Antioxidants

By Xavier Fox

How many times have you been at your local health food store looking for a supplement and you notice many of the vitamins have the word “antioxidant” on them? For those that are unaware of what an antioxidant is, intuitively, the word makes you think of something that would inhibit oxygen production. Then your next thought would be that oxygen is something the body needs, and this type of thing would not be good for those that exercise. However, antioxidants play a very critical role in maintaining our health, and everyone that exercises should make them a staple in their diet.

It would be simple just to tell you to take antioxidants because they are good for you and leave it at that. BodyFitness readers are more intelligent and simply do not follow directions without knowing why they are doing what they are doing, so it is critical that they understand exactly why they need antioxidants. To do that, it is important to understand what free radicals are, how they are formed, and what potential damage they can cause. In addition, knowing all about free radicals and antioxidants will give you more knowledge on the inner workings of your body and how it is affected by exercise and diet.
Most of us were required to take chemistry in school, and we had to study atoms, which are made from neutrons, protons and electrons. As long as you were not like me in school, and you actually paid attention or were not sleeping, then you remember that atoms are called “stable” when their outer most shell has an equal number of electrons as the underneath shells do with electrons spinning in the opposite direction. With free radicals, the outer shell is missing an electron so that there is an “unpaired” electron in the atom that needs an electron to balance it. This makes the free radical highly reactive, especially if it is an oxygen free radical, because they will have two missing electrons in the outer shell. It just so happens that our system is full of oxygen and exercise greatly increases the amount of it in our body, so it is easy to see that free radical production will also increase tremendously with exercise.
Free radicals roam around the system looking for electrons to steal in order to become stable. When they finally pilfer one from another atom, guess what happens next? The atom it took the electron from becomes a free radical. Therefore, the newly formed free radical starts looking for an electron to steal and the chain continues. The chain reaction can become so long that it actually disrupts the function of the cell and the cell will have to be removed by the immune system. If the cell is removed from the body it obviously cannot perform its intended functions, so the body is left without a resource. Concerning oxygen in particular, research shows that oxygen consumption increases 10 to 20 times during exercise and up to 5% of that oxygen will end up as free radicals known as super oxide radicals, which are the most damaging type.
Our cell membranes get their fluidity from the polyunsaturated fatty acids we consume, and the low-density lipoprotein (LDL cholesterol) in our system is also made from polyunsaturated fatty acids. Due to the ease at which the covalent bonds in polyunsaturated fatty acids break (especially in a hydrogen-carbon bond), they are a favourite target for electron scavenging free radicals. The process is known as lipid peroxidation. The fatty acids are a favourite target of oxygen-based free radicals. Oxygen reacts with the carbon free radical that had its hydrogen atom lose an electron to form the peroxy radical, and that is where the term peroxidation comes from. The peroxy radical will then steal an electron from a different lipid molecule during a process known as propagation. As you can tell, there are many opportunities for free radical chain reactions to occur.
Although there are many different types of free radicals, we are sticking with the oxygen based ones, since they are the type that those who exercise will produce most often. In addition, hydroxyl radicals (OH) that are a product of an oxygen atom with only one electron missing in its outer shell and a hydrogen peroxide (H₂O₂) molecule are the radicals responsible for the most damage in the system. Copper and iron can gain and lose electrons relatively easily, and they also react with hydrogen peroxide to form hydroxyl. Iron has a strong pro-oxidation affect, which makes it potentially harmful to cellular membranes. Copper, iron, and hydrogen peroxide (formed during many different reactions within the body) are all found in abundance in most people, so, as was mentioned earlier, there are always many opportunities at any time for free radicals to form and cause damage within the body. There are also other products of the oxygen-based reactions that may be harmless at first, but then can create reactions with other molecules at a later time to produce free radicals.
When the body is producing more free radicals than it can combat, the free radicals will begin to cause lipid peroxidation at high rates. Scientists believe that free radicals play a role in the causation of cardiovascular disease, cancer, Alzheimer's disease, Parkinson's disease, and aging of the body. Therefore, the key becomes to create an atmosphere where your body has the best chance at fighting these free radicals by keeping the antioxidant levels high enough so that free radicals are being repaired faster than they are being produced.
For weight lifters in particular, free radicals can form at high rates within the muscle cells and begin destroying muscle tissue. Obviously, this will cause fatigue, loss of strength, sub-optimal muscle performance, inadequate recovery, and possibly injury. Most of the free radical formation within the muscles takes place within the first 24 hours following exercise, and they are formed during the muscle’s response to being inflamed from the workout. Getting antioxidants in the system in conjunction with your post-workout nutrition is a great way to offset the potential damage free radicals can do following training.
In the past two paragraphs, we have mentioned how antioxidants should be used to combat free radicals, but what exactly are antioxidants? The term antioxidant itself means “against oxidation”. The main purpose of the antioxidant is to inhibit peroxidation of lipids by free radicals. Antioxidants can accomplish this task, because they are a special type of molecule that has the ability to give up an electron from their outer shell while maintaining its properties and remaining non-reactive. This allows them to donate an electron to a free radical and break the chain reaction. The free radical now has its outer shell full, and the antioxidant can still perform its functions and does not need to search for a replacement electron. Everyone is happy, and all the atoms can go about their business without any stealing going on.
The cell actually has two areas where antioxidants work on free radicals. In the fat-soluble cellular membranes, vitamin E, beta-carotene, and coenzyme Q10 are three of the more common antioxidants, which combat free radicals. Vitamin E is the most effective of the three. Within the cell, the antioxidants are water soluble, and they include vitamin C, glutathione peroxidase, superoxide dismutase (SD), and catalase.
Vitamin A and selenium are also popular antioxidants that are effective. Vitamin A is more of generic term that is used to explain fat-soluble compounds that are similar in structure and biologic activity to retinol as well as the carotenoids which are pre-cursors to vitamin A, with beta-carotene being the most common. A retinoid is a compound that is similar in structure to retinal or retinol and shows activity that is the same a vitamin A. Our vision is highly reliant on vitamin A where it helps process light into vision. Vitamin A also helps fight skin diseases, supports reproductive processes, bone development, maintenance and immune system function, and plays a major role in the development of the fetus. Vitamin A is thought to play a key role in glycoprotein synthesis. The most common sources of retinol (active form of vitamin A) are egg yolks, liver, fish oil, whole milk and butter. Carotenoid forms of vitamin A are found on many plant foods, especially green vegetables and those that are bright orange or yellow in colour. Vitamin A has a high bioavailability rate with most of it being absorbed in the intestines and stored in the liver. Recommended dosages are 1000mg per day for men and 800mg per day for women.
Vitamin C, which is also known as ascorbic acid, seems to be the vitamin that gets all the good publicity. When you go to the store the counters have all kinds of vitamin C lozenges, foods are fortified with it, and when you catch a cold everyone tells you to take more vitamin C. This is because it is the most powerful of the water-soluble antioxidants. Unfortunately for us humans, we are one of only a few animals that cannot convert glucose into vitamin C. Luckily for us though, Mother Nature made sure there are many different fruits and vegetables available that have plenty of vitamin C in them that has an absorption rate of 85-90%. Oranges, lemons, peaches, strawberries, bananas, grapefruit, cabbage, broccoli, cauliflower, leaf lettuce, tomatoes, potatoes and beans are among the best sources. As a matter-of-fact, vitamin C first got its fame from being a cure for scurvy due to studies of feeding oranges and lemons to infected specimens, and the term ascorbic acid was given to portray vitamin C’s capacity to thwart scurvy. Vitamin C is also helpful in combating toxins that enter the body, and it is part of many mechanical, physical, and biochemical functions including maintaining the immune and endocrine systems. Vitamin C is also very involved in the health and recovery of tendons and other white tissues, it stabilizes the hydroxyl radical, and it helps regenerate reduced vitamin E back to the active state, which makes it of particular importance to body builders. One interesting thing about vitamin C is that it is better to take several small doses than one large dose. For example, one gram of vitamin C has a 50% absorption rate which nets 500mg. A dose of 20 grams has a 16% absorption rate which nets in 3.2 grams. Therefore, by increasing the dose by 20 times, the body only holds six times more. Taking vitamin C along with zinc or pectin can inhibit its absorption. The recommended daily supplemental amount of vitamin C is 90mg for men and 75mg for women, and some research suggests that athletes and weight lifters should take as much as 300mg per day.
There are four fat-soluble vitamins and vitamin E is one of them, which means that almost all vitamin E will be found in the body’s adipose tissue. It is manufactured via the photosynthesis process in plant food sources, but there is also small amounts found in the fatty tissues of animal food sources. The main function of vitamin E is to be the first line of defence in the cell against lipid peroxidation, but it also helps red blood cells make their way through the arteries. Its ability to stabilize cell membranes allows vitamin E to have a major role in the prevention of muscle damage. It also makes vitamin E a popular supplement prescribed to those with anaemia and muscular dystrophy. Creatine kinase is a commonly measured indicator of oxidative stress, and vitamin E has been shown to prevent the escape of creatine kinase, which means that vitamin E is combating oxidative stress and sparing muscle damaged by free radicals. Anywhere from 15-45% of vitamin E will be absorbed, and like vitamin C, the higher the dosage the lower the percentage that is absorbed. It is recommended that individuals take no more than 1500IU per day.
Vitamins B2, B3 and B6 have also been shown to have antioxidant properties. Vitamin B2 (riboflavin) plays a major role in regulating and producing red blood cells and therefore adds increasing energy to your workout. It is also involved in the production of hormones as well as your growth and development. Riboflavin is important to the other B vitamins, because it works in conjunction with them so they can do their work. B2 leads to higher energy on cellular levels, but more importantly it promotes better health by helping produce cells that lead to a better immune system, respiratory system, and digestive system. B3 (niacin) is required in the proper functioning of more than 200 metabolic enzymes, it plays a role in a wide range of bodily processes, including synthesis of hormones and blood cells and the release of energy from fats, carbohydrates and proteins. Studies have even shown that this vitamin can help lower cholesterol and triglyceride levels. Luckily it can be found in chicken, red meat, tuna and milk… some of bodybuilders’ favourite foods. Vitamin B6 functions primarily as a “coenzyme”, which is to act as a catalyst for other enzymes that require support to accomplish their task (it is involved in over 70 enzyme functions). Neurotransmitters, proteins, and red blood cells all require Vitamin B6 in order to be formed; and it is also required for the metabolism of foods into energy (conversion of glycogen to glucose).
Selenium is an antioxidant that also plays other important roles in our system. It supports healthy immune system activity and is necessary for good thyroid health. Selenium is used by our bodies to produce glutathione peroxidase, which is an enzyme that plays a big part in the body's natural antioxidant defence system. It protects cells against oxidative stress. Selenium and vitamin E combine to protect cell membranes from free radicals, and selenium helps detoxify harmful compounds in the liver so they can be transported out of the body. Although selenium is a good antioxidant, there is a slight risk that it can build up in your system and become toxic, so stay below dosages of 500IU per day.
Coenzyme Q10 is a vitamin-like substance that is found in all human cells and responsible for the production of energy within the mitochondria. Coenzyme Q10 is involved in 95% of all our body’s energy requirements by converting adenosine triphosphate (ATP) to energy, and it combats free radicals in the mitochondria and lipid membranes. Coenzyme Q10 also plays a very critical role in the body’s ability to regenerate vitamin E, which is another antioxidant. Since coenzyme Q10 is an integral part of the respiratory chain, it is stored in abundance exactly where most free radicals are generated. The recommended dosage for coenzyme Q10 is normally in the range of 60-120mg per day.
Be aware of the damage that free radicals can cause in your system, especially if you hit the weights with a lot of intensity. Supplement your diet with antioxidants to ensure that your body has the artillery it needs to combat the stresses caused by them. Those of us that work out place much higher demands on our bodies, and we need to be sure that we support our systems with the things they need to keep us healthy. If we do not, all the effort in the gym could be for naught, and we could end up being over-fatigued, losing muscle tissue, and having our entire system thrown out of whack. Do not let radicals run free in your body.