Exercise, Nutrition & Immune Function

Strenuous exercise is linked with depression of the immune system, according to a 2008 study published in the British Journal of Sports Medicine. This study found that immune protection, particularly of the upper respiratory tract, was depressed in rowers compared with a control group of non-athletes. A study published in the Journal of Sport Sciences in 2004 explains that this depression of the immune system is closely linked to nutrition. It states that insufficient protein and other nutrients inhibit immunity to illness and disease in athletes and people who exercise intensively. A varied, balanced diet that provides plenty of protein, complex carbohydrates, iron, and vitamins and minerals is recommended, according to the Sports Injury Bulletin website.

Carbohydrates

• Athletes who consume enough complex carbohydrates have a lower production of the stress hormones cortisol and adrenaline, which can cause illness and reduced immunity if produced consistently over a period of time. People who train regularly should have one meal per day that includes a portion of brown rice. Whole-wheat pasta is a good source of energy that you can eat about two hours before training sessions and competitions. Whole grains such as buckwheat and oats can be cooked and kept in the fridge, to be eaten instead of quick release, sugary carbohydrate snacks.

Protein

• Protein consists of 22 amino acids that are the building blocks of the cells that make up our muscles and organs. Whereas carbohydrate releases instant energy, protein releases energy slowly, so it is equally important for intensive training. It aids stamina and endurance. Protein is also one of the building blocks of the immune system, so it is vital that you add it to an intensive training diet. Sources of protein that you should eat daily are nuts and seeds, soy products, such as tofu, lentils and beans. You can eat eggs three or four times per week, and white meat such as fish and turkey five or six times per week.

Zinc

• Zinc is closely linked to protein because it is involved in your body's conversion of dietary protein into the building blocks that make up the immune system, organs, tissues and muscles. Zinc also plays its own role in protecting the immune system, and its levels in the body become depleted more quickly during intense training. Foods rich in zinc that you should add to your diet are poultry, meat, eggs and leafy green vegetables.

Iron

• The key components of the immune system are natural killer cells, lymphocytes and neutrophils. Iron is essential for their formation and effectiveness. You can get iron from a wide variety of foods. The most iron-rich foods are leafy green vegetables, eggs, red meat, dark chocolate, curry leaf, pulses and legumes, and grains such as oats, barley and rye.