The World Keeps Running

Strenuous bouts of prolonged exercise and heavy training stress the body. Adequate intakes of energy, protein, iron, copper, manganese, magnesium, selenium, sodium, zinc, and vitamins A, C, E, B6 and B12 are particularly important to health and performance.

These nutrients, as well as others, are best when obtained from a varied diet based largely on nutrient-rich foods such as vegetables, fruits, beans, legumes, grains, lean meats, fish, dairy products and unsaturated oils.

The recommended intakes for vitamins and minerals can be obtained from eating everyday foods. However, those at risk of sub-optimal intakes of these micronutrients include people who:

• Restrict their energy intake, especially over long periods, to meet weight loss goals;
• Follow eating patterns with restricted food variety and reliance on foods with a poor nutrient-density.

Using supplements is warranted in only a small number of cases - for example, when travelling in countries with a limited food supply or if an individual is found to be suffering from a lack of a particular vitamin or mineral.

For the vast majority of runners, supplements will have no benefit.

Anti-oxidant nutrients are important in helping protect the body's tissues against the stresses of hard exercise. It is not known whether hard training increases the need for dietary antioxidants, as the body naturally develops an effective defence with a balanced diet.

There is little evidence of benefit from taking supplements though it is known that over-supplementation can diminish the body's natural defence system.

Ideas for promoting dietary variety and nutrient-rich eating

Do:

• Be open to trying new foods and new recipes;
• Make the most of foods in season;
• Explore all the varieties of different foods;
• Mix and match foods at meals.

Think carefully before banishing a food or group of foods from your eating plans.

Include fruits and vegetables at every meal - the strong colours of many fruits and vegetables are a sign of a high content of various vitamins and other food anti-oxidants. Aim to fill your plate with highly coloured foods to ensure a good intake of the range of these health-promoting dietary compounds.

It is good to ensure that you "eat a rainbow" each day by choosing fruits and vegetables from each of the following schemes:

• White - e.g. cauliflowers, bananas, onions, potatoes;
• Green - e.g. broccoli, lettuce, green apples and grapes;
• Blue/Purple - e.g. blueberries, plums, purple grapes, raisins;
• Orange/Yellow - e.g. carrots, apricots, peaches, oranges, cantaloupe, mangoes;
• Red - e.g. tomatoes, watermelon, cherries, berries, red apples, red peppers.

Iron

Iron deficiency is the most common nutrient deficiency in the world. It may occur in runners and can impair training and performance. Unexplained fatigue, especially in vegetarian eaters, should be explored with a sports physician and sports nutrition expert.

Routine use of iron supplements is not wise: too much is just as harmful as too little. Self-medication with iron supplements may not address the real problem that is causing fatigue, or solve the cause of poor iron status.

Iron-rich eating:

• Consume moderate servings of red meats (well-absorbed iron) in 3-5 meals per week.
• Choose iron-fortified cereal products such as breakfast cereals.
• Combine plant and non-meat sources of iron (e.g. legumes, cereals, eggs, green leafy vegetables) with food factors that enhance iron absorption. These include vitamin C and a factor found in meat/fish/chicken. Examples of clever matching include fruit juice or fruit with breakfast cereal, or chili con carne (meat and beans).

Calcium

Calcium is important for healthy bones. The best sources are dairy foods, including low fat varieties. Fortified soy foods may provide a useful substitute where runners cannot consume dairy foods. Three servings a day are required by adults, with an increased requirement during growth spurts in childhood and adolescence, and for pregnancy and lactation. As with iron, it is recommended that women ingest more calcium than men, even though they generally eat less food. This means that female runners must be more careful in the food choices that they make.

Calcium-rich eating:

• Runners should aim to include at least three servings of dairy foods in their daily eating plans (e.g. 200 ml of low fat milk, 30 g cheese or a 200 ml carton of low fat yoghurt);
• Calcium-fortified soy versions of dairy foods are also suitable (e.g. soy milk, soy yoghurt). An additional one to two daily servings are required during growth spurts in childhood and adolescence, and for pregnancy and when breast feeding;
• Fish eaten with bones (e.g. tinned salmon, sardines) and leafy green vegetables (e.g. broccoli, spinach) provide a useful source of additional dietary calcium