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Zinc & Leptin

May 1, 2011 | By Tina Andrews
Zinc & Leptin
Photo Credit weigh in image by Kimberly Reinick from Fotolia.com

The hormone leptin has garnered attention as a possible target in the struggle against obesity and being overweight. Your fat cells produce leptin, which suppresses hunger and increases your metabolic rate. In general, the more body fat you have, the higher your blood leptin level. Zinc may affect leptin production, a factor that has led to interest in whether zinc supplementation may boost leptin levels and promote weight loss. Be sure to talk with your doctor before taking zinc or other nutritional supplements.

How Leptin Works

An area of your brain called the hypothalamus is the primary site of appetite regulation. Many nervous system signals and hormones feed information to your hypothalamus and influence your experience of hunger. Your leptin level tells your hypothalamus how much body fat you have stored. Your hypothalamus interprets a low leptin level as an indicator of low body fat, which triggers increased hunger. A high leptin level sends the opposite message, normally leading to decreased appetite. Because changes in your body fat stores occur slowly, leptin is considered a long-term regulator of body weight and metabolism.

The Zinc Link

A zinc deficiency may reduce leptin production from your fat cells. In a small study conducted by Dr. Christos Mantzoros and colleagues and published in the "Journal of the American College of Nutrition," experimentally induced zinc deficiency decreased leptin levels. Reversal of the deficiency with supplemental zinc led to a corresponding increase in blood leptin.

Data from animal research support the existence of the zinc-leptin link. Ming-Der Chen, Ph.D., and colleagues reported in a March 2000 article published in "Hormone and Metabolic Research" that leptin levels increased when a moderate dose of zinc was fed to mice with experimentally induced diabetes. Interestingly, both zinc deficiency and high-dose zinc suppressed leptin production.

From Research to Reality

Observations made in a research setting do not always translate into effective clinical interventions. Although there is good evidence of a zinc-leptin link, controlling leptin levels through zinc supplementation has not been shown to promote weight loss. In the Mantzoros study, participants did not experience weight or body fat changes despite varying leptin levels. In a 1997 article published in "Obesity Research," Susan Roberts, Ph.D., and colleagues also found no association between blood leptin levels and energy expenditure, a measure of metabolic rate. These findings suggest that factors other than leptin are major regulators of hunger and body weight.

Another complicating factor is variable responsiveness to leptin. Even though a person who is overweight or obese has excessively high levels of leptin, the hormone fails to suppress his appetite. Researchers speculate that being overweight and obesity may cause leptin resistance, meaning your hypothalamus does not respond normally to the hormone.

The Bottom Line

Zinc is not a magic bullet that will curb your appetite and lead to effortless shedding of extra pounds. Moreover, manipulation of leptin levels to control obesity and a tendency to become overweight may be a less promising remedy that was once hoped. Overweight and obesity are complex problems that involve multiple contributing factors and are unlikely to be "solved" by altering only one of those factors. Although it is theoretically possible that zinc supplementation may reduce hunger if you have a deficiency, this nutritional deficit is rare among Americans. Talk with your doctor if you are concerned about a possible zinc deficiency to determine whether supplementation is appropriate and safe for you.

References

Article reviewed by Knuckles Last updated on: May 1, 2011

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