Ghrelin

What is ghrelin?

Ghrelin is a hormone produced by your stomach. Other parts of your body, such as your brain, small intestine and pancreas, also release small amounts of ghrelin.

Often known as the “hunger hormone,” ghrelin has numerous functions in addition to telling your brain you’re hungry. For example, ghrelin:

• Increases food intake and helps your body store fat.
• Helps trigger your pituitary gland to release growth hormones.
• Plays a role in controlling sugars and how your body releases insulin, the hormone responsible for processing sugar.
• Has a role in protecting your muscles from weakness and bone formation and metabolism.

What is the difference between ghrelin and leptin?

Ghrelin and leptin are two of many hormones that control your appetite and fullness. They’re involved in the vast network of pathways that regulate your body weight. Leptin decreases your appetite, while ghrelin increases it.

Ghrelin is made in your stomach and signals your brain when you’re hungry. Your fat cells produce leptin. Leptin lets your brain know when you have enough energy stored and feel “full.”

Ghrelin plays a role in the short-term control of appetite while leptin controls long-term weight control.

What does the ghrelin hormone do?

Ghrelin has several key functions. The hormone:

• Signals part of your brain called the hypothalamus to increase appetite.
• Promotes fat storage.
• Stimulates your pituitary gland to release growth hormones.
• Stimulates your digestive system to move food from your stomach through your small and large intestines.
• Contributes to controlling insulin release.
• Plays a role in protecting your cardiovascular health.

What triggers ghrelin?

Your stomach releases ghrelin when it’s empty or mostly empty. Ghrelin levels are typically highest right before mealtimes.

What conditions and disorders affect ghrelin?

Ghrelin levels increase when your stomach is empty. Your body releases ghrelin to let your brain know when it’s time to eat. Then, when you eat, your ghrelin levels decrease.

Some conditions can lead to chronically low or high ghrelin:

Low ghrelin

Ghrelin levels are usually lower in people who have obesity. Some researchers think this connection could mean that people who have obesity have bodies that are naturally more sensitive to ghrelin. The theory is that these individuals may feel much hungrier with lower levels of ghrelin.

Certain gastrointestinal diseases are also associated with low ghrelin, including:

• Chronic gastritis.
• Functional dyspepsia.
• H. Pylori infection.
• Irritable bowel syndrome (IBS).

High ghrelin

People may have increases in ghrelin levels if they restrict their caloric intake, such as while on a restrictive diet. High ghrelin may also be associated with biological and genetic conditions such as:

• Anorexia nervosa.
• Cachexia, a condition that causes your muscles to waste away.
• Celiac disease.
• Inflammatory bowel disease (IBD).
• Prader-Willi syndrome.

How does gastric bypass surgery affect ghrelin levels?

Gastric bypass surgery and sleeve gastrectomy are two of the surgical therapies for severe obesity. People have sustained lower levels of ghrelin after these operations which are thought to be responsible for long-term weight control. A reduced stomach size is thought to be one of the causes of weight loss after bariatric surgery and is responsible for the lower ghrelin levels.

What can I do to keep ghrelin levels healthy?

You can keep ghrelin and other hormone levels healthier by practicing good lifestyle habits, such as:

• Avoid fad or yo-yo dieting, where you gain and lose weight frequently.
• Eat a diet high in healthy carbohydrates, such as whole grains and lean proteins, like chicken or fish.
• Limit processed foods, especially foods high in sugar, high-fructose corn syrup and salt.
• Sleep at least seven to eight hours nightly.
• Stay hydrated by drinking plenty of water and eating water-filled foods such as fruits and vegetables.
• Control your stress responses as stress may increase ghrelin.

What foods suppress ghrelin?

No specific food suppresses ghrelin. In general, eating foods high in healthy carbohydrates (such as whole grains) and protein can lower your ghrelin levels.

How do you lower ghrelin?

Ghrelin levels tend to rise and fall with how much you eat. Ghrelin may decrease when you are hydrated and increase when you’re dehydrated.

The types of foods you eat affect ghrelin. For example, eating foods high in protein or healthy carbs lower ghrelin levels more than eating foods high in fat.

A note from Cleveland Clinic

Ghrelin is a hormone produced in your stomach. Your stomach releases ghrelin when it’s empty to signal your brain that it’s time to eat. Ghrelin is often called the hunger hormone, but it does more than control hunger. It also signals your pituitary gland to release growth hormones, plays a role in insulin release and protects your cardiovascular health.