Effects of very low-calorie ketogenic diet on hypothalamic-pituitary-adrenal axis and renin-angiotensin-aldosterone system

BACKGROUND

The hypothalamic-pituitary-adrenal (HPA) axis is a neuroendocrine system involved in controlling stress responses in humans under physiological and pathological conditions; cortisol is the main hormone produced by the HPA axis. It is known that calorie restriction acts as a stressor and can lead to an increase in cortisol production. Renin-angiotensin-aldosterone system (RAAS) is a complex endocrine network regulating blood pressure and hydrosaline metabolism, whose final hormonal effector is aldosterone. RAAS activation is linked to cardiometabolic diseases, such as heart failure and obesity. Obesity has become a leading worldwide pandemic, associated with serious health outcomes. Calorie restriction represents a pivotal strategy to tackle obesity. On the other hand, it is well known that an increased activity of the HPA may favour visceral adipose tissue expansion, which may jeopardize a successful diet-induced weight loss. Very low-calorie ketogenic diet (VLCKD) is a normoprotein diet with a drastic reduction of the carbohydrate content and total calorie intake. Thanks to its sustained protein content, VLCKD is extremely effective to reduce adipose tissue while preserving lean body mass and resting metabolic rate.

PURPOSE

The purpose of this narrative review is to gain more insights on the effects of VLCKD on the HPA axis and RAAS, in different phases of weight loss and in different clinical settings.

Depression: another cortisol-related comorbidity in patients with adrenal incidentalomas and (possible) autonomous cortisol secretion

PURPOSE

Hypercortisolism is associated with a high prevalence of depression and impaired health-related quality of life (QoL). According to the available literature, studies examining the depression risk in patients with adrenal incidentalomas (AI), nonfunctioning and the ones with (possible) autonomous cortisol secretion ((P)ACS) are scarce. The aim of this observational, case-control study was to screen patients with nonfunctioning adrenal incidentalomas (NAI) and the ones with (P)ACS for depression and to assess their QoL.

METHODS

The total studied group consisted of 92 subjects-26 with NAI, 34 with (P)ACS and 32 age-matched healthy controls (HC). To screen for depression, we used the Beck Depression Inventory-II (BDI-II) and to assess the QoL, we used the Short-Form 36 Health Survey (SF-36).

RESULTS

Patients with (P)ACS had significantly higher BDI-II scores and substantially lower QoL than patients with NAI or HC. Midnight cortisol level was the most significant predictor of BDI-II and SF-36 score. The receiver operating characteristic curve analysis demonstrated that a midnight cortisol value of 86.95 nmol/l had a high sensitivity (82.8%) and high specificity (80%) for detection of mild depression in patients with (P)ACS.

CONCLUSION

Screening for depression and QoL assessment should become an integral part of clinical evaluation in patients with (P)ACS.