0.0001), but the MD reached a higher reduction in both waist circumference (p = 0.0010) and FM (p = 0.0006) and a greater increase in total body water (p = 0.0017) and FFM (p = 0.0373) than VLCKD. The population was also stratified according to gender, age, and BMI. These two nutritional protocols are both effective in improving anthropometrical parameters and body composition, but they take different time spans to reach the goal. Therefore, professionals should evaluate which is the most suitable according to each patient's health status.

Calcium Citrate Versus Calcium Carbonate in the Management of Chronic Hypoparathyroidism: A Randomized, Double-Blind, Crossover Clinical Trial.

In hypoparathyroidism (HypoPT), calcium supplementation is virtually always required, although the disease is likely to be associated with an increased risk of nephrolithiasis. The use of calcium citrate (Ca-Cit) theoretically could have a positive impact on the nephrolithiasis risk because citrate salts are used to reduce this risk. Our objective was to evaluate the potential therapeutic advantage of Ca-Cit in comparison with calcium carbonate (CaCO3 ) in HypoPT, on nephrolithiasis risk factors, as well as to their ability to maintain desirable serum calcium levels. We also evaluated these preparations on quality of life (QOL). This randomized, double-blind, crossover trial recruited 24 adults with postsurgical chronic hypoparathyroidism at Campus Bio-Medico University of Rome. Participants were randomized 1:1 to Ca-Cit or CaCO3 for 1 month and then crossed over to the other treatment for another month. The primary outcomes were changes in albumin-adjusted serum calcium and in ion activity product of calcium oxalate levels (AP[CaOx] index). Secondary efficacy outcomes included changes in SF-36 survey score, fatigue score, constipation, and adverse events. No difference in terms of AP(CaOx) index was observed between the two groups. However, Ca-Cit was associated with a significant reduction in the oxalate/creatinine ratio compared with CaCO3 (-2.46 mmol/mol [SD 11.93] versus 7.42 mmol/mol [SD 17.63], p = 0.029). Serum calcium and phosphorus concentration was not different between the two calcium preparations. Ca-Cit was associated with less constipation (p = 0.047). No difference was found in QOL scores. Although Ca-Cit did not modify the AP(CaOx) index when compared with CaCO3, it was associated with a reduction in urinary oxalate excretion that could have a potential beneficial effect on nephrolithiasis risk. These results are likely to have clinical implications in HypoPT, particularly those who do not tolerate CaCO3 and those affected by nephrolithiasis. A longer-term experience is needed to confirm these findings. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Cardiovascular Autonomic Neuropathy as a New Complication of Postsurgical Chronic Hypoparathyroidism.

Postsurgical hypoparathyroidism (hypoPT) increases fatigue and seems to affect the risk of mortality. Cardiovascular autonomic neuropathy (CAN) is an impairment of the cardiovascular autonomic system, a cause of increased mortality, and associated with increased fatigability. The aim of this study is to evaluate CAN in hypoPT and its relationship with hypocalcemia, PTH levels, and hyperphosphatemia. This is a cross-sectional study comparing 51 postsurgical hypoPT patients treated with calcium and calcitriol and 43 control subjects without any PTH/calcium/phosphate disorders who underwent thyroidectomy. CAN was assessed by heart rate (HR) response to deep breathing, HR response to the lying-to-standing test, HR response to the Valsalva maneuver, and blood pressure response to standing. Participants were considered to have "early CAN" if they had one abnormal result in the HR tests and "definite CAN" with two or more abnormal results. The prevalence of CAN was 23% in the control group and 78% in the hypoPT group (OR 11.48; 95% CI, 4.48 to 32.17). Patients with hypoPT and serum calcium (sCa) ≥8.5 mg/dL had a prevalence of early CAN of 72.4% and the prevalence was 86.4% in those with sCa <8.5 mg/dL. Definite CAN was found in 2.3% of the control group, 24.1% of the hypoPT group without hypocalcemia, and 59.1% of the hypoPT group with hypocalcemia. In the hypoPT group, the OR for definite CAN in the patients with hypocalcemia compared to the patients with normocalcemia was 4.54 (95% CI, 1.36 to 15.11). The association between low sCa and definite CAN was confirmed after adjustment for confounders with OR 13.62 (95% CI, 2.12 to 149.84). No association was found between definite CAN and PTH levels or high phosphate levels. HypoPT is associated with CAN and hypocalcemia seems to affect its severity. Larger and prospective studies are needed to confirm our findings. © 2018 American Society for Bone and Mineral Research.

Irisin as a regulator of bone and glucose metabolism.

In humans, irisin is produced mainly by skeletal muscle in response to physical activity. It has been demonstrated that irisin plays a pivotal role in inducing fat browning and regulating energy expenditure. New findings from various studies conducted in both animals and humans suggest that irisin can affect bone and glucose metabolism. In particular, irisin is able to increase bone cortical mass by stimulating the osteoblast pathways, and irisin levels are inversely correlated with the incidence of fragility fractures among postmenopausal women affected by osteoporosis. Most available evidence shows that irisin significantly influences glucose and energy homeostasis. Indeed, higher irisin concentrations are inversely correlated with type 2 diabetes. Unfortunately, contradictory findings exist concerning the role of irisin in humans, and most of the human studies that have analyzed interactions between bone health, glucose metabolism, and irisin have several limitations; therefore, their results must be interpreted with caution. The purpose of this narrative review is mainly to describe the effects of irisin on glucose and bone metabolism.

Radiofrequency ablation for the management of thyroid nodules: A critical appraisal of the literature.

The majority of benign thyroid nodules are asymptomatic, remain stable in size and do not require treatment. However, a minority of patients with growing nodules may have local symptoms or cosmetic concerns, and thus demand surgical therapy. The timely use of ultrasound-guided, minimally invasive thermal therapies has changed the natural history of benign, enlarging thyroid nodules (TNs). These procedures produce persistent shrinkage of TNs and an improvement of local symptoms. Among the various procedures, percutaneous ethanol injection represents the first-line treatment for thyroid cysts, while in solid cold nodules, laser and radiofrequency ablation (RFA) have proven to be very effective and safe techniques in producing significant volume reduction that remains stable over several years. In particular, RFA seems to be suited for the management of small and medium nodules, while larger nodules may require repeated RFA treatments, and could be difficult to treat if they extend into the chest. RFA is performed in outpatient clinics and has a lower risk of complications compared to surgery. However, to date, there is still no unanimous consensus on the percutaneous treatment of benign nodules using such minimally invasive thermal techniques. In this review, we critically revise the literature to identify patients who are more likely to benefit from RFA treatment as an alternative to surgery.