Can We Prevent Aging?

People are living longer. In 1970, the average life expectancy at birth was 70.8 years; in 2000, it was 76.9 years; and by 2030 is it estimated that the “oldest-old,” age 85 and older, could grow to 10 million people.Views on aging are also changing. It no longer necessarily means physical decline and illness—in the last two decades, the rate of disability among older people has declined dramatically.

The National Institute on Aging (NIA), part of the Federal Government’s National Institutes of Health (NIH), investigates ways to support healthy aging and prevent or delay the onset of diseases that disproportionately affect us as we age. These studies not only may increase what is known as “active life expectancy”—the time of advancing years free of disability—but also may promote longevity. NIA’s research includes hormone and dietary approaches, including calorie restriction.

Results from NIA-sponsored studies and others are likely to improve our understanding of the benefits and risks of hormone supplements, calorie restriction, and other interventions to promote healthy aging. This tip sheet provides an overview of what we know about hormone supplements and calorie restriction and the research needed to learn more. Until we have a better understanding, it is a good idea to be skeptical of claims that hormone or other supplements can solve your age-related problems. Instead, focus on what is known to help promote healthy aging: healthy eating and physical activity.

What Is a Hormone?

The word “hormone” comes from the Greek word, hormo, meaning to set in motion. Hormones are chemical messengers that set in motion different processes to keep our bodies working properly. For example, they are involved in our metabolism, immune function, sexual reproduction, and growth. Hormones are made by specialized groups of cells within the body’s glands. The glands—such as the pituitary, thyroid, adrenals, ovaries, and testes—release hormones into the body as needed to stimulate, regulate, and control the function of other various tissues and organs involved in biological processes.

We cannot survive without hormones. As children, hormones help us “grow up.” In teenagers, they drive puberty. As we get older, some of our hormone levels naturally decline. But what does that mean? Scientists do not know exactly. In order to know more, NIA investigates how replenishing hormones in older people affects frailty and function. Many of these studies focus on hormones that decline with age, including:

• Growth hormone
• Melatonin
• Dehydroepiandrosterone (DHEA)
• Testosterone
• Estrogen and progesterone (as part of menopausal hormone therapy)

How Hormones Work

Most hormones are typically found in very low concentrations in the bloodstream. But a hormone’s concentration will fluctuate depending on the body’s activity. Like a key that unlocks a door, a hormone molecule is released by a gland and travels through the blood until it finds a cell with the right fit, a “receptor.” The hormone latches onto a cell’s receptor and a signal is sent into the cell. These signals may instruct the cell to multiply, make proteins or enzymes, or perform other vital tasks. Some hormones can even cause a cell to release other hormones.

One hormone may fit with many types of cells but may not affect all cells in the same way. For example, one hormone may stimulate one cell to perform a task but it might also turn off a different cell. Additionally, how a cell responds to a hormone may change throughout life.

For more information on health and aging, contact:

National Institute on Aging Information Center
P.O. Box 8057
Gaithersburg, MD 20898-8057
800-222-2225 (toll-free)
800-222-4225 (TTY/toll-free)
www.nia.nih.gov