What are the nutritional characteristics of cereals, potatoes, meats, eggs, fish, legumes, and nuts?
Cereals are highly energetic, with high carbohydrate content, iron, and B-group vitamins. They are also a source of protein, although they are deficient in lysine. The fat content is low, but it can change depending on the type of cereal product and the accompaniments.
Potatoes are also an energetic food, mainly composed of complex carbohydrates (starch), which are absorbed slowly. They are a good source of high-quality protein, with high lysine content, making them complementary to cereal protein. They are low in fat, and the fat they contain is unsaturated. They are a good source of potassium, and they contain small amounts of magnesium and iron. They are also rich in vitamins B1, B6, folic acid, and vitamin C.
Meats and sausages provide high-quality protein, fats, minerals (iron, potassium, phosphorus, zinc), and vitamins (especially B-group vitamins). The protein content is high and of high quality, with high digestibility and absorption. The fat they contain is mostly saturated, although the total amount and type of fat differ depending on the type of meat and the chosen cut. They also contain variable amounts of monounsaturated fats (oleic acid) and essential fatty acids (arachidonic acid and linoleic acid), which are more abundant in poultry and Iberian pork. The iron content is more abundant and more easily absorbed in red meats (beef, lamb, game, Iberian pork) than in white meats (white pork, chicken, turkey, rabbit). It is recommended to consume 3-4 servings (preferably lean meat) per week.
Eggs provide very high-quality protein (the highest quality of all foods), essential fats, vitamins (especially A, D, B2, and B12), and minerals (zinc, phosphorus, and selenium). They are an easily digestible food, especially when consumed soft-boiled. The egg proteins are of high biological value, as they contain all the essential amino acids in a balanced amount, and their utilization by the body is 100%. For this reason, egg consumption is very important, especially in stages where there is a greater need for proteins in both quantity and quality (e.g., childhood and pregnancy) or when increasing muscle mass (e.g., in athletes and the elderly). The majority of the proteins are concentrated in the egg white. It is recommended to consume 3-4 eggs per week.
Fish are an important source of high-quality protein, polyunsaturated omega-3 fatty acids (especially in oily or fatty fish: sardines, salmon, anchovy, bonito, mackerel, etc.), vitamins (B1, B2, B3, B12, and in fatty fish, A and D), and minerals (especially iodine in marine fish, but also calcium, phosphorus, magnesium, zinc, iron, and potassium). The lipids are mostly concentrated in the fat layer that exists under the skin in oily fish and in the liver in lean fish. The main fatty acids in fish are EPA (eicosapentaenoic acid) and DHA, which belong to the group of so-called omega-3. For this reason, their consumption is especially important in pregnant women, lactating women, and children. It is recommended to consume 3-4 servings of fish per week.
Legumes (beans, peas, chickpeas, fava beans, lentils, soybeans) are characterized by their high protein content, complex carbohydrates (fiber and starch), water-soluble vitamins, and minerals (calcium, iron, and zinc). They contain a large amount of protein, although not as much as animal protein, as they have a low amount of two essential amino acids (methionine and cysteine) and less digestibility. However, cooking and combining legumes with cereals make their protein nutritional value almost as high as that of animal proteins. The main carbohydrate they contain is starch, except in the so-called oleaginous legumes (peanuts, soybeans). It is recommended to consume 2 servings of legumes per week as a main dish and 2 servings as a side dish.
Nuts are an important source of protein, unsaturated fats, fiber, vitamins, and minerals. They also have a high caloric content. The most important characteristic is that they contain 50% of their weight in fat. Most of their lipids are monounsaturated fatty acids (especially in hazelnuts, almonds, and macadamia nuts) and polyunsaturated omega-3 fatty acids.