Proper nutrition is a complex science about food and its effects on health. Nutrients that the body itself cannot synthesize should come from food. Among the nutrients necessary for normal life, include:
- amino acids;
- fatty acid.
Some of these substances (trace elements) the body needs in very small quantities, others, on the contrary, slightly more (macroelements). The lack of any of the nutrients often causes serious illnesses. Excess often leads to obesity and side problems.
- 1 Macronutrients: Basic Information
- 2 Carbohydrates – A Tasty Source of Energy
- 3 Monosaccharides and disaccharides
- 4 Polysaccharides: starch, cellulose and resistant starch
- 5 Energy sources
- 6 What is the glycemic index
- 7 Protein – the basis of everything
- 8 What are amino acids?
- 9 Fats and undeservedly bad reputation
- 10 Fat Types
- 11 Essential Omega-3 and Omega-6
- 12 “Bad” Fats
- 13 Sources of lipids in foods
- 14 How the body uses proteins, carbohydrates and fats
- 15 Instead of an epilogue
Macronutrients: Basic Information
Macronutrients, or macronutrients, are nutrients that provide the body with the necessary energy and calories. They are necessary for normal growth, metabolism and maintenance of body functions.
Already from the name, it becomes clear: macronutrients are a group of substances necessary for a person in large quantities. Among the macronutrients belong: proteins, fats, carbohydrates.
Many are puzzled by the question of what should be the percentage ratio of these substances in the daily diet and how many grams of each element must be received daily. But in order to answer it, it is important to understand what these elements are and what functions they perform.
The three classes of macronutrients named are complex groups, each of which consists of many components. You can eat the same amount (in grams) of proteins, lipids and carbohydrates every day, but each time providing the body with different microelements is the whole reason for the sources of these substances. For example, in identical portions of olive oil and fat, lipids are radically different. Therefore, it is important to adhere to a balanced diet and a varied diet to maintain harmony in the body. And immediately the first conclusion: it is not so much the amount of consumption of useful micro and macro elements (although this is also an important nuance), but their quality.
But when it comes to calorie supply, it’s still worth remembering that the energy value in 1 grams:
- carbohydrate – 4 calories;
- proteins – 4 calories;
- fat – 9 calories.
Carbohydrates – A Tasty Source of Energy
Carbohydrates are a combination of different molecules that provide approximately 45 percent of the energy for the body. True, some types of carbohydrates, such as fiber and resistant starches, do not serve as a source of energy, but at the same time play an equally important role:
- strengthen the health of the digestive system;
- promote easy digestion of food and absorption of nutrients;
- rid of toxins and toxins.
Functions in the body
Carbohydrates obtained from food are broken down in the human body to the state of glucose and other monosaccharides. They increase the level of sugar in the plasma, supply the person with energy. In general, the role of most carbohydrates for humans comes down to the fact that they:
- are an excellent source of strength;
- all cells and tissues of the body use them for energy;
- they accumulate in the cells of the liver and in the muscle tissue, so that they can be activated when necessary;
- necessary for the nervous system, brain, muscles (in particular, the heart), kidneys;
- beneficial effect on maintaining intestinal health.
Carbohydrates are made up of carbon, hydrogen and oxygen. There are simple and complex carbohydrates.
Monosaccharides and disaccharides
Simple carbohydrates are composed of monosaccharides and disaccharides. They are able to quickly increase the level of glucose. Sweet to the taste, quickly absorbed and instantly provide the body with energy.
Monosaccharides are simple sugars, because they consist of one unit. In this form, they can be absorbed by the body. Unlike other carbohydrates, they do not require digestion during digestion. Therefore, monosaccharides from food quickly enter the blood, almost instantly increasing the amount of sugar in the plasma, immediately supply energy to the body.
Examples of monosaccharides: glucose, fructose, galactose. Simple sugars in different quantities are part of the products from different categories. Their content is especially high in ripe fruit and honey.
Monosaccharides are important sources of energy. But consuming large amounts of simple sugars, without balancing with polysaccharides or oligosaccharides (which digest longer and therefore provide the body with long-term energy) can cause a significant increase in blood glucose levels, followed by a sharp drop in the indicator. As a result, first there is a large and sharp release of energy, which also quickly gives way to a feeling of fatigue. Frequent repetition of such fluctuations can cause diabetes.
Disaccharides are combinations of 2 monosaccharides. To disaccharides belong:
- lactose (milk sugar);
- sucrose (table);
- isomaltose (sugar formed as a result of the breakdown of starch).
Disaccharides, like monosaccharides, give the food a sweet taste, and the body provides fast energy. Due to these biochemical properties, they are also referred to as simple sugars. In large quantities are presented in processed foods. Frequent consumption of disaccharides can also lead to an increase in blood glucose.
Since disaccharides contain 2 “pieces” of sugar before being absorbed in the body, they undergo a process of “separation.” Therefore, for each disaccharide, the body “procured” its own digestive enzyme. Thus, the enzyme sucrase acts on sucrose, lactase – on lactose. The necessary enzymes are produced in the intestines. The absorption of disaccharides proceeds quite easily. The exception is lactose.
Many people lack the lactase enzyme, which means that their organisms are not able to break down lactose into the 2 element, which is manifested in the so-called lactose intolerance. This means that the consumption of dairy products for such people is a problem. Lactose intolerance is more often observed in old age. Undigested milk sugar is not absorbed and contributes to the development of “bad” (unfavorable for the body) bacteria in the digestive tract. As a result, this process leads to flatulence, heartburn, and nausea. In addition, the acid produced by “bad” bacteria worsens the intestines as a whole (reduces its ability to produce enzymes for digesting food) and damages the cells of the digestive system. It is important for such people to refuse food, which contains lactose. Some studies prove that with such digestive disorders it is useful to use dietary supplements containing lactobacilli.
Polysaccharides: starch, cellulose and resistant starch
Large carbohydrate molecules (such as fiber or starch) are a compound of several monosaccharides bound together. The composition of some may contain up to several hundred mono-sugars. Such a complex is called polysaccharides (from “poly” – a lot). The specificity of complex compounds is that they more slowly increase the glucose level in the human body, but act for a longer time. Group of complex carbohydrates are starches and fiber.
Plants accumulate their energy by combining a variety of mono-sugars. Such a complex may consist of several hundred (sometimes up to several thousand) glucose molecules. Herbal products (for example, seeds that should provide shoots by force) contain a lot of starch. When a young plant begins to grow, starch is broken down into glucose and provides it with the necessary energy.
If a person eats starchy foods, such as corn or potatoes, the body uses polysaccharides from it in much the same way as plants. The digestion of starches requires more time than the process of processing disaccharides.
A poem can be said that starch is a sustainable source of energy. They do not cause a sudden blood sugar saturation, the work of starch is designed for slow, consistent and long-term maintenance of forces in the body. And it is considered ideal for health.
The food presents 2 main types of starches:
Amylopectin is digested by the body faster. The process of absorption of food starch is preceded by the stage of splitting substances into smaller elements – individual units of carbohydrates.
Dietary cellulose, or fiber, is also a representative of polysaccharides – a family of complex carbohydrates. But in this substance “sugar” blocks are connected according to a slightly different principle and the body cannot break the chains connecting them. Instead, cellulose passes through the small and large intestines in its original form. Due to this fiber performs important functions for the body:
- accelerates the elimination of toxins and slags;
- relieves constipation.
Useful cellulose is found in vegetables, cereals, legumes. In particular, there is more fiber in unprocessed foods. For example, bran contains a lot of fiber, and already in the flour it is not. Cellulose is also inherent in the peel of fruit, but is completely absent in drinks made from them.
Much has already been written about the benefits of fiber. Experiments prove the link between a diet based on a high content of fiber, and a reduction in the risk of developing oncological diseases, including in the intestine and mammary glands. Some researchers explain this by the ability of cellulose to remove toxins and toxins from the body, which contributes to healthy digestion.
Therefore, foods that contain a lot of fiber, should be included in a diet for weight loss. In addition, fiber maintains the state of the intestinal microflora, on which the whole body’s immunity depends. Lack of cellulose in the diet causes constipation, increases the likelihood of hemorrhoids or colon cancer.
The beneficial effects of fiber:
- reduces the possibility of developing cardiovascular diseases;
- prevents the development of obesity;
- reduces cholesterol.
The last category of polysaccharides, or complex carbohydrates, is resistant (stable) starch. It got its name due to the fact that it can not be processed in the small intestine. As a result, this type of starch acts more like cellulose than starch. Passing through the digestive tract and entering the colon, like fiber, contributes to the development of beneficial bacteria in the intestine. Resistant starch is found in wild rice, barley, whole wheat and buckwheat.
In addition, in the “sugar family” there are so-called oligosaccharides. This is a cross between mono-and polysaccharides. Their structure can be from 1 to 10 monosaccharides.
Sources of simple carbohydrates:
- fruits and berries;
- milk products;
- sweeteners (sugar, honey, syrup);
- soft drinks.
Source of complex carbohydrates:
- bakery products;
- starchy vegetables;
- green pea;
Many of these products are also sources of fiber. Complex carbohydrates are in most vegetables, fruits, nuts, seeds, legumes, as well as whole grains.
What is the glycemic index
How quickly sugars increase glucose in the blood indicates the glycemic index. Its range is the scale from 1 (the slowest effect on the body) to 100 (the fastest saturation, this figure is equivalent to the speed of the action of pure glucose).
Glycemic index table of some foods
|Bread||whole rye flour||49|
|Dairy produce||milk, yogurt, ice cream||34-38|
Carbohydrates with a high glycemic index raise glucose in the circulatory system quite quickly. As a result, the amount of insulin in the blood increases, causing hypoglycemia and a feeling of hunger. All this leads to the use of excess calories, which means excess weight.
Carbohydrates with a low glycemic index contribute to a slow increase in plasma glucose, which eliminates the sharp jumps in insulin production. Eating foods with lower GI reduces the risk of obesity, diabetes, or its complications.
Protein – the basis of everything
Proteins are an important component of the body, as they are included in the structure of most tissues, including bone and connective tissue. The significance of proteins is already indicated by their name: “protein” from Greek means “taking first place”. Proteins are involved in almost all enzymatic processes in the body. Moreover, enzymes are also proteins. The body needs constant replenishment of proteins that take the place of dead cells or damaged tissues. Also, the growth and development of the body depends on them. From 10 to 35 percent of the calories of your daily diet should come from protein foods.
The role of proteins:
- contribute to the normal growth of children and adolescents;
- essential for maintaining the health of pregnant women;
- restore tissue;
- strengthen the immune system;
- provide the body with energy when there is not enough carbohydrates;
- support muscle mass (promote muscle growth);
- promote the production of hormones and enzymes.
How does the body benefit from proteins?
Proteins are broken down into peptides and amino acids. They are necessary for the growth and replacement of “damaged” tissue. But if the body does not receive the necessary calories for life, protein can also be used as a source of energy.
From 20, the amino acids 9 are indispensable. A person cannot synthesize them, therefore it is important to ensure the replenishment of these substances from food.
Protein Consumption Rates
The daily protein norm is determined on the basis of several parameters. One of them is the growth rate. That is, children in the period of active development need more proteins than adults.
Standards of protein intake (per day):
- children up to 3 years old – 2,2 g per kilogram of weight;
- from 3 to 5 years – 1,2 g per kilogram of weight;
- adults – 0,8 g per kilogram of weight.
People who want to increase muscle mass also need an increased dose of protein.
Sources of protein:
- lean meat;
- soy products;
Proteins from plant foods, as a rule, contain less fat and cholesterol, supply the body with fiber and other essential nutrients.
Replenishment of protein in the body is achieved by providing the necessary amino acids.
Daily need for amino acids
|Name||Children 4-6 months||10-12 years old||Adults|
|Methionine and cysteine||72||24||13|
|Phenylalanine and tyrosine||120||24||14|
|All essential amino acids (except histidine)||715||231||86|
What are amino acids?
Proteins are made up of smaller molecules (amino acids) that are linked together. The structure of the protein resembles a string of beads strung on a chain. Activated protein acquires a slightly different form – a three-dimensional structure (the chain twists and twists around). Like carbohydrates, amino acids are made up of carbon, hydrogen, and oxygen. But unlike them, they also contain nitrogen.
It is important that proteins come in different sizes. Some chains of amino acids are rather short and consist of 50 elements, but most contain 200-400. Individual proteins can unite and form the so-called protein complexes. The largest protein complexes are bones, skin, nails, hair, teeth. They are formed from collagen, elastin and keratin. Collagen, for example, consists of 3 of thousands of amino acids twisted into a long cylindrical chain. This chain is held together with other collagen chains and creates thicker and stronger cylinders called fibrils. Fibrils can combine collagen chains from 6 to 20, which means there are tens of thousands of amino acids in their composition. And this is the structure of only one single protein.
A single amino acid resembles a simple carbohydrate. At least, by the fact that the body, on the principle of digesting carbohydrates, also breaks down the protein structure to the amino acid state before absorption. And only after this, it digests one small “block”.
Where to look for amino acids?
A healthy person needs about 40-65 grams of different amino acids per day. If the body does not receive the necessary protein norm, it begins to draw reserves from its own muscles, destroying them. Inadequate use of amino acids can cause growth to stop, poor muscle development, thin and brittle hair, skin diseases, weakening of the immune system and other troubles.
The source of amino acids are proteins from food of plant and animal origin. The most concentrated protein food: nuts, legumes, fish, meat and dairy products. In processed foods, protein is sometimes presented in the form of a peptide, a hydrolyzed protein (composed of amino chains formed from 2-200 amino acids). Such products are digested faster and easier to digest.
Essential Amino Acids
There are 20 varieties of amino acids and the body needs all of them, since each is involved in the creation of protein at a certain level. The body can synthesize many of these amino acids on its own. However, the source of 9 of these is only food. They are called basic, or essential, amino acids. These include leucine, methionine, phenylalanine, tryptophan and others.
For the body is important the correct ratio of amino acids among themselves. Animal food, for example, contains amino acids in proportion, as in the human body. Proteins from plant foods have a slightly different structure. Many nutritionists are concerned that vegetarians, who refuse meat, do not get all the necessary proteins in full measure. Other researchers reject this theory. They suggested: since various plant products contain various essential amino acids, it is easy to get all the vital building blocks by eating various foods (from whole grains, legumes, and other vegetables). In addition, some herbal products, such as soy, contain protein that is similar in composition to meat proteins.
Fats and undeservedly bad reputation
Fats, or lipids, are perhaps the most complex macromolecules in food. There are many types of lipids.
Unfortunately, fats have received a bad reputation, partly due to the fact that excess calories are converted to subcutaneous fat. The second reason – saturated lipids, trans fats, cholesterol cause many health problems (from cardiovascular diseases to obesity). However, the facts assure that not all fats are bad. Most of them, on the contrary, are vital for the organism. So, when it comes to fats, you need to be able to distinguish between good and bad, to understand what kind of lipids can be obtained from a particular food.
According to nutritionists’ advice, the daily calorie intake per 25-35 percent should consist of healthy fats.
Role in the body:
- promote normal growth and development;
- serve as a source of energy;
- essential for the absorption of fat-soluble vitamins;
- are part of the building material for cells;
- create “depreciation” for internal organs.
Fats, like other macromolecules, are composed of carbon, hydrogen and oxygen. But the peculiarity of their structure is that they are insoluble in water. These are the so-called hydrophobic substances. Fats are broken down into fatty acids and glycerin. They are essential for tissue growth and hormone production.
By chemical properties, fats are saturated, monounsaturated and polyunsaturated.
Saturated lipids: “bad” fats, who are you?
Saturated lipids are made up of the right molecules. They retain their solid form at room temperature (except palm and coconut oils). Sources of such fats: butter and fats contained in meat.
More than 50 years ago, researchers began to talk about the relationship of saturated fat and the rate of increase in cholesterol in the blood, which is the cause of atherosclerosis, cardiovascular diseases. The food industry quickly responded to the statement by the food industry – products “low in fat” or “completely fat free” appeared on the shelves of supermarkets.
Excessive intake of saturated fat and truth can adversely affect health. But the problem is that the fact concerning exclusively saturated fats has erroneously spread to other types of lipids needed by the body.
Saturated fats are found in large quantities in meat products, in particular in pieces with white solid fat. Minimizing saturated fat intake is a good idea. However, you can not refuse all fats. It is important to consider the fact that the brain is almost 60 percent composed of lipids. In addition, a diet low in all types of fat increases the risk of hormonal disorders, promotes the development of cardiovascular diseases, and also reduces immunity and brain activity.
The importance of monounsaturated fats
Monounsaturated fats have attracted the attention of scientists after it was observed: people who follow the Mediterranean diet are less likely to develop heart disease, certain types of cancer, rheumatoid arthritis. Scientists explained this fact that the traditional Mediterranean diet contains a large amount of olive oil, rich in monounsaturated oleic fatty acid. In addition to the product of olives, monounsaturated lipids are rich in avocados, almonds and cashew nuts.
Monounsaturated fats (for example, olive oil) at room temperature retain the structure of the liquid, but harden in the refrigerator.
Scientists continue to conduct experiments and prove their theory about the beneficial properties of monounsaturated fats. But no less actively studying the function of polyunsaturated lipids, in particular the omega-3 fatty acid.
Polyunsaturated fats (PUFA) consist of molecules, the nature of the bonds between which is different from other lipids. This is the secret why they remain liquid at low temperatures.
There are many polyunsaturated fats. Most of them can be produced by a person independently, except for Omega-6 and Omega-3. And since these fatty acids are indispensable for people, it is important to replenish their stores of food.
Polyunsaturated lipids are present in large quantities in oils from grains and seeds (for example, linseed oil).
Essential Omega-3 and Omega-6
When it comes to lipids, one can not forget about the essential fatty acids – linoleic (Omega-6) and linolenic (Omega-3). They are necessary for the formation of biologically active lipids (eicosanoids), including prostaglandins, thromboxanes, prostacyclins and leukotrienes. Regular consumption of omega-3 fatty acids prevents the development of coronary heart disease.
The body’s need for essential fatty acids varies with age.
- linoleic acid – 2% of daily calories;
- linolenic acid – 0,5% of total calories.
Linoleic acid, also known as Omega-6, is found in large quantities in oils from grain crops, in nuts, beans, and in seeds of sunflower, sesame, corn, soybeans, peanuts, and pumpkin. Omega-6 deficiency is rare because this fatty acid is present in many foods. In addition to those already mentioned, beef and poultry are a good source of linoleic acid.
The lack of omega-3 (linolenic acid) is associated with the development of diseases such as chronic inflammation (from inflammation in the intestine to rheumatoid arthritis), cardiovascular disease, distraction and hyperactivity. Alpha-linolenic acid is found in large quantities in pumpkin, flaxseed, rapeseed, soybean oils, some leafy vegetables, but most of all – in oily sea fish.
But not enough – just regularly use omega-3 and omega-6. It is important to adhere to a certain ratio between these fatty acids. Nutritionists offer an optimal ratio of omega-3: omega-6 – 1 to 2. Meanwhile, in practice, for many, this ratio is 1: 25. In order to achieve a more beneficial ratio, it is important to reduce the amount of omega-6 in the diet and increase omega-3. This is easily achieved by reducing the consumption of meat, milk and refined products. But at the same time, on the contrary, increase portions of fish (better than salmon), flaxseed oil, walnuts, green leafy vegetables.
Partial hydrogenation of unsaturated fatty acids (used in the food industry) leads to the formation of trans fats. They even at room temperature retain a solid or semi-solid texture. A high amount of trans fatty acids is found in cookies, cakes, crackers, chips. In cooking, this substance is used to extend the shelf life of confectionery. But trans fats lead to an increase in the level of cholesterol in the blood, which can later provoke the development of coronary heart disease.
One of the most important functions of fats is that lipids are the main component of membranes in all cells of the human body. But different types of fats – unsaturated, monounsaturated and polyunsaturated – are needed in varying amounts. Cells are primarily in need of polyunsaturated and partially monounsaturated fats. These lipids allow membranes to maintain flexibility and mobility. When the level of saturated fats is too high, cell membranes become stiff, their functional abilities decrease, they lose their ability to protect the internal parts of cells.
Sources of lipids in foods
- olive oil;
- peanut butter;
- corn oil;
- soybean oil;
- linseed oil;
- oily fish;
- some seeds.
- fat red meat;
- Palm oil;
- Coconut oil;
- milk desserts.
How the body uses proteins, carbohydrates and fats
The human body is an amazing machine that can learn to survive with any kind of food, adapting to a variety of diets. And this ability has been inherited by modern man from his ancestors, whose food frequency and diet depended on subjective factors (successful hunting or, for example, the quality of the berries in the neighborhood).
Modern man gets calories in much larger quantities and without much energy. And all the nutritional difficulties that remain with Homo Sapiens are to correctly combine essential macronutrients for life, to ensure a balance of protein, fat and carbohydrate intake. But even this many, alas, fail.
At that moment, when a person bites off a slice of meat, cake or vegetable, the complex process of digestion starts. The body recycles every accepted piece of food, breaking it into the smallest organic matter. A complex of chemical reactions transforms food from a habitual for the person look into separate chemical components which serve as “fuel” for many processes. Proteins, carbohydrates and fats pass a long way of metabolism. And in each macronutrient it is unique.
Provided that these three substances are presented in the required quantity, first of all, sugars and fats are used as an energy source, because there is an interrelation of carbohydrate and lipid metabolism. Proteins at this time serve as “raw material” for muscles, hormones and other biological “equipment”.
Protein derived from food, the body breaks into pieces (amino acids), which are then used to create new proteins with specific functions. They accelerate some chemical reactions in the body, contribute to the relationship between cells. With a deficiency of carbohydrates and fats are a source of energy.
Lipids, as a rule, provide the body with almost half of the required energy. The fat obtained from food is broken down into fatty acids that “travel” in the blood. Triglycerides are stored in fat cells and have unlimited possibilities.
But carbohydrates can be stored in the body only in small quantities. Sugar obtained from food, the body also breaks into small parts and already in the form of glucose, they enter the liver and circulatory system, affecting the “sweetness” of blood. As the researchers are convinced, the body will willingly accept and “digest” a larger portion of sugars than fat. Carbohydrate residues (those that the liver cannot contain for the production of glucose) are converted into “long-term storage” fat. When the body feels a lack of carbohydrates, it uses fats from the bins for energy.
And although lipids are a good source of energy for almost the entire body, there are several types of cells that have special needs. The main things on this list are brain cells. They work easily if the diet consists solely of carbohydrates, but almost can not be workable only on fats. A low carb diet is dangerous for the brain.
No less dangerous and protein deficiency: with a lack of protein, the body begins to “eat” the cells of its own muscles.
Instead of an epilogue
Macronutrients serve as building blocks. Healthy fats, in particular, take care of the preservation of cell membranes and prevent inflammation. The menu, composed of healthy products, is a guarantee that the body will receive complex carbohydrates, “good” fats and proteins in the required amount. In addition, a balanced diet is a complete range of healthy nutrients, minerals, vitamins and trace elements. It is the interconnectedness of the elements of the full spectrum of nutrients that will protect against diseases and early aging, provide the necessary energy and strength. Well, and of course, do not forget about the glasses of water recommended by nutritionists 6-8, in which our life is.
Table of proteins, lipids and carbohydrates in some products
|Product (100 g)||Proteins||Fats||Carbohydrates|
|Fruits and berries|
|Cottage cheese p / w||16,8||9,1||1,4|
|Products of animal origin|
|Pork n / w||16,3||27,9||–|
|Red caviar (sturgeon)||28,8||9,8||–|
|White mushrooms (fresh)||3,2||0,5||1,7|
|Nuts and Seeds|
|Vanilla ice cream||3,5||11||23,6|
Fiber Content Rating
|Product (100 g)||Fibre|
|dried mushrooms||20-25 g|
|Dried fruits||15 g|
|Whole wheat bread||7-9 g|
|Fruit (sweet)||2-5 g|