Chapter 5- Carb, Sugars, Starches, and Fiber

maltose

(malt sugar) has two glucose molecules bound together. Common for starch digestion.

sucrose

(table sugar) consists of a molecule of glucose and molecule of fructose. Although it occurs naturally, much of sucrose is refined from sugarcane and sugar beets. The table below compares nutritional values of honey with certain forms of sucrose

lactose

- (milk sugar) forms when a galactose molecule bonds to a glucose molecule

What makes a carb complex?

- A carb is complex if it contains many units of sugar linked together. Ex. Polysaccharide (multiple sugar units)

What makes a carb simple?

- A carb is simple if it contains only one or two units of sugar. Ex. Monosaccharides (one sugar unit) or disaccharides (two sugar units)

disaccharides

- A simple sugar that has two monosaccharides linked (bonded) together. - Result from condensation reactions - Maltose, sucrose, and lactose are main ones

hypoglycemia

a condition that occurs when the blood glucose level is too low to provide enough energy for cells. This can be diagnosed when blood glucose is less than 70 mg/ dl. Rarely effects healthy people

ketosis

a metabolically adaptive state of the body in which fat is being used as primary energy source. This happens when ketone body levels rise in the blood to detectable levels. This state allows humans to consume low levels of glucose and maintain body function

hemoglobin

a protein in red blood cells that carries oxygen. Person with diabetes have blood glucose levels much higher than normal, and as a result, the individual's hemoglobin will have a higher percentage of HbA1c

high fructose corn syrup (HFCS)

additive that contains approximately the same amount of fructose as found in sucrose. No conclusive evidence that consuming HFCS is more detrimental to health than consuming regular table sugar. Associated with excess caloric intake which can contribute to increased risk for diabetes and heart disease. Used a lot because fructose is sweeter, and corn is ready available in the US

Some examples of alternative sweeteners

aspartame, saccharin, sucralose, advantame, highly purified stevia leaf, neotame

what happens when glucose levels are too low so body cannot use glucose metabolism?

body switches to fat metabolsim

lactase

breaks down the lactose from the milk in glucose and galactose molecules

fiber and colorectal cancer

cancer in last portion of large intestine. A person's diet, including dietary fiber and fruit and vegetable intake, is thought to contribute to the risk for development of colorectal cancer. Specifically, consuming a well-balanced diet rich in dietary fiber appears to reduce one's risk for colorectal cancer

complex carbohydrates

carbohydrates comprised of three or more monosaccharides bonded together

insoluble fiber

cellulose and lignin, generally do not dissolve in water. Other examples are whole grains (brown rice). Refined grains are low in fiber because they lack the fiber-rich bran seed. May ease bowel movements by increasing fecal bulk speeds

carbohydrates

class of nutrients that is a major source of energy for the body. Without a steady supply of energy, cells cannot function and they die. - Carbs also serve as "glue" that hold cells together in tissues - Cell membranes have carbohydrates that signal the cell's identity to other cells.

Polysaccarides

complex carbs comprised of more than 10 monosaccharides bonded together> most common polysaccharides are digestible and nondigestible forms

metabolic syndrome

condition that increases risk of type 2 diabetes and CVD. One in three Americans have this. Has 3 or more of signs listed in table below. Excess fat and insulin resistance are primary risk factors for condition. Also high fasting lood glucose, low HDL cholesterol

nutritive sweeteners and how many kcals are supplied by them

contribute energy to food—that's why sugars are nutritive sweeteners. Each gram of mono- or disaccharide supplies 4 kcal.

insulin

decreases blood glucose levels by sending signal to liver to take glucose out of blood and put it into storage

increasing fiber intake

eating excessive amount of fiber results in intestinal blockage, especially if fluid intake is low. Intestinal bacteria produce gases when they metabolize fiber; therefore, dietitians recommend that people gradually increase their fiber intake to reduce the likelihood of having uncomfortable and embarrassing flatulence. Practices that result in swallowing air, such as eating quickly; drinking carbonated beverages, especially with a straw; and chewing gum, also contribute to flatulence.

pancreatic amylase

enzyme secreted by pancreas that breaks down starch into maltose molecules

Hemoglobin A1c test

glycated hemoglobin; blood test used to measure a person's average blood glucose over several months. A1c is a component of hemoglobin that attracts some glucose that is in the blood

high-intensity sweeteners

group of compounds that elicit an intensely sweet taste when compared to the same amount of sugar. Also known as nonnutritive sweeteners. Very small amounts of nonnutritive sweeteners are needed to sweeten a food, and they supply little or no energy per serving. Nonnutritive sweeteners can help people control their energy intake.

what can be permanently damaged by uncontrolled diabetes

heart, kidneys, eyes

glucagon

increases blood glucose levels by telling liver to take glucose out of storage and put it into the bloodstream

what can type I diabetics take to release insulin? What about type II?

injections of exogenous insulin type II uses Avandia, which increases cell sensitivity to normal insulin

carbohydrate absorption: Where do monosaccharides go after the small intestine?

- Absorption of monosaccharides occurs almost exclusively in the small intestine. Intestinal cells absorb glucose and galactose by active transport; fructose is absorbed by facilitated diffusion. The monosaccharides enter the capillary network of the villus. - The hepatic portal vein transports the monosaccharides to the liver. The liver can use the simple sugars to make glycogen or fat, but if the body needs energy, the organ releases glucose into the bloodstream. Both galactose and fructose are converted into glucose in the liver

type I diabetes

- An autoimmune disease that occurs when certain immune system cells malfunction and do not recognize the body's own beta cells - As result, the immune system cells attack and destroy the beta cells, and the affected person must obtain an exogenous ("outside the body") source of insulin regularly. - Genetic susceptibility and environmental factors, particularly exposure to certain viral intestinal infections, are associated with the development of type 1 diabetes

what happens when blood glucose rises in: 1. nondiabetics 2. type I diabetics 3. type II diabetics

- As blood glucose levels rise after containing a meal, nondiabetics release insulin. Insulin signals cells in muscle and liver to take glucose from the blood, returning blood glucose to normal - In untreated type 1 diabetes, no insulin is released and blood sugar levels remain high. Type 1 is treated with injections of exogenous insulin - In type 2 diabetes, insulin is released in response to blood glucose increase, but cells do not receive the signal. One treatment is Avandia, which is an oral thiazolidinedione that increases cell sensitivity to normal insulin

why do carbs decrease body's ability to expend energy and burn calories?

- Carbs also decrease body's ability to expend energy and burn calories. This is because insulin is secreted more readily when carbs are consumed, not when fat or protein is consumed - Insulin acts as storage hormone and leads to body fat accumulation

oligosaccarides

- Complex carbs comprised of three to 10 monosaccharides - Most common in foods are raffinose and stachyose—foods with these include onions Brussel sprouts, broccoli, legumes, whole grains - Other oligosaccharides include inulin and oligofructose. Chicory root, onions, garlic, leeks, legumes, asparagus, cow's milk, and wheat are among the richest natural sources of inulin and oligofructose. - In the large intestine, bacteria can use oligosaccharides as a source of energy, producing waste products (various gases) as a result

Why is sucralose better for baking than aspartame

- During normal cooking and storage conditions, sucralose resists destruction by heat, a feature that makes it better for sweetening baked products than aspartame, which breaks down when heated.

fiber effects on health

- Eating high-fiber foods many reduce risk of obesity, type 2 diabetes, intestinal tract disorders, and cardio diseases. - The insoluble fiber in food contributes to the formation of a large, soft fecal mass that applies pressure to the inner muscular walls of the large intestine. This pressure stimulates the muscles to push the residue through the colon and into the rectum. - People who often eat foods that contain insoluble fiber have easier and more regular bowel movements, and they are less likely to strain while having bowel movements than people whose diets lack fiber.

when do blood glucose levels drop vs. fall

- If a person has not eaten for a while, blood glucose levels begin to fall, the person starts to feel hungry, and the stomach likely growls. - In this case, the individual may grab an apple or a cheese sandwich to eat, and as the carbohydrates in these foods are digested, the glucose from these foods is absorbed into the bloodstream and transported to the liver - When blood glucose rises, pancreas secretes insulin, which enables glucose to enter cells, reducing blood glucose to normal levels

what happens to blood glucose if someone ignores hunger signals?

- If someone ignores hunger signals, alpha cells secrete glucagon and promotes breakdown of glycogen, and releases glucose into bloodstream, keeping blood glucose from dropping too low.

added sugar consumption- how has it changed? How many kcal are supplied by a gram of sugar?

- In 2017, the average American consumed about 22 teaspoons of added sugars per day, which is about 18% of the energy in a diet that supplies 2000 kcal/day - Each gram of sugar supplies 4 kcal - According to guidelines, we should limit our added sugar intake to less than 10% total calories - Natural sugars may supply same amount of calories as sugary sodas, except they are higher in micronutrients and antioxidant phytochemicals

epinephrine and when is it released?

- In response to rapidly declining blood glucose levels, the body responds by secreting epinephrine (adrenaline), which is produced by adrenal glands - Epinephrine increases supply of glucose and fatty acids in blood steam, but it can also make someone with hypoglycemia feel restless, shaky, and sweaty.

how are glucose, galactose, and fructose absorbed?

- Intestinal cells absorb glucose and galactose by active transport; fructose is absorbed by facilitated diffusion

type II diabetes

- Most common form of diabetes - Beta cells usually produce insulin, but the hormone's target cells are insulin-resistant, which means they do not respond properly to the hormone and do not allow glucose to enter them. - As a result, the level of glucose in the bloodstream becomes abnormally elevated, and the signs and symptoms of diabetes occur. - Individuals who are physically inactive (sedentary), overweight, and genetically related to a close family member with type 2 diabetes are more likely to develop the disease than persons who do not have these characteristics. - Americans who have Hispanic, Native American, Asian, African, or Pacific Islander ancestry are more likely to develop type 2 diabetes than Americans who are not members of these racial or ethnic groups

How many people have diabetes? Do more have type I or type II?

- Over 34 million Americans have diabetes (10.5% of US population) - 5-10% have type 1 (juvenile diabetes). Majority have type 2, which used to be called adult-onset diabetes. More children get type 1 compared to type 2

beta cells vs. alpha cells

- Pancreas contains beta cells, which are clusters of special cells that produce insulin, and alpha cells, that produce glucagon

what happens when blood glucose level gets too high? What happens when it gets too low? AKA. how is balance maintained?

- Pancreas notices when glucose concentration gets too high, and it releases insulin hormone. - Insulin makes blood glucose levels go down by sending signal to liver and muscles to take in glucose out of blood and put it into storage - Liver and muscles have limited capacity, and when they are full, liver turns glucose into fat, which gets shipped out into the body - Fat cannot be turned back into glucose - After a few hours after you have ate, levels of blood glucose decline. Pancreas notices this and releases glucagon. - Glucagon makes blood glucose go up by telling liver to take glucose out of storage and put it into the bloodstream

pancreas transplants for diabetes

- Risks outweigh benefits - Most surgeries result in patient's body rejecting the donor pancreas not long after the procedure, up to 10-20% die a year after - People must take immunosuppressive drugs to reduce chances of rejection - Many experts believe that pancreatic islet transplantation is a better option for those with type 1 diabetes. In this procedure, healthy islet cells are taken from a donor pancreas and transferred into a person with type 1 diabetes. The healthy islet cells begin to produce and secrete insulin, thus reducing the need for daily injections of insulin

mucins

- Saliva, mucus, and the fluid that lubricates skeletal joints contain mucins, a class of carbohydrates that are chemically associated with proteins.

Why do some people have to avoid the alternative sweetener aspartame?

- Some people must avoid aspartame and certain protein- rich foods because they have phenylketonuria (PKU) a rare inherited disorder that results in abnormal phenylalanine metabolism. Aspartame has been blamed for many diseases, yet it has not been proved

hydrolysis of sucrose

- Sucrase catalyze the hydrolysis of the disaccharide sucrose (table sugar), into its component monosaccharides glucose (blood sugar) or fructose (fruit sugar) - When the sucrose molecule binds to active site of sucrase, enzyme confirmation is changed, so that the oxygen bridge between the two monosaccharides is exposed to water molecule in solvent - This exposure permits the water molecule to actually break the bond—the oxygen bridge—and attach the components of water and OH to one of the monosaccharides and an H to the oxygen which is still attached to second monosaccharide - The effectively cleaves between the two monosaccharides and converts the disaccharide into two separate sugars - Once this happens, the enzyme is put back to normal shape and the two monosaccharides float away.

fiber

- The fiber in oats is not digested by the human small intestine, so the fiber eventually enters the large intestine. Then beneficial intestinal bacteria that reside in the large intestine can break down and metabolize (ferment) the soluble fiber for energy. In contrast, insoluble or nonfermentable fiber does not break down completely and, as a result, contributes to softer and easier-to-eliminate feces. - Body can use by-products of bacterial metabolism of fiber for energy - A gram of fiber is estimated to add fewer than 3 kcal to human diets.

carbohydrate digestion

- The small intestine is the main site for carb digestion and absorption, but minor amounts of starch digestion begins in mouth when salivary amylase converts some of oat starch molecules into maltose - Starch digestion stops as soon as food enters acidic environment of stomach - Fiber in oats slows rate in which chyme empties from stomach, and promotes satiety - disaccharides and complex carbs are broken down into monosaccharide's glucose, fructose, and galactose

tooth decay and consuming carbohydrates

- Tooth decay is clearly associated with consuming carbohydrates, particularly simple sugars that stick to teeth. If a person does not follow good dental hygiene practices, the debris becomes food for bacteria that live on teeth. - As the bacteria metabolize carbohydrate for their energy needs, they produce acid that damages tooth enamel and results in decay.

Lipolysis

- breakdown of triglycerides into glycerol and fatty acids, stimulated by glucagon. Liver uses glycerol to produce glucose, and most cells can metabolize fatty acids for energy - When individual is well fed the body stores the extra glucose as glycogen. When it reaches its maximum capacity, liver can convert excess glucose into fat

what happens overtime do poorly controlled hyperglycemia?

- damages nerves, organs, and blood vessels. In fact, poorly controlled diabetes is a major cause of heart disease; kidney failure; blindness; and poor blood circulation, particularly of the lower limbs, which can require amputation.

diabetes mellitus

- group of serious, chronic conditions characterized by abnormal glucose, fat, and protein metabolism - Physicians Banting and Best conducted lab experiments on dogs to find treatment for diabetes in 1921. They removed pancreas of dog and made an extract from tissue. When extract was injected into diabetic dog, their signs/ symptoms disappeared. They named this extract insulin.

Glycogen

- human body stores limited amounts of glucose in this form. Muscles and the liver are the major sites for glycogen formation and storage. Although muscles contain glycogen, most animal foods not sources of this complex carbohydrate because muscle glycogen breaks down quickly.

lactose intolerance

- inability to digest lactose completely. People with lactose intolerance do not produce enough lactase, the enzyme that breaks lactose into glucose and galactose. - When a lactose-intolerant person consumes lactose, the disaccharide is not completely digested and absorbed by the time it enters the large intestine. - Bacteria that reside in the large intestine break down lactose and produce irritating gases and acids as metabolic by-products.

therapeutic lifestyle changes

- people may reduce their risk of type 2 diabetes by avoiding excess body fat, exercising daily, and improving their diets. Dietitians and other medical practitioners refer to these actions as therapeutic lifestyle changes (TLC). - Improving dietary practices may help prevent type 2 diabetes. A diet rich in vegetables, legumes, fruits, poultry, and fish appears to prevent type 2 diabetes, whereas a diet high in refined grains, high-fat dairy, eggs, and fried foods may contribute to the development of type 2 diabetes - High-fiber diets, particularly those containing cereal fiber and whole grains, may protect against diabetes. - Dietary factors seem to have the greatest impact on type 2 diabetes risk in persons who have a genetic predisposition for this form of diabetes, that is, a family history of the disease

starch and how many kcal it supplies?

- storage polysaccharide in plants; composed of amylose and amylopectin. Foods rich in starch include wheat, rice, corn, oats, squash, beans, etc. Plants store glucose in this form. It is a carb made of multiple units of glucose attached in a form the body can digest - Sports drinks and energy bars often include modified starches such as maltodextrin and dextrin. Regardless of its source, each gram of starch supplies 4 kcal, the same as other digestible carbohydrate sources.

glucose

- sugar containing 6 carbons. Fruits and vegetables, potatoes, are good food sources of glucose. Glucose is the most important monosaccharide in the human body because it is a primary fuel for muscle and other cells. Under normal conditions, red blood cells as well as brain and other nervous system cells burn mostly glucose for energy. - When cells metabolize glucose, energy is released

monosaccharides and the three types

- the simplest type of sugar that is the basic chemical unit of carbohydrates - Glucose, fructose galactose - All contain carbon, hydrogen, and oxygen in 1:2:1: ratio - Commonly found in table sugar, fruits, and milk

gestational diabetes

- type of diabetes that can develop during pregnancy usually after the 24th week of pregnancy. As many as 9.2% of pregnant American women develop this form of diabetes. - The fetus of a woman with gestational diabetes receives too much glucose from its hyperglycemic mother. As a result of obtaining the excess glucose, the fetus gains weight rapidly and can be abnormally heavy at birth, weighing 9 pounds or more. - 5-10% of women who get gestational diabetes continue to have it after birth. Women with it are more likely to have miscarriages, still births, and premature deliveries - Treatment for woman who are diagnosed with gestational diabetes generally includes a special, carbohydrate-controlled diet to help manage blood glucose levels and regular physical activity.

what is the RDA for carbs

130 g/ day

what are the AI's for fiber

25 g/day for young men and women, respectively, but the typical American diet supplies only about 16 g of dietary fiber/day

what should your HbA1c level be below (percentage)?

7%

fiber and heart health

Diets rich in fiber, particularly soluble types of fiber, can reduce the risk of cardiovascular disease by improving blood lipid levels, lowering blood pressure, and reducing markers of inflammation. Going above recommended limit has no health benefits for fiber.

what is the average fasting blood glucose level

In a healthy person, the body maintains fasting blood glucose levels between 70 and 99 milligrams per deciliter of blood (mg/dl).

physical activity effect on diabetes

Physical activity increases glucose uptake by muscles, reducing blood glucose levels and improving the body's insulin response. Regular physical activity can also help overweight people with type 2 diabetes lose weight. By losing even a small amount of excess body fat, people with type 2 diabetes can often reduce their insulin resistance.

reactive hypoglycemia/ postprandial

low blood glucose that occurs within 4 hours of eating. Typically, the individual consumes too many highly refined carbohydrates, and the pancreas responds by releasing too much insulin. However, these individuals generally have normal fasting blood glucose levels. People with reactive hypoglycemia may feel better if they avoid eating large amounts of sugary foods and eat smaller, more frequent meals that contain a mixture of macronutrients.

diet for controlling diabetes

moderate intake of whole grains, vegetables, fruits, legumes, poultry, fish, and low-fat dairy foods. Additionally, the patient's simple sugar and starch consumption should be limited. Choose Your Foods took, and carb counting are two options—most should have 45 to 60 grams

ketone bodies

molecules formed from the metabolism of fat. They are small molecules that serve as alternative fuels for certain cells in the body when glucose levels are low.

can diabetes be prevented?

no, but you can reduced your risk by practicing TLC

is fiber an essential nutrient

no- body can live without it

raffinose

nondigestible oligosaccharide made of three monosaccharides

dietary fiber

nondigestible plant material; most types are polysaccharides comprised of monosaccharides connected by bonds that human enzymes cannot break. Cellulose, hemicellulose, pectin, gums, and mucilage are carbohydrate forms of fiber; lignin is the only type of fiber that is not a carbohydrate. Although fiber is not digested, it may be metabolized (fermented) by gut microbiota

Stachyose

nondigestive oligosaccharide made of four monosaccharides

resistant starches

not broken down by human GI tract. Some occur naturally in foods (seeds, legumes, unripe bananas, raw potatoes), whereas some are formed by chemical changes that take place during cooking/ processing

ketoacidosis

occurs in individuals with untreated type 1 diabetes, in which insulin levels in body are insufficient. In this case, body produces uncontrolled excessive amount of ketone bodies that can acidify the blood.

soluble fiber

pectin and gums, dissolve or swell in water. Other examples are oatmeal, beans, apple, carrots, oranges, citrus fruits. Can help reduce blood cholesterol levels, but also delay stomach emptying and glucose absorption

fiber and weight control

people at normal weights have higher fiber intakes then those who have obesity. High-fiber foods tend to be "filling" by increasing the volume of food eaten, which results in satiety. Additionally, a serving of a high-fiber food generally has a lower energy content than the same volume of a low-fiber food.

hyperglycemia

primary sign of diabetes and it is abnormally elevated blood glucose levels. Some experience it because their beta cells do not produce insulin and body does not respond properly to hormone. Major symptoms are excessive thirst, poor wound healing, frequent urination, blurred vision

Fructose

same chemical formula as glucose but has slightly different structure. Considered fruit sugar, naturally found in fruit, honey, and some vegetables. The body has little need for fructose, but certain cells in the liver can convert fructose into glucose or into fat.

Galactose

same chemical formula, but different structure from glucose. Not commonly found in foods. It is important component of lactose, the simple carb in milk

two classes of carbs

simple carbs and complex cards, which include starch and most forms of dietary fiber

sucrase

small intestinal enzyme that splits each sucrose molecule from the brown sugar, forming one glucose and one fructose molecule in the process

alternative sweeteners

substances added to food that sweeten the item while providing few to no kcal. Also known as artificial sweeteners. They include sugar alcohols

added sugars and examples

sucrose and HFCS—widely incorporated into foods during processing or preparation. They are in foods to inhibit growth of mold, decrease moisture content, contribute to flavor, and increase tenderness of food

glycemic load

the grams of carbs in a serving of food multiplied by the food's GI; this figure is then divided by 100. Compared to the GI, the GL may be a more realistic way of rating foods because the value indicates the relative rise in blood glucose levels after eating a typical serving of a carbohydrate-containing food.

liver and fiber

the liver uses cholesterol to make bile, just helps digest fats. Gallbladder releases it into small intestine when fats are consumed. Intestinal tract breaks it down and enters it into the liver, which recycles the bile and makes new bile. When soluble fiber is consumed, it interferes with bile recycling process and prevents them from being absorbed. Thus, bile is eliminated as feces, so blood cholesterol levels drop as liver removes cholesterol from blood

glycemic index

tool to measure the body's insulin response to a carbohydrate-containing food. Way of classifying foods by comparing the rise in blood glucose that occurs after eating a sample of food that supplies 50 g of digestible carbs to the rise that occurs after eating a standard source of carbs, such as 50 g of glucose or white bread

sugar alcohols

unlike sugars, these do not promote dental decay. Alternative sweeteners used to replace sucrose in some sugar-free foods, sorbitol, xylitol, and mannitol. Sugar alcohols are not fully absorbed by the intestinal tract, and as a result, they supply an average of 2 kcal/g. Because sugar alcohols are incompletely absorbed, the alternative sweeteners may cause diarrhea when consumed. Ex. Xylitol, sorbitol, mannitol

hyperinsulinemia

when people are carb sensitive and develop this after eating foods that have GIs of 70 or more. Hyperinsulinemia occurs when the pancreas releases an excessive amount of insulin, and as a result, cells remove too much glucose from the bloodstream. Eventually, this condition may overtax the beta cells' ability to produce adequate amounts of insulin. Thus, hyperinsulinemia may contribute to the development of type 2 diabetes