Your Aging Immune System: What You Need to Know - Part 1
Immunosenescence and Inflammaging
Have you seen or heard these terms?
These are the new catch phrases to describe the decline in the immune system after age 50!
“Immunosenescence” refers to the general wearing-out of immune cells with age, with a gradual decline in immune function.
“Inflammaging” is a combination of the words inflammation and aging. It’s a new branch of research into the effects of chronic inflammation on the rate that we age. As the immune system ages, it creates a pro-inflammatory environment in the body - and that speeds up the aging process for all systems involved.
It’s important for us to know that this is happening. This fact alone - that a state of chronic inflammation will cause us to age faster - should make us sit up and pay attention.
Inflammaging causes immunosenescence...and we don’t want that!
Well, I know what I do want...I want to live a long, healthy life. Don't you?
So I'm here to tell you that there is a ton we can do to support our immune system, and slow down the inner and outer effects of advancing age.
In Part 1 of this series, I’ll outline the issues so you’ll have a good understanding of your hard-working immune system.
And in Parts 2 and 3, I’ll focus on all the things we can do to support and balance it for the next - oh, say - 50 years?
So...what is the immune system?
The immune system is an intricate network of cells, tissues and organs that protects us against invading microbes and allergens, and heals our injuries.
It is headquartered in the lymphatic system, which is composed of the bone marrow, spleen, and thymus gland, as well as the lymph nodes and ducts. But there are still more immune cells scattered throughout the body - in the mucous membranes of the nose, throat, lungs, bladder and vagina, and very importantly, all throughout the lining of the gut.
In the circulatory system, specialized immune blood cells (lymphocytes and leukocytes) are on the front lines to protect us against invaders of all types - bacteria, viruses, parasites and fungi - and also allergens or any cell that they ‘see’ as ‘foreign’. This is termed the immune response.
Our immune system also detects and removes any of our own cells that show disease processes, for example the abnormal cell division seen in precancerous cells. Zap! They’re gone. This happens without us knowing it hundreds of times a day.
Most of the time, the immune response is a healthy one and we recover from any invasion. But in certain situations and for various complicated reasons, our immune system will mistakenly target our own cells - and we have an ‘autoimmune’ disease result. Our immune system is now destroying our own cells. Examples include Hashimoto’s thyroiditis (a common type of hypothyroidism), Type 1 diabetes and rheumatoid arthritis.
Our immune system is also responsible for the inflammatory response - or inflammation. We know it as heat, pain or itching, swelling, redness. It can also be a healthy response, as it’s the first step in healing any wound. But, again, the inflammatory response can run amok, being driven by an immune system gone wrong, and the result is a state of chronic inflammation and tissue damage.
It's a bit of a paradox. An exhausted and stressed immune system will not have enough functioning ‘guard’ cells to recognize and neutralize invaders and abnormal cells. But on the other hand, an over-stimulated, reactive immune system won’t be able to turn off the inflammatory response.
A balanced response is the hallmark of a healthy immune system.
What happens as we age?
After 50, there is a dramatic decline in the ability of our immune system to protect us against infections and cancer. Our wounds don’t heal as well or as quickly. And our responses to vaccines, for example the flu shot or the shingles vaccine (which has been developed because our aging immune system can’t keep the chicken pox virus under wraps any more), are impaired.
The combination of a shrinking thymus gland and malfunctioning B and T lymphocytes (the front line protector cells mentioned above) are the main signs of an old, tired immune system.
The thymus gland makes our T cells and is actually most active during childhood - when our T cells are busy recognizing and remembering bacteria, viruses, fungi, and allergens for life.
So the thymus has done it’s work by our early teens, when it starts to shrink, and its active cells are replaced by fat cells. Which we’ve become very familiar with elsewhere in our bodies, right?
Immune system aging accelerates a number of diseases, and as we age, we become more susceptible to conditions such as diabetes, hypertension, cardiovascular disease, arthritis, dementia, sarcopenia (muscle wasting) and cancers. All of these common conditions of the elderly are underpinned by inflammation.
And...why?
The reasons that the immune system declines with age are not fully understood, but it appears that there are a number of probable causes.
First and foremost, we are living longer. The life span of humans is expected to reach 100 years for children born in 2000. Our immune system, from an evolutionary standpoint, was designed to last about 40 years. It has some catching up to do!
Then there is the long list of cellular changes that we see in the immune system after 50 - which appears to be the result of overwork. We have old immune cells that are not able to protect any more, and other immune cells that have become altered so that they are now pro-inflammatory, creating the chronic low level of inflammation mentioned above, called inflammaging.
This inflammaging then drives more immune system dysfunction, which then creates more inflammation, continuing a downward spiral.
Here are some of the other factors that negatively affect a normal immune system:
chronic stress
hormones
the gut - which includes poor diet, overweight and obesity, and altered flora (healthy bacteria, yeasts and fungi)
medications, infections, and chronic disease
Interestingly, or perhaps I should say overwhelmingly, all of these factors interact with each other to make the situation very complicated for physicians to assess and for immunity researchers to unravel.
Stress
How often do you feel stressed out? Off and on...or constantly?
The detrimental effect of sustained stress on the immune response has long been known. Chronic, prolonged physical and/or emotional stress impairs our ability fight infections and can result in a state of chronic inflammation through persistent activation of the adrenal glands.
When we’ve been injured or are suddenly frightened, the adrenal glands secrete cortisol - the hormone that drives our stress response and prepares us to run or fight in an emergency. The stress impulse is shot to the adrenals via the nervous system, which simultaneously sends the alarm to the immune system to get ready to defend.
There’s a lot going on at the same time when you are injured or under attack. Here, the nervous-endocrine-immune connection is shown to be key to protection and safety. But if the stressor is persistent and becomes chronic - like a long-term illness, an abusive relationship, or a heavy demands at work - the immune system becomes exhausted, is not able to fight infections or heal wounds as well, and can’t keep inflammation under control.
Chronic stress has been linked to arthritis, fibromyalgia, heart attacks and ulcers - all diseases of chronic inflammation in the body.
Hormones
Who knew? Estrogens appear to trigger the immune response, while male hormones like testosterone, suppress it. It’s a known fact that women are at higher risk for rheumatoid arthritis, lupus, and hypothyroidism, for example.
But overall, the decline in both male and female reproductive hormones at midlife causes a drop in general immunity, and is thought to be one of the causes of immunosenescence.
This area needs more study - there’s not enough good research available yet to recommend hormone replacement therapy to boost immune status. But if you’re already taking menopausal hormone therapy (MHT), it could turn out be a good thing for your immune system. Early studies show some positive results.
The gut
If you want to fix your health, start with your gut. - Dr Mark Hyman
The health of the GI tract is a very important player in overall immune status. Did you know that 70% of our immune cells reside in the lining of our gut? That’s because it’s the first point of entry for all the food we eat - and all the potential allergens and invading bugs therein!
Alongside our gut immune cells, living in harmony in a symbiotic relationship, are the 10-100 trillion(!!) gut bacteria - known as our microbiota. These helpful, healthy bacteria and yeasts help fight germs, break down food, and produce vitamins.
What scientists have seen over the past 100 years is a change in the makeup of the human microbiota - to one that allows or even promotes inflammation in the body.
The Standard American Diet is felt to be the culprit. In North America, and the western world in general, our diet has become one of highly processed edibles (I hate to call it food!) - high in sugar and fat, and low in fiber - it has substantially altered our gut bacteria. And not in a good way.
Allergies, arthritis, autoimmune diseases, irritable bowel syndrome, acne, chronic fatigue, mood disorders, autism, dementia and cancer are all attributed to the altered gut bacteria caused by the appalling way people eat and the overuse of antibiotics.
According to Dr Mark Hyman, author of Food: What the Heck Should We Eat and prominent functional medicine physician, the Standard American Diet has virtually poisoned our gut bacteria, throwing off our immune systems and resulting in the diseases of inflammation we see so pervasively in our population today.
A high calorie diet also leads to overfed fat cells (adipocytes) that will ‘act like they’re infected’ and set off an inflammatory response in the tissue surrounding them. This fact has been under study for decades and it has come to light that certain bloated fat cells send out a false distress signal that triggers an immune response. What occurs eventually - in some people - is type 2 diabetes.
Medications, chronic infections, and diseases
...especially autoimmune conditions - add insult to injury to an already fatigued immune system at middle age. Antibiotics, as we all know, kill off the healthy bacteria in the gut at the same time as they are treating an acute infection - and physicians are strongly encouraged only to prescribe them when necessary.
The bottom line
Your immune system is aging, as is the rest of your body
The immune system is suppressed by physical and emotional stress
The more fat cells, the higher the risk for inflammatory diseases
As sex hormones decline with age, there is lower immunity and more inflammation
Diet and lifestyle affect gut health, which affects immune status
There are many interrelated reasons for immune system decline with age
All are amenable to supportive therapy and can change for the better
Wondering what you can do to support your immune system?
We all age differently, according to our genetics, lifestyle, and environmental exposures.
I believe there will come a time when we'll all be stratified, or grouped, according to similar characteristics of our medical and health history, genetics, and exposures so that each of us will receive a personalized immune support plan. But for now, we'll focus on the long list of general recommendations for boosting and balancing your immune system.
In Parts 2 and 3 of this series, I’ll be outlining the latest research-based tips for immune support, so you can get started on your way to building a strong, balanced immune system.
A strong immune system means a longer, healthier life!