Carbohydrates
In our previous blog post, we assessed the essential nutrients required by the body. These essential nutrients were classified as either macro-nutrients or micro-nutrients, you identified that carbohydrates are macro-nutrients; meaning they are essential nutrients (have to be included in the diet), which are required in large amounts by the body.
Carbohydrates are also referred to as energy-giving foods. They are the main source of energy for the body. Similar to proteins, each gram of carbohydrate when broken down releases 4 calories.
Chemical Structure
Carbohydrates contain carbon,oxygen and hydrogen molecules.The difference between one carbohydrate and another arises due to the change in the number of carbon, hydrogen, and oxygen molecules contained in its structure.Carbohydrates are broken down to glucose(C6H12O6) to release energy for the body.
Carbohydrates are made up of smaller groups constituting;
- Monosaccharides– the simplest form of carbohydrates. From their name –mono-they contain only 1 sugar unit. – Examples include; glucose, fructose, and galactose. Monosaccharides combine to form either disaccharides or polysaccharides.
- Disaccharides– from their name di- contain 2 sugar units (2 monosaccharides). Examples include; lactose (galactose and glucose), sucrose (fructose and glucose), and maltose( glucose and glucose).
- Oligosaccharides – contain 3-10 molecules of monosaccharides. Examples are raffinose and stachyose, which are mainly found in legumes and some vegetables.
- Polysaccharides– contain more than 10 molecules of monosaccharides. Examples include starch, cellulose, and glycogen.
Types Of Carbohydrates
There are 2 main types of carbohydrates namely:
- Simple carbohydrates have a basic chemical structure. They may constitute monosaccharides or disaccharides. These carbohydrates are easily digestible and readily broken down before being absorbed into the bloodstream. Hence, they have a more immediate impact on blood glucose levels. Various foods contain simple carbohydrates including; white bread, potatoes, honey, sugar, and baked goods.
- Complex carbohydrates contain longer, more complex chains of sugar molecules. They are formed by a combination of either oligosaccharides or polysaccharides. Complex carbohydrates take a longer time to be digested when compared to simple carbohydrates. Hence, they do not immediately affect blood glucose levels. Examples include;whole grains (oats, barley, millet),legumes such as lentils and beans, starchy vegetables-including yams, sweet potatoes, and maize, and non-starchy vegetables- including courgette, asparagus, and broccoli.
You should opt for unrefined and unprocessed forms of carbohydrates to ensure a nutritious diet. Of course, even while you choose your complex carbohydrates, ensure that you limit frying; instead, opt for other cooking methods such as stewing. Because while you might as well be consuming complex carbohydrates such as yams or sweet potatoes; they become more like processed foods when you fry them.
Functions Of Carbohydrates
- Source of energy- As aforementioned, carbohydrates are the main source of energy for your body. After ingestion, they are broken down to glucose, which releases energy that is used by the brain and the rest of the central nervous system, heart muscles, and kidneys. In other words, all the body’s cells and organs require energy and they rely majorly on carbohydrates for this.
- Provide stored energy – The excess carbohydrates are stored in either the liver or muscles to provide energy when carbohydrate intake is deficient.
- Protein-sparing action- Indeed, other macronutrients such as fats and proteins can also provide energy for the body but only in particular instances like when there is a deficiency of carbohydrates. Otherwise, carbohydrates remain the major source of energy for the body. Therefore, carbohydrates should be consumed to allow proteins to be involved in their main functions.
- Serve as a structural component – The combination of carbohydrates with lipids(fats) form the cell membrane. The glycosaminoglycans in humans and cellulose in plants also contain carbohydrate constituents.
- Synthesis of other biochemical elements in the body- From the basic carbohydrate molecule structure, we note that carbohydrates contain carbon molecules. These carbon molecules are combined with other molecules such as nitrogen and phosphorus, and utilized in the production of proteins, lipids, nucleic acids(DNA and RNA), and coenzymes
Food Sources
- Quinoa
- Yams
- Sweet potatoes
- Rice
- Bread
- Maize
- Cereals
- Whole grains e.g oats, millet, sorghum,barley
RDA
Generally, carbohydrates should comprise 55% -60% of the total calorie intake in a day. To illustrate, a healthy individual normally requires about 2400 Kcals /day; hence, the carbohydrate intake should be:
55/100 ×2400 Kcal=1320Kcals
60/100×2400 Kcal=1440 Kcals
Therefore, this individual requires about 1320- 1440 Kcals of carbohydrates in a day.
The total kilo calories required in a day (obtained from carbohydrates, proteins, and fats) are bound to vary depending on health status or activity level and even weight. As such, the total amount of calories per day also varies from one individual to another. A person involved in more physical activity may require more total calories than a person who has a sedentary lifestyle.
Thus , in this next example, this individual requires 2000 Kcals in a day. Therefore, the carbohydrate intake per day for this person will be slightly less compared to that person who requires 2400 Kcals but the percentage of carbohydrates to total calorie intake per day remains between 55%-60%. The carbohydrate intake should be:
55/100×2000Kcal=1100Kcals
60/100×2000Kcal=1200Kcals
This individual requires between 1100-1200Kcals of carbohydrates in a day.
Most importantly, carbohydrate intake per day should range between 55%-60% of total calories. Even individuals with type 2 diabetes should ensure that their carbohydrate intake ranges between 55%-60% of total calorie intake: However, they should ensure that they opt for complex carbohydrates as opposed to simple carbohydrates, or better yet, they should choose carbohydrates with low glycemic index.They should also ensure that they do not consume all carbohydrates at once, but instead space them out as per the meals and snacks in a day.
And yes, even those trying to lose weight, should still include carbohydrates in their diet, the only difference is that they should cut back slowly on the total calorie intake, instead of completely omitting one nutrient. This is because carbohydrates are necessary for the energy required by the brain as well as metabolic functions that keep the body functioning optimally.
In our next blog posts, we’ll look into the effects of excessive carbohydrate intake, and what happens when we omit carbohydrates altogether.