The Functions of Carbohydrates in the Body

Sugar molecules serve as the basis for carbohydrates, which are categorised based on how many sugar units are included in each molecule. Monosaccharides, commonly referred to as single-unit sugars, include galactose, fructose, and glucose. Disaccharides, also known as double-unit sugars, include the most well-known forms of lactose and sucrose (table sugar and milk sugar, respectively).

The terms “simple carbohydrates” typically refer to mono- and disaccharides. Complex carbohydrates are long-chain compounds like starches and dietary fibres. Yet, there are actually more pronounced disparities. Table 1 provides a summary of the main categories of carbohydrates found in human diet.

The primary purpose of carbs, one of the three macronutrients in our diet along with fat and protein, is to fuel the body. They are present in a wide variety of substances, including whole grains, fruit, and vegetables, as well as dietary fibre and carbohydrates. In this post, we look at the many types of carbohydrates that are present in our diet and their purposes.

Carbohydrate kinds

Polysaccharides

Polysaccharides are made up of sugar units and are often divided into two categories. Root vegetables including onions, carrots, potatoes, and whole grains include starch, which is the main source of energy. The glucose is found in granules that vary in size and shape depending on the plants they are found in and has varied length chains that are more or less branching. Animals have a carbohydrate called glycogen that corresponds to this one. Resistant starches are those that can only be broken down by the gut bacteria and not by our own digestive systems.

Polysaccharides other than starch, which are categorised as dietary fibre (although a few oligosaccharides such as inulin are also considered dietary fibre). Examples include gums, pectins, cellulose, and hemicelluloses. Vegetables, fruits, and whole grains are the principal sources of these polysaccharides. Because humans cannot digest non-starch polysaccharides—and actually all dietary fibers—they have a lower average energy value than most other carbs. Yet, some types of fibre can be broken down by gut bacteria, producing healthy substances for our bodies like short-chain fatty acids. In our article on “whole grains” and “dietary fibre,” you may read more about dietary fibres and their significance for human health.

The various designations result from the fact that carbohydrates are divided into groups based on their chemical makeup as well as their function or source in our diets. Even the most prominent public health agencies cannot agree on a uniform definition for the many categories of carbs.

Functions of carbohydrates

Our diets need to include carbohydrates. Most crucially, they supply the energy for both the most evident bodily functions, such moving and thinking, as well as the majority of the time unseen “background” processes. Digestive enzymes break down multi-sugar carbs into their monosaccharides during digestion, whereupon they are then directly absorbed and cause a glycemic reaction.

Muscle, the brain, and other cells all use glucose directly as an energy source. Certain carbs cannot be digested and instead are either fermented by the bacteria in our guts or pass through the gut unchanged. It’s interesting to note that carbs are crucial for cell growth and maintenance.

Dietary Fibre and Gut Health

Despite the fact that dietary fibre cannot be digested in the small intestine, fibre promotes healthy gut function by adding to the physical bulk of the colon and so accelerating intestinal transit. when the non-digestible carbs reach the big intestine.

Gums, pectins, and oligosaccharides are a few examples of fibre types that the gut bacteria can break down. The composition of our gut microbiota is benefited by this since it raises the total mass in the colon. Moreover, it causes the production of short-chain fatty acids, bacterial waste products that have positive health effects when released in the colon.

The glucose response and glycemic index

The glycaemic response is the process by which blood glucose levels increase after consuming a diet high in carbohydrates and subsequently fall again. It represents how quickly glucose is absorbed and digested, as well as how well insulin works to keep blood sugar levels normal. The glycaemic response’s rate and length are influenced by a number of factors.

Within two hours of eating, the effects of various foods and food processing methods on the glycaemic response are rated in relation to a reference, often white bread or glucose. The term for this measurement is “glycaemic index” (GI). A food or beverage with a GI of 70 will result in 70% of the blood glucose response that would be seen with the same amount of pure glucose or white bread, however most of the time, carbs are consumed in combination with proteins and fats, which all affect the GI.

Carbohydrates as energy source

The preferred source of energy for our body is carbohydrate breakdown to mostly glucose because all of our cells, including those in our muscles, brain, and other tissues, directly utilise monosaccharides for energy. Different types of carbohydrates contain various quantities of energy per gramme.

The small intestine immediately absorbs monosaccharides into the bloodstream, where they are delivered to the cells that require them. The digestive system also includes a number of hormones, such as glucagon and insulin. By eliminating or reintroducing glucose to the bloodstream as necessary, they keep our blood sugar levels stable.

Red blood cells and the brain in particular depend on glucose for energy, yet in extreme conditions, such as prolonged hunger, they can also utilise alternative sources of energy from lipids. This necessitates that the ideal level of blood glucose be continuously maintained. To meet the energy requirements of the human brain alone, 130 g of glucose are required each day.

One of the three macronutrients in our diet, carbohydrates are crucial for the body’s normal operation. They are found in many of the foods we eat and can take on a variety of shapes, from sugars to starches to dietary fibre.