When we think about hormones and aging, many of us focus on
estrogen, progesterone and testosterone, and the changes that occur as we move
into middle age. However, these are just three of many hormones metabolized by
our bodies; hormones which also change as we age. Hormones are natural
chemicals produced in one location, released into the bloodstream, and used by
other target organs and systems.
In fact, aging is
comprised of a whole variety of “symptoms”, functional signs and body
composition changes that occur over time. Let’s review a few of them to
determine what happens to our metabolism as we age and whether there is
anything we can do to slow the process.
Metabolism and Hormones
The word metabolism comes from the Greek word meaning “to change”. Metabolism isn’t just how fast or slow we burn
calories; it includes all the ways that our bodies store and use energy from
food. It turns proteins, carbs and fats into compounds that grow and maintain
cells, muscle and adipose tissue. To keep your body’s systems working healthily,
a whole series of hormones must be in balance. Too much or too little of any hormone
can impact not only your weight but many aspects of your overall health. The
metabolic pathways impacted during aging affect insulin resistance, body composition,
a decline in growth hormone and sex steroids. As we age, changes occur to the
way our body systems are controlled, and in general, the body metabolizes
hormones more slowly.
The Endocrine System
The endocrine system is made up of organs and tissues that
produce hormones. The hormones it produces target organs. Some organs have
their own internal control systems, and other hormones control many of the
organs that produce hormones. In other words, it’s complicated! Aging changes
this complex process. For example, the hypothalamus produces hormones that
control the endocrine system and the pituitary gland. The thyroid, which
releases hormones that regulate metabolism, is one of the organs that can
change with age. As metabolism slows, thyroid hormones may rise, leading to
increased cardiovascular risk. Parathyroid hormones can impact calcium and
phosphate levels, which in turn impact bone strength. The adrenal glands
produce other hormones that decrease with age, including aldosterone, which can
lead to blood pressure changes.
One relatively recent discovery is how important adipose
tissue (or fat) is to the endocrine system – it is, in fact, part of it. Fat
cells play an essential role in the storage and release of energy throughout
the body, but that’s not all they do. Adipose tissue contains other types of
cells that produce hormones in response to signals from the rest of the body. These
fat cell hormones play an important role in regulating glucose and cholesterol,
amongst other functions.
Aging, Hormones and Weight
Weight management is a common concern for women and men of
all ages. Changes in estrogen and progesterone, which are produced by the ovaries,
occur in middle age. Menopause is often the time when women find that they
develop fat around the middle. It happens because these hormones regulate where
fat sits in the body, as well as determining whether your metabolism will burn
sugar or fat. Abdominal obesity, in
either men or women, can predispose you to any number of health risks, even if
you have a normal BMI (body mass index). Many additional hormones also
contribute to weight, however.
Insulin – the
main fat storage hormone in the body, it allows your cells to take in blood
sugar for energy or storage, depending on what is needed. It also tells fat
cells to store fat or prevents stored fat from being broken down. Insulin
resistance occurs when cells in your muscles, body fat and liver start
resisting or ignoring the signal that insulin is trying to send out—which
is to grab glucose out of the bloodstream and put it into our cells. When cells
are insulin resistant, both blood sugar and insulin levels go up significantly.
The average fasting glucose level increases after age 50, becoming less
sensitive to the effects of insulin. If not actively managed, insulin
resistance can lead to diabetes.
Leptin – a
satiety hormone, it communicates with the brain to tell it to tell you that you
feel full. Unfortunately, this hormone can get out of balance as we age if we
don’t have a healthy lifestyle, leading to feelings of hunger and subsequent overeating.
Cortisol – known
as the stress hormone, chronically elevated levels of it can lead to
overeating, as many of us can attest. Nighttime stress in particular, which can
lead to insomnia, can cause cortisol and blood sugar levels to rise, prompting your
body to produce fat cells. It’s one of the many reasons why it’s important to
get a good night’s sleep. Cortisol may drop with age, but usually remains
stable in the bloodstream, so it’s vital to minimize unhealthy stress in every
stage of life.
Aging and
Inflammation
A related factor that can exacerbate age-related conditions
is an increase in inflammatory cytokines as we get older. An inflammatory
cytokine is a type of signalling molecule produced by immune and certain other
cell types that promote inflammation. They can interfere with insulin
regulation and are also associated with age-related visceral fat. It’s
important, therefore, to do everything we can to dial back inflammation,
through a healthy diet and other natural solutions.
Slowing the Hands of Time
– Aging and Caloric Restriction
One of the most notable findings in the research on aging
has been the ability of caloric
restriction (CR) to, if not prevent, then significantly delay some of the
age-related processes that we have been discussing here. We know that it
modulates many of these complex metabolic systems, although we do not have a
handle on exactly how it impacts all of them yet.
Although experts say
extreme caloric restriction may be the best anti-aging strategy we have, it’s
not for everyone in terms of quality of life. In certain cases, it can lead to
side effects like lowering of bone density and muscle mass. However, choosing moderate
caloric restriction and an exercise regimen, as well as supplementing with a natural supplement that mimics the
effects of CR, is an alternative most of us can achieve. By committing to
healthy strategies, it is possible to tweak our metabolism and enjoy better
health, for longer.