Nutrients – The Building Blocks of Life
Nutrients represent the basic units that constitute foods. Nutrients are oxidized for the production of readily available energy or reserve energy by means of biochemical transformations (metabolism). They can play a plastic/constructive role (proteins), an energy role (fats and carbohydrates), or a protective/regulative role (vitamins and minerals). Nutrients can provide or not provide calories, they can be essential or non-essential for our body and they can be found in varying amounts and sources from different food groups.
Proteins are organic substances composed of sequential units of amino acids. They perform important functions in our body, such as plastic functions (building blocks), regulating functions (enzymatic functions, hormonal functions, gene expression control, control of neurotransmission and membrane transport control), and can be a secondary source of energy (from lack of fat or carbohydrate intake). Proteins are divided into two categories, those of animal origin (biological value greater) and those of vegetable origin (biological value lower). They are contained mainly in fresh and preserved meats, milk and dairy products, eggs, fish, cereals, legumes, nuts and dry fruits.
Carbohydrates are organic substances formed from carbon, hydrogen and oxygen. They are an important energetic source for our body. Carbohydrates also participate in the formation of vitamin and enzymatic factors, and of cellular structures. They are classified as: simple carbohydrates (also called “sugars”, highly digestible, such as: glucose, fructose and sucrose) and complex carbohydrates (formed by the union of simpler chemical units, such as: starch). With the exception of dietary fiber (impossible to digest), carbohydrates are easily digested. Carbohydrates are in pasta, rice, bread, cereals, potatoes, milk, sweets, fruit, vegetables.
Fats are organic substances insoluble in water. In our body, their main function is to act as energy reserves, but they also take part in important regulation and transport functions. From the nutritional point of view, the fats of most interest are the triglycerides. Fat is essential for the body.
Fats fall in two categories: saturated fats and unsaturated fats. Saturated fats are mainly of animal origin. They are harder to digest and considered “bad” for their “atherogenic” ability. Unsaturated fats are considered healthier than saturated fats. Belonging to the category of unsaturated fats is monounsaturated oleic acid, which is found in good quantities in olive oil and the polyunsaturated fats such as omega-6 and omega-3, which is found in fish, nuts and walnuts. Fats in general are mainly in vegetable oils, butter, lard, margarine, meat, fish, eggs, milk and dairy products.
Water is the most abundant constituent of our body (65-70%). The water present in our body is divided into two large compartments (intracellular and extracellular). Water regulates heat balance and conveys important substances in the body. Water participates in the metabolic processes of our body and purifies it of harmful and unwanted waste. In is contained mainly in foods of plant origin, and we receive a large portion of our water intake through ingested food.
Vitamins, Minerals and Phytonutrients
Vitamins, Minerals and Phytonutrients are substances of great importance to ensure the normal functions of our body. In general, we should know that to ensure an adequate supply of these nutrients, it is necessary to practice a varied and balanced diet full of plenty of fruits and vegetables.
Vitamins are substances needed in small quantities for the human body. They do not provide energy. Vitamins act as biocatalysts (co-enzymes) in metabolic processes and are found widespread in plant and aminal foods (especially fresh and seasonal, and not subjected to excessive cooking). Vitamins have to be introduced through diet because they are not synthesized by the body in sufficient quantities.
They are divided into two groups: fat-soluble vitamins and water-soluble vitamins. In the first group we have: the vitamin A (it is important for vision, healthy skin, it protects against cellular aging and infections), the vitamin D (it promotes calcium absorption improving bone health), the vitamin E (it carries significant antioxidant functions) and the vitamin K (it participates in the synthesis of some blood clotting factors). In the second group instead we have: the vitamin C (it intervenes in the formation of collagen, it prevents infections, it possesses antioxidant activity and promotes the absorption of iron) and the B-complex vitamins such as: thiamine (B1) and pyridoxine (B6), which are important for the functionality of the nervous system. Riboflavin (B2), niacin (B3), pantothenic acid (B5) and biotin (B8) are involved in metabolic processes. Folic acid (B9) and cyanocobalamin (B12) participate in the formation of red blood cells.
Minerals are substances present in foods. They are essential for our body, but they cannot be synthesized and must be introduced through diet. They are divided into two groups: macronutrients and micronutrients. In the first group we have: calcium, which is involved in bone formation and participates in blood clotting and muscle contraction. Phosphorus, component of nucleic acids and of important energy molecules. Magnesium, which regulates the neuro-muscular activity. Sodium and potassium regulate the cellular balance and blood pressure. In the second group we include: iron, component of hemoglobin and enzymatic factors. Zinc and copper have antioxidant activity and they are components of enzymes. Iodine, component of thyroid hormones. Selenium presents antioxidant activity and it purifies from the heavy metals.
Phytonutrients are bioactive substances present in plant foods. They show antioxidant activity and anti-inflammatory activity and can help prevent chronic-degenerative disorders, especially cardiovascular diseases and cancer. Furthermore they perform functions of regulation of cell life, of hormonal regulation and of numerous genes. The latest scientific research highlights a large potential for these substances, however, there is still not reliable data related to their daily intake and to their possible toxicity.
Among the vast amount of phytonutrients, the following deserve mention: The carotenoids (plant pigment precursors of vitamin A, responsible for the characteristic color yellow-orange/red of the plants). The polyphenols (abundant in fruits and vegetables, red wine, tea, legumes and cereals. The best known substances in this group are flavonoids, including the anthocyanins: plant pigments responsible for the color blue-purple). The monoterpenes (found mainly in herbs and spices). The isoflavones (plant hormones found mainly in soybean, chickpeas, beans, lentils, whole grains and fennel). The glucosinolates (abundant in turnips, broccoli, cabbages, cauliflowers). The saponins (compounds found in abundance in legumes). The lignans (well represented in flax seeds, whole grains, nuts, cabbages, carrots, broccoli, berries). The sulfur compounds (substances found in garlic, onion, shallot and leek).