Serotonin: Function & Levels

What is Serotonin?

• Also known as 5-hydroxytryptamine (5-HT)
• Acts as a neurotransmitter and hormone
• Carries messages between nerve cells in the brain (CNS) and throughout the body (PNS)
• Influences learning, memory, happiness
• Regulates body temperature, sleep, sexual behavior, hunger
• Lack of serotonin linked to depression, anxiety, mania
• Majority (90%) found in the gut, 10% in the brain
• Produced from tryptophan, an essential amino acid from diet

Functions of Serotonin

• Mood: Regulates mood, known as the body's natural "feel-good" chemical. Low levels linked to depression.
• Digestion: Controls bowel function, speeds digestion in response to irritants, reduces appetite.
• Nausea: Triggered by rapid serotonin release in the gut.
• Sleep: Involved in sleep quality, necessary for melatonin production.
• Wound Healing: Released by platelets, helps form clots and heal wounds.
• Bone Health: High gut serotonin may weaken bones, linked to osteoporosis.
• Sexual Health: Involved in regulating sexual desire.

Problems Associated with Low Serotonin Levels

• Linked to multiple health conditions
• Ongoing research on serotonin's role in the body and disease

Causes of Low Serotonin Levels

• Insufficient serotonin production or ineffective use
• Possible lack of serotonin receptors or malfunctioning receptors

Ways to Increase Serotonin

• Diet: Increase tryptophan-rich foods (salmon, eggs, cheese, turkey, tofu, pineapples, nuts, oats, seeds)
• Sunlight: 10-15 minutes daily exposure, or light therapy for seasonal affective disorder
• Supplements: Tryptophan, probiotics, SAMe, herbal supplements (ginseng, St. John's wort)
• Exercise: Regular aerobic and strength-training exercises

Medications to Increase Serotonin Levels

• Antidepressants: SSRIs (e.g., Paxil), SNRIs (e.g., Effexor), tricyclics (e.g., Elavil), MAOIs (e.g., Nardil)
• Others: Triptans (headaches), opioid pain relievers, dextromethorphan (cough), anti-nausea drugs

High Serotonin Levels: Serotonin Syndrome

• Caused by excessive increase in serotonin levels
• Symptoms range from mild (shivering, confusion) to severe (high fever, seizures)
• Can be fatal if untreated