In this week’s research review we have two articles:
Increased ratio of cortisol/DHEA in treatment resistant depression
Early dietary exposures and feeding practices: role in pathogenesis and prevention of allergic disease
The ratio of cortisol/DHEA in treatment resistant depression
(Markopoulou, Papadopoulos et al. 2009) Download
OBJECTIVE: Hypercortisolaemia has been well described in depression and may be a factor associated with treatment resistance. The role of the more abundant adrenal steroid dehydroepiandrosterone (DHEA) has been recently investigated, with some evidence that it may have an antiglucocorticoid effect. This study measured cortisol, DHEA and their ratio in treatment resistant depression (TRD) and healthy controls and also related these measures to treatment outcome. METHOD: Plasma cortisol, DHEA and cortisol/DHEA ratio were determined at 0900h in 28 patients with TRD and 40 healthy controls. The measures were repeated following inpatient treatment in a subgroup of 21 patients and related to the outcome of such treatment. The stability of cortisol/DHEA ratios was assessed with 2 hourly samples from 0900 to 1700h in a subgroup of 15 controls. RESULTS: Basal levels of cortisol and the cortisol/DHEA ratio were higher in patients compared to controls. Whilst cortisol levels were lower after treatment, there was no relationship between cortisol levels and treatment outcome. In contrast, treatment responders had significantly lower DHEA on admission and a higher cortisol/DHEA ratio both on admission and on discharge. Cortisol/DHEA ratios were stable between 9 a.m. and 5 p.m. CONCLUSIONS: In addition to cortisol, the cortisol/DHEA ratio is raised in TRD; thus, there is no evidence that DHEA levels could negate the increased glucocorticoid activity in TRD. Patients with a more abnormal cortisol/DHEA ratio, possibly indicating greater biological dysfunction, responded preferentially to inpatient therapy, though the raised cortisol/DHEA ratio persisted after response. The cortisol/DHEA ratio is stable throughout the day and may be a more practical biological marker of TRD.
Early dietary exposures and feeding practices: role in pathogenesis and prevention of allergic disease?
(Jennings and Prescott 2010) Download
Immune dysregulation has become a hallmark of the modern era. This has led to an epidemic of disease states that result from failed immune surveillance and inappropriate or maladaptive immune responses to self-antigens (autoimmunity) and environmental antigens (allergy). Although environmental change is clearly implicated, the specific causes are still unconfirmed. Any hope to reverse such immune dysfunction must be based on a clearer understanding of the causal pathways and the environmental factors that may be driving the concerning surge in disease rates. This review explores the role of modern dietary changes that, through their known documented immune effects, may play a role in either promoting or preventing disease. Food allergen avoidance has been largely unsuccessful, and most expert bodies no longer recommend delayed complementary feeding or the avoidance of any specific allergenic foods, unless symptoms develop and allergy is confirmed. Rather, focus has shifted to other factors that may influence the ability to develop immune tolerance. There is now evidence that specific nutrients, such as folate, have the capacity to promote an allergic phenotype by epigenetically altering gene expression during early development. A number of other dietary factors including n-3 polyunsaturated fatty acids, oligosaccharides, probiotics, vitamin D, retinoic acid and other antioxidants may also clearly influence immune function and immune development. This review summarises the current evidence, recommendations and future directions in the context of allergy, with the aim of highlighting the need to further investigate the role of diet and nutrition in disease pathogenesis and prevention.
Jennings, S. and S. L. Prescott (2010). "Early dietary exposures and feeding practices: role in pathogenesis and prevention of allergic disease?" Postgrad Med J 86(1012): 94-9.
Markopoulou, K., A. Papadopoulos, et al. (2009). "The ratio of cortisol/DHEA in treatment resistant depression." Psychoneuroendocrinology 34(1): 19-26.