What is the Role of Oxidative Stress in the Aging Process?
As researchers learn more about the process of aging, an interesting trend takes shape: the very processes that make our bodies function sometimes play a role in undermining our own vitality.
Oxidation is a perfect example of this. For our cells to get the fuel they need, they convert the sugars from our food into energy. Oxidation occurs as sugar breaks down to produce ATP (energy), carbon dioxide and water. This reaction also causes the release of free radicals—particles which can do significant damage to the tissues and organs in our bodies.
The release of free radicals occurs naturally in the body—specifically, in the cell’s cytoplasm and in the mitochondria (where oxidation takes place). The body has a safety mechanism in place to catch free radicals, but external factors can compromise this mechanism. When the body can no longer catch all of the free radicals released during oxidation, it begins to experience what is known as oxidative stress. We can draw a clear line between oxidative stress and the aging process.
As the research bears out time and time again, lifestyle plays a big role in our bodies’ ability to regulate free radicals and the stress they cause.
In this post, we outline everything science understands about cellular oxidation: its mechanism, how we came to understand it and what role it plays in aging.
How Oxidation Creates Stress That Causes the Body to Age
When sugar gets to the cell’s mitochondria, it typically arrives as a simple molecule known as glucose (C6H12O6). As the mitochondria breaks this molecule down, energy is released, just as a campfire breaks down wood and releases heat energy.
As that C6H12O6 molecule breaks down, some atoms peel off—we call those atoms radicals. Radicals aren’t necessarily bad things. In fact, they’re useful in facilitating chemical reactions. Researchers at Colorado State’s VIVO Pathophysiology department do a great job of explaining this: when the glucose molecule breaks down, oxygen atoms often break free—these are a special class of radicals known as reactive oxygen species, or ROS. An ROS is highly reactive because it has two free electrons with which it can bond to other atoms. In some cases, that’s good. For example, white blood cells can produce oxygen radicals that kill pathogens.
In other cases, an ROS is toxic to cells because those unpaired electrons can cause real damage to lipids (i.e. fat molecules), proteins and nucleic acids. That’s how free radicals affect telomere length.
This free radical damage is especially troublesome because it goes hand-in-hand with inflammation. Oxidative stress and inflammation actually have a mutually reinforcing relationship: free radicals can cause chronic inflammation, and the presence of inflammation can cause the release of more free radicals. This process accelerates cellular damage, reduces our longevity and compromises our overall well-being.
Why Does the Body Let Oxidative Stress Happen?
The human body is capable of amazing feats of self-repair. We see this every time a paper cut heals and a bruise disappears. So, if oxidation causes the body so much harm, why doesn’t the body do something about it?
Actually, it does. In a vacuum, a normal, healthy cell has all the enzymes it needs to combat the oxidative stress caused by reactive oxygen atoms. In fact, recent research from the University of Aarhus in Denmark demonstrates that the body’s own radical-response system strengthens in response to mild stress, similar to how our muscles grow when we exercise. Through a process called hormesis, low doses of toxins such as free radicals give our cells a mild workout.
Unfortunately, our cells don’t exist in a vacuum but rather in a dynamic environment full of dangers. The National Center for Complementary and Integrative Health has an excellent guide describing how free radicals from things like cigarette smoke, air pollution and sunlight enter our bodies every day. These external toxins can overwhelm our cells’ own natural self-defense mechanisms.
Further, researchers Nada Sallam from Cairo University and Ismail Laher from The University of British Columbia note that defective mitochondria play a major role in aging. These mitochondria, which fail to produce enough cytochrome C oxidase (complex IV), “create a long trail of reactive oxygen species” that over time damage skeletal muscles and vital organs.
What We Have Learned From Studying the Brain
The link between oxidative stress and aging has thus far been the most obvious in the brain, where the degenerative effects of free radicals manifest in conditions such as Parkinson’s disease, Alzheimer’s disease and dementia—conditions that overwhelmingly affect older people.
“Stress” is a key word when describing the effects of oxidation on the brain. In 2015, researcher Louis-Eric Trudeau, Ph.D., and his team from from the University of Montreal found that the same specific clump of brain cells in different mice were responsible for causing Parkinson’s. These cells had intense energy requirements, produced more oxidative waste than other brain cells and ultimately burned themselves out.
“Like a motor constantly running at high speed, these neurons need to produce an incredible amount of energy to function,” Professor Trudeau notes. “They appear to exhaust themselves and die prematurely.”
Similarly, research has shown that oxidative stress might be responsible for some forms of anxiety. New York Times health reporter Gretchen Reynolds points to one study in which rats had the oxidative stress levels in their brains artificially elevated; these rats responded by demonstrating extreme anxiety.
Just as in other cells, neurons appear to have their own defense mechanism for combating oxidative stress. Jonathan Borkum, Ph.D., at the University of Maine says many of us are already familiar with this process—migraines, after all, are a form of cerebral self-defense.
In all of these neurological studies, each of the researchers explored a consistent avenue for treatment: lifestyle changes. Among the anxious rats exposed to oxidative stress, the ones that had exercised “were relatively nonchalant under stress,” Reynolds reports.
Further, nutritional epidemiologist Martha Clare Morris at Chicago's Rush University Medical Center co-authored a study on dementia that found nutrients such as vitamin E—a powerful antioxidant—”protect against neuron loss, oxidative stress and inflammation.”
Melissa Matthews at Newsweek, reporting on Morris’ study, writes that participants who ate antioxidant-rich leafy greens every day “had brains that were roughly 11 years younger” than those of other participants.
Proven Methods for Fighting Oxidative Stress
What we’ve learned about combating oxidative stress in the brain can be applied to the rest of the body. Science now shows us that lifestyle changes such as diet, exercise and kicking bad habits can have a huge impact on our lifespans—likely even more so than genetic heritage.
In fact, Anne Newman, MD, MPH, professor and chair of the Department of Epidemiology at the University of Pittsburgh, argues that human longevity “is only about 20–30% heritable.” Lifestyle choices make up the rest.
Here are four lifestyle choices that science-backed research has shown can fight the effects of oxidation on the body.
1. Take Antioxidant Supplements
Antioxidant supplements are not a cure-all for oxidative stress, but they are a part of the solution. As the Harvard School of Public Health’s blog, The Nutrition Source, points out, antioxidant vitamins rich in vitamin C, vitamin E, beta-carotene and zinc have been shown to offer protection against “the development of advanced age-related macular degeneration” in people who were genetically predisposed to the condition.
Sallam and Laher’s study into defective mitochondria found that regular exercise “ameliorates age-associated oxidative stress in the heart, liver, plasma, arteries and skeletal muscles.”
Yoga has been shown to be especially helpful in combating oxidative stress. In 2015, researchers from Narayana Medical College in India found that healthy people who practiced yoga—even if they were otherwise sedentary—had longer telomeres in their leukocytes than those who didn’t practice yoga.
3. Eat the Right Foods
Several studies have shown that diets rich in antioxidants reduce oxidative stress on the brain and protect against the development of dementia. Judith C. Thalheimer, RD, LDN writes that foods rich in vitamin E and omega-3 fatty acids are excellent for long-term brain health.
In fact, Gary Small, MD, Director of the UCLA Center on Aging, says that eating fish just once per week might be enough to combat dementia and aging in the brain.
4. Quit Smoking
Dr. J F Donohue at the University of North Carolina at Chapel Hill has done extensive research into the causes of chronic obstructive pulmonary disease (COPD), which has emerged as one of the leading causes of death globally. “There is considerable evidence that the oxidative burden is increased in the lungs of patients with COPD and may be involved in the pathogenetic processes in the lung and in the systemic manifestations of weight loss and muscle dysfunction,” Dr. Donohue says.
Many of those oxidative stresses come from bad lifestyle habits like smoking. In fact, a single puff of a cigarette contains about 100,000,000,000,000,000 (one hundred quadrillion) oxidant molecules.
By giving up smoking, you can massively reduce the number of oxidants your body is exposed to.
Ongoing Research: How People Can Take Control of the Aging Process
Scientists continue to learn more every day about the link between oxidation and aging.
At Auburn University, Geoffrey E. Hill has been exploring whether ornamentation (i.e. the biological characteristics that make us attractive to mates) is an expression of efficient cellular respiration. If so, that could indicate a fascinating evolutionary connection wherein people who outwardly demonstrate an ability to limit the effects of oxidative stress are more successful at reproduction.
Elsewhere, Robert H. Shmerling, MD, at Harvard Health Publications has a great summary on the ongoing research into flavanols, substances found in dark chocolate and cocoa that have so far shown mixed but promising results in combating inflammation and oxidation.
The research is exciting, as is what we already know: certain lifestyle factors can decrease the negative effects of aging. Unsure of where to start? We’ve got plenty of articles on lifestyle to check out for further reading. And, of course, our own VitaYears™ Anti-Aging Multivitamin provides nutritional antioxidants and anti-inflammatories to help your body fight back against oxidative stress, allowing you to live a longer, healthier life.
images by: stockbroker/©123RF Stock Photo, Shaquille Dunbar/Nappy.co, dolgachov/©123RF Stock Photo