Carbohydrates are a predominant source of fuel for some cells, especially in brain, red blood cells and nervous system. Muscles depend on a supply of carbohydrates to energize intense physical activity. Carbohydrates provide on average 4 kcal per gram and are a readily available fuel for all cells, both in the form of blood glucose and in the form of glycogen stored in the liver and muscles. The glycogen stored in the liver can be used to maintain blood glucose concentrations in times when you have not eaten for several hours or the diet does not supply enough carbohydrates. Regular intake of carbohydrates is important as liver glycogen stores are reduced in about 18 hours if carbohydrates are not consumed. Then body is pressurized for production of carbohydrates, largely from breakdown of proteins in the body. This eventually leads to health problems, including the loss of muscle tissue. To obtain adequate energy, the Food and Nutrition Board of the Institute of Medicine recommends that 45% to 65% of the calories we consume each day be from carbohydrates.
Despite their important role as a calorie source, some forms of carbohydrate promote health more than others. As you will see in this chapter, whole-grain breads and cereals have greater health benefits than refined and processed forms of carbohydrate. Choosing the healthiest carbohydrate sources most often, while moderating intake of less healthful sources, contributes to a healthy diet. It is difficult to eat so little carbohydrate that body fuel needs are not met, but it is easy to overconsume the simple carbohydrates that can contribute to health problems.
Green plants synthesize the carbohydrates in our foods. Leaves capture the sun’s solar energy in their cells and transform it into chemical energy. This energy is then stored in the chemical bonds of the carbohydrate glucose as it is produced from carbon dioxide in the air and water in the soil. This complex process is called photosynthesis.
6 carbondioxide + 6 water + solar energy → glucose + 6 oxygen
(CO2 ) (H2O) (C6H12O6) (O2)
Food Sources of Carbohydrates
|Food name||Weight (g)||Carbohydrates (g)||DV%|
|Syrups, corn, light||341||261||200%|
Where do carbohydrates come from?
For forming energy-providing carbohydrates from non-energy-providing molecules: H2O and CO2 are limited to plants or bacteria. In a process called photosynthesis, life-forms are capable to couple H2O and CO2 by controlling solar energy. With carbohydrates, oxygen is also a part of this reaction:
6CO2 + 6H2O → C6H12O6 + 6O2
Humans are unable to perform photosynthesis and thus we eat plants and its products such as fruits, legumes, vegetables and grain products to acquire a rich supply of carbohydrates. Beyond plants and their products, milk and dairy are also good sources of carbohydrates. In fact, milk and some dairy products are the only considerable source of carbohydrate from animal foods. It should be mentioned that although humans cannot perform photosynthesis, we do possess the ability to make some carbohydrate in our body.
Are there various types and classes of carbohydrates?
As you may guess, numerous different kinds of carbohydrates are found in nature. However our discussion will be limited to those carbohydrates found in greater amounts in our diet and those important to our body. Monosaccharides are the simple form of carbohydrates including glucose, fructose & galactose. Its other examples include mannose, xylose and ribose which are not familiar to us. There are more than hundred different monosaccharides available in nature which serve as a building blocks for larger carbohydrates, such as disaccharides, starches, oligosaccharides, and fibers (most).
What are Monosaccharides and what foods have them?
Monosaccharides are as small as carbohydrates get. In another terms, monosaccharides can’t be segregated into smaller carbohydrates. Other carbohydrates are formed of monosaccharides connected together. For instance, disaccharides are composed of two monosaccharides linked together.
Glucose and fructose can be found in foods either independently or as part of larger carbohydrates. Fructose is what makes honey and many fruits sweet and is used commercially as a sweetener either as fructose or high-fructose corn syrup. On the other hand, while some galactose is found in certain foods, it is mostly found as part of larger carbohydrates.
What are Disaccharides?
Maltose or malt sugar may be part of diet naturally in seeds and alcoholic beverages. Sucrose is extracted from the sugar cane plant and the beet, and the sucrose-rich product is called “sugar.” Lactose is the primary carbohydrate found in milk and dairy products. Nutrition scientists often refer to disaccharides and monosaccharides as “simple sugars” due to its relatively small carbohydrate size and their sweet taste.
What are Oligosaccharides and Starches?
Monosaccharides not only serve as building blocks for disaccharides but also for some larger forms of carbohydrates as well. Starch is the most well known larger carbohydrate. Starch is available in various degrees in plants or its products (such as legumes, fruits, vegetables,and grains). It consists of large, straight and branching chains of monosaccharide glucose. Some shorter branching chains are used by food manufacturers for foods production. The short or branching chains which practiced by manufacturers of food termed as maltodextrins or is derived from incomplete digestion of corn starch.
In the human diet, we can also find limited carbohydrates, termed oligosaccharides, composed from just a few monosaccharides (three to ten) linked together. Since these are found in relatively small amounts, they are not as essential to discuss. However, a few of these carbohydrates (for example, raffinose and stachyose) will require mention later on, not only for its nutritional value but also for effects in digestive tract.
Plants create starch for storing energy such as mammals storing fat. On other hand, plant fibers are not necessarily stored energy but serve more structural roles for plants. Similar to starch, fiber consists of straight or branching chains of Monosaccharides but building block of Monosaccharides do not limit to glucose only.
How much Carbohydrate do we eat?
We are eating more calories today than in the past several decades and carbohydrates are making a greater contribution to those calories. In countries such as the United States and Canada, about half of the energy adults eat comes by way of carbohydrates. Half of this carbohydrate is found in form of starch and other in form of simple sugars. Sucrose makes about half of simple sugars we consume. In Asia and Africa, intake of sucrose has lower contribution with high intake of grains such as wheat, rice, vegetables and fruits.
What are the recommendations for Carbohydrate consumption?
The RDA for carbohydrates is 130 grams per day for adults. This is based on the amount needed to supply adequate glucose for the brain and nervous system, without having to rely on ketone bodies from incomplete fat breakdown as a calorie source. Somewhat exceeding this amount is fine; the Food and Nutrition Board recommends that carbohydrate intake should range from 45% to 65% of total calorie intake. The Nutrition Facts panel on food labels uses 60% of calorie intake as the standard for recommended carbohydrate intake. This would be 300 grams of carbohydrate when consuming a 2000-calorie diet.
North American adults consume about 180 to 330 grams of carbohydrates per day, which supply about 50% of calorie intake. Worldwide, however, carbohydrates account for about 70% of all calories consumed and, in some countries, up to 80% of the calories consumed. One recommendation on which almost all experts agree, including the 2010 Dietary Guidelines, is that one’s carbohydrate intake should be based primarily on fruits, vegetables, whole-grain breads and cereals, and beans, rather than on refined grains, potatoes, and sugars.
Health Benefits of Carbohydrates
Some health benefits that could be experienced with an intake of Carbohydrate rich foods:
- Mood regulation
Mood can go from perfect to nasty in few hours. Especially this could be noticed when one is hungry and the reason behind this is carbohydrates. Additionally, low level of blood sugar makes one feel lethargic and irritated so low intake of carbohydrate is related with depressive illness and other mental problems. Carbohydrates have stimulating effect on serotonin production which is one main regulator of good mood in brain. Low levels of serotonin levels in brain are seen in depression patients and less than ideal mental states.
- Maintain waistline
Carbohydrates are available in various foods. Fiber is a carbohydrate which is slow digesting and offers enormous health benefits. People with diet rich in fiber maintain ideal body weight and even assist to lose weight. Fiber promotes satiety which makes to eat less and be satisfied for longer time period. Fiber absorbs water in stomach or intestines resulting bulk. This does not refer to processed whole grains as it loses much nutritive benefits.
- Healthy heart
Carbohydrates could improve or worsen the heart health which relied on what carbohydrate is consumed. If can of soda is a preferred carbohydrate source then it does not offer any benefits. Instead if one opts for steel cut oats, then it improves blood lipid values by lowering bad cholesterol and triglyceride aspects of lipid profile. These lipids if highly circulated promote chances of atherosclerosis causing damage to heart.
- Brain function
This is the major benefit which carbohydrate offers. People with ketogenic or low carb diet have inhibition in deep mental co-ordination and performance. They also experience brain fogs or period where they become unable to process thoughts and recall memories. Furthermore, carbohydrates are demanded for brain functioning.
- Lower the chances of cancer
Tomatoes, onions, bell peppers and various vegetables contain carbohydrates which one should aim for. It is packed with antioxidants and assists to combat abnormal cellular growth. Foods with high fiber promote removal of waste and cholesterol. Foods with wholesome carbohydrates combat early stage of cancer as cell needs glucose as its basic fuel source. Intake foods which convert slowly to glucose can lower nutrient supply and apoptosis or cell death may occur.
- Promote sleep
Foods with slow digesting carbohydrates contribute to sound sleep. Furthermore, neurotransmitter serotonin assures to provide restful sleep. People having diet with low content of carbohydrates experience harder time synthesizing serotonin with insomnia. Milk is regarded to be the best carbohydrate for sound sleep.
- Proper digestion
Most of the natural carbohydrate rich foods have high content of fiber which is essential for intestinal health. Fiber helps in moving food and waste material along unobstructed throughout the body. These foods absorb water, prevent constipation and minimize the risk of colon cancer by shortening time waste spends in contact with healthy cells.
- Enhance metabolism
Metabolic crash occurs when calories and carbohydrates are lowered. It is a primary response by body to survive as it is hardwired in our DNA those periods of low feeding associate to starvation. As a response, body slows non-essential metabolic activities and does adequate so that we live. We know that we are not starving; body just does its job. Carbohydrates are required to support normal thyroid hormone or overall metabolic activities by allowing burning more calories throughout the day.
- Improves performance of athletes
Carbohydrates are crucial for those who get involved in sports or athletics. The body requires adequate supply of energy to perform effectively. Though fat offers an alternative source of energy, it could not beat what carbohydrate provides.
- Packed with energy
Carbohydrates are the primary source of energy. It is converted in glucose required for ATP production-energy currency used in body. Low carbohydrate diet is required for facilitating glucose production and supplementing it with other alternative source of energy. When feeling lethargic, meal with sufficient carbohydrates might be helpful.
- Promote muscle mass
Bodybuilders or anyone who is interested in growing muscle mass should consume quality protein to promote glycogen stores. It makes muscles to look fuller and facilitates its increase in strength which goes with larger muscles.
- Promote satiety
On the basis of serotonin actions and gastric enzymes, carbohydrate foods makes one feel satisfied after consumption. For best results, combine it with other macronutrients.