Metabolism - Ghrelin & Leptin:

Question 1

Ghrelin

Answer 1

• Ghrelin = an important digestive hormone that controls appetite.

Question 2

Ghrelin & Appetite

Answer 2

• Ghrelin is produced by the stomach cells when the stomach is empty to stimulate feeding behaviour, and its secretion is suppressed after a meal.
• Obese subjects have been found to have reduced post-prandial ghrelin suppression.
• Studies show ghrelin levels increase after weight loss – this might explain why it is harder to keep weight off once you have lost it.
• Dysregulated sleep and elevated cortisol levels are associated with increased ghrelin secretion; whereas exercise has been shown to decrease ghrelin concentrations.
• High-protein meals (35% of calories) with moderate carbohydrates (45%) have been shown to be better for suppressing ghrelin.
  Ghrelin = an important digestive hormone that controls appetite.

Question 3

Leptin & Appetite

Answer 3

• Leptin is an adipokine produced by white adipose cells in proportion to overall bodyfat (Adiposity).
• Increased adiposity = Increased leptin = Suppressed appetite.
• However, whilst leptin levels are often elevated in overweight people, obesity promotes a number of inflammatory cellular processes that weaken leptin signalling leading to leptin resistance and its failure to suppress appetite.
  Adipokines = a family of hormones and cytokines secreted by adipose tissue.

Question 4

Adipokines

Answer 4

• Adipokines = a family of hormones and cytokines secreted by adipose tissue.

Question 5

Leptin Resistance

Answer 5

• Excess Leptin can modify insulin sensitivity, tissue metabolism, stress responses, and reproductive function, all mediated via the hypothalamic-pituitary axis.
• Over time, these changes in metabolism produce abdominal weight gain in both men and women, as well as thigh and hip weight gain in females, chronic fatigue, sleep problems, cardiovascular distress, and a host of other changes.
• Additional adipose tissue then contributes further to leptin resistance (becoming a vicious cycle).

Question 6

Increasing Leptin Sensitivity

Answer 6

• Go Gluten-Free: Wheat gluten has been shown to stop leptin binding to the leptin receptor.
• Reduce sugar consumption: Especially fructose as this has been shown to induce leptin resistance.
• Support gut flora with prebiotics: Some evidence to show that prebiotics can improve leptin sensitivity.
• Reduce Inflammation: Following an anti-inflammatory diet can contribute to restoring leptin sensitivity.
• Regular exercise: Shown to increase leptin sensitivity.
• Sleep hygiene: Poor sleep can adversely affect leptin sensitivity.