Influences on Aging - Oxidative Stress
by: Neil Speight M.D.
The most notable contribution to aging is the influence of environmental oxidative stress on our bodies. Before launching into this explanation it will be helpful to define a few terms. An atom is one of the most basic building blocks of life. Simply, one can think of atoms as combinations of positive and negative charges interacting with each other. The positive charges are called protons and form the center or nucleus of the atom; the negative charges rotating around the nucleus are electrons.
The periodic chart or “ Table of Elements” is a summation of all of the elements scientists have discovered, such as oxygen, hydrogen, etc., along with a description of the total numbers of protons and electrons in each atom. The individual elements combine to form molecules such as water, amino acids, carbohydrates, fats, etc.
“Oxidation” is the process by which an electron (an unpaired negative charge) is extracted from an atom. Free radicals are atoms with a single unpaired electron in the outer most shell (atoms have layers of electrons typically traveling in pairs, spinning around a nucleus of protons).
These molecules are very unstable and they are constantly trying to steal another electron from your body’s tissues. In that process, they alter other molecules making them unstable in a domino-like chain reaction. Ultimately, free radicals can pierce the cell’s membrane just as a bullet might penetrate the wall of a house. This will damage the cell’s molecular pumps, damaging vital fatty acids and proteins, and even finding their way to the nucleus where the chromosomal blueprint resides.
Another area of the cell that is potentially very susceptible to oxidative stress is the mitochondria. Mitochondria are sausage-like structures that are in essence the cell’s electrical generator. Our food is broken down into fats and other derivatives that are converted in the mitochondria to energy via a cascade of electron activity that ultimately keeps us alive.
The numbers of mitochondria are highest in tissues where the metabolic demands are the greatest such as the heart and skeletal muscles. Their outer and inner membranes are both very susceptible to damage from free radicals. Imagine trying to run your car after a bullet has ripped through the gas tank. It wouldn’t be long before your engine eventually sputtered and then stopped for lack of fuel. In a similar fashion, someone that has mitochondrial damage due to oxidative stress may develop memory problems, diminished heart function, numbness and tingling, and muscle weakness. Eventually, the tissue engine just sputters and stops.
Ironically, mitochondrial metabolism is the largest source of reactive oxygen species (ROS), or free radicals. The major step to energy is the final transfer of electrons from a substance known as NADH to molecular oxygen along the cytochrome system (a series of electron transfers) in the inner mitochondrial membrane. This process is known as oxidative phosphorylation and involves oxygen near the end of the process. Whenever oxygen serves as an acceptor for electrons the potential for creation of highly reactive oxygen species (free radicals) is great.
Good free radicals
The most abundant free radicals in your body are derived from oxygen, which we obviously cannot do without. Not all free radicals are bad however. There are species of radicals that are generated by certain defense cells to destroy invading bacteria and help to keep our tissues safe. Therefore, the solution to oxidative stress as it relates to aging is really one of balance. We need them, but not too many of them and some are worse for our tissues than others.
Managing free radical balance
One way that cells manage free radicals is by transferring the unwanted electron to a vitamin or antioxidant enzyme, often found in various foods and supplements. The enzymes involved in this process require trace minerals such as copper, zinc, manganese and selenium to function properly and quickly to neutralize free radical activity.
The most notable antioxidant enzymes are Glutathione Peroxidase (utilizing selenium) and Superoxide Dismutase (utilizing manganese in the mitochondria and copper/zinc in the cytoplasm (fluid part of the cell), and copper in the plasma version of the enzyme). It stands to reason that if one is deficient in the trace minerals or the amino acids making up the antioxidant enzymes or one of the key vitamins that serves as a receptor of free radicals, cellular injury and thus tissue injury advances much more quickly. Indeed, this is an accepted fact.
Markers of oxidant damage to fatty acid membranes, proteins, and DNA are now commercially available and provide a means of monitoring environmental exposures leading to excessive oxidative stress as well as monitoring treatment protocols to improve health.
Oxidative damage caused by free radicals is the basic mechanism underlying aging and many age-related disorders including atherosclerosis, cancer, rheumatoid arthritis, allergies, respiratory distress, chemical sensitivity induced by heavy metals, solvents, and pesticides, radiation injury, Parkinson’s disease, diabetic neuropathy, and liver disorders.
Some of the common red flags of oxidative stress include:
- Lipid peroxide levels, (most notably malondialdehyde)
- isoprostanes which are metabolites of arachidonic acid ( a fat rich in red meat)
- 4-hydroxy-2-nonenal ( HNE) an extremely mutagenic and genotoxic aldehyde product of fat oxidation
- oxidized, low –density lipoprotein ( “ bad cholesterol”)
- 8-oxo-deoxyguanosine, 8-oxodG for short. Age associated decline in the function of mitochondria is implied by finding elevated levels of 8-oxodG.
So what can you do about it?
First, consider having the markers (red flags) mentioned above drawn by one of the labs that provide molecular medicine assays such as Metametrix Labs, Quest Diagnostics, or Specialty Labs.
Second, measure the mineral catalysts and amino acid levels involved in the antioxidant enzymes that help neutralize free radicals.
Third, measure the levels of the antioxidant vitamins, A, C, E, lutein, zeaxanthin, lycopene, and B-carotene as healthy levels of these nutrients will help slow oxidative damage and therefore slow aging. It most be noted however that single high levels of an antioxidant nutrient do not necessarily correlate with health.
Note: You must remember, that neutralization of free radicals depends on a complex interdependent network of antioxidants. Increasing the amount of any single nutrient may in fact result in the worsening of your condition because of an imbalance.
- You also should work to reduce the amount of chemicals in your environment contributing to increased free radical stress in your body. Be cautious about exposure to dry cleaning fluids, copier ink and fluids, and excess gasoline fumes. These products can easily increase your exposure to free radicals. This would also include screening via blood for heavy metals (like lead, cadmium, and mercury) and if present then looking in your environment for sources of these metals.
- Reducing the use of pesticide laden foods
- Decrease the amount of exposure to intense sun rays between 10am and 2pm
- Eliminating excess alcohol and totally eliminating the use of tobacco products.
- Finally, a good diet rich in fruits and vegetables especially the pigmented fruits like blueberries, elderberry, etc are very helpful in neutralizing free radical stress.
Oxidant and antioxidant markers should probably be measured annually as part of a screening physical exam. Sadly, they are rarely if ever done. As this information becomes common knowledge in medicine, your physician will hopefully make this a part of your routine blood work.
Other contributors to aging include the decline of hormone levels. This will be the topic of our next article on Influences on Aging.
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(Dr. Speight is the owner of The Center for Wellness in Charlotte, NC, specifically dedicated to supportive treatments and therapies through nutritional and environmental medicine.)