L5_CHO 2.pdf

# Basics of Human Nutrition ## NUTR 202 **Department of Clinical Nutrition** **Imam Abdulrahman Bin Faisal University** ## **Carbohydrates** **Ms. Asia S. Jamal, RDN** **Collaborator Teacher, Clinical Nutrition Department** **Imam Abdulrahman Bin Faisal University, Dammam** **Department of...

# Basics of Human Nutrition ## NUTR 202 **Department of Clinical Nutrition** **Imam Abdulrahman Bin Faisal University** ## **Carbohydrates** **Ms. Asia S. Jamal, RDN** **Collaborator Teacher, Clinical Nutrition Department** **Imam Abdulrahman Bin Faisal University, Dammam** **Department of Clinical Nutrition** ## **Learning Objectives** - Define carbohydrates and identify classes of CHO. - Comprehend the importance and health benefits of CHO's. - Determine the difference between simple and complex CHO. - Describe CHO digestion, absorption and explain how the body maintain normal blood glucose level. - Define glycaemic index and give examples on low and high glycaemic index CHO. - Identify valuable sources of CHO. - Identify dietary recommendations for CHO. ## **Carbohydrates** - Carbohydrates are nutrients made of **carbon, hydrogen, and oxygen**. (C:H2:O) - There are two types of **carbohydrate** which provide the body with energy - **sugars and starches**. - **CHO** are obtained almost exclusively from plants. - They are the preferred energy source. - **Dietary fiber** is also a form of carbohydrate and is **important** for digestive health, however this is not digested to provide the body with energy. - Milk is the only animal derived food that contain a significant amount of CHO. - 1g of carbohydrate provides 4 kcal (17kJ). ## **Importance of carbohydrates** - It is the major source of energy in most of the tissues, Allowing protein to be used for growth and maintenance (**protein – sparing**). - The only source of energy for RBCs and is also needed for proper brain function. - A small amount is needed to prevent ketosis. - Fiber has several beneficial effects on health. - Associated with Pathological Conditions (Diabetes Mellitus, Lactose Intolerance). ## **Simple Vs Complex carbohydrates** | Simple Carbohydrates | Complex Carbohydrates | | :------------------------------------------------------- | :---------------------------------------------------------------------------- | | Are sugars that enter the bloodstream rapidly and provide quick energy. | Made up of sugars that are linked together chemically to form long chains. | | Provide calories but few vitamins and minerals. | **Starch** - food substance that is made and stored in most plants.<br/>Provide long-lasting energy. | ### **Simple Carbohydrates** - Fruits - Honey - Milk - Sugars added to cookies, candies, soft drinks ### **Complex Carbohydrates** - Grains (bread & pasta) - Vegetables (potatoes & beans) - Rice - Cereals - Wheat - Tortillas - Whole-wheat rolls ## **SIMPLE CARBOHYDRATES VERSUS COMPLEX CARBOHYDRATES** | Simple Carbohydrates | Complex Carbohydrates | | :------------------------------------------- | :---------------------------------------------------------------------------- | | Refer to the carbohydrates that contain single monosaccharide units. | Refer to a polysaccharide that is made up of hundreds or thousands of monosaccharide units. | | Easy to digest. | Take time to digest. | | Types include monosaccharides and disaccharides. | Types include polysaccharides such as starch. | | Contain sweetness. | Less sweet than simple carbohydrates. | | Quickly raise blood glucose levels. | Slowly raise blood glucose levels. | ## **COMPLEX CARBS VS SIMPLE CARBS** This image shows various foods commonly categorized as Complex or Simple Carbohydrates. ## **Simple Vs Complex carbohydrate's chemical structure** This is a diagram showing the molecular structure of glucose, sucrose, and amylose starch. Simple carbohydrates are shown as being composed of one or two molecules, while complex carbohydrates are shown as being composed of many molecules. ## **Classification of carbohydrates** - **CHO** are classified according to the **number of sugar units**. 1. **Monosaccharide** ? glucose and fructose 2. **Disaccharides** ? sucrose, maltose and lactose 3. **Polysaccharides** ? starch and glycogen 4. **Non starch polysaccharides (Fiber):** components of dietary plants that cannot be broken down by human digestive enzymes ? **cellulose and pectin**. ## **Classification of carbohydrates** ### **Monosaccharide** - All carbohydrates are composed of monosaccharides, alone or combined. - All CHO except fibers can be converted to glucose in the body. - Green plants make glucose through the process "photosynthesis” (CO2, H2O, chlorophyll, sun light). - Monosaccharides is a basic component of disaccharides and polysaccharides. - Can have three to seven molecules, the most important are six-carbon hexoses; **glucose, fructose, and galactose**. ## **Monosaccharide: Glucose (Dextrose)** - The form that circulates in the blood. - Glucose is the body fuel oxidized by cells to provide energy. - Obtained from digestion of other sugars (starch). - Moderately sweet sugar, found naturally in few foods "corn syrup" sometimes known as grape sugar. - Fasting plasma glucose levels normally range from **70 – 100 mg/dl**. - After a CHO meal blood glucose rise, then return to normal within two hours. - **Hyperglycaemia** "elevated blood glucose levels" - **Hypoglycaemia** "low blood glucose levels **NOTE:** Prefix Hyper- - Excessive or high Prefix Hypo- - Low ## **Monosaccharide: Fructose** - The **sweetest** of monosaccharides, 40% more than sucrose and 75% more than **glucose**. - Found in fruits and honey and as part of other sugars such as table sugar. - **Fructose** is absorbed less efficiently than glucose. - **High fructose corn syrup** is used in many soft drinks, fruit drinks, baked products and desserts. It is **intensely sweet and, inexpensive**. - High fructose syrups have been associated with increase synthesis of fatty acids and development of hyperlipidaemia and obesity. - The **major advantages** of fructose in food processing is that it does not crystalize at low PH and has good freezing properties. ## **Monosaccharide: Galactose** - Galactose is not found free in food. - Galactose is released through the **digestion of lactose**, then converted to glucose in the liver. - In lactation, glucose is reconverted to galactose for use in milk production. - Infants born with inability to digest galactose have **Galactosemia**. ## **Classification of carbohydrates** ### **Disaccharides** - They are made up of **two monosaccharides** joined by glycosidic linkage between the keton carbon and hydroxyl on the other sugar. - The **three important disaccharides** are; - **Sucrose = glucose + fructose** - **Lactose = glucose + galactose** - **Maltose = glucose + glucose** ## **Digestible Disaccharides in Food** A diagram showing the molecular structure for Sucrose, Lactose, and Maltose. ## **Classification of carbohydrates** ### **Oligosaccharides** - Made up of **3 - 10 monosaccharide units**. - Water soluble and often sweet. - Present in plants (Leek, garlic, onions, beans). - Prebiotics Enzymes in the brush border of the intestine break bonds in disaccharides. Larger molecules with different linkage are non-digestible and are called **dietary fibers**. ## **Classification of carbohydrates** ### **Polysaccharides** - Complex CHO are called polysaccharides **(WHY?)**. - Contains over 10 monosaccharide unit. - The most important polysaccharide is **starch**. - Plants store polysaccharides as starch, they make **two types of starch:** - **Amylose** ? smaller linear less than 1% branched. - **Amylopectin** ? highly branched, more abundant in food. - Other polysaccharides are dextrins (digestion process) and glycogens (stored liver and muscle cells). ## **FIGURE 4-6 Glycogen and Starch Compared** This image shows a diagram comparing the molecular structure of glycogen and starch. Glycogen is a highly branched molecule, while starch is a less branched molecule. ## **Dietary Fiber** - Most fibers are **polysaccharides**. - They have different bonds between the glucose units that **cannot** be digested. - Some are partially broken down by intestinal bacteria. - Those that have been shown to have beneficial effects in humans are termed **functional fiber**. - **Recommended intake (Al) for total fiber:** - 38 g/d for men ages 14 - 50 years - 25 g/d for **women** ages 19 – 50 years - When isolated from plant fibers can be used as: - Thickening jelly (pectin) - Keep dressings from separating (guar gum*) - Provide bulk (wheat) ## **Insoluble Vs Soluble Fiber** | Insoluble | Soluble | | :------------------------------------------------------------------------------------------------------------- | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Binds with water to help produce bowel movements (prevent constipation). | Eating foods with soluble fiber reduces your blood cholesterol level and your risk of developing heart disease. | | Associated with reduced risk of colon cancer. | | | **Good sources:** wheat products, leafy vegetables, and fruits. | **Good sources:** wheat, bran, barley, rye, oats, whole grain pasta, breads, cereal. | | | | ## **Characteristics of Soluble and Insoluble Fiber** | Soluble Fiber | Insoluble Fiber | | :----------------------------------------------------------------------------------------------------------------- | :-------------------------------------------------------------------------------------------------------------------------------------- | | Slows digestion and assists the body in absorbing vital nutrients from foods. | Does not dissolve in water, but increases the movement of waste through the intestinal tract. | | Dissolves in the water found in the large intestine and forms a gel. | Has been associated with decreased cardiovascular risk and slower progression of cardiovascular disease, particularly in high-risk individuals. | | Can aid in lowering total cholesterol levels and low-density lipoprotein cholesterol levels, as well as improve glycemic index in patients with diabetes. | Prevents constipation and may also aid in removing toxic waste in the colon. | | Examples of foods high in soluble fiber include oat and rice bran, barley, peas, beans, apple pulp, citrus fruits, strawberries, and psyllium husk. | Examples of foods high in insoluble fiber include wheat bran, whole grains, rice, flax seed, nuts, popcorn, cabbage, beets, carrots, Brussels sprouts, turnips, cauliflower, and apple skin as well as other fruits and vegetables with skins. | ## **TABLE 4-1 The Carbohydrate Family** | Monosaccharides | Disaccharides | Polysaccharides | | :---------------- | :--------------------------------------------- | :----------------------------------------- | | Glucose | Maltose (glucose + glucose) | Glycogen^a | | Fructose | Sucrose (glucose + fructose) | Starches (amylose and amylopectin) | | Galactose | Lactose (glucose + galactose) | Fibers (soluble and insoluble) | | | | | ^Glycogen is a polysaccharide, but not a common dietary source of carbohydrate. ## **Summery** This is a table showing the various categories of carbohydrates and their components. ## **Coffee Break..** This is an image of a coffee mug. ## **Sources of carbohydrates** - Starch can be found in food such as bread, potatoes, rice, pasta, breakfast cereals and other starchy foods. - Most dietary carbohydrates **come from plant origins** and include sugars, oligosaccharides, starch and dietary fiber. ## **Sources of carbohydrates** ### **Sugars can be divided into:** - **Intrinsic sugars** - These are found within the cellular structure of foods, e.g. sugars in whole fruits and vegetables. - They include fructose, glucose and sucrose, which do not begin to break down in the mouth and are therefore generally less cariogenic than extrinsic sugars. - **Extrinsic sugars** - These are not bound to a cellular structure, e.g. the lactose in dairy products. Other examples include honey, confectionery, fruit juices and table sugar, and are known as **non-milk extrinsic sugars (NMES)**. ## **Sources of carbohydrates** **Non-milk extrinsic sugars (NMES) include:** - Sucrose. - Fructose. - Glucose. - Dextrose. - Maltose. ## **Sources of carbohydrates** However, it is not quite as simple as that. Fructose in the skin of an apple (which begins absorption in the small intestine) is less cariogenic than fructose in apple juice which is classified as an extrinsic sugar. Therefore, although fruit juice can be labelled as having no added sugar it is rendered cariogenic, as fructose is removed from the plant cell wall and is broken down by salivary amylase in the mouth. ## **Free sugars** - **Free sugars:** all monosaccharides and disaccharides added to foods by the manufacturer, cook or consumer, plus sugars naturally present in honey, syrups and unsweetened fruit juices. - Under this definition lactose (the sugar in milk) when naturally present in milk and milk products and the sugars contained within the cellular structure of foods (particularly fruits and vegetables) are excluded. ## **TOTAL SUGARS** This is a diagram showing the categories of sugars: Total sugars, Intrinsic sugars, Extrinsic sugars, Milk sugars, and Non-milk extrinsic sugars (NMES). ## **Digestion of CHO** - In the mouth **salivary amylase** from the parotid gland breaks down starch. - **Peristalsis** in the stomach mix food with gastric secretion, no enzyme in the stomach to breakdown CHO. - HCL* stops the action of salivary amylase - **Chyme** passes to the small intestine. - **In the small intestine** - **Pancreatic amylase** further breaks down starch. - Cells in the brush boarder of the small intestine secrets sucrase, lactase and maltase they act on their respective **CHO**, **which class?** To release the monosaccharides for absorption. - A diet rich in whole food slows pace of glucose absorption. *HCL= Hydrogen chloride. ## **Absorption of CHO** - Glucose is absorbed by **active transport** or pumping system with **sodium** as carrier. - Of the total CHO absorbed, - 80% in the form of **glucose**. - 20% in the form of **galactose and fructose**. - The monosaccharides enter the **portal blood** and are transported to the **liver**. - Here fructose and galactose are converted to **glucose.** - Glucose exits the liver, enters the circulation and is available for **insulin uptake**. - Glucose can be used immediately for energy or converted to glycogen for storage in muscles, liver, or adipose tissue. ## **Digestion & Absorption of CHO** This is an image of a box of Triscuit crackers with nutritional information highlighted. ## **Major regulators for blood glucose** - Amount of digested CHO - Absorption and degree of liver uptake - Insulin secretion - Sensitivity of peripheral tissue to insulin action. ## **Carbohydrates and blood glucose** - The pattern of the rise in blood glucose level differs after the intake of different types of carbohydrate containing foods. - The term **glycemic index (GI)** was introduced to compare the effect of different types of food on blood glucose. ## **Glycemic index (GI)** - **Glycemic index (GI):** is the area under the blood glucose curve seen after ingestion of meal with carbohydrate-rich food, compared with the area under the blood glucose curve observed after a meal consisting of the same amount of carbohydrate in the form of glucose or white bread. - Food with low GI are useful in dietary management of diabetes, and give a feeling of satiety for a longer period (help weight control). - In general, whole grains, legumes, fruits, vegetables have low GI's (lower than the same amount of white rice). - It was found that the processing of grains increase their GI. ## **Glycemic index (GI)** | Classification | Gl range | Examples | | :-------------- | :--------- | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | High GI | 70 and above | Baked Potatoes, White Bread, Rice Pasta, Corn Flakes, Fruit Roll-Ups, Special K(Kellogg's), Rice Cakes, Dates, Soda Crackers, Doughnut | | Medium GI | 56-69 | Macaroni & Cheese, Table Sugar, Brown Rice, Sweet Potato, Banana, Raisins, Grapefruit Juice Unsweetened | | Low GI | 55 or less | Most Fruits and Vegetables, Beans, Whole Grains, Meat, Eggs, Milk, Nuts, Fructose and Products Low in Carbohydrates. | ## **Glycemic index (GI)** This image shows a diagram comparing the blood glucose levels after eating high GI vs low GI foods. ## **Glycemic Index** This table provides a list of various foods and their glycemic index (GI) values. The table is categorized into grains/starches, vegetables, fruits, dairy, and proteins. ## **Factors influencing Gl** - Not only the type and amount of CHO that affects the GI, but it was also found that it is affected by many other factors including: - Nature of starch - The presence of fat, protein, fiber - The way of food preparation - Sugar content - Acid content - **Food processing.** ## **Recommendations of carbohydrates** - It is recommended that meals are based on **starchy foods**. - The Carbohydrates of Acceptable Macronutrient Distribution Ranges (AMDR) should provide **45%- 65% of dietary energy**. - On average a person should take minimum of **130g/day**. - The recommendation to **limit added sugars** to no more than 10 percent of calories is a target that applies to all calorie levels to help individuals move toward healthy eating patterns within calorie limits. ## **Guidelines for choosing CHO's** - Recent nutrition goals aims for fewer processed food and more whole food - More plant-based diet - During processing **nutrients are lost** - Choose whole grain pasta, rice, cereal and bread. **Why?** - Eat plenty of fruits and vegetables with skin on, raw or cooked for minimum time - Limit consumption of refined products **such as???** ## **End of class** - Please open **Mentimeter** ## **For inquiries contact reach me on:** - [email protected] ## **Thank you** - Any Questions? **Department of Clinical Nutrition** **Imam Abdulrahman Bin Faisal University**