Aging is less about a number and more about the myriad of internal and environmental factors causing physical and anatomic changes that cause decline in function. Advances in science have identified some factors behind the aging process. These factors include exposure to cellular stress, chronic inflammation, dysregulation of lipid metabolism, and programmed cell death.

Today, the goal is not so much to prolong lifespan, but to prolong “health span,” the period of life characterized by the absence of disease and disability. It just may be that the normal human process of “autophagy” is at the heart.

Importance & Biology of Autophagy
Simply put, autophagy is the process that rids the body of damaged and non-functioning cells and genetic material. In the course of daily life, cells get damaged or mutations occur, making them function inappropriately or not work at all. To maintain health, these abnormal cells must be removed. Autophagy is the body’s mechanism for clearing out these cells and their debris and recycling usable components into new, healthy, functioning cells.

Autophagy also comes into play when the body needs fuel. When the body doesn’t get enough fuel from food, its cells ramp up autophagy. The process breaks down cells so that the cellular components can provide fuel to the “starving” body. This is the mechanism behind the intermittent fasting concept. It’s thought that intermittent fasting causes weight loss as well as promotes the healthful effects of autophagy.

The phenomenon of autophagy was first described in 1963. It took until 1990 for Yoshinori Ōhsumi to decode the underlying. After many experiments with yeast cells, Ōhsumi succeeded in uncovering the genetic basis of autophagy. In 2016 he was awarded the Nobel Prize for Medicine for this discovery.

Since then, numerous researchers have been studying autophagy and its role in the development of chronic disease and the physical changes associated with aging. Researchers know that autophagy declines with aging. They suspect that inhibited autophagy can potentiate development of  diseases and conditions, many associated with chronic inflammation, such as arthritis, heart disease, cancer, diabetes, Alzheimer’s, and Parkinson’s diseases.

A very simple explanation is, in the face of flagging autophagy, dysfunctional or non-functional cells that should have been discarded, remain in the system. They either make faulty structural or regulatory proteins, or none at all.

What is Autophagy?
Autophagy works like a cellular waste recycling program. It helps your cells clear out damaged or misfolded proteins and large organelles that can lead to age-related illness and recycle their components into functional cellular parts. It can be said that autophagy is critical to a long and healthy life. As we age, autophagy slows, making us more susceptible to disease and physiologic aging. However, scientific evidence shows we can boost autophagy through fasting and providing supplemental polyamines to the diet.

Spermidine: Activity, Sources & Supplements
Polyamines, especially spermidine, are vital to the process of autophagy. Spermidine regulates enzymes needed to stimulate the process of autophagy. Unfortunately, as people age, spermidine levels decline, necessitating spermidine supplementation.

Humans get spermidine and other polyamines from three primary sources: biosynthesis, production by the gastrointestinal microbiome, and from the diet. In mammalian cells, spermidine is biosynthesized from amino acids. Aging reduces intracellular spermidine synthesis.

In the human gut, bacteria convert dietary amino acids and other polyamines into spermidine. Poor intake of precursor substances, changes in gut microbiome, and alterations in transport and metabolism related to aging reduce levels of spermidine.

Because polyamines are present is more than 250 foods, they are readily provided by the diet. Polyamines are especially abundant in wheat germ and other grains, sweet potato, and soybeans, vegetables, mushrooms, and nuts. Animal-derived foods contain less spermidine than plant-derived foods. Unfortunately, our modern diet contains few of these high-spermidine foods. Further, age-related alterations in digestion, absorption, and metabolism of nutrients combine to reduce spermidine levels.

Spermidine supplementation repletes spermidine levels, resulting in rejuvenated autophagy and reversal or alleviation of chronic conditions. Maintaining polyamine levels is important because deficiency interferes with the process of autophagy. Scientists see spermidine supplementation as a viable intervention for maintaining this process.

A special thanks to the team at Longevity Labs (spermidineLIFE) for their insights and contributions to this column.

About the Authors: Greg Stephens, RD, is president of Windrose Partners, a company serving clients in the the dietary supplement, functional food and natural product industries. Formerly vice president of strategic consulting with The Natural Marketing Institute (NMI) and Vice President of Sales and Marketing for Nurture, Inc (OatVantage), he has 25 years of specialized expertise in the nutritional and pharmaceutical industries. His prior experience includes a progressive series of senior management positions with Abbott Nutrition (Ross Products Division of Abbott Laboratories), including development of global nutrition strategies for disease-specific growth platforms and business development for Abbott’s medical foods portfolio. He can be reached at 267-432-2696; E-mail: gregstephens@windrosepartners.com. Sheila Campbell, PhD, RD, has practiced in the field of clinical nutrition for more than 30 years, including 17 years with Ross Products Division of Abbott Laboratories. She has authored more than 70 publications on scientific, clinical and medical topics and has presented 60 domestic and international lectures on health-related topics. She can be reached at smcampbellphdrd@gmail.com.