The minerals found in foods contribute to a healthy diet and a healthy body. However, some cooking methods can leach the minerals, vitamins and other nutrients out of foods. The jury is still out on whether the effect of cooking is negligible or significant, but you can take steps to ensure that your family receives the maximum amount of nutrients from cooked foods.
Cooking does cause some mineral loss. The amount of minerals lost is a matter of debate, however. According to Vanderbilt University, a 1990 study published in the "Journal of Nutritional Science and Vitaminology" found that cooked foods contained about 60 to 70 percent of the minerals calcium, copper, iron, magnesium, manganese, phosphorus, potassium, sodium and zinc found in uncooked foods. Boiled, soaked, parched, fried and stewed vegetables lost the most minerals. Water-soluble nutrients, such as thiamin, folic acid and vitamins B6 and C, are especially affected by excessive cooking, according to the University of Kentucky and Harvard Medical School.
Less-Loss Cooking Methods
Another study, published in the same 1990 issue of the "Journal of Nutritional Science and Vitaminology," found that steamed foods retained the most amount of nutrients. Pressure cooking and stir-frying also retained a high percentage of nutrients as compared to other cooking methods. One of the simplest ways to reduce mineral loss is through using less water to cook vegetables. Much nutrient loss occurs when vegetables are cooked in large amounts of water; the nutrients leach into the water, which is then discarded. Leave the skins, peels or outer leaves on greens, fruits and vegetables whenever possible, as most of the nutrients are concentrated in these areas. Cut vegetables or fruits into large, rather than small, pieces before cooking, as a greater surface area helps nutrients break down for consumption more easily. Don't overcook food; as far as mineral loss goes, the less cooking time the best. Finally, cover your cooking container tightly to keep steam -- and nutrients -- from escaping.
Raw or Cooked
Proponents of a completely raw food diet, sometimes called raw foodists, claim that the cooking process destroys most minerals, vitamins and enzymes that naturally occur in foods. According to the University of California, one study from the Roswell Park Cancer Institute in Buffalo, New York found that a diet high in uncooked cruciferous vegetables, like cauliflower and broccoli, reduced the risk of bladder cancer. However, some beneficial nutrients, such as beta carotene and lycopene, found in carrots and tomatoes, are more accessible after cooking. There is little question that adding raw fruits and vegetables to a diet is a healthy choice, but cooked vegetables and fruits still provide necessary minerals, vitamins and other nutrients.
If you're worried that your family isn't getting enough minerals, you can always add more fruits, vegetables and other mineral-rich foods to their diet. Good sources of calcium include broccoli, bok choy, cabbage, mustard and turnip greens, beans and dairy products. Your body doesn't need much copper, but it is found in organ meats, seeds and nuts, mushrooms and chocolate. Iron is found in meat, poultry, seafood, dairy products, lentils, beans and bran cereals. Get magnesium from brown rice, nuts, leafy greens and dairy products. Foods rich in potassium include potatoes, bananas, tomatoes, nuts, seeds and citrus fruits.