Nutrition II: The Micronutrients

Centrum Specialist Multivitamins and Minerals
(photo from www.walmart.com)

              This is article is not intended to be a complete discussion on nutrition. Rather it is to set-up the reader for an article on bioenergetics. The main goal of this article is to discuss the role of each of the nutrients in body. As such, the article gives a simple discussion on each nutrient and its role in exercise. It is recommended that one should consult with a licensed nutritionist on proper nutrition practices.

Vitamins

            Vitamins are organic compounds required by the body in minute amounts. They are generally regarded as accessory nutrients. They neither supply energy nor contribute substantially to body mass. They are required, however, to perform specific functions to promote growth and maintain health. They function as organic catalysts in metabolic reactions and are essential in reactions that release energy.  (2, 4, 5) 

Kinds of Vitamins

            There are two kinds of vitamins, fat-soluble and water-soluble vitamins. Fat-soluble vitamins are vitamins A, D, E, and K. As the name implies, these vitamins require fat for transport. The vitamins dissolve and remain mainly in the body’s fatty tissues.

Water-soluble vitamins act largely as co-enzymes, small molecules combines with a large protein compound. When combined they form an active enzyme which accelerates the interconversion of chemical compounds. These co-enzymes participate directly in chemical reactions.  These remain intact even after the chemical reactions and can participate in other reactions. (2, 4)

            A list of some of the water-soluble vitamins is listed below. This is not a complete list. Complete listings of all water-soluble vitamins are available elsewhere. Some of the water-soluble vitamins include the following: (2, 4)

• Vitamin C
• Thiamine (B-1)
• Riboflavin (B-2)
• Pyridoxine (B-6)
• Niacin (Nicotinic Acid)
• Folic acid (Folacin, Folate)
• Vitamin B-12 (Cobalamin)
• Biotin

             Water –soluble vitamins dissolves and disperses in water, or more specifically in the body’s fluids. These vitamins do not store in the tissues. Most of these vitamins are active for 8-14 hours after they are absorbed by the body. Any excess consumption of water-soluble vitamins is void in the urine. (2, 4)

Role of Vitamins

            Listed below are some of the roles played by vitamins in the body.  Again, this is not an all-inclusive list. This is just merely to give the reader a general idea of what the roles and functions are of vitamins. (4)

• Vitamin K – blood clotting
• Vitamins A, C, B-6, Naicin, Riboflavin, Pantothenic acid – skin
• Vitamin A – reproductive system
• Vitamin A, D, C – Bones
• B-6, B-12, C, Folate – Blood
• A – Eyesight
• A, D, C – Teeth
• E – Blood cells
• A, B-6, Pantothenic acid – Hormone formation
• A, B-6, B-12, Thiamine, Niacin, Pantothenic acid – Neuromuscular function
• E – Cell membrane
• Thaimine, Riboflavin, Naicin, Biotin, B-6, Pantothenic Acid – Energy release

        Aside from their function as regulators of metabolism, some vitamins also function as antioxidants. Vitamins C, E, and Beta Carotene protect muscle from damage after intense exercise. They counter the effects of free radicals and lipid peroxidation. (3)

 Vitamins in Exercise Performance

            The vitamins studied by exercise physiologists in relation to exercise performance are vitamin B-complex, C, and E. The B-complex and E most specially function as co-enzymes in regulation of energy yielding reactions during the catabolism of carbohydrates, fats, and protein. (4, 5)

As one can see above, vitamins itself contain no useful energy for the body. They serve as essential links and regulate metabolic reactions that release energy from foods. (4)

Excess Vitamin Intake

            Vitamins taken in excess (mega doses) are harmful and can function like drugs in the body. For example, excess doses of vitamin C can raise uric acid levels and may cause gout. Another is example is in iron deficient individuals, where excess vitamin C can destroy vitamin B-12. Excess vitamin B-6 can induce liver disease and nerve damage. Excess riboflavin, on the other hand, can impair vision. A mega dose of niacin functions as a vasodilator and inhibits fatty acid mobilization. This in turn speeds up glycogen depletion. (4)

However, the examples mentioned above are water-soluble and usually any excess can be excreted in the urine. Most likely, diarrhea, nausea, and cramps will be the side effect as these unabsorbed vitamins pass through the digestive tract.

Fat-soluble vitamins should not be consumed in excess without medical supervision.  Excess consumption of fat-soluble vitamins can cause toxic reactions in the body.  Examples of toxic reactions from excess fat-soluble vitamins consumptions are listed below: (2, 4. 5)

• High risk of birth defects in pregnant women
• In children, bulging fontanelle and papilledema
• Double vision
• In adults, nausea, headache, drowsiness, blurry vision, hair loss,  diarrhea, and calcium loss from bones
• Excess vitamin D can cause kidney damage
• Excess vitamin E and K can is rare but yield no know benefits.

Articles on mega dosing of vitamins and minerals can found here, http://www.livestrong.com/article/449374-health-effects-from-excess-vitamins-and-minerals/ and here, http://www.webmd.com/vitamins-and-supplements/nutrition-vitamins-11/fat-water-nutrient. Other articles on vitamin mega dosing can also be found the internet. 

Minerals

            These are inorganic substances required by the body in minute amounts (5). Some of these minerals will make up approximately 4% of body mass (4). There are about 22 elements required by the body. They serve as constituents of enzymes, hormones, and vitamins (4).

            They can exist in high concentrations, such bones and teeth, or as ions combined with various organic compounds (5).

Kinds of Minerals

            There are two kinds of minerals required by the body. Minerals, which are required by the body in excess of 100 mg per day, are major minerals. Some authors will term them as macro minerals (2, 4, 5). A short list of major/macro minerals are listed below (4):

• Calcium
• Phosphorous
• Potassium
• Sulfur
• Sodium
• Chlorine (Chloride)
• Magnesium

           Minerals required by the body in amounts of less than 100 mg daily are termed as trace minerals (2, 4, 5). Again, a short list is provided below (4):

• Iron
• Flouride
• Zinc
• Copper
• Selenium
• Iodine (Iodide)
• Chromium

Role of Minerals

            Minerals play three basic roles in the body: a) They provide structure in forming bones and teeth; b) They help maintain normal function (such as the nerve transmission); c) They help regulate metabolism. (4)

           As mentioned in the previous paragraph, minerals help regulate metabolism. In metabolism, there are two basic processes: catabolism and anabolism. (4)

           In catabolism, the body usually breaks down food into it’s basic format. In the case of the macronutrients, it’s glucose, fatty acid, and amino acids respectively. Minerals, which participate in this metabolic process, are listed below: (4)

• Calcium
• Cobalt
• Copper
• Iron
• Magnesium
• Manganese
• Potassium
• Sulfur
• Zinc

         Anabolism is the build up of tissues and other substances required by the body. Examples of the build-up of substances required by the body would be when glucose is converted to glycogen, fatty acids to fats, and amino acids to protein. Minerals which participate in this process is listed below: (4)

• Calcium
• Chlorine
• Magnesium
• Manganese
• Potassium

Minerals in Exercise Performance

            Minerals are less likely to be supplemented by athletes since there is less ergogenic properties assigned to them (5).

Some mineral losses do occur in sweating (sodium, chloride, and potassium) during prolonged exercise along with water. An example given by Mcardle et al for mineral loss is when an athlete losses 5kg/L of water during prolonged exercise. This may correspond to about 8.0 g of salt loss. Each kg/L of sweat lost corresponds to about 1.5 g of salt loss. (4)

            During times of intense sweating during vigorous exercise, the body release certain hormones, vasopressin and aldosterone along with the enzyme renin to reduce the sodium loss along with water. (4)

            Mild potassium loss can occur during intense exercise; however, an adequate and well balanced diet can ensure the level of potassium remains adequate. (4)

            Exercise can also accelerate the loss of certain trace minerals: (4)

• Chromium – required for carbohydrate and lipid catabolism, proper insulin  function, and protein synthesis
• Copper – required for red blood cell formation
• Manganese – component of the body’s antioxidant defense system
• Zinc – tissue repair and cell growth

Dietary Recommendations

            One should consult proper dietary reference intake (DRI) levels for both vitamins and minerals. A licensed nutritionist should also be able to furnish the reader with such information and how to structure the diet so that adequate levels of vitamins and minerals are met.

            The DRI consists of four components: Estimated Average Requirement (EAR), Recommended Dietary Allowance (RDA), Adequate intake (AI), and Tolerable Upper Intake Level (UL). The EAR is the average level of daily nutrient intake to meet the requirement of one-half of the healthy individuals in particular life stage and gender. This actually provides a useful value to determine the prevalence of inadequate nutrient intake in particular population. The RDA is the average nutrient intake sufficient to meet the requirement of about 97% of healthy individuals in a particular life stage and gender group. The AI provides an adequate nutritional goal when RDA exists. Lastly, the UL value represents the highest average daily nutrient intake level that would likely pose no threat to health to almost all individuals in a life-stage group. (4) DRI tables are available from the USDA website here http://fnic.nal.usda.gov/dietary-guidance/dietary-reference-intakes/dri-tables.

            The easiest recommendation would be, as per Corbin et al, to consume amounts of both minerals and vitamins in amounts equal to the RDA daily. Consumption of food servings of carbohydrates, protein and fats will most likely meet these RDA standards. It is also recommended that extra serving of complex carbohydrates and other non-animal sources of foods high in fiber, vitamins, and minerals. (1) If supplementing with a multivitamin, it is recommended that it is best taken with one's most complete meal of the day.

            As mentioned above, vitamins and minerals play certain roles in the body. Often, due to the marketing of multivitamins and minerals, people often confuse the role of vitamins and minerals in the body and in physical activity. One of the important roles they participate in is metabolic reactions that help release energy. We tend to be swayed that if we take in more vitamins and minerals, we get more energy. The human body doesn’t work that way. Any excess of vitamins and minerals can either cause toxicity and pose health risks. One should consult a doctor and/or nutrionists before supplementing with multivitamins and minerals.

Bibliography:

1.     Corbin, Charles B., Gregory J. Welk, William R. Corbin and Karen A. Welk “Concepts of Fitness and Wellness: A Comprehensive Lifestyle Approach 9th edition” 2011

2.     Powers, Scott K. and Edward T. Howly “Exercise Physiology: theory and Application to Fitness and Performance 4^th edition” 2001

3.     Heyward, Vivian H. “Advanced Fitness Assessment and Exercise Prescription 4th edition” 2002

4.     Mcardle William D., Frank I. Katch and Victor L. Katch “Exercise Physiology: Energy, Nutrition, and Human Performance 7th edition” 2010

5.     Wilmore, Jack H. and David L. Costill “Physiology of Sport and Exercise 2nd Edition” 1999