NUTR 251 Exam 1 Notes

Hey guys,

These are the exam notes for my Nutrition 251 class from FALL 2014.  Please remember, just like the other entries that are my exam notes, that the information can change due to updates in policy and guidelines every five years.  2015 is one of these years!

Feel free to message me if you have any questions!!

Marquita

Nutritional Sciences Major | Kinesiology Minor |

Pennsylvania State University 2017

Text Book: Understanding Nutrition

Nutrition 251 Exam 1 Study Guide

Study Questions for Exam 1: 

1. Define an “essential” nutrient 

• A part of a diet that is essential for the body to function properly; nutrients that are either not created by the body or are not created in significant enough amounts and must be ingested. 

2. List Six classes of essential nutrients 

• Carbohydrates, Lipids, Protein, Vitamins, Minerals, H2O 

3. Serving sizes as per USDA/FDA 

• 1 c fruit = 1 cup canned peaches 
• 1 c veg = 1 cup of cut raw carrots 
• 1 oz grains = 1 slice of bread or .5 cup of cooked pasta/rice 
• 1 oz of protein food = 1tbls of peanut butter 
• 1 c of milk = 1 c yogurt 

4. How many servings of veg and fruit should you get based on a 2000 kcal diet? 

• 2 c fruit, 2.5 c veg 

5. Define: 

• DRI – Dietary Reference Intakes 

• standards that define the amounts of kcal, nutrients, other dietary components, and physical activity to support the best health which are based on scientific studies. 

• AI – Adequate Intakes 

• Based on estimates that I person may need because we do not know enough about the nutrient to give a RDA (Recommended Dietary Allowance) 

• RDA – Recommended Dietary Allowance 

• Suggested dietary intakes based on what 90% of a healthy population would need 

• EAR – Estimated Average Requirements 

• Requirements based on the average, this is the center of the curve. 50% will need less, 50% will need more. 

 

UL – Tolerable Upper Intake Levels 

• the amount of a substance that the average person can consume before experiencing any negative side effects 

• EER – Estimated Energy Requirements 

• average dietary energy intake (kcal/day) to maintain energy balance in a person with a healthy body weight and certain levels of activity. 

• AMDR – Acceptable Macronutrient Distribution Ranges 

• Carbohydrate: 45 – 65% 
• Fat: 20 - 35% (S. Fat < 10%) 
• Protein: 10 – 35% 

6. Nutrient Density vs Energy Density 

• Nutrient Density: Nutrients/kcal 
• Energy Density: Carbs + Protein + Fat/kcal 

7. Processed vs Unprocessed grains 

• Processed: foods that have been treated to change their physical, chemical, microbiological, or sensory properties. 

• Fortified: adding in nutrients that weren't present in the unprocessed version of the food; use to prevent widespread deficiency diseases (like scurvy). 

• 
  Enriched: adding BACK IN of nutrients LOST during processing. 

• Iron 
• Niacin 
• Thamin 
• Riboflavin 
• Folate 

• Unprocessed (whole) grains: maintains the same proportions of endosperm, germ, and bran as the original plant (doesn't contain the husk); maintains the nutrient density of the plant. 

• Total grains, 50% should be whole grain 

• List four (4) nutrients LOST during processing and NOT added back in 

• B6, Fiber, Zinc, Mg 

8. Food Label 

• Daily Value – based on a 2000 kcal diet, gives the % of specific nutrients contained within one serving of a product. 

• Fat, Fiber, Vit A, C, Ca, Fe, Cholesterol, Na, Carbohydrate 

• Cal per gram  

• Fat = 9Carb = 4Protein = 4 
• Be able to use grams of a nutrient to find total kCal of a food 

• Ex. Which one is has the highest kcal? 

Teriyaki Stix's Chicken Bowl: Fat = 15g, CHO = 101g, Protein = 45g 

Sbarro's Spaghetti: Fat = 23g, CHO = 144g, Protein = 27g 

• “High” vs “Good” vs “Low” claims of nutrient source 

• High: 20% + DV 
• Good: 10 – 19% DV 
• Low: <10% DV 

9. Digestion, Absorption, and Transport 

• Define: 

• Lumen – the inner space of the GI (gastrointestinal) tract 

• Small Intestine's parts 

• Duodenum → Jejunum → Ileum 

• Valves/sphincters (top to bottom) 

• Even -            Epiglottis 
• U -                 Upper esophageal sphincter 
• Like -             Lower esophageal sphincter  
• Purple-          Pyloric sphincter 
• Icecream -     Ileocecal valve 
• Two valves at the exit of the colon. 

• Describe the digestion and/or absorption for Wheaties (mainly starch and fiber) and peanut butter (protein, fat, and fiber) from start to finish. 

• Chewing to break up large pieces of food plus saliva amylase, secreted by the salivary glands, begin the breaking down of food, with amylase breaking down amylose.  
• Food is swallowed and passes through the pharynx and passes over the epiglottis to prevent food from entering lungs 

• Food passes through the upper esophageal sphincter and into the esophagus where it is moved downwards via parastalsis.   
• Food passes through the lower esophageal sphincter located just at the diaphragm (a layer of muscle that separates the lungs/heart from the stomach/liver/etc below. 
• Food enters the stomach where it is churned in gastric juices (HCl, H2O, and enzymes) to further break down the food and turn it into a liquid mass. (chyme)  

• Lining of the stomach is coated in mucus to prevent HCl from eating through the stomach.   
• Stomach is lined with gastric pits with a gastric gland at the bottom of each that secretes the gastric juice. 

• Food leaves the stomach 1tsp at a time through the  Pyloric sphincter to enter the small intestine's duodenum then the jejunum and then the ileum. 

• Pancreas secretes bicarbonate to neutralize HCl from stomach 
• Pancreas secretes  

• pancreatic amylase to break down carbohydrates into monosaccharisdes 
• proteases – break down protiens 
• lipases – break down fats and glycerol 

• Food (bolus) is subjected to digestive juices (bicarbonate, digestive enzymes, and bile salts) which enter the small intestine via bile duct. 

• Liver makes bile salts 

• Bile salts emulsify fats to aid in absorption process. 
• Gallbladder holds extra bile salts for when large and fatty meals are eaten. 

• Excess bile production can lead to gallstones because bile contains waste like cholesterol. 
• Villi, lined with microvilli, are responsible for most of the absorption in the system.  Enzymes in Sm. Int. break food down to basic units and they are absorbed (if they can be) through the villi.   

• Water-soluble nutrients (monosaccharides, amino acids, water soluble vitamins/minerals, and small fatty acids are absorbed directly into blood stream to be taken to the liver.   
• Fat soluble nutrients (cholesterol, fatty acids, fat soluble vit) are absorbed via lymphatic system and put into the blood stream via thoracic duct  by the heart. 

• Chylomicrons – wrapping over fat soluble nutrients to transport them. 

• Endogenous H2O is secreted into the sm. Int. from the body to aid in keeping chyme...chymey.  It'll later be reabsorbed in the large intestine. 

• Chyme passes through the Ileocecal sphincter to enter the large intestine.  

• Mainly insoluble fibers and water here.  Bacteria can ferment some of the fibers making fatty acids. 
• Most of H2O is reabsorbed into the body, leaving bolus. 

10. Peptic Ulcers 

• mucous lining of the stomach becomes thinned and stomach wall comes into contact with HCl 

• major causes: 

• infection by H. pylori (bacteria) 
• certain anti-inflammatory drugs (ibuprofin/aspirin) 
• excessive gastric secretion 

11. Small Intestine 

• duodenum → Jejunum → Ilenum 
• lined with villi, which are covered with micro villi to maximize surface area 

• ea. villi has vascular and lymphatic system tied to it. 

• Vascular takes water-soluble → liver for processing → rest of blood stream 
• Lymphatic takes non-soluble wrapped in chrylomicrons → thoracic duct by heart to enter blood stream 

12. Pancreas 

• inferior and posterior to the stomach 
• connects to bile duct in sm. Intestine, jus tlike gall bladder 
• endocrine cells = hormones 

• exocrine cell = digestive enzymes and bicarbonate 

• MOST are exocrine (99%) 
• digestive enzymes 

• pancreatic amylase 
• carbohydrase 
• proteases 
• lipases 

13. Liver 

• Superior, anterior, and lateral to the stomach 
• Makes bile salts (bile) from cholesterol 

• bile salts go down bile duct (which connects with the gall bladder) and into duodenum. 
• Bile sales emulsify fats 
• gall bladder stores extra bile as a back up 

14. Diffusion 

• Simple Diffusion 

• molecules does down their concentration gradients 

• only can be done by water-soluble because cell membrane outer layers are hydrophillic 

• Facilitated Diffusion 

• molecule is wrapped up, like our chrylomicrons, and released into the cell 

• Active Transport 

• requires ATP to happen 

15. Symptoms of excessive gastric juice productions 

• Ulcers 

• most commonly caused by bacteria H. pylori → antibiotics 
• Help: 

• avoid coffee, caffeine, and alcohol 
• avoid foods that aggravate the stomach 
• minimize aspirin/ibuprofen/naproxen use 
• no smoking 

16. hormones 

• Gastrin 

• tells stomach to make more HCl to keep pH between 1.5 – 1.7 
• less acid = higher pH 

• Secretin 

• tells pancreas to secrete bicarbonate-rich pancreatic juice into duodenum 

• takes pH to 7.35 

• Cholecystokinin (CCK) 

• stimulates the release of bile and pancreatic juices into the small intestine when high fat food arrives. 

• Purposes: 

• slow down GI tract 

• cause gallbladder to release bile 
• stimulates pancreas to release pancreatic juice 

The Universe Within. Example questions:  

What can cause stomach ulcers?  

What is the role of bile?  

Why are feces brown?  

- bile that remains in the bolus 

Are bacteria present in the small intestine and are they absorbed?  

• yes, but they are not absorbed because they are too large to fit between the microvilli 

What are the roles of the liver in terms of glucose storage, cholesterol monitoring, and detoxification?  

• enzymes in the liver convert glucose into chains of glucose as glycogen which is stored in the liver and the muscle 
• excess cholesterol is recycled and made into bile in the liver and sent to the gallbladder 

Carbohydrates 

1. Chemist's terms: 

• simple sugars: 

• monosaccharides 

• glucose, fructose, galactose 

• disaccharides (made via condensation) 

• sucrose (glucose + fructose), lactose (galactose + glucose), maltose (glucose x2) 

• complex sugars: 

• polysaccharides 

• starch (amylose + amylopectin), gylcogen (branched glucose), fiber/cellulose 

2. Common terms: 

• added-sugar (added sucrose from beets or sugar cane, sweet syrup) 

• DRI < 25% of total energy 
• baked goods, soda 

• naturally-occurring sugars 

• ex, milk, fruit, juice 

3. amylose (alpha 1-4 glucose linkages) + amylopectin (branched, alpha 1-4 and alpha 1-6 glucose linkages) 

4. cellulose (beta 1-4) 

5. What would happen if carbohydrates were cut from diet? 

• The hormone glucagon would tell the liver to release glycogen to raise blood sugar 
• The body would start turning fatty acids into ketones, which could lead to ketosis. 

6. Glucose vs Fructose 

• structural differences: glucose is a hexagon and fructose is a penta 
• fructose is sweeter than glucose 

7. Pre and post digestion/absorption 

• Table sugar 

• sucrose → sucrase breaks down to → glucose and fructose 

• Honey 

• .33 sucrose + .33 fructose + .33 glucose 

• sugar in apples 

• .5 sucrose + .25 fructose + .25 glucose 

• High fructose corn syup 

• glucose + fructose 

• Dextrose 

• 100% glucose 

• Cellulose 

• resists absorption, large intestine ferments some and creates some fatty acids and gas. 

8. Starch vs Cellulose vs Glycogen 

• starch 

• amylose (chain of glucose – alpha 1-4 linkages) 
• amylopectin (branched glucose – beta 1-4 and 1-6 linkages) 

• cellulose (chain of glucose – beta 1-4 linkages) 
• glycogen (branched ball of glucose) 

9. Results of excess sugar intake 

• loss of nutrient density, more energy in but no nutrients to go along with it (empty kcal) 
• tooth decay from bacteria that ferments the sugar which eats through enamel.  

10. Lactose Intolerance 

• side effects: 

• not enough manufacturing of lactase 
• GI distress (gas, excess water retention → bloating, pain/discomfort, diarrhea)  

11. Regulating blood sugar 

• glucagon – tells liver to start converting glycogen into glucose in order to raise blood sugar 
• insulin – tells cells to take in glucose in blood stream and takes it to the liver for conversion to glycogen or (if in excess) fat. 

12. Artificial Sweeteners 

• stevia – herbal product 
• sugar alcohol (polyols) 

• lower glycemic response than sucrose 
• side effects – intestinal gas, discomfort, and diarrhea 

• aspartame 

• digested and absorbed 
• degrades with heat, used in drinks because it is stable at room temps 

• sucralose 

• no kcal 
• not absorbed 
• heat stable 
• made from sugar 

13. Diabetes Mellitus 

• Type 1: 

• on set under 30 years old 
• pancreas doesn't produce insulin 

• life long dependence on insulin injections or pump 

• body type normally lean 
• symptoms (severe) 

• weight loss despite increased eating and appetite, hyperglycemia, excessive thirst, frequent urination, diabetic acidosis from excessive ketone production, diabetic coma 

• Type 2: 

• on set over 30 years old 
• cells because resistant to insulin or not enough insulin is produced to handle load 

• medication to increase insulin production, insulin injections 
• lifestyle changes (weight loss, eating nutrient densely) 

• regular physical activity IMPROVES insulin sensitivity 

• symptoms (moderate) 

• hyperglycemia, excessive thirst, frequent urination, increased appetite, weight gain 
• Long term complications 

• thickening of blood vessels (micro and macro vascular diseases) 
• neurological damage results in loss of sensation in extremeties 
• loss of sight 

• kidney disease 

14. Glycemic Index 

• how large of a spike in blood sugar levels a food would have in comparison to the same amount as just glucose 

• spike is less severe when mixing foods, especially when adding foods that slow down the digestion process 
• focus is switching to glycemic LOAD = total carbohydrates present in a meal 

• Rank the food in GIx from highest to lowest 

• banana, milk, peanuts, white bread, table sugar, and ice cream 

• white bread > table sugar > ice cream > milk > banana > peanuts