Nutrition for racing
In the modern world of sport, making it to the top requires commitment at many levels. These days it's no longer sufficient to rely on fitness, talent and desire to win. No single factor can turn someone into a sporting legend – most good athletes use many tools to help them perform at their best. The right parents, the right training and the right skills are all important factors in performance.
Eating well is also part of the package. As most of your life as an athlete is spent in training it is important to understand your nutritional needs during hard work-outs. There is no secret formula or magic eating plan that works for everyone. Eating well is specific to you – to your special nutritional needs and to your schedule of training and competition.
Everyday eating must tackle a number of goals that include reducing the amount of fats and oils, replacing fluids throughout the day, ensuring that your diet has adequate intake of carbohydrates, and that electrolytes are replaced as they are lost throughout the day. It is important to have a diet balanced with proteins, carbs and fats, but even more important to avoid dehydration and loss of electrolytes during training and racing.
Severe dehydration can reduce performance markedly, and therefore it is important to have a plan to replace lost fluid.
Fluids are probably the most neglected aspect of the athlete's diet. It is not uncommon for recreational athletes to report that they consume on an average day an intake something like this: several cups of coffee, 2 colas and a few beers. That kind of fluid intake is not sufficient for several reasons, and physical performance will suffer as a result.
Heat is inevitably produced in the body during exercise. Our most effective way of removing heat is through sweating. For each 1 gram of sweat EVAPORATED from the skin, approximately 0.6 kcal of heat are removed. Fluid losses during exercise due to sweating can exceed 2 quarts or 4 pounds per hour. This is especially true in humid environments or in sports where padding is used since the sweat is not evaporated effectively. As dehydration progresses, performance becomes impaired. A loss of 2-3% in body weight due to sweating can reduce aerobic ability by more than 10%, while losses of 5% or more in body weight can result in heat stroke. Clearly, even relatively mild dehydration will significantly hamper competitive possibilities.
Nutritional needs are also different between men and women, with most male athletes being able to get by without extra nutritional supplements, other than a multivitamin. For females, iron is perhaps the most important nutritional necessity, and this is particularly true for endurance athletes such as adventure racers, marathon and ocean racers. These athletes are prone to iron deficiencies due to restrictions in diet, high carbohydrate consumption ( which decreases iron absorbtion) and long distance exercise. Many times fatigue and decreased performance can be blamed on unsuccessful training, when the real culprit is often a lack of iron.
You can boost your levels of iron by changing your diet; increasing the level of certain foods in your diet that are know to be high in the mineral. These foods, such as red meat, fish and poultry are often not a planned part of a restricted competitive diet and as iron-rich foods are often absorbed best in the presence of carbohydrates and dairy, it is often easier to take a mineral supplement.
Most athletes know that iron is a mineral required for the formation of the red blood cells used to transport oxygen to hard-working muscles. And that insufficient iron causes anaemia, which is characterised by fatigue, listlessness and a general lack of energy.
They also know that a proper diet aimed at maintaining iron status, and checking red blood cell or haemoglobin (Hb) levels, are vital for peak performance.
However, most athletes are far less aware of the fact that iron is one of the most difficult minerals to absorb, and that sports players are especially vulnerable to iron depletion through training-induced losses, especially if their event involves endurance work.
There may be other reasons for including protein and other nutrients such as vitamins and minerals in snacks and meals eaten immediately after exercise. These nutrients are important in other recovery processes—for example, repair and rebuilding activities and immune responses—and an immediate intake may be useful in promoting these activities. This issue is still awaiting research. In the long term, eating patterns must balance carbohydrate recovery goals with many other nutritional concerns. Choosing carbohydrate-rich foods that are also good sources of other nutrients can help to achieve a number of everyday nutrition goals simultaneously. In tricky situations, particularly during or immediately post-exercise, the practical aspect of meeting a carbohydrate need may be the first priority, and the nutrient content of carbohydrate foods or drinks may be of less importance. However, in the bigger picture of the everyday training diet, or competition seasons lasting over weeks and months, the focus on nutritious carbohydrate-rich foods and drinks makes good sense. With a little creativity, the athlete can find foods that are both practical and nutritious.
Vitamins serve crucial functions in almost all bodily processes (immune, hormonal and nervous systems) and must be obtained from food or supplements as our bodies are unable to make vitamins.
There are thirteen vitamins classified as either water soluble (C and B complex) or fat soluble (A, D, E and K).
Fat Soluble Vitamins
Fat-soluble vitamins are absorbed, together with fat from the intestine, into the circulation. Any disease or disorder that affects the absorption of fat, such as coeliac disease, could lead to a deficiency of these vitamins. Once absorbed into the circulation these vitamins are carried to the liver where they are stored.
Vitamins A, D, E and K make up the the fat soluble vitamins. Vitamins A, D and K are stored in the liver and vitamin E is distributed throughout the body's fatty tissues.
Water Soluble Vitamins
Water-soluble vitamins, such as Vitamin C and the B vitamins are stored in the body for only a brief period of time and are then excreted by the kidneys. The one exception to this is vitamin B12, which is stored in the liver. Water-soluble vitamins need to be taken daily.
Vitamin C (ascorbic acid) and the B complex group make up the nine water soluble vitamins. The B complex group comprises of vitamins:
- B6 (pyridoxine)
- B1 (thiamine)
- B2 (riboflavin)
- B12 (niacin, pantothenic acid, biotin, folic acid and cobalamin)
Vitamin sources, uses and deficiency problems
Vitamin A (fat-soluble)
- Sources: Dairy products, eggs, liver. Can be converted by the body from the beta-carotene found in green vegetables, carrots and liver.
- Uses: Maintains the health of the epithelium and acts on the retina's dark adaptation mechanism.
- Deficiency leads to: Keratinisation of the nasal and respiratory passage epithelium, night blindness
Vitamin B1 (thiamine) (water-soluble)
- Sources: Yeast, egg yolk, liver, wheatgerm, nuts, red meat and cereals
- Uses: Carbohydrate metabolism
- Deficiency leads to: Fatigue, irritability, loss of appetite; severe deficiency can lead to beri-beri
Vitamin B2 (riboflavin) (water-soluble)
- Sources: Dairy products, liver, vegetables, eggs, cereals, fruit, yeast
- Uses: Intracellular metabolism
- Deficiency leads to: Painful tongue and fissures to the corners of the mouth, chapped lips
Vitamin B12 (water-soluble)
- Sources: Liver, red meat, dairy products and fish
- Uses: Essential for manufacturing of genetic material in cells. Involved in the production of erythrocytes
- Deficiency leads to: pernicious anaemia
Vitamin C (ascorbic acid) (water-soluble)
- Sources: Green vegetables and fruit
- Uses: Essential for the maintenance of bones, teeth and gums, ligaments and blood vessels. It is also necessary for ensuring a normal immune response to infection
- Deficiency leads to: Scurvy
Vitamin D (fat-soluble)
- Sources: Fish liver oils, dairy produce. Vitamin D is formed in the skin when it is exposed to sunlight
- Uses: Has a role in the absorption of calcium, which is essential for the maintenance of healthy bones
- Deficiency leads to: Rickets
Vitamin E (fat-soluble)
- Sources: Pure vegetable oils; wheatgerm, wholemeal bread and cereals, egg yoke, nuts sunflower seeds
- Uses: Protects tissues against damage; promotes normal growth and development; helps in normal red blood cell formation
- Deficiency leads to: May cause muscular dystrophy
Vitamin K (fat-soluble)
- Sources: Green vegetables
- Uses: Used by the liver for the formation of prothrombin
- Deficiency leads to: Bleeding due to delayed clotting times caused by lack of clotting factors. Patients may show signs of bruising easily and have nosebleeds.
Dehydration & Electrolytes: A Primer
Here's what you need to know about electrolytes:
Important for bodily functions
Electrolytes such as sodium, potassium, and chloride are necessary for:
· Maintaining fluid levels in the body
· Muscle contractions; and
· Nerve impulse transmission
Lost during sports
· Sweating results in the loss of both electrolytes (particularly sodium) and water
· Water losses are proportionately greater than electrolyte losses, so the body's cells end up with a greater electrolyte concentration (this is the imbalance that is believed to lead to heat cramps)
· As the body becomes acclimated to the heat, the sodium content of sweat decreases
Replaced by foods in balanced diet
· Salt: Your child's regular diet should provide an abundance of salt. For instance, a 2-pound loss of sweat results in a loss of only 1 gram of sodium -- an amount easily replaced by moderate salting of food (one half teaspoon of salt).
Recommendation: Do not give your child salt tablets
· Potassium: Replacing the small amount of potassium lost during exercise is easy. Orange juice, bananas and potatoes are all excellent sources of potassium. For instance, a large glass of orange juice will replace the potassium lost in about 4 pounds of sweat.
Recommendation: Do not give your child potassium supplements: not only are they unnecessary, they can cause excessively high potassium levels in the blood, resulting in an abnormal heart rhythm.
When deficits occur
Electrolyte deficits, particularly sodium, can occur under the following conditions:
· When acclimating to a hot environment (remember: children don't adjust as well to heat and have other special fluid needs)
· Following repeated workouts in hot weather
· During ultra-endurance events (50-mile runs, 100-mile cycling races,
Symptoms of low blood sodium (hyponatremia) include:
· Muscle cramping
· Mental confusion
Low blood sodium is a rare condition (heat illnesses occur far more often), but can be fatal if left untreated.
Sports drinks help
Sports drinks containing sodium:
· Reduce the risk of hyponatremia
· Promote re-hydration following exercise by maintaining thirst (which keeps your child drinking) while delaying the production of urine. By contrast, drinking plain water eliminates thirst so your child stops drinking, and stimulates urine production.
· Encourage fluid intake because the sodium makes them taste better
What Are Vitamins?
Vitamins are complex "organic" (ones that contain carbon molecules) substances that the body cannot make on its own but that it requires in small amounts for a number of important bodily functions.
What Types Of Vitamins Are There?
Vitamins are divided into two groups: fat-soluble and water-soluble:
· Include A, D, E, and K
· Stored in body fat, principally in the liver
· Can be toxic at high doses. Because the body cannot get rid of excess amounts, too much vitamins A and D can have cause serious adverse side effects.
o Too much vitamin A can result in: loss of appetite, headaches, irritability, liver damage, bone pain, and neurological problems, including brain damage
o While vitamin A is only found in animals, dark orange-yellow and green leafy vegetables contain carotenes (e.g., beta-carotene) that the body can use to make vitamin A. Unlike vitamin A, carotene is fairly safe when consumed in large amounts because the body stores excess carotenes (which can make the skin look yellow-orange) rather than converting them to vitamin A.
o Too much vitamin D can cause weight loss, vomiting, irritability, destructive deposits of excess calcium in soft tissues (like the kidneys and lungs) and potentially fatal kidney failure)
Water soluble vitamins
· Include vitamin C, vitamin B1 (thiamin), niacin, riboflavin, B6, B12, pantothenic acid, biotin, folic acid
· Not stored in body; must be replaced each day
· Excess eliminated in the urine
· Can be toxic at high doses. Consuming excess amounts of water-soluble vitamins can cause dangerous side effects:
o Large amounts of niacin can cause severe flushing, skin disorders, liver damage, ulcers, and blood sugar disorders, interfere with fat metabolism and speed up glycogen depletion
o Large doses of vitamin C have been associated with diarrhea, kidney stone formation, and impaired copper absorption
o Excess vitamin B6 can cause neurological symptoms similar to multiple sclerosis, including numbness and tingling of the hands, difficulty in walking, and electric shocks shooting down the spine.
What Are Minerals?
Minerals are "inorganic" (they don't contain carbon) compounds that the body needs in very small amounts to perform a variety of functions.
What Types Of Minerals Are There?
Minerals are classified into two groups based on the body's need: Major minerals and Minor minerals
· Needed in amounts greater than 100 milligrams per day
· Include calcium, phosphorous, magnesium, sodium, potassium, chloride, and sulfur
· Like fat-soluble vitamins, excess amounts of minerals are stored in the body and can gradually build up to toxic levels. An excess of one mineral can also interfere with the functioning of others.
· Needed in amounts less than 100 milligrams per day (hence called "trace" minerals)
· Include iron, manganese, copper, iodine, zinc, cobalt, fluoride, selenium
· Like fat-soluble vitamins, excess amounts of minerals are stored in the body and can gradually build up to toxic levels. An excess of one mineral can also interfere with the functioning of others:
o High iron intake can produce an iron overload (hemochromatosis) in genetically predisposed people and cause deficiencies of other trace minerals (zinc and copper). If left untreated, iron overload can damage the liver, pancreas, and heart.
o Excess zinc consumption may reduce HDL ("good") cholesterol levels, impair immune function, and inhibit copper absorption from foods, possibly leading to anemia.
o In susceptible people, excess calcium can increase the risk of kidney stones; excess calcium from diet or supplements may also interfere with the absorption of iron.
o Copper supplementation isn't recommended as athletes aren't usually copper deficient and there is no evidence to suggest copper enhances athletic performance.
o Selenium supplementation isn't recommended as most people get enough selenium and an excess intake may be harmful.