Vitamins are substances required in small amounts for normal growth, development and reproduction. They are needed to extract the energy from food and assist in regulating bodily processes. Vitamins are contained in a wide variety of foods including meats, grains, fruits, vegetables, dairy, fats and fortified foods. Diets that are sub-optimal may lack certain vitamins, leading to deficiencies and possibly chronic disease.[1,2,3]
Minerals are essential for bodily structures and regulation. Calcium and phosphorus can be found in teeth and bones, whereas sodium and potassium are required for fluid balance and muscular contraction. Minerals are found in plant and animal foods and insufficient intake may lead to health problems. Calcium and vitamin D intake tends to be lacking among youth and adults which increase the risk of osteoporosis, or bone weakening. Iron intake is typically insufficient in the United States which results in anemia (iron deficiency). Excessive intake of minerals can also lead to adverse health effects. For example, a high salt (sodium chloride) intake is associated with elevated blood pressure.
Water is the most essential nutrient for the human body. Approximately 60 percent of the adult human body is made up of water. Nearly 75 percent of skeletal muscle is water while only ten percent of body fat is water. Water is required for metabolic, fluid and temperature regulation and is lost constantly through the skin, breathing and elimination. Water must therefore be replenished continuously. The average daily requirement is 10 to 12 eight-ounce cups which most people meet through the foods and beverages they consume. Contrary to popular belief, eight to 10 cups per day of plain water is not necessary since food provides approximately half of the daily fluid needs and beverages provide the rest. It is important to note that caffeine alone does NOT cause dehydration. Rather, insufficient fluid intake and excess fluid loss lead to dehydration. Physical activity and environmental conditions may increase individual fluid requirements.
Guidelines for exercise
- Before exercise
- Two to three cups (16-24 fluid ounces) two hours prior to exercise
- During exercise
- Three to six fluid ounces every 15 minutes
- Water is the preferred choice when exercise is less than 60 minutes and hydration and energy needs are being met through an adequate diet
- If exercise exceeds 60 minutes or multiple bouts of exercise are performed, use a sports drink (four to eight percent carbohydrate)
- Increase your intake of fluids in hot or humid weather
- After exercise
- Drink 16 ounces of fluid for every pound of weight lost during exercise
1 Calvo, M.S., & Whiting, S.J. (2003). Prevalence of vitamin D insufficiency in Canada and the United States: Importance to health status and efficacy of current food fortification and dietary supplement use. Nutrition Reviews, 61(3), 107–113.
2 Calvo, M.S., Whiting, S.J., & Barton, C.N. (2005). Vitamin D intake: A global perspective of current status. The Journal of Nutrition, 135(2), 310–316.
3 Ryan-Harshman M, Aldoori W. Vitamin B12 and health. Can Fam Physician. 2008 Apr;54(4):536-41. Review.
4 Dawson-Hughes B, Bischoff-Ferrari HA. Therapy of osteoporosis with calcium and vitamin D. J Bone Miner Res. 2007 Dec;22 Suppl 2:V59-63. Review.
5 Wish JB. Assessing iron status: beyond serum ferritin and transferrin saturation. Clin J Am Soc Nephrol. 2006 Sep;1 Suppl 1:S4-8. Review.
6 Sarafidis PA, Bakris GL. State of hypertension management in the United States: confluence of risk factors and the prevalence of resistant hypertension. J Clin Hypertens (Greenwich). 2008 Feb;10(2):130-9. Review.
7 American College of Sports Medicine, Sawka MN, Burke LM, Eichner ER, Maughan RJ, Montain SJ, Stachenfeld NS. American College of Sports Medicine position stand. Exercise and fluid replacement. Med Sci Sports Exerc. 2007 Feb;39(2):377-90. Review.