What Is Ghrelin?

Understanding the “Hunger Hormone” and Its Deficiency Symptoms

In the complex system of human hormones, few have a more direct impact on how we eat and feel than ghrelin. Often called the “hunger hormone,” ghrelin plays a key role in stimulating appetite, regulating energy balance, and even influencing mood and digestion.

But what happens when your body doesn’t produce enough ghrelin? While ghrelin excess is more commonly discussed in the context of obesity or overeating, ghrelin deficiency can also disrupt your health in subtle but important ways.

In this article, we’ll break down what ghrelin is, what it does, and the signs that your body might not be producing enough of it.

What Is Ghrelin?

Ghrelin is a hormone primarily produced in the stomach, with smaller amounts released by the small intestine, pancreas, and brain. It’s secreted when your stomach is empty and signals your brain to feel hungry. In this way, ghrelin plays a key role in short-term appetite regulation.

The hormone was discovered in 1999 and is now recognized as one of the major players in energy homeostasis, the process by which your body balances calories in versus calories out.

Functions of Ghrelin

Though often labeled as the hunger hormone, ghrelin has several important functions beyond appetite:

1. Stimulates appetite
   It increases food intake by acting on the hypothalamus in the brain.

2. Promotes fat storage
   Ghrelin signals the body to conserve energy and store fat, especially in fasting conditions.

3. Supports gastrointestinal function
   It enhances motility and acid secretion in the stomach, helping with digestion.

4. Regulates blood sugar levels
   Ghrelin can influence insulin sensitivity and glucose metabolism.

5. Supports growth hormone release
   Ghrelin binds to receptors in the pituitary gland, stimulating the secretion of growth hormone (GH).

6. Affects mood and cognitive function
   Emerging research suggests ghrelin may play a role in anxiety, stress, learning, and memory.

Ghrelin and Appetite: How It Works

When your stomach is empty, ghrelin levels rise. These signals are sent to the hypothalamus, the brain’s hunger center, to stimulate appetite. After eating, ghrelin levels fall, contributing to the feeling of fullness or satiety.

This cycle is part of your body’s natural circadian rhythm and is influenced by:

• Meal timing
  
• Sleep quality
  
• Stress levels
  
• Body weight and metabolism
  

What Is Ghrelin Deficiency?

Ghrelin deficiency occurs when your body does not produce enough ghrelin to maintain normal appetite and related physiological processes.

This condition is rarely diagnosed in isolation but may occur as a side effect of certain medical treatments, surgeries, or health conditions. It can lead to reduced appetite, unintentional weight loss, and other metabolic disturbances.

Symptoms of Ghrelin Deficiency

If ghrelin levels are too low, the following signs and symptoms may appear:

1. Reduced Appetite

The most common and direct symptom of ghrelin deficiency is a lack of hunger, even after long periods without food.

2. Unexplained Weight Loss

Without adequate appetite stimulation, calorie intake may drop, leading to unintentional weight loss and potential malnutrition.

3. Delayed Gastric Emptying

Ghrelin helps stimulate stomach contractions. Low levels may result in slower digestion, leading to bloating or early fullness.

4. Low Energy and Fatigue

Inadequate food intake may lead to chronic fatigue, low stamina, and reduced physical performance.

5. Growth Issues (in children and adolescents)

Since ghrelin stimulates growth hormone release, deficiency may impact growth and development in younger individuals.

6. Mood Changes

Some studies suggest low ghrelin levels are associated with depression, low motivation, and reduced stress resilience.

Causes of Ghrelin Deficiency

Several conditions and factors may contribute to decreased ghrelin production:

• Bariatric surgery, especially gastric bypass (which reduces the ghrelin-producing part of the stomach)
  
• Chronic inflammation of the stomach lining (gastritis)
  
• Certain eating disorders, such as anorexia nervosa (though ghrelin may initially rise, it can drop in prolonged malnutrition)
  
• Aging, as ghrelin levels tend to decline naturally over time
  
• Hypothalamic or pituitary dysfunction
  
• Cancer treatments, such as chemotherapy or radiation, which affect the digestive tract
  
• Prolonged illness or stress
  

Diagnosing Ghrelin Deficiency

There is currently no routine test for ghrelin used in everyday clinical practice. However, in research or specialized care settings, ghrelin levels can be measured through fasting blood samples.

More commonly, diagnosis is based on:

• Detailed symptom history
  
• Nutritional assessments
  
• Evaluation of related hormone levels (e.g., growth hormone, leptin, insulin)
  
• Gastrointestinal tests if delayed gastric emptying is suspected
  

At Erdem Hospital, our endocrinologists and internal medicine specialists can assess appetite and metabolism disorders holistically, considering all potential hormonal and nutritional contributors.

How Is Ghrelin Deficiency Treated?

There is no FDA-approved ghrelin replacement therapy, but several strategies may help manage symptoms or address the underlying cause:

1. Nutritional Support

• High-calorie, nutrient-dense meals
  
• Appetite stimulants (under medical supervision)
  
• Small, frequent meals to support intake
  

2. Treating the Underlying Cause

• Managing gastritis or digestive conditions
  
• Adjusting medications that suppress appetite
  
• Supporting recovery after surgery or illness
  

3. Hormonal Therapy (if appropriate)

• If growth hormone deficiency is also present, GH therapy may be considered in children or adults with confirmed diagnoses.
  

4. Psychological Support

• In cases related to eating disorders or depression, therapy may be necessary to support recovery.
  

Final Thoughts

Ghrelin is often discussed in the context of overeating and obesity, but low levels of this critical hormone can also lead to real health concerns, particularly around nutrition, energy, digestion, and emotional health.

If you’re experiencing persistent appetite loss, weight loss, or fatigue especially after surgery or chronic illness it’s important to get evaluated by a healthcare provider who understands the role of hormones like ghrelin.

At Erdem Hospital, with over 37 years of experience, our team provides personalized care for hormonal imbalances, gastrointestinal issues, and nutritional concerns helping patients restore balance and feel well again.