A balanced diet should provide the right proportions of carbohydrate, fat, protein, vitamins and minerals, water and dietary fiber.

Energy is the most important nutritional factor for any form of physical activity. Carbohydrate and fat are the main fuels used by exercising muscles. Vitamins and minerals are also crucial in energy metabolism. A diet deficient in vitamin and minerals can compromise sporting performance.

The importance of a high-vitamin diet

In order to obtain vitamins and minerals, athletes need to eat a wide assortment of nutrient-dense foods in amounts that will maintain energy balance. This means that a person must consume 1,200 to1,500 kilo-calories a day.

Meeting vitamin and mineral requirements when energy intake is 3,000 kcal/day or higher (as is among male and female ice hockey and cross country skiers) is actually easy. Even athletes whose energy intakes may be about 2,000 kcal/day can meet their vitamin and mineral needs from food alone.

As long as a wide variety of foods are eaten, vitamin and mineral intake is adequate. Supplementation therefore is not necessary.

High in vitamins are fruits and vegetables. Many of these are good antioxidants sources as well. High-color food choices mean high vitamin content thus high energy storage. Look for yellow-orange, red, deep green, and blue in your food. For athletes, five to nine fruit and vegetable servings are recommended each day. Grains also contain both vitamins and minerals.

Is more better?

Athletes usually meet two-thirds or more of the Recommended Dietary Allowances (RDAs) for vitamins and minerals. Athletes who have high calorie intakes of about 5,000 to 6,000 kcal/day may achieve 200% or more of the RDA for some vitamins and minerals just from foods they eat.

Despite this fact, most of the athletes who are concerned with sports nutrition take supplements to boost performance. While vitamin and mineral deficiencies impair physical performance, research indicates that supplementation of a nutritionally adequate sports diet does not improve physical work capacity, endurance, oxygen consumption, cardiovascular function, muscle strength, or resistance to fatigue.

For example, because B-vitamins release energy from nutrients, athletes with high energy expenditures have increased requirements for B-vitamins. However, eating more food provides the needed extra B-vitamins.

When are vitamin supplements needed?

Vitamin supplements are commonly used if an athlete's diet is not enough for his energy requirements. Vitamin supplements provide "health insurance," as sort of back-up to ensure optimal sports nutrition.

Multivitamin supplements with no more than 100% of the Daily Value (DV.) provide a safe and adequate balance of vitamins. However, it should not be forgotten that the goal is still to eat a wide variety of foods. Food contains fiber and a multitude of phytochemicals that provide many health benefits.

Supplements should never be replacements for food. While many sports supplements contain the antioxidant beta carotene, at least 450 carotenoids are only found in food. Antioxidant value exists in other carotenoids as well.

Minerals for injury prevention

Minerals like calcium, iron, and zinc are especially important for athletes.Recommendations of calcium intake are based on levels than can promote calcium retention, maximize bone mineral density, and inhibit bone loss. Lower calcium intake subjects the athlete to increased risk of stress fracture. Food that provide good calcium stores are the following: dairy products, fish with bones, broccoli, and fortified cereals and juices.

Iron makes up hemoglobin, myoglobin and oxidative enzymes and affects oxygen transport and aerobic metabolism. To achieve optimal aereobic endurance, consuming adequate amounts is a must. Iron depletion, the first stage of iron deficiency is the most common type of iron deficiency among athletes. Lean red meats, dark poultry, fortified cereals, whole grains, and legumes are good iron sources.

Zinc, which is found in meat, poultry, seafood, and whole grains, is essential for protein synthesis, healing, and immune function. Zinc is also found in antioxidant enzymes and enzymes involved in energy metabolism.

Although minerals are needed to work hand-in-hand with vitamins to ensure good sports nutrition, we must remember that consuming any mineral excessively can interfere with digestion and the absorption of other minerals. This may lead to mineral imbalances. Also, all minerals can be toxic in large doses.