Metabolic and Endocrine System Networks
What are the most effective strategies to optimise health and performance? There are ever more emerging possibilities, permutations and combinations to chose from.
The simple answer is that the most effective option will depend on your starting point and what you are trying to achieve. In all cases exercise and activity levels are the fundamental basis for health and performance. Regarding nutritional strategies to support effective exercise adaptations, no single component of your dietary intake can be considered in isolation. After all, the metabolic pathways and Endocrine axes in your body work as an interactive network, with an important temporal dimension.
Emerging evidence implicates resistance to the anabolic pancreatic hormone, insulin, as the underlying pathological process in the development of metabolic syndrome. What type of diet might drive or conversely counter this process involving metabolism and the Endocrine system? The standard approach, of calorie restriction and aggressive pharmacological treatment of raised lipids, does not produce the anticipated reduction in cardiovascular mortality. Rather the synergistic effect of a diet high in both fat and carbohydrate induces hypothalamic inflammation and dysfunction in the control system of energy metabolism. The hypothalamus is the neuroendocrine gatekeeper providing the crucial link between internal and external stimuli and homeostasis of the internal milieu through integrated Endocrine responses. Intriguingly there is as an inflammatory component to the pathogenesis of cardiovascular disease.
The interaction between metabolic, Endocrine and inflammatory networks is seen in polycystic ovary syndrome (PCOS). The clinical diagnosis of PCOS relies on two of three diagnostic criteria (menstrual disturbance, hyperandrogenism, ovarian morphology). However, the underlying metabolic disruption for all phenotypes of the condition, from overweight to slim, is insulin resistance. The link between adverse body composition, metabolic and Endocrine dysfunction has recently been described. Adipokines, a class of cytokine, including adiponectin and resistin are produced by adipose tissue and exert an effect on metabolism, including insulin sensitivity and inflammation. Changes in plasma concentrations and/or expression of adipokines are seen in metabolic dysfunction and potentially have direct and indirect effects on the hypothalmic-pituitary-gonadal axis in PCOS.
Further evidence of the crucial interaction between metabolic and Endocrine systems and health was found in a longitudinal study of children, quantifying heart rate variability and the energy and inflammatory related biomarkers leptin (atherogenic) and adiponectin (anti-atherogenic) as potential predictive markers in cardiovascular screening/prevention.
Exogenous hormones impact not only the endogenous Endocrine system, but have metabolic effects. The intended purpose of the combined oral contraceptive pill (OCP) is to suppress ovulation. Another effect on the Endocrine system is to increase production of sex hormone-binding globulin (SHBG), which binds free testosterone. This has a therapeutic effect in the treatment of PCOS to lower elevated testosterone, however this may not be such a desirable effect in female athletes, where higher range testosterone levels as associated with performance advantages in certain power events. In the case of female athletes with relative energy deficiency in sports (RED-S), use of the OCP masks underlying hypothalamic amenorrhoea and is not effective in bone health protection. Further areas where Endocrine manipulation impacts metabolism are an increase in oxidative stress with OCP use and alterations in nutritional requirements due to alteration of absorption of vitamins and minerals such as vitamin B complex and magnesium, which are vital for enzymic processes involved in energy production. Yet an elevation of ferritin as an acute phase reactant is seen. These interactions of Endocrine and metabolic networks are particularly important considerations for the female athlete.
There is no single elixir for health and performance. We are individuals with subtle differences in our genetic and epigenetic make up, including the diversity of our microbiome. Furthermore, the Endocrine and metabolic milieu changes during our lifespan. Personalised health and performance strategies must take account of the complex, intricate interactions between the Endocrine and metabolic networks.
For further discussion on Health, Hormones and Human Performance, come to the BASEM annual conference
One road to Rome: Metabolic Syndrome, Athletes, Exercise Dr N.Keay
Endocrine system: balance and interplay in response to exercise training Dr N. Keay
Dietary sugars, not lipids, drive hypothalamic inflammation Molecular Metabolism June 2017
Saturated fat does not clog the arteries: coronary heart disease is a chronic inflammatory condition, the risk of which can be effectively reduced from healthy lifestyle interventions British Journal of Sport and Exercise Medicine
Adiponectin and resistin: potential metabolic signals affecting hypothalamo-pituitary gonadal axis in females and males of different species Reproduction: Journal for the Society of Reproduction and Fertility 2017
Longitudinal Associations of Leptin and Adiponectin with Heart Rate Variability in Children Front. Physiol 2017
AKR1C3-mediated adipose androgen generation drives lipotoxicity in women with polycystic ovary syndrome J Clin Endocrinol Metab 2017
Hormones and Sports Performance Dr N. Keay
Mechanisms for optimal health…for all athletes! Dr N. Keay, British Journal of Sport and Exercise Medicine
Oxidative Stress in Female Athletes Using Combined Oral Contraceptives Sports Medicine – Open
Oral contraceptives and changes in nutritional requirements European Review for Medical and Pharmacological Sciences
Inflammation: Why and How Much? Dr N. Keay, British Association of Sport and Exercise Medicine 2017