How free radicals/oxidative stress affect your lifespan.
Before we begin, make sure to check out part one of the Immortality Series — if you haven’t already. While this is optional, it’ll provide a better understanding of the topics I discuss here.
Alright, now we’re set.
Free Radicals: The Basics
Free radicals are also known as reactive oxygen species (ROS). These work hand-in-hand with oxidants, or reactive nitrogen species (RNS). Please note that “ROS/RNS” and “free radicals” will be used interchangeably in this article, but they relate to the same subject.
What They Are & How They’re Created
Our bodies need oxygen. In fact, our cells use oxygen to create energy. However, while the mitochondria (the powerhouse of the cell) creates ATP, a molecule for transferring/storing energy inside cells, free radicals are created.
Free radicals are oxygen molecules with one or more unpaired valence electrons. Valence electrons are the outermost electrons in an atom (heh, chemistry) and they like being paired. When they aren’t paired, they seek out to find a pair. This results in them stealing an electron from another molecule, and now that molecule has an unpaired electron. And so the chain reaction begins, with molecules taking electrons from each other left and right. It’s like stealing from a thief, that thief stealing from another thief, and so on.
When a chemical bond between molecules is broken, free radicals may be formed. Each fragment that was separated now retains an electron, and they’re both unpaired. Very sad.
ROS/RNS are also highly unstable, but very reactive.
Free radicals can actually be produced from exogenous (outside the body) or endogenous (inside the body) sources. Air pollution, cigarette smoke, alcohol, and specific drugs are metabolized/decomposed once they enter the body. This results in the generation of free radicals, exogenously. From inside the body, inflammation, cancer, and mental stress are also capable of creating ROS/RNS.
Now, the problem. When there is an overload of ROS/RNS, oxidative stress is created.
Oxidative stress is a phenomenon that occurs in the body when there is a disproportion in neutralization and formation of free radicals. The cells aren’t able to get rid of the overproduction of ROS/RNS. This can cause damage to many structures in the body, such as the cell membrane, lipids, and proteins. Protein damage causes a lack of enzymatic activity and structural changes, which shouldn’t happen. Oxidative stress may also harm the DNA, which may lead to lesions that result in mutations. Yikes.
You see the problem, yes?
But there is a solution.
Fortunately, there is a mechanism made to fight oxidative stress. These are called antioxidants. And chances are, you’ve heard of them before.
Ever seen a commercial advertising how healthy their food is, claiming that it’s “rich in antioxidants”? This is why.
Antioxidants combat free radicals. They use two methods to carry out this function: chain-breaking and prevention.
In the first approach, antioxidants stabilize the chain created by a molecule taking an electron and creating other free radicals (thief stealing from a thief, remember?) Chain-breaking antioxidants include vitamin C and E. In the second method, an antioxidant prevents oxidation from occurring by decreasing the rate by which a chain is initiated. This can be seeking out initiative free radicals and getting rid of them, or stabilizing transition metal radicals (iron, copper, etc.)
Antioxidants may be naturally produced in the body (endogenous), or administrated through foods (hence, the ads). When these mechanisms destroy a free radical, they actually become oxidized. That’s why we need to constantly replenish our antioxidants. Eat your strawberries, guys.
There’s a catch, though. Antioxidants, like many mechanisms in the human body, are double agents. They may be beneficial in certain situations, but completely ineffective in others. Sometimes, an antioxidant can become a pro-oxidant. It may actually create ROS/RNS — the compound it’s literally supposed to destroy.
Wait, But… Free Radicals Can Help?
Yes. Yes, they can. Free radicals are both beneficial and toxic for the body, which is essentially the issue. When there is a low or modest amount, ROS/RNS aid in the maturity of certain cell structures. They may also operate as weapons in the host defense system. Phagocytes (cells that can ingest foreign particles) sometimes release free radicals, in order to combat pathogenic microbes.
For this reason, we can’t get rid of free radicals entirely. We still need them. This makes finding an external solution more complex, since we have to stay in the “golden zone.”
How It Contributes to Aging
Oxidative stress plays a hand in aging. Many studies have been conducted that found a correlation between ROS/RNS and organisms’ lifespan. In model organisms (including fruit flies and mice), lifespan was found to increase when oxidative damage was decreased. And the same effect occurred vice versa — producing more free radicals decreased lifespan.
The free radical theory of aging was actually proposed by Denham Harman (1950s). He hypothesized that organisms age due to the accumulation of oxidative damage. Oxidative stress also plays a part in many chronic and degenerative illnesses, including arthritis and cardiovascular disease.
So, What’s the News?
Free radicals may be bad, but they aren’t entirely bad. Still, you should always be making sure you’re finding ways to consume antioxidants and eat healthily. This puts you at a smaller risk for the overaccumulation of free radicals and, overall, will never hurt you.
Scientists are actively studying ways to deal with free radicals and safely lessen their negative effects. For now, your future is in your own hands. Live a salutary lifestyle.
Now we’ve learned another cause of aging! Check out more reasons why you’re slowly being killed in my review article, here.
And keep an eye out for the rest of the Immortality Series!
- Free radicals are also known as reactive oxygen species (ROS) and work with oxidants (RNS). They’re created from oxygen molecules with unpaired valence electrons, which causes a chain reaction.
- Free radicals can actually be produced from exogenous (outside the body) or endogenous (inside the body) sources.
- When there’s an overload of free radicals, oxidative stress occurs. Oxidative stress is a phenomenon that occurs in the body when there is a disproportion in neutralization and formation of free radicals.
- Fortunately, antioxidants are made to combat ROS/RNS. They become oxidized when they destroy a free radical, which is why we must replenish them.
- Oxidative stress plays a hand in aging. Many studies have been conducted that found a correlation between ROS/RNS and organisms’ lifespan.
- Eating a healthy lifestyle can help your body and produce more antioxidants to combat free radicals!
A Quick Message
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Check out resources used to learn more about this topic.
Free Radicals, Antioxidants in Disease and Health
Free radicals and oxidants play a dual role as both toxic and beneficial compounds, since they can be either harmful or…