You learn something new everyday.

by morganallison

Right now in my pathophysiology class, we’re learning about cell injury. The online lecture (most of my class is online, which is new for me) focused heavily on one aspect of the chapter–reactive oxygen species, or ROS. These are what are commonly known as “free radicals.”

Free radicals are oxygen molecules or atoms that have either lost or gained an electron, making them reactive and unstable. The reason free radicals are dangerous is because they will react with components of a cell, such as the membrane, that affect what travels in and out of the cell. This can potentially change the structure of the cell or even kill it. Furthermore, free radicals sometimes initiate a chain reaction in the phospholipid bilayer of cells (which composes the membrane, the cell’s main line of defense), causing the lipids to become free radicals themselves, and in turn change other lipids into free radicals until eventually the entire structure of the cell is different and the cell can no longer carry out its intended purpose. This is called “lipid peroxidation.”

Free Radical

Other types of damage caused by free radicals include: DNA mutations in the nucleus, inactivation of enzymes, impaired protein synthesis, uncontrolled cell divisionI won’t go into too much detail here about it except to explain the basics of why high levels of free radicals are dangerous and what you can do to diminish their effect.

Why are free radicals so harmful?

While it isn’t possible (or necessary) to completely extinguish the existence of free radicals in the body, high levels of these ROS (reactive oxygen species) can cause potentially irreversible tissue damage. Cancer, which is ultimately the progressive accumulation of mutated cells, is a possible result of excessive free radicals.

What can you do to decrease your risk?

There are many common sense things you can do to diminish your risk and get rid of free radicals. Perhaps first and most obvious is: stay as healthy as possible! Get plenty of rest, drink a lot of fluids and keep yourself in the best shape you can. This will keep your body performing at a high level of performance and allow optimal natural removal of these free radicals. Always remember that your body is an incredibly efficient creation. It does a lot of the work itself! However, if you want some added protection, there are a number of antioxidants and vitamins you can include in your diet to help the process along.


Antioxidants are substances that essentially “take the hit,” so to speak, in either taking on or giving up an electron in order to stabilize the free radicals they encounter. This prevents the chain reaction by stopping the free radical from reacting with essential cell structures.

Carotenoids (beta carotene and lycopene)

Beta carotene is a Vitamin A precursor and essential in breaking the lipid peroxidation chain. Common sources of beta carotene include carrots, pumpkin, and sweet potato.

Lycopene is found especially in cooked tomatoes

Vitamin A

Vitamin A is especially significant in retinal health and plays an important role in vision. Many of the same foods that contain beta carotene also include vitamin A since beta carotene eventually becomes vitamin A. Other sources include spinach, kale, and cheddar cheese

Vitamin C

Also called ascorbic acid, Vitamin C is water soluble (as opposed to lipid soluble). This means that Vitamin C, rather than breaking the lipid peroxidation chain, functions by eliminating circulating free radicals. In addition to citrus fruits, good sources of Vitamin C include: guava, kiwifruit, red peppers and green hot chilis. Although oranges get a lot of press for being rich in Vitamin C, strawberries actually contain more of the vitamin.

Vitamin E

Also an important factor in breaking lipid peroxidation. Commonly found in green leafy vegetables, vegetable oils, whole wheat, nuts (almonds, hazelnuts), milk and egg yolks


Flavonoids are plant polyphenols that are found in bright, colorful plants. These are the antioxidants often heard about on television commercials and in the media. Flavonoids are found in wine, tea, dark chocolate, and citrus fruit.

Maintining a healthy balance

Even though the antioxidants I mentioned are good ways to decrease your risk, it is important to remember not to go overboard. Too much of any antioxidant can turn them into “pro-oxidants” which means they will basically turn into free radicals themselves! While incorporating these nutritious and beneficial foods into your diet, be mindful of the daily recommended servings. Speak with your doctor before starting any vitamin supplements. Like I said, the body is very efficient and unless you are having a particular deficit of a vitamin, it can be detrimental to your health to take more than the recommended daily serving.