Carbohydrates!

When someone hears the word carbs, they usually think of bread, rice and potatoes (trust me, this is verified).

It is right as carbohydrates are the first and most direct energy source from which the body prefers to use them as the primary energy source. They are called carbohydrates because of the carbon, oxygen and hydrogen they contain. In their chemical formula, they have the same amount of carbon molecules as water, hence their name: "hydrated carbon".

The basic carbohydrate molecules in the human diet are three:

• Glucose

• Fructose

• Galactose

Glucose is the most common molecule in the human diet and is often referred to as "blood sugar". Fructose is found in fruits and honey and has the sweetest taste, and Galactose is only present in milk. Carbohydrates are divided into two categories, simple and complex.

Simple carbohydrates

It is the fastest form of energy with the fastest absorption by the body, given that simple carbohydrates are digested quickly and through the bloodstream. They also deliver the quickest form of energy to the body without passing through the stomach called sugars.

They have very little nutritional value for the body, so their consumption should be limited to small amounts. The body absorbs them immediately, and their digestion is done very quickly compared to complex carbohydrates due to their simpler chemical structure. There are two types of simple carbohydrates:

• Monosaccharides

• Disaccharides

Monosaccharides

Glucose, Fructose & Galactose

The name comes from the Greek words MONO = One and Saccharite, meaning that their chemical structure contains only one unit (molecule) of sugar in their molecular chain. They are absorbed from the small intestine and enter the bloodstream immediately at the point of use. This is the smallest possible unit which you divide into three sub-categories:

Glucose

Glucose is a type of sugar found mainly in starchy foods (bread, rice, pasta, potatoes), fruit, juices, soft drinks, honey, jams and table sugar. Glucose, also known as dextrose or grape sugar, can be absorbed directly into the bloodstream during digestion.

It was formed, during digestion, by the hydrolysis of disaccharides and polysaccharides. After absorption from the small intestine, the portal vein transports the glucose to the liver, where it can be stored as glycogen, a form of polysaccharide. Glucose, inside cells, is used to synthesise pentoses, ribose and deoxyribose for RNA and DNA, respectively.

Glucose metabolism in the body

Glucose is stored in the body as glycogen. Insulin and glucagon work together to keep blood glucose concentrations regular.

The liver is an important storage site for glycogen.

When the blood glucose concentration is low, glycogen is mobilised and converted to glucose by gluconeogenesis. Glucose can also be produced by gluconeogenesis from non-carbohydrate precursors, such as pyruvate, amino acids and glycerol.

It is gluconeogenesis that maintains blood glucose concentrations, for example, during fasting and vigorous exercise.

Fructose

It is absorbed more slowly than glucose and is used faster by the tissues as it helps the development of normal intestinal flora. It is converted in the liver to glucose or, more often, to some product of glucose metabolism.

It has the sweetest taste of all sugars. For this reason, it is used in limited quantities, in various diets (e.g. diabetic), as an alternative to ordinary sugar (sucrose) because it does not cause a significant increase in glucose and insulin in the blood. The reason is that insulin is not necessary to enter fructose into the cells. Hence, the required amounts are smaller (because it has a tremendous sweetening capacity).

An alternative to sucrose for patients who have diabetes.

Fructose from plant sources is found in the roots of vegetables, berries, white grapes, fruits, honey, agave nectar, etc. Commercially, fructose comes from sugar cane, onions, sweet potatoes and beets.

Metabolism of fructose in the body

The main difference between fructose and glucose is that fructose is 100% metabolized in the liver and stored as fat faster, while glucose is only 20%.

Insulin allows cells to take in glucose to use as an energy source. Excess glucose can be converted to glycogen and stored in the liver and muscles; insulin and cortisol facilitate this process.

After digestion, some of it is converted into active glycerol, which is used as a substrate for the conversion of free fatty acids (FFAs), into VLDL lipoproteins and into triglycerides which accumulate as fat in the liver and skeletal muscles, causing resistance to insulin and non-alcoholic fatty liver disease, i.e. fatty infiltration (NAFLD) with consequent elevation of cholesterol and triglycerides, which is not the case with glucose.

Metabolism of fructose by the liver increases the production of uric acid as a byproduct, with a concomitant increase in blood pressure.

Fructose harms two hormones associated with satiety and hunger, ghrelin and leptin. Fructose intake creates a vicious cycle of hunger with increased food intake and fat storage.

When fructose is consumed in liquid form in soft drinks and sugary drinks, it is not bound to other carbohydrates or fibre, so it is absorbed and metabolized much more quickly than if ingested from high-fibre fruits.

Galactose

Galactose has less sweetness than glucose, but it is not found freely in nature, but it can join with glucose and turn into Lactose, turning its structure into a disaccharide, and we find it in milk. Galactose is not an essential nutrient, meaning you don't need to get it from food to be healthy, and galactose can be synthesized in the human body from glucose.

The metabolism of galactose in the body occurs when most of the absorbed galactose enters the liver. It is mainly converted into glucose, which is then either incorporated into glycogen or used as energy.

Effects of galactose on health

A recent study from Sweden, published in the scientific journal BMJ, comes to shake the waters in our belief about milk's beneficial properties for our bones and health. So those who drank more milk suffered from more bone fractures, and instead, it may be associated with an increased death rate!

In addition, higher dairy consumption has been linked to prostate cancer, ovarian cancer, multiple sclerosis, diabetes, increased cholesterol levels, oxidative stress, brain inflammation and degeneration, food allergies, constipation, etc.

A research study by the Universitat Autònoma de Barcelona (UAB) in collaboration with the University of La Laguna (ULL) shows that high consumption of milk or dairy products, galactose actively accelerates ageing in men, affecting it on a sensory and motor level as and in the neuro-immune-endocrine system. Women show impairments in learning, perception and their ability to register information about their environment and orientation.

Disaccharides

They are polysaccharides, a union of two monosaccharides (hence their interpretation), broken down by digestive enzymes into simple sugars. Disaccharides include three categories which are:

Lactose: The name comes from the Latin Lac = milk, the extract from sweet or sour whey. The bond of a molecule of glucose with a molecule of galactose and we will have lactose, usually found in the milk of mammals and in a percentage that you sleep from 1.5 to 8% depending on the animal).

Maltose: Also known as malt sugar, with two glucose molecules in its molecular structure. With more maltose units, maltotriose can be produced & with further units, you can get maltodextrin production.

Sucrose: the bond with a molecule of glucose + a molecule of fructose, we can get a molecule of sucrose. It is simple table sugar and comes from plant sources, and two of the essential sugar crops are sugar cane and sugar beet.

Complex Carbohydrates

Complex carbohydrates are chemical structures consisting of three or more sugars, usually linked together to form a chain. These sugars are mainly rich in fibre, vitamins and minerals, known as starch, and their molecular structure has three or more linked sugars.

Because of this complexity, they take a little longer to digest, which contributes to them not increasing blood sugar levels as quickly as simple carbohydrates. They also need more time to provide energy which comes during their processing through digestion.

Complex carbohydrates are the body's fuel and contribute significantly to energy production. Similar to simple carbohydrates, complex carbohydrates are divided into two categories:

• Oligosaccharides

They consist of a small number of monosaccharides, which starts from 3 and do not exceed 9 in number, e.g. inulin, lignin and related plant components. They are also essential in the absorption of certain minerals and for the formation of fatty acids.

• Polysaccharides

When monosaccharides are united in amounts from 10 to thousands of sugar molecules in linked groups, they are known as polysaccharides. Complex carbohydrates are usually found in whole grains (bread, cereals), vegetables such as spinach, sweet potatoes, broccoli, green beans, zucchini, and all legumes and have more nutritional value than simple carbohydrates.

Carbohydrates are not classified as essential nutrients for humans. It could take all our energy from fat and protein if we had no choice, and the body, under these conditions, would convert fat into energy through ketones, but that is not our topic for now. The energy for each gram of carbohydrate amounts to approximately 4 calories or otherwise kcal.

The main polysaccharides in the human body

• The glycogen

A polysaccharide, but its common name is animal starch, the storage form of glucose in the liver and muscles. The formation of glycogen is made from carbohydrate sources. It is called glycogenesis, one from non-carbohydrate sources such as protein and is called gluconeogenesis and finally, the conversion of glycogen into glucose called glycolysis.

Glycogen is the form in which excess carbohydrates are stored in the liver and muscles; insulin and cortisol hormones facilitate this process.

When blood glucose levels decrease, the liver converts glycogen into glucose. This process is facilitated by the hormone glucagon or, in stressful situations, by epinephrine. In cells, glucose undergoes oxidation to carbon dioxide and water with the simultaneous release of energy in the form of ATP (adenosine triphosphate) and heat.

In muscle cells under anaerobic conditions, glucose is metabolized only to lactic acid and oxygen is required to convert lactic acid back to glucose, mainly in the liver.

Glycogen plays an important role in the glucose cycle. The most common disease in which glycogen metabolism is abnormal is diabetes, which is caused by abnormal amounts of insulin that have increased and cannot be absorbed. Glycogen in the liver may be abnormally accumulated or even depleted.

• Starch

It is a macromolecule consisting of a polymer linear chain of glucose molecules, amylopectin, the main component, and another molecular linear chain, amylose. Starch is produced only in plants through photosynthesis with the extra production in glucose which is converted into starch and stored in the fruit, roots, stem or leaves. When the plant needs energy, it converts the starch back into glucose.

In the human body, when we consume starchy foods, the breakdown/conversion is the same because the starch is converted into glucose, but when the energy is more than what is needed, the body, not having the ability to expel it, converts it and stores it as fat, which and to remove it from us, it is also our biggest problem!

Starch is not water-soluble. Humans and animals need the amylase enzyme to break it down in the stomach, and with the hydrolysis method, digestion takes place. When starchy foods are raw, they provide plenty of vitamins, minerals and fibre, but the energy they contain is relatively low. Rich sources of starches for humans are potatoes, rice and wheat etc.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>To be continued to the fibre article.