Hormones are the chemical messengers of the human body. Hormones regulate your blood pressure, affect your sex drive, manage your metabolism, control your sleep and determine how you respond to pain. Hormones are regulated by the endocrine system. If too much or too little of any hormone is secreted by a part of the endocrine system, you have a hormonal imbalance. Caffeine affects hormone function in a number of body systems.
Hormones
Many glands release hormones. Your sweat glands, ovaries, testes, pancreas and thyroid all produce and respond to hormone signals. Hormones are guided by changes in body chemistry; for example, the pancreas releases insulin when the blood sugar is too high. Menopause affects the secretion of sex hormones in women. Hormonal imbalances include conditions such as menopause and diseases such as diabetes. If the thyroid gland malfunctions, you could have too much or too little thyroid hormone, another case of hormonal imbalance.
Caffeine and Sex Hormones
The June 2009 “Cancer” reported a study of pre- and post-menopausal women who participated in the Nurses’ Health Study. Caffeine intake in premenopausal women decreased estradiol, an estrogen hormone, but increased progesterone. In post-menopausal women, coffee and caffeine increased a substance called the sex hormone binding globulin, or SHBG.
Caffeine and Growth Hormone
Caffeine may affect growth hormone, which is secreted by the pituitary gland in the brain. The pituitary gland has been called the “master gland” because it influences so many other body organs. Growth hormone stimulates children’s growth and helps maintain muscle and bone mass in adulthood. A study in the February 1984 “Journal of Endocrinological Investigation” reported that caffeine stimulated growth hormone secretion in rats by acting directly on the pituitary cells.
Caffeine and Melatonin
Since you may associate caffeine with helping you wake up in the morning, it may seem surprising to find that caffeine can actually increase the effect of melatonin, a hormone secreted by the pineal gland that may help to control your sleep patterns. According to Drugs.com, 200 milligrams of caffeine increased the plasma concentration of melatonin whether given before or after melatonin. Nonsmokers were more strongly affected than smokers in this experiment.
Caffeine, Hormones and Parkinson's Disease
Even when caffeine doesn’t cause an actual hormonal imbalance, it can interact with hormones in a way that predisposes to a disease. In 2003, the National Institute of Neurological Disorders and Stroke reported that caffeine intake increased the risk of developing Parkinson’s disease in women who also used hormone replacement therapy. Post-menopausal women on hormone replacement therapy who drank more than 5 cups of coffee a day were one-and-one-half times more likely to develop Parkinson’s disease than women who were heavy coffee drinkers but did not use the hormones.
Final Words
The endocrine system is an extremely complex part of your overall health. Although caffeine in moderation may not make much of a difference to the endocrine system, some people are more sensitive to its effects than others. If you think caffeine might be causing endocrine symptoms or if you have questions or concerns about a possible hormone imbalance, consult a health care professional.
References
- Drugs.com: Melatonin
- Patients Medical; Overview of Hormonal Imbalance; September 2005
- National Institute of Neurological Disorders and Stroke; New Findings About Parkinson's Disease: Coffee and Hormones Don't Mix; Tania Zeigler; April 2003
- “Cancer”; Relationship Between Caffeine Intake and Plasma Sex Hormone Concentrations in Premenopausal and Postmenopausal Women; Joanne Kotsopoulos, et al.; June 2009
- The Hormone Foundation: The Endocrine System: Diseases, Types of Hormones & More
- The Hormone Foundation: Endo 101: Factors That Affect Endocrine Function
- “Journal of Endocrinological Investigation”; Caffeine Stimulates Growth Hormone Secretion by Cultured Rat Pituitary Cells; Z. Hochberg; February 1984
