Aging and Chronic Disease – Familiar Bedfellows
Chronic disease is currently the leading cause of death in the European Union, accounting for 85% of all deaths (1). While people are certainly living longer, the extra years getting tacked on at the end are not “healthy” years. At age 65, Europeans can expect to see approximately 20 more years of life, nine of which will be healthy. The balance is spent with one or more chronic diseases including heart disease, cancer, cerebrovascular disease, type 2 diabetes, and Alzheimer’s disease.
The biggest risk factor driving chronic disease is aging. While chronic disease can strike at any time, and the age of onset is getting younger and younger, the risk for chronic disease and death increases exponentially as we age. This has led to a sort of renaissance in chronic disease treatment models.
Our current model views disease as a failure in one or more isolated systems that needs to be addressed individually. A new model is beginning to emerge where instead of treating individual disease, treating aging will give more bang for your buck. Therefore by treating aging, you can reduce the risk of many diseases at once.
But this brings up 2 important questions:
- Is aging a disease?
- Can we really cure it?
It may seem the stuff of science fiction, but the data seems to point to the answer to both as “yes”. But that all depends on how you define “aging”.
Chronological Aging vs Biological Aging
Many of us have watched our friends, family, and ourselves age. As time goes by, our muscles get weaker, bones get more brittle, skin wrinkles, immune function flounders, and we become more frail. But two separate things are happening. Time is going by, and our systems are breaking down. The two are related, but not one-to-one.
Chronological aging is the process of time passing and is the same for everyone. Anyone born on June 1st, 1980 is the same age chronologically. But biologically, they may be vastly different. Some of this is genetic, and some of it is behaviorally driven.
People who drink excessively, smoke cigarettes, overeat, are sedentary, get poor sleep, and don’t manage stress are more likely to breakdown. It’s very similar to cars. Two people can have the exact same year, make, and model of car, but one may last much longer than the other. It all comes down to the mileage on the car, how well it’s been taken care of, and the maintenance schedule.
So when we look at the chronological age of a car, we’re simply looking at the year it was made. When we look at the biological age of a car, we are looking at how likely it is to break down in the next 10 years. In humans, it’s exactly the same. As chronological age increases, your risk of death within the next 10 years increases too. But they’re not the same.
Pathways of Aging
We do not get oil changes or tune-ups. But our maintenance systems work similarly. You can’t do an oil change on a car with the engine running without killing it. Instead, you bring your car to a mechanic, he/she shuts off your car, performs the oil change, and you start your car and leave.
Interestingly, signaling in the human body works essentially the same. We have an active period where our cells are being used, and a rest period when they are repaired. This is the basis behind circadian rhythms (our evolutionary preferred wake and sleep patterns).
But for this to work, our cells must sense when to repair. This is handled by nutrient sensing pathways such as insulin, one you may have heard of, and others such as mTOR, sirtuins and AMPK (more on these in future blogs). These pathways work by signaling to the cell when to build (anabolism) or when to break down (catabolism). They are also the pathways through which calorie restriction extends lifespan (2).
Biological Aging can Slow Down and Potentially Reverse by Healthy Habits
As we get older, we are destined to break down. But this is something we can slow down and, dare I say it, potentially reverse. We can slow it down by practicing healthy habits such as maintaining a healthy weight, prioritizing sleep, eating a nutrient dense diet, exercising and not smoking.
The slowing and potential reversal of biological aging is a hot area of research. In fact, a recent study found that 4000 IUs of vitamin D per day led to an almost 2 year decrease in biological age in overweight African American men in just 16 weeks (3). Another study found that the use of medical growth hormone, DHEA (a hormone that helps to make testosterone and other hormones) and metformin (a medication used to help to lower blood sugar levels and insulin sensitivity) caused a 1.5 year decrease in biological age after one year of treatment – a 2.5 year improvement compared to no treatment (4). These studies are two separate instances of biological age reversal in humans.
What was thought to be impossible 10 years ago is not so much the stuff of science fiction anymore. Aging should be considered a disease and we certainly have evidence to show that biologically it can be drastically slowed down at the very least. The reality is that science is showing us how to live longer, healthier lives and most importantly this can be done through low risk behaviours such as exercise, sleep, and fasting/calorie restriction.
This is a guest post. The opinions expressed are the writer’s own.