Minerals are inorganic substances that are critical to many enzyme functions in the body. Approximately twenty-five minerals have important roles in bodily functions. Minerals are contained in all cells and are concentrated in hard parts of the body—nails, teeth, and bones—and are crucial to maintaining water balance and the acid-base balance. Minerals are essential components of respiratory pigments, enzymes, and enzyme systems, while also regulating muscular and nervous tissue excitability, blood clotting, and normal heart rhythm. Table 6.7 outlines the major sources and functions of specific minerals, as well as lists deficiency symptoms for those minerals.
Two groups of minerals are necessary in an individual's diet: macrominerals and microminerals. Macrominerals are the seven minerals the body needs in relatively large quantities (100 mg or more each day). These seven minerals are: calcium, chloride, magnesium, phosphorus, potassium, sodium, and sulfur. In most cases, these minerals can be acquired by eating a variety of foods each day.
While microminerals are essential to healthy living, they are needed in smaller quantities (less than 100 mg per day) than macrominerals. Examples of these minerals include chromium, cobalt, copper, fluoride, iodine, iron, manganese, molybdenum, selenium, and zinc.
Facts about Selected Minerals
Vitamin Functions Deficiency Problems Effect of Excess Amounts Dietary Sources
Calcium Helps build strong bones and teeth, control of muscle contractions and nerve function, supports blood clotting Stunted growth in children, bone mineral loss in adults Muscle and abdominal pain, calcium kidney stones Milk and milk products, tofu, green leafy vegetables, fortified orange juice and bread
Fluoride Formation and maintenance of bones and teeth Higher occurrence of tooth decay Increased bone density, mottling of teeth, impaired kidney function Fluoridated drinking water, tea, seafood
Iron Helps carry oxygen to body tissues Anemia, weakness, impaired immune function, cold hands and feet, gastrointestinal distress Liver disease, arrhythmias, joint pain Red meat, seafood, dried fruit, legumes, fortified cereals, green vegetables
Iodine Component of thyroid hormones that help regulate growth, development, and metabolic rate Enlarged thyroid, birth defect Depression of thyroid activity, sometimes hyperthyroidism Salt, seafood, bread, milk, cheese
Magnesium Facilitates many cell processes Neurological disorders, impaired immune function, kidney disorders, nausea, weight loss Nausea, vomiting, nervous system depression, coma, death in people with impaired kidney function Widespread in foods
Phosphorus Works with calcium to build and maintain bones and teeth, helps convert food to energy Bone loss, kidney disorders Lowers blood calcium Dairy products, egg yolks, meat, poultry, fish, legumes, soft drinks
Potassium Vital for muscle contractions and nerve transmission, important for heart and kidney function, helps regulate fluid balance and blood pressure Muscular weakness, nausea, drowsiness. Paralysis. Confusion. disruption of cardiac rhythm Slower heartbeat, kidney failure Milk and yogurt, many hilts and vegetables (especially oranges. bananas, and potatoes)
Sodium Maintains fluid and electrolyte balance. Supports muscle contraction and nerve impulse transmissions Muscle weakness, loss of appetite, nausea, vomiting Edema, hypertension Salt, soy sauce, bread, milk. meats
Zinc Involved in production of genetic material and proteins. Ability to taste. Wound healing, sperm production, normal fetus development Night blindness, loss of appetite. Skin rash, impaired immune function. Impaired taste. poor wound healing Nausea and vomiting. abdominal pain Seafood, meats, eggs, whole grains
Antioxidants are compounds that aid each cell in the body facing an ongoing barrage of damage resulting from daily oxygen exposure, environmental pollution, chemicals and pesticides, additives in processed foods, stress hormones, and sun radiation. Studies continue to show the ability of antioxidants to suppress cell deterioration and to "slow" the aging process. Realizing the potential power of these substances should encourage Americans to take action by eating at least five servings of a wide variety of fruits and vegetables each day.
There are many proven health benefits of antioxidants. Vitamin C speeds the healing process, helps prevent infection, and prevents scurvy. Vitamin E helps prevent heart disease by stopping the oxidation of low-density lipoprotein (the harmful form of cholesterol); strengthens the immune system, and may play a role in the prevention of Alzheimer's disease, cataracts, and some forms of cancer, providing further proof of the benefits of antioxidants.
Antioxidants and Their Primary Food Sources
Fortified milk; egg yolk; cheese; liver; butter; fish oil; dark green, yellow, and orange vegetables and fruits
Papaya, cantaloupe, melons, citrus fruit, grapefruit, strawberries, raspberries, kiwi, cauliflower, tomatoes, dark green vegetables, green and red peppers, asparagus, broccoli, cabbage, collard greens, orange juice, and tomato juice
Vegetables oils, nuts and seeds, dried beans, egg yolk, green leafy vegetables, sweet potatoes, wheat germ, 100 percent whole wheat bread, 100 percent whole grain cereal, oatmeal, mayonnaise
Sweet potatoes, carrots, squash, tomatoes, asparagus, broccoli, spinach, romaine lettuce, mango, cantaloupe, pumpkin, apricots, peaches, papaya
Purple grapes, wine, apples, berries, peas, beets, onions, garlic, green tea
Lean meat, seafood, kidney, liver, dairy products, 100 percent whole grain cereal, 100 percent whole wheat bread