Our body has the ability to know when it needs fuel to function properly, and when he should rest. Indeed, a very complex system of hormones and proteins (peptides) regulates our feeling of hunger and our feeling of satiety to let digestion take its course. When we’re hungry, it’s actually because ghrelin is responsible for stimulating our appetite. But in some cases, this digestive hormone malfunctions. We take stock.
Ghrelin is often nicknamed “hunger hormone”. It was identified in 1999 by researcher Masayasu Kojima and his team. Its name is directly related to its role as a growth hormone activating peptide (growth hormone-releasing peptide) whose root is ghre, which means “to grow”.
This digestive hormone is essentially produced by our stomach when it is empty. As mentioned above, it signals to the body that it needs food, which leads to the feeling of hunger. In fact, she plays important role in appetite regulation – and inevitably in weight gain (it is often singled out for snacking or excessive appetite). It is also involved in other processes such as the growth, fat storage and the reproduction.
Ghrelin is primarily secreted in the stomach by ghrelinergic cells (located in the gastrointestinal tract) which communicate with the central nervous system. When the stomach is empty, these cells release ghrelin into the bloodstream. Said ghrelin then travels to the brain, where it activates specific receptors in the hypothalamus, which send signals to the body to tell it that it needs food. It is this phenomenon that leads to the feeling of hunger and prompts a person to eat. When she finally starts to eat, the stomach fills up and produces less ghrelin, which reduces the feeling of hunger. Note: the pancreas, small intestine and brain also produce ghrelin in small amounts.
The “effects” of ghrelin depend on its concentration in the body. As we have explained to you, this hormone has the role of causing the feeling of hunger. But an abnormally high production of ghrelin can, for example, lead to weight gainwhile a decrease in its secretion can promote weightloss.
In addition, it stimulates the release of growth hormone from the pituitary gland, which helps maintain metabolic balance, break down body fat and increase muscle mass.
Some studies have also shown that it plays a role in reproduction and could have effects on behavior and mood (we know, for example, that it acts on regions of the brain involved in reward processing, such as the amygdala). However, the discovery of this hormone is very recent and researchers have yet to carry out many studies to understand how this hormone works.
Leptin is considered the satiety hormone. It works in concert with ghrelin to allow optimal nutrition and provide for the energy needs of our body. Concretely, it plays the opposite role of ghrelin: produced by adipose cells (fat cells), it warns the brain when our body has enough fat reserves. Thus, the feeling of satiety sets in and we stop eating, which limits weight gain in the long term. Conversely, if the body has too few reserves, the production of leptin decreases, which stimulates appetite and promotes weight gain.
Several other hormones can influence appetite regulation:
A blood sample is essential for measuring ghrelin. Once sent to an analysis laboratory, it will make it possible to measure the concentration of ghrelin in the blood and to interpret it.
To note : the “normal” level of ghrelin can vary from person to persondepending on factors such as age, weight or lifestyle.
In general, ghrelin levels increase before meals (to stimulate appetite) and then decrease after meals (to indicate that the body has enough reserves).
Otherwise, certain medical conditionssuch as obesity or diabetes, can disrupt the normal regulation of ghrelin and lead to abnormal variations in its concentration.
As explained above, ghrelin levels change throughout the day depending on food intake and metabolism of each. But other factors may come into play, including:
Otherwise, certain gastric surgeries (including surgical gastric bypass) reduce gastric volume capacity, but also significantly decrease plasma ghrelin levels, resulting in faster satiety.
As you may have guessed, several conditions can impact ghrelin levels:
Strictly speaking, no medication can increase or decrease the concentration of ghrelin. When the abnormal variations are linked to a specific pathology, see your doctor. Some drugs, for example, target ghrelin receptors in the brain to treat obesity and other diet-related disorders.
There are also several ways to better control your ghrelin levels, including eating a balanced diet and exercising regularly. Here are some tips to help you better control your ghrelin levels:
A regular and sufficient sleep pattern stabilizes ghrelin and leptin levels. As noted above, sleep deprivation is associated with increased ghrelin levels.
At mealtimes, eat slowly, mindfully, to give hormones time to do their job. Thus, you will enjoy your meals more and reduce the amount of food ingested.
Regular physical activity is the key to good health. In this case, exercise can help regulate blood sugar and lower ghrelin levels. The authorities recommend engage in moderate to vigorous physical activity for at least 30 minutes a day, 5 days a week.
Stress and anxiety can disrupt ghrelin regulation and increase appetite (you may crave comfort food and snack). It is therefore important to find solutions to learn how to manage your emotions. Bet for example on yoga, meditation, relaxation, hypnosis or the practice of another activity that calms you and promotes your well-being.
Significant weight variations and overly restrictive diets can disrupt the hormonal system and appetite. If you lose weight through crash dieting, you’ll tend to have higher levels of ghrelin, which increases your risk of picking up old — and bad — habits (the feeling of hunger becomes too strong and we unfortunately end up cracking). The key to healthy weight loss is a balanced diet, coupled with physical activity suited to our adjectives.
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