Leptin seen as one of our ‘good’ appetite hormones, resides in all fat cells and communicates directly with the hypothalamus in the brain.
Leptin provides information about how much energy is currently stored in the body’s fat cells. It functions in what is referred to in biology as a negative feedback loop e.g. when fat cells decrease in size, leptin decreases, sending a message to the hypothalamus to direct the body to eat more.
Leptin production is chiefly regulated by insulin-induced changes in fat cell metabolism. The consumption of fat (and fructose) actually results in lower circulating leptin levels, which can lead to overeating and weight gain.
Conversely, when fat cells increase in size, leptin increases and the message sent to the hypothalamus is to instruct the body to eat less. However, it appears that the primary biological role of leptin is to facilitate energy intake when energy storage is low, as opposed to slowing down over-consumption (which may contribute to obesity) when energy storage is high (Havel 2002).
Increased leptin levels are heavily associated with suppression in appetite and weight loss. Studies have shown that a zinc deficiency resulted in a low leptin level thus increases the preferred food choice of primarily high saturated fat foods.
Recent studies have also shown that a high intake of MSG can lead to a leptin insensitivity leading to an out of control appetite thus contributing to. Other studies have investigated the role of leptin in weight-loss management displaying those subjects who had recently lost weight showed a significant leptin deficiency that may contribute them to re-gaining weight.
It has been discovered that those with congenital deficiency in leptin are obese and treating those subjects with leptin lead to a dramatic loss in a weight & a reducing in food intake. However, most the obese subjects leptin-resistant and treatment with leptin will not have the weight loss effect.
Way to improve Leptin levels include
- Exercising regularly,
- Practicing good stress management through diet, exercise, relaxation and meditation.
- Reducing hydrogenated fats found in margarine, some packed foods (ie: crisps, biscuits)
- Reducing trans fats found in fast foods, some snack foods (ie: crisps), fried foods
- Increasing omega 3 fatty acids found in fish, nuts, seeds and avocado
- Increasing bioflavonoids such as apricots, blackberries, black currants, broccoli, cherries, grapes, oranges and lemons
- Increasing Zinc rich foods: cashews, almonds, pumpkin seeds, sunflower seeds, sprouts, turkey, spirulina, walnuts, ginger, beef, chicken and seafood
- Having sufficient vitamin D from the sun, supplement or food sources ie: salmon with bones
- Increasing green tea, minimum of 2 cups per day.
Adams, M & Veracity, D 2009, Natural Appetite Suppressants for Safe, Effective Weight Loss, Truth Publishing, Arizona.
Kelesidis, T et al. 2010, Narrative Review: The Role of Leptin in Human Physiology: Emerging Clinical Applications, Physiology in Medicine, vol. 152, no. 2, pp.93-100.