Epigenetics 6/1/2020

Stress and Aging

What’s the deal with oxidative stress and aging?

In this course you will learn how the stress and energy demands of living (and reproducing!)
set you up to age, and what you can do about it.

39 Cards

The zebra finch, a cute striped Australian bird, has a very human source of stress…  Kids!

Zebra finches that have larger broods of chicks are more stressed…  and they age quickly.

But this isn’t parenting stress.  It’s all about energy, and it starts in the finch’s cells.

Stress may remind you of work or relationship issues.  But cells in your body, the building blocks of your organs, get stressed too.

For a cell, stress is a byproduct of living and creating chemical energy.  It happens when harmful chemicals attack a cell’s insides.

Burning any fuel has a price.  Burning wood makes smoke.  Burning sugar makes…  electrons!

As your cells break apart sugars, fats and proteins to create chemical energy, they tend to make a mess.

Cells often spill some of the high-energy electrons that they break off of sugars.

These spilled electrons react with oxygen in the cell, creating
reactive oxygen species.

Reactive oxygen species, ROS for short, “poison” DNA with oxygen and unfold proteins.

Hydrogen peroxide, the stuff that fizzes when you disinfect a cut
with it, is a ROS.

A small amount of ROS in a cell is normal.  A large amount causes oxidative stress that injures a cell’s DNA and proteins.

This is the kind of stress that zebra finches suffer from when they have a large brood!

This stress also contributes to aging, as cells injured by ROS struggle to work like they should.

In the next cards, we will look at conditions that increase ROS in your cells, but also how you can fight ROS!

A cell makes more ROS when it is exposed to toxins, like chemicals in cigarettes.

A cell makes more ROS when it has to burn lots of sugar from your diet.

But like a tired parent, a distracted cell that doesn’t manage its stress is most vulnerable to ROS.

For a finch, reproducing is stressful and takes a lot of energy.  So the finch’s cells fill up with ROS.

Luckily, cells know the dangers of ROS and work hard to protect themselves.  They have cleanup crews called antioxidants.

Antioxidants work to oppose (“anti”) the effects of ROS (“oxidants”).  Antioxidants neutralize or inactivate ROS.

Cells can even make proteins called antioxidant enzymes that turn ROS into water!

But there’s a catch: It takes a LOT of energy for cells to run this cleanup effort.

For finches and other animals, mating takes a lot of energy.
So finches have to budget.

The more of its energy a finch
uses for reproduction, the less
it uses for ROS cleanup.

This is why animals that reproduce more when they are young tend to age more quickly.

Sacrificing ROS cleanup for reproduction means that DNA and proteins get more injured over time…

Do you remember what causes aging?  DNA and protein injuries that zombify cells!

You take much longer to reach sexual maturity than a finch, and you live much longer.

You aren’t a finch.  Pregnancy may even be a cleanup cue for a mother’s cells, to help her live longer to care for children!

But your body still conserves energy by cleaning up ROS slowly most of the time.

Your ROS cleanup crews also slow down with age, leading to more ROS and faster aging.

But there’s good news.  You can trick your body into using more energy to clean up ROS!

Exercise stresses your muscle, heart and other cells just enough to make them speed up cleanup.

Exercise and intermittent fasting are mild stressors that activate your antioxidant enzymes.

Colorful chemicals in some fruits and vegetables also activate ROS cleanup crews in your cells.

That might be why finches eat so many fruits and berries - for their antioxidant power!

In summary, your body saves energy by not always cleaning up ROS and repairing damage in your cells.  This ages you.

Train your cells to fight stress and ROS with exercise and colorful foods!

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Sources
  • Catoni et al., 2008, doi:10.1111/j.1365-2435.2008.01400;
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