ISSA SN Chapter 7: Vitamins

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Chapter Goals:

  • Discuss and define the main terms that involve vitamins.
  • Know the main vitamin functions.
  • Find the benefits of vitamins as they relate to the performance and health of the athletes.
  • Find the sources of the various vitamins.


Vitamins are naturally occurring nutrients that we can find in foods and supplements. We need them for basic requirements like good health, normal metabolism functioning, growth, recovery, and optimal performance. 

The significance of vitamins in terms of athletes:

  • Vitamins are needed for normal metabolism, growth, and tissue maintenance. 
  • Adequate vitamin intake is needed for health and performance.
  • When the intake of vitamins is deficient, our health and performance are compromised. 
  • Athletic performance and health improvements are experiences with supplements of vitamins.

Diet surveys show athletes are deficient in one or more vitamins.

Optimal intake of vitamins is found in supplements and food.

We are classifying vitamins based on their characteristics of solubility. 

The Lipid-Soluble Vitamins – A, D, E, and K

The fat soluble vitamins are the vitamins A, D, E, and K. These are the vitamins requiring lipids to get used by the body. They dissolve in these fats. Harmful levels can be reached, and when that happens, we get vitamin poisoning which is vitamin toxicity. 

Proper absorption and digestion of the fat-soluble vitamins may need the presence of fat even to be used in the diet. Athletes that try out low fat diets and some lower calories diets will likely see problems arising from absorbing these vitamins.

Vitamin A – Retinol and Pro-vitamin A

The function of vitamin A is for our vision and it is one of the most known vitamins. When we are children, we are often told to eat carrots to better our vision, so we do not need glasses. 

The main compound of vitamin A is going to be retinol. This belongs to the retinol group of chemicals. They have varying activity levels with vitamin A. retinoids found in animals. 

There do not appear to be any problems that occur from having too many carotenoids in the body at one time. 

But, with excess intake of vitamin A, we will see effects like headaches, vomiting, mucous membrane dryness, abnormalities in our bones, and damage occurring to the liver. Toxicity is found to happen after 15,000 micrograms of retinol and 6,000 micrograms of retinol for children and infants ages. These are well above the RDA guidelines and actually quite difficult to intake to this level. 

The athletic performance of individuals has been shown through research to be affected by the maintenance of health and performance. Mega doses of vitamin A are not recommended in any way. 

Vitamin A and Beta-Carotene in Food and Supplements

It is commonly found in supplements and this is in the form of Vitamin A acetate and palmitate. These are more effective and easier to get in these forms. The natural forms of Vitamin A are more expensive due to the challenging concentration and extraction. 

Beta carotene is many times more expensive than Vitamin A.

In the diet, we can find vitamin A and beta carotene in sources like liver and fish oils, egg yolks, whole milk, margarine, butter, and creams, to name a few.

Vitamin D

This was originally seen as a nutrient active in cod liver oils and used primarily for treating disorders such as rickets. It was later found that light would cure rickets, leading us to find the relationship between vitamin D and sunlight. 

Vitamin D has many important functions for our body and is needed for things like our growth and development. The absorption and metabolizing of calcium and phosphorous for the body could not be done without it. Both of those help with the health of our teeth and bones. 

Vitamin D deficiency is shown in the poor mineralization of bones and other deformities that may result from that. It can even get as severe as resulting in rickets at a young age. Vitamin D is essential and even more crucial in times of development and for athletes. People spending too much time inside should also do their best to receive vitamin D from some dietary sources. 

No research supports any mega doses of vitamin D to improve athletic performance. 

Vitamin D in Food and Supplements

The types of vitamins we see in our supplements are actually going to be D2 ad D3. They are mostly seen in the dry forms we take them in. These are good and should be sought out. 

Some sources of vitamin D in the diet would be fish liver oil, eggs, butter, creams, and many shellfish and other fish.

Vitamin D is often fortified in the kinds of milk sold, especially so in the united states. 

Vitamin E

Finding the role of Vitamin E led to many popularizations of supplements. This is due to the role of enhancements in performance sexually. On top of this, we also see roles like the activity of antioxidants, which protect the body in many ways from oxidative and free radical damage. 

The two major compounds found inside vitamin E are tocopherol and tocotrienol. 

Deficiencies in vitamin E have been seen in other animals, but they do not appear to well in humans, so it is hard to peg down. For infants, though, we have seen things such as dermatitis and hemolytic anemia resulting from their deficiencies. 

The toxicity of vitamin E is really low, but it is important to know that the varies greatly based on the person. Some people have been seen to give themselves mega doses of vitamin E in hopes of curing some disorders, but it will mostly just halt the activity of other vitamins such as K. this lengthens the time it takes our blood to clot. 

Vitamin E in Food and Supplements

Both natural and synthetic forms are found in supplements. We prefer to take in the natural form, as it absorbs better than the synthesized one. 

In the diet, these vitamins are found in vegetable oils and margarine, nuts, or wheat germ products. Other meats can be low in their containment of vitamin E. 

Vitamin K

Vitamin K was found to be involved in the clotting of our blood in many ways. There are many forms of this vitamin that we can take in. 

The vitamin functions as a coenzyme for forming prothrombin and procoagulants. These both are essential for the clotting of blood. Vitamin K also acts to help in the metabolism of bones and bone tissues. When athletes train hard and damage their tissues, it is important to ensure they receive a good amount of vitamin K. 

It is rare to see any deficiencies occurring in vitamin K when you have a healthy and balanced diet. You could likely develop a deficiency if you lack green vegetables in some form in the diet. We can sometimes see this happening in infants.

Mega doses of vitamin K are also not supported by any research as beneficial to athletic performance. 

Vitamin K in Food and Supplements

K1 and K2 are the most often used forms in our supplements. This will be in powder and in gel form. Having the two combined is best. 

Some dietary sources include dairy products, vegetables, cereals, and eggs. 

The Water Soluble Vitamins

These will be the vitamins that we do not usually store in the body and will require water to be used, unlike the previous fat soluble vitamins. These vitamins include C, B1, B2, B3, B6, folate, B12, biotin, and pantothenic acid. 

Vitamin C

Scurvy is the most famous disease from a deficiency of vitamins. It was found that vitamin C intake prevented this from some fruits. 

Another name for vitamin C is going to be Ascorbic acid. This is a water soluble vitamin that functions mainly as an antioxidant. We cannot make this anywhere in the human body, so that it will be an essential nutrient. 

Vitamin C is used as a cofactor and as a coenzyme. The main roles are the forming and maintenance of collagen fibers. These are essential for our connective tissues’ durability and skin components. 

Deficiencies again will lead to scurvy, which shows the body’s collagen tissues weakening and potentially hemorrhaging. It is not seen often in the united states, but it is potentially if not watched in the infant and elderly population.

Excess intake is seen as more than 3 – 5 grams every day or more. 

Mega dosing has not been reported to work for anything, but some people do so when they have a cold and they feel that they get over it quicker than normal. 

Vitamin C in Food and Supplements

The main form of vitamin C is the synthetic form of ascorbic acid. This is used most often in our supplements. 

In our diet, we can find this vitamin in fruits and vegetables, especially those that are citrus, green and red peppers, broccoli, spinach, and strawberries.


This is also known to us as vitamin B1. Thiamin works with the phosphate in the body to make TPP, also called TDP. These function as a coenzyme for the metabolism of carbs and BCAAs. Thiamin is soluble in water and it is not readily absorbed into the body. Another function of the vitamin is to make ribose. We need that for our RNA and DNA. 

Deficiencies in thiamin will show problems with the metabolism of carbs. This will show fatigue, appetite loss, lack of bowel movements, depression, confusion, and poor coordination. One disease that can come from this deficiency is known as beriberi. 

The kidneys clear excess intake of thiamin, and it is extremely rare to see toxicity due to excess thiamin. 

Some acute performance enhancements can occur from consuming mega doses of thiamin for 3 – 5 days before some big competition. But, other than that, it is not recommended much.

Thiamin in Food and Supplements

The two forms of thiamin we take via supplements are Thiamin HCl and thiamin mononitrate. Both forms are practically equal for us. 

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Dietary sources are yeast, peas, pork, whole grains, organ meats, and then grains and cereals that are enriched and fortified. 


This is mainly going to function as a coenzyme used for cell respiration and the production of energy. It is going to be vital for the body due to those roles. It is needed for the health of all tissues in the body. 

Deficiencies of riboflavin include problems like lips becoming inflamed, cracking skin, reductions in our growth, loss of hair, cataracts occurring, dermatitis, and some behavioral changes. It will be needed for the use of vitamins like B6 and niacin. 

Mega doses are not recommended and are not supported by any research available. 

Riboflavin in food and supplements

We use pure riboflavin for our supplements.

The sources of riboflavin in the diet will be similar to those we had for thiamin. 


This water soluble vitamin is in the B family also. It is known as vitamin B3. We also know it as nicotinic acid and niacinamide.

It functions as two essential coenzymes: NAD and NADP. These are around in every cell and they function to help the metabolic processes. It is also known for reducing the levels of fatty acids and cholesterols in the blood stream. Niacin has some smaller roles to fill in the growth and development of the body, the formation of tissues, and the maintenance of the metabolizing nutrients. 

We do have the ability to make niacin in the body with the amino acid tryptophan. This can make up for any lacking amounts of niacin intake. Tryptophan is a limiting amino acid and its use as niacin should be minimal. 

Excessive intake of niacin will reduce your performance. This happens when consumed right before exercising most often. This can cause the glycogen to deplete too fast, leaving you without energy stores.

Mega doses are not supported for this vitamin.

Niacin in Food and Supplements

Both forms of niacin should be taken in through supplements and are very common in nutrition formulas. 

Some dietary sources are just like riboflavin and thiamin vitamins.

Vitamin B6

This is also called pyridoxine. This essential nutrient is used as a coenzyme, most notably its use in amino acid metabolization. It has three forms; it is found in nature and they all work to serve some purpose as transamination reactions. 

Deficiencies that come from low intakes of B6 will include depression, skin problems, the improper healing of wounds, fatigue symptoms, anemia, and some seizures in severe cases. Severe nervous system problems may arise when overdosing for months on end on this vitamin. 

It is not recommended to mega dose ever on this.

Vitamin B6 in food and Supplements

It is commonly found in supplements in the form of pyridoxine and hydrochloride. 

We see it most often in the diet of chicken, fish, kidney, liver, eggs, rice, soybeans, and some nut types. 


This can also be called folacin. It is a B vitamin, so it is going to be water-soluble. It is often found in supplements and in foods that have been fortified. 

The main role is in amino acid metabolism and nucleic acid uses. It is a main cofactor in our DNA and RNA. We see this come into more important during pregnancy. 

Deficiencies see problems with birth defects, anemia, problems regarding the digestion processes, fatigue, bad memory, and damage to some organs. 

Mega doses are not going to be recommended at any time for folate. 

Folate in Food and Supplements

It is in supplements such as folic acid. 

The sources in the diet are similar to vitamin B6.

Vitamin B12

This is often viewed in the realm of sports nutrition as the main vitamin for energy. It is not uncommon for some athletes to get shots of vitamin B12 during a season. It plays an essential role in performance, but it is not the only one doing this job really. 

B12 makes many vital coenzymes that are needed for the development of neural tissues and the function of the nervous system. This includes everything from DNA synthesis to immune system function. It has very many tasks it plays a part in. 

Mega dosing B12 is not needed, and there hasn’t been a study to show immediate performance increases. 

Vitamin B12 in Food and Supplements

It is found in supplements in the form of cyanocobalamin. Other forms are steered away due to their unstableness. 

In the diet, we see it included in animal products of all kinds, eggs, and tofu. 


This is a water soluble B vitamin with sulfur and its main function will be as a coenzyme. It functions to be a coenzyme in carboxylation reactions. 

Important roles are played in amino acid metabolization, metabolization of the macronutrients, urea formation, energy production, and protein synthesis. 

Deficiencies occur from the sources simply being low in biotin. The deficiencies cause nausea, vomiting, depression, dermatitis, and muscle tone loss. 

Mega doses of biotin are not studied much.

Biotin in Food and supplements

This is very common in vitamin formulas and is not found in single dose form. 

The dietary sources include liver, egg yolk, nuts, yeast, and legumes. 

Pantothenic Acid

This vitamin will play roles throughout the metabolism of most things and also as a coenzyme specifically for coenzyme A., it is also involved in the synthesis of steroids and cholesterol, as well as the phospholipid formation. It may have some performance enhancing effects on athletes.

Mega doses of this may benefit the athletes who partake in long events. This must be done one to two weeks before the competition.

Pantothenic Acid in Food and Supplements

It is found in our supplements as d-calcium pantothenate.

We see it most in the diet in potatoes, eggs, pork, beef, whole grain cereal, fruits, and veggies.


This is primarily involved in the metabolism of fatty acids, the function of our liver, and the integrity of the cell membrane structure. We use lipotropic to describe the effect of choline and other substances meant to stop fat from depositing in the liver. 

Deficiencies in choline see major things occur to the memory, the liver, the function of our nerves, and our growth in general. It is rarely seen in humans.

Choline in Food and Supplements

It is common to see this vitamin in the normal formulas for vitamins. It has three forms that we get it in. 

The dietary sources of choline will be fatty foods, meats, egg yolks, liver, and some veggies.


This is lipotropic, just like choline. It is involved in the metabolism of fatty acids and carbs and the calcium mobilization in the cells. 

We have no reports of mega dosing effects relating to athletic performance. 

Deficiencies in this are likely to cause the building up of fat inside the liver and poor function of our nervous system. It is also seen as pretty nontoxic for healthy people.

Inositol in Food and Supplements

It is common in normal formulas and fat metabolizing enhancing supplements. 

The sources in our diet will be organic meats, whole grains, fruits, milk, and veggies. 

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Tyler Read

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