Food is any material consumed to give nutrition to organisms. Food is generally of animal, plant or fungi origin, and has important nutrients, including vitamins, proteins, carbohydrates, or iron. It is the process of gathering food and breaking it down that changes its nutritional value. Plants, animals and fungi all need food to survive.
When animals or plants eat, their digestive tracts come into contact with the food particles they are meant to eat, breaking these particles down to simpler compounds that are nutrient sources. This process is called digestion. Fungi, plants and animal cells also feed by using enzymes to break down the food particles. There are three types of nutrients found in foods, which are vitamins, minerals and carbohydrates. The body needs a combination of all three to maintain its health and function normally.
Vitamins are substances necessary to maintain the functions of the body’s organs and tissues. They are found in fruits, vegetables, grains, dairy products and proteins. They are water-soluble, which means they must be dissolved before they can be absorbed. They include Vitamin A, B, C, E and K to name a few. Foods rich in vitamins and minerals are used by the immune system to strengthen and support it against pathogens, a characteristic of healthy nutrition.
Minerals are elements that cannot be digested by the human digestive tract. Common minerals include calcium, phosphorus, magnesium, bromine, iodine and zinc. Foods that contain large amounts of these minerals include spinach, beans, broccoli, baked potatoes, tuna fish, halibut, salmon and lean meat. To meet recommended daily allowances of some of these minerals, a dietary fiber from whole grains is needed.
The third group of nutrients is fats and oils. Fats, mainly omega-3 fatty acids, provide the body with essential fats that are necessary for cell membranes and hormones. Oils are made from partially hydrogenated vegetable oils and may contain several vitamins. Seeds and nuts are sources of vitamin E, another fat-soluble nutrient. Legumes, nuts, whole grains, cheese, butter, avocados and other healthy oils are important nutrients for maintaining a healthy body weight.
Milk products are another source of nutrients for the body. Milk provides the calcium, protein, iron, zinc and calcium. Many people believe that a serving of milk contains about the same amount of nutrients as a glass of skim-milk. However, a serving of milk contains more fat, calories and sodium than it does sugar.
Other foods that contribute to weight gain and the development of diseases are animal fats and oils, sweets and snacks, fat-containing beverages, and legumes and grains. The fats and oils most commonly used in the United States diet come from beef, pork, poultry and eggs, with small amounts from fish, shellfish, nuts and vegetables. All these foods contain calories and fat, but they are not as likely to raise a person’s total energy level as is the saturated fat found in beef and pork. Saturated fats are more likely to raise blood cholesterol levels and increase the risk of heart disease.
One of the foods that contribute to the development of diseases and weight problems is red palm oil. Red palm oil, which comes from the deep forest of Africa, is widely used for cooking and in salad dressings. It contains a number of polyphenols, antioxidants that are believed to have health benefits. Among them are folic acid, which has been shown to lower the risk of developing certain cancers; flavonoids, which reduce blood clots; and terpenoids, which have been shown to protect cells from damage by free radicals.
Aside from the polyphenols, antioxidants may also play a role in preventing the development of cancers and heart disease. They help by neutralizing unhealthy LDL fats and other pollutants, which can increase the risk of heart disease. Vitamins and minerals are also thinking to benefit from the polyphenols and other nutrients. However, it is unclear whether these nutrients alone improve health or whether other nutrients help as well.
The nutrient composition of foods can vary significantly depending on what the food is made of. For example, one serving of ice cream contains 70 calories, whereas two servings contain only 20 calories each. Because of the variation in nutrients in the various foods, nutrition labels often list added sugars as a percentage of the total calories in the product. One serving of ice cream has about five grams of added sugar, while two servings contain about eight grams of added sugar.
What you don’t see on the nutrition label may be more important than what you see. The carbohydrates, fats, and sugars included in a serving of food may actually cause health issues. Even foods that are considered to be whole grains are not devoid of carbohydrates, even though they may appear to be so. The carbohydrates found in whole grains include those found in whole fruits, whole vegetables, legumes, nuts, and whole grain breads.