Vitamins and Mineral Needs
Athletes both young and old may have an increased need for vitamin and mineral intakes for a number of reasons:
- Increased need for them due to high energy turnovers
- Increased loss due to sweating, urination and/or muscle damage
- Increased need for tissue maintenance and repair
Research has shown that a direct relationship exists between overall energy intake and vitamin and mineral intake. High-energy intakes are required by both younger and older athletes in order to meet the energy demands of physical training and competition. It would thus be expected that the micronutrient intake in these groups should be in excess of the recommended daily intakes, assuming that a well-balanced diet is eaten. Thus, vitamin and mineral deficiency may be aggravated in athletes who restrict energy intakes to reduce body weight or have chronic medical conditions that may disturb micronutrient absorption or utilisation.
Numerous studies examining the dietary practices of younger athletes have shown that dietary intakes of the minerals zinc, iron, magnesium, copper and calcium, together with the vitamins B6, B12, and D are below the RDA. The few studies that have examined nutritional intakes of older endurance athletes suggest low intakes of the minerals calcium, iron, zinc, and magnesium and vitamin D, despite consuming energy intakes above the RDAs.
Masters athletes may be at a greater risk of micronutrient deficiencies for a number of reasons. Deficiencies may be due to age-related changes in the ability to absorb and metabolise these compounds, different baseline requirements, increased medication use, and the presence of chronic disease states. Those older athletes at greater risk of vitamin and mineral deficiencies may also be those on low-fat diets, those on weight loss diets and those with limited intakes of fruit and vegetables.
Research has shown that the minerals low in the diets of all athletes, especially females, are calcium, iron and zinc. Low intakes of these minerals are usually attributed to dieting, or avoidance of animal products such as meat, fish, poultry, and dairy products.
|Mineral||Food Sources||Functions||Deficiency Symptoms||Symptoms of Excessive Consumption|
|Calcium||Dairy products (milk, cheese, yoghurt, ice cream) egg yolk, dried peas and beans, dark green vegetables)||Bone formation, nerve impulses,muscle contraction||Osteoporosis, impaired muscle contraction, cramps||Constipation, kidney stones, calcification of soft tissues|
|Iron||Organ meats (liver, kidney), shellfish (NB oysters), dried peas and beans, wholegrains, green leafy vegetables, dried apricots, dates, figs and raisins, iron cookware||Hemoglobin and myoglobin, aerobic energy production||Fatigue, anemia, decreased resistance to infection||Liver damage, hemochromotosis (excessive absorption of iron leading to bronzed pigmentation and eventual heart failure)|
|Zinc||Organ meats, meat, fish, poultry, oysters, dairy products, nuts, wholegrains, asparagus, spinach||Co-factor in energy metabolism, protein synthesis, immune function||Depressed immunity, impaired wound healing||Increased cholesterol, impaired immune function|