The Fat Soluble Vitamins: A, D, E, and K

The fat soluble vitamins, A, D, E, and K, are stored in the liver and fatty tissues of the body until they are needed. They are found most often in the fat and oil of foods. The body can survive weeks without consuming foods that contain these vitamins as long as the diet as a whole provides average amounts that approximate DRI recommended intakes. Because these vitamins are stored by the body, toxicity is easier to reach if you take in too much.

Vitamin A (retinol): Vitamin A is a versatile vitamin that has a role in gene expression, maintenance of body linings and skin, immune defenses, bone and body growth and normal development of cells. The role of vitamin A in vision is probably the most familiar, helping to maintain a healthy cornea.

Vitamin A deficiency is a worldwide health problem because of poor nutrition and starvation. Researchers are close to developing a Vitamin A rich rice to serve to the world’s children who lack the vitamin. On the other side, Vitamin A toxicity, over 3000 micrograms/day, can pose health problems such as skin rashes, hair loss, birth defects, liver failure, and death.

DRI: Men 900 micrograms/day; Women 700 micrograms/day
Food Sources:
1c fortified milk 150 micrograms
½c carrots 671 micrograms
3 apricots 100 micrograms

Vitamin D (calciferol): Vitamin D is unique in that the body can get the amount it needs by synthesizing sunlight. This sounds simple, as being in the sun each day would mean you would not need to consume Vitamin D in food. However, research has shown many people are deficient in this vitamin. To counter this, many foods are being fortified with Vitamin D.

Vitamin D helps to regulate blood calcium and phosphorus levels to help maintain bone integrity. Vitamin D also plays a role in the functions of the brain, heart, stomach, pancreas, skin and reproductive organs.

Too little Vitamin D can cause rickets, an abnormality in the bones. Too much Vitamin D can cause too much calcium to be deposited in soft tissues and organs causing them to malfunction. More is not always better, especially in children and young adults.

DRI: Adults (19-50yr) 5 micrograms/day
Food Sources:
3oz salmon 4.3micrograms
1c fortified milk 2.5micrograms
3oz shrimp 3.0micrograms

Vitamin E (alpha-tocopherol): Vitamin E is an antioxidant and serves as a defender against damage to cell components and membranes. This action is very important in the lungs. White blood cells also depend on Vitamin E. Excess Vitamin E from supplements can increase the effects of anticoagulant medications.

DRI: 15mg/day
Food Sources:
Widespread in foods, especially those containing oils.
2tbs sunflower seeds 9mg
1tbs canola oil 2.4mg
1tbs mayo 3.0mg

Vitamin K (menadione): Vitamin K helps to clot the blood by synthesizing proteins. It is also needed for synthesis of some bone proteins. It is important to know that Vitamin K may interfere with blood thinning medications. Some bacteria in the intestines can synthesize Vitamin K for the body’s use.

DRI: Men 120 micrograms/day; Women 90 micrograms/day
Food Sources:
½ cauliflower 20micrograms
1c lettuce 60micrograms
1tbs canola oil 19micrograms

It seems that athletes may need more of Vitamins A and K, than their non-athlete counterparts. Typically, the higher needs are met by the increased number of calories required for in an athlete’s diet to power performance and maintain energy levels. There have not been conclusive studies showing that supplementation can actually increase performance.

Next week, we will focus on the minerals needed by the body.

Sources:
Bonci, L. Sports Nutrition for Coaches. 2009.
Sizer, F. and E. Whitney. Nutrition Concepts and Controversies, 10th ed. 2006.
Skolnik, H. and A. Chernus. Nutrient Timing for Peak Performance. 2010.

The Water Soluble Vitamins: Vitamin C and the B Vitamins

Water soluble vitamins, Vitamin C and the B Vitamins, are absorbed directly into the bloodstream and travel freely. For the most part, these vitamins are not stored in tissues to a great extent and excesses are excreted from the body. This also means that these must be ingested each day. While these vitamins seldom reach toxic levels, high amounts in some supplements can cause levels in the body to reach toxicity.

Vitamin C (ascorbic acid): Vitamin C works to maintain connective tissue and assists enzymes in performing their jobs, in particular enzymes involved in formation and maintenance of collagen. Collagen helps heal wounds, mend fractures, and support capillaries, preventing bruises. Immune system cells maintain high levels of Vitamin C as well. Vitamin C promotes iron absorption in the intestines.

A popular belief is that Vitamin C will prevent colds. Studies have shown that taking extra Vitamin C does not actually prevent a cold, although it may shorten its duration and lessen the severity of the symptoms.

Too much Vitamin C can be dangerous for people who have an overload of iron in their system or for those on medications to prevent blood clotting.

DRI: Men 90mg/day; Women 75mg/day
Food sources:
½ c red pepper 142mg
½ c orange juice 62mg
½ c strawberries 43mg
½ c sweet potato 20mg

B Vitamins: B Vitamins work together, and as a whole, help the body use fuel from carbohydrates, fat and proteins. Thiamin, Riboflavin, Niacin, Biotin and Pantothenic Acid support energy metabolism in every cell of the body.

Thiamin (B1) also aids nerve function.
DRI: Men 1.2mg/day; Women 1.1 mg/day
Food sources:
½ whole wheat bagel .19mg
¾ cup enriched cereal .38mg
1 baked potato .22mg
½ cup green peas .23mg

Riboflavin (B2) also supports normal vision and skin health.
DRI: Men 1.3mg/day; Women 1.1mg/day
Food sources:
1 c milk .45mg
1 c cottage cheese .32mg
½ c spinach .21mg
3 oz pork chop .23mg

Niacin (B3) contributes to skin health and nervous and digestive system function.
DRI: Men 16mg/day; Women 14mg/day
Food sources:
3 oz chicken breast 8.9mg
3 oz tuna 11.3mg
¾ c enriched cereal 5.0mg
1 baked potato 3.3mg

Biotin
DRI: 30 micrograms/day
Food sources: Meat, milk, egg yolk, legumes, most vegetables

Pantothenic Acid
DRI: 5mg/day
Food sources: meat, eggs, most vegetables, whole grain cereal products

Folate helps the body make new cells.
DRI: 400 micrograms/day
Food sources:
1 c spinach 58 micrograms
½ c avocado 45 micrograms
½ c pinto beans 145 micrograms

Vitamin B12 (cobalamin) helps to convert folate to its active form and helps maintain the sheath around nerve cells.
DRI: 2.4 micrograms/day
Food sources:
3 oz sirloin steak 2.0 micrograms
1.5 oz Swiss cheese 1.5 micrograms
1 c cottage cheese 2.0 micrograms

Vitamin B6 (pyridoxine) is needed in protein metabolism and helps convert one amino acid to another.
DRI: 1.3mg/day
Food sources:
1 Banana .66mg
3oz chicken breast .35mg
½ c spinach .22mg

Athletes may need more of some water soluble vitamins than their non-athlete counterparts. Typically, the higher needs are met by the increased number of calories that an athlete already needs to power performance and maintain energy levels, as long as the calories come from a combination whole grains, vegetables, fruits, meat and dairy, and not from an extra bag of chips. There have not been conclusive studies showing that supplementation of the B Vitamins or Vitamin C can actually increase performance.

Next week, we will discuss the fat soluble Vitamins A, D, E, and K.

Sources:
Bonci, L. Sports Nutrition for Coaches. 2009.
Sizer, F. and E. Whitney. Nutrition Concepts and Controversies, 10th ed. 2006.
Skolnik, H. and A. Chernus. Nutrient Timing for Peak Performance. 2010.

Introduction to Vitamins and Minerals

Vitamins and Minerals are nutrients the body needs to carry out its processes. Often, the REC receives questions regarding the supplementation of different vitamins and minerals. There are many products on the market, including multivitamins, that boast positive health affects and an ability to help athletic performance. Many athletes, and even the general public, aren’t aware of their needs when it comes to vitamins and minerals, or what food sources they come from.

Some people operate on the assumption that if vitamins and minerals are good for you, then it can’t hurt to take more than you need. This isn’t necessarily true. Vitamins and minerals can be toxic at certain levels and may also interfere with medications an individual is on or with the actions of other vitamins and minerals in the foods you eat. If you eat well and have a balanced diet, including a wide variety of fruits and vegetables, supplementation is not necessary unless you have a specific deficiency. Remember as an active athlete, your caloric and nutrient needs may be higher than non-athletes. This makes it even more important that you consume a diet that includes all food groups. We will give you examples of foods and their nutrient levels to show you how food can help you reach the amount of nutrients your body needs.

The Recommended Dietary Allowance (RDA) is a nutrient intake goal for healthy individuals (no nutrient deficiencies) in certain age and gender categories. The Adequate Intake levels are set for nutrients when there is not enough scientific evidence to support an RDA value. Daily Reference Intakes recommended intakes (DRI) will be used to describe nutrient intakes as there is no need to distinguish between them for our purposes. DRI recommended intakes are different from the Daily Values that are listed on food labels. Daily Values allow consumers to compare nutrient and energy contents of packaged foods and are percentages based on certain caloric intake levels. The DV does not take into account different needs for different age and gender groups and are intended to help compare nutritional value of foods.

This month, we will take a look at different vitamins and minerals and their functions, DRI recommended intakes, and what food sources supply them. We will start next week by focusing on the water soluble vitamins. Then we will explain fat soluble vitamins and their actions within the body. The final post of the month will focus on minerals.