HUN 1201 Chapter Four
Recommended Intakes of Starch and Fiber
DRI for carbs includes 45-65% of energy requirement, RDA for carbs includes 130 grams per day, DRI for fiber includes 14 grams per 1000 calories. 25 grams for women and 38 grams for men that requires no UL.
Exceptions of Small Intestine Digestion
Dietary fibers are not digested in small intestine with lack of enzymes for fiber digestion in the human body. Rather, it goes through the large intestine, where fibers attract water which softens the stools for passage without straining.
carbohydrate digestion
Has the ultimate goal for glucose absorption and use as energy. Either undergo hydrolysis via enzymes, in the mouth, and in the stomach.
Carbohydrates
One of the three macronutrients that is an important energy source for the entire body. It is the preferred energy source for nerve cells and primarily derives from plant foods. This is due to plants, making glucose (a form of carbohydrate) through photosynthesis.
health benefits of fiber
a high fiber diet protects agains colon cancer, prevents colon cancer by binding/removing cholesterol and with bacterial fermentation generate short chain fatty acids, phytochemical provision, vitamin provision, and mineral provisions.
diabetes
blood glucose rises after a meal and remains above normal levels, due to insulin inadequate or ineffective. type one is less common and happens when the pancreas fails to produce insulin. type two is more common, happens when the cells fail to respond to insulin, and the chronic condition tends to occur as a consequence of obesity.
Glucose
blood sugar that is an essential energy source. This is part of every disaccharide. Preferred source for brain, nerve cells, and developing red blood cells. Blood glucose maintains homeostasis by insulin, lowering glucose levels and moving glucose from blood into cells. Glucagon and epinephrine raises blood glucose levels and brings glucose out from storage.
Glucagon
can signal the liver to break down glycogen stores, in order to generate glucose.
Soluble fibers
dissolve in water to form gels and are easily digested by bacteria in the colon. Found in oats, barley, legumes, and citrus foods.
insoluble fibers
do not dissolve in water and promote bowel movements/alleviate constipation. Found in whole grains(bran) and veggies.
Carbon
four bonds
Lactose
galactose and glucose
Sucrose
glucose and fructose
carbohydrate metabolism
glucose is a key player, being stored as glycogen in the liver by condensation. Can be also store in the muscles for use during exercise. Hydrolysis contrary releases glucose when needed.
Starches
glucose molecules linked together in branched or unbranched chains. This is a polysaccharide stored in plants. The branched chains are known as amylopectin and the unbranched chains are known as amylose.
Glycogen
glucose molecules linked together in highly branched chains. This is a polysaccharide stored by animals. Needs a special protein for attachment of the first glucose.
Etiology
inadequate amount of lactase produced from the intestinal cells. So, the digestion and absorption of disaccharide lactose require lactase. This is highest immediately after birth and declines with age. this leads to lactose intolerance.
the carbohydrate family
includes monosaccharides, disaccharides, and polysaccharides.
Polysaccharides
large molecules composed of chains of monosaccharides, complex carbohydrates.
Dietary changes with lactose intolerance
manage diary consumption rather than restrict, increase intake of milk products gradually, utilize fermented milk products, individualize diet. This may into filling in the gaps for potential nutrient deficiencies like riboflavin, vitamin D, and calcium.
The Small Intestine in Digestion
most carbohydrates digestion occurs here. Pancreatic amylase is the major carbohydrate-digesting enzyme that breaks down remaining starch into maltose/sucrose/lactose. Then either maltase breaks maltose into two glucose molecules, sucrase breaks sucrose into one glucose and one fructose molecules, or lactase breaks lactose into one glucose and one galactose molecule. All monosaccharides are absorbed by the small intestine and enter the bloodstream.
complex carbohydrates
oligosaccharides and polysaccharides. includes glycogen and starches.
Hydrogen
one bond
Galactose
only in a few foods
sugar
pleasure in moderate amounts, the taste preference for sweets is inborn. Has health effects, like nutrient deficiencies with providing energy with few other nutrients, obesity, chronic disease, and dental caries. Dietary Guidelines for Americans choose and prepare foods and beverages with little added sugars.
Monosaccharides
single sugars, simple carbohydrates, glucose, fructose, and galactose. All three monosaccharides have the same number and kinds of atoms, but differ in sweetness.
Dietary fibers are
structural parts of plants. They include polysaccharides that differ from starches, soluble fibers, and insoluble fibers.
disaccharides
sugars composed of pairs of monosaccharides, maltose, sucrose, and lactose. Has condensation that links two monosaccharides together and hydrolysis that breaks a disaccharide into two monosaccharides.
Fructose
sweetest of all sugars that occur naturally in fruits and honey.
Carbohydrate Digestion Last step
the monosaccharides enter the capillaries of the intestinal villi. They travel to the liver via the portal vein. Then in the live, galactose and fructose share metabolic pathways with glucose.
carbohydrate digestion in the mouth
the salivary enzyme amylase starts to hydrolyzing starch to shorter polysaccharides and to the disaccharide maltose.
Nitrogen
three bonds
oxygen
two bonds
Maltose
two glucose units
lactose intolerance
where more lactose consumed than the available lactase can handle. Lactose molecules remain in the intestine undigested, attracting water and causing bloating, abdominal discomfort, and diarrhea. Can be caused by damaged intestinal villi by other diseases, medicines, prolonged diarrhea, or malnutrition. Also there is seen that trait has the genetic component.
