Nutrition Exam 1
Vitamin functions (the "glow" nutrient)
- 13 essential vitamins - Yield no energy - Organic - Individual units, not linked like the macronutrients - Complex in nature and must be intact to work - Vulnerable to destruction by heat, light, and chemicals (can function only when intact) Functions: - Many vitamins function as coenzymes - Vitamins also activate enzymes that participate in building bone and muscle, energy production, fighting infections, and maintaining healthy nerves and vision
Mineral functions (another "glow" nutrient)
- 16 essential minerals - Yield no energy - Inorganic - Simplest nutrient - Indestructible, but can be lost during food-refining processes or during cooking when they leach into the water Functions: - Help build bones and teeth - Maintain fluid balance throughout the body - Aid in muscle function - Help our nervous system transmit messages
Celiac disease
- A genetic, autoimmune disorder that causes damage to the small intestine when foods containing gluten are consumed - Causes the small intestinal villi to flatten out, causing nutrient malabsorption
4. High nutrient density
- A measure of the nutrients a food provides relative to the energy it provides - The more nutrients and the fewer calories, the higher the nutrient density *Nutrient dense: maximal nutrients, minimal calories!!!
Water (the "critical" nutrient)
- A person can survive only 3 days without water Makes up ~60% of body weight - Lean muscle tissue: 75% water - Blood: 83% water - Body fat: 25% water - Bone: 22% water - You lose ~64-80 ounces of water a day - Functions: body temperature regulation, lubrication, cushioning, carries nutrients and wastes, may protect against kidney stones, and cancers of the bladder, prostate, and breast
Gut microbiome
- Around 95% of the cells in and on our bodies are bacterial - Our bodies have 10 times more microbes than human cells (10:1 ratio) - Your gut hosts 500 - 2,000 species of microorganisms - DIVERSITY is key! - The average adult carries 3 to 5 pounds of microbes in their gut - WOW!!
Large intestine
- Ascending colon - Transerve colon - Descending colon - Sigmoid colon
Additional roles of gut microbiome
- Break down indigestible carbohydrates creating short chain fatty acids that support colon health - Synthesize vitamins such as vitamin K, Biotin and vitamin B12 - Enhance mineral absorption - Metabolize bile acids to reduce blood cholesterol levels - Certain types of microorganisms have been associated with a reduced risk of obesity
How many calories per Gram in the macro and micronutrients?
- Carbohydrate: 4 kcal/g - Fat: 9 kcal/g - Protein: 4 kcal/g - Saturated fat: 9 kcal/g - Alcohol: 7 kcal/g
The energy yielding macronutrients
- Carbohydrate: the "go" nutrient - Fat: the "concentrated go" nutrient - Protein: the "grow" nutrient
Acceptable macronutrient distribution ranges (AMDR)
- Carbohydrates: 45-65% of total daily calories - Fats (lipids): 20-35% of total daily calories - Proteins: 10-35% of total daily calories *Saturated fats: 10% of calories max (none is better)
Chemical digestion
- Catalysts that facilitate a chemical reaction, but remain unchanged in the process - Make, break, rearrange and exchange molecules - All are proteins •Sensitive to heat, light, agitation, acid and base, alcohol, heavy metals and other agents - ase ending (salivary amylase)
Anatomy of the stomach
- Chief cells: Pepsinogen, gastric lipase, ? leptin - Parietal cells: HCl, intrinsic factor for vitamin B12 absorption
Structure of small intestine
- Circular folds - Villi - Microvilli
Salivary glands
- Contain water, salts, mucus, and enzymes that initiate carbo digestion Saliva: - Helps form a bolus - Protects the teeth and linings of the mouth, esophagus, and stomach - We make ~1 quart of saliva/day
Energy in the body
- Energy is trapped within bonds that keep molecules together - Bonds break during metabolism and energy is released - The energy can then be used to digest and absorb the meal, contract muscles, fuel the heart, and synthesize new cells, as well as other functions - Unused energy is stored predominantly as fat - Using more energy than is consumed results in fat breakdown
Pancreas
- Exocrine function: secretes digestive enzymes into the small intestine - Endocrine function: releases hormones to maintain blood glucose levels
Characteristics of a well designed research study
- Experimental and control groups Placebo - Randomization - Double blinded (or at least single blinded) - Sample size (50+) - Adequate duration - Approved by a peer-reviewed journal - Results are replicated and applicable to multiple populations - Investigate who funded the research
Daily values for food labels
- Fat: 35% of kilocalories - Saturated fat: 10% of kilocalories - Carbohydrates: 55% of kilocalories - Protein: 10% of kilocalories - Added sugar: 10% of kilocalories - Cholesterol: 300 mg - Sodium: 2,300 mg
Factors exacerbating gastroesophageal reflux (GERD)
- Foods such as spicy foods, tomatoes, citrus fruits, garlic, onions, chocolate, coffee, alcohol, carbonated drinks, caffeine, peppermint or excessive intake of high fat or fried foods - Eating or drinking excessive amounts at one time or over time - Obesity, stress, smoking, some medications, tight clothing, changes in position (lying down, bending over) and sphincter defects
Protein function (the "grow" nutrient)
- Growth, maintenance, and repair!!!! Act as building blocks: - Muscles, bone and skin - Collagen (scars, tendons, ligaments, and the foundation of bones and teeth) - Help your blood to clot - Allow your eyes to see (opsin) - Make antibodies, hormones and enzymes so your body can function
Chemical digestion: hydrolysis of disaccharide
- Hydro = water - Lysis = breaking
Liver
- Largest internal organ (~3 pounds) - Essential for digestion, absorption, and transport of nutrients - Carbohydrate metabolism - Protein synthesis - Bile salts synthesis required for fat digestion - Removes and degrades toxins and excess hormones (alcohol and drug metabolism)
GERD
- Lose weight, if necessary - Small meals - Liquid between meals - Eat slowly - Sit up while eating - Wait 1 hour after eating before lying down - Wait 2 hours after eating before exercising - Refrain from tight-fitting clothing - Avoid bothersome foods - Refrain from tobacco use - 8-week course of proton pump inhibitors (PPIs) - Elevated risk of fractures, low magnesium levels and increased risk of Clostridium-difficile-associated diarrhea
Nutrition as an essential health promotion tool
- Lower the incidence of obesity, the root cause of many chronic diseases - Reduce risk of four of the top ten leading causes of death - Prevent or manage other harmful diseases and conditions - Heart disease - Cancer - Stroke - Diabetes
Estimated Average Requirement (EAR)
- Meets nutrient needs for 50% of individuals - Scientists use it to calculate the RDA
Reccomended Dietary Allowance (RDA)
- Meets nutrient needs for 97-99% of individuals - Aim for this amount *Cannot determine without an EAR
Large intetsine
- No absorption of the energy-yielding macronutrients - Bacteria produce vitamin K, thiamin, riboflavin, biotin, and vitamin B12, but only biotin and vitamin K can be absorbed - Bacteria ferment soluble fibers producing short chain fatty acids - Most of the water, salts, and minerals are reabsorbed - Fiber, bacteria, dead cells and unabsorbed nutrients are excreted
Prebiotics
- Prebiotics are a special class of carbohydrates and soluble fibers that are not digested in the upper GI tract - Instead, they make their way down to the colon where they naturally ferment - This fermentation process selectively promotes the growth of beneficial bacteria which help support intestinal and overall good health
Carbohydrate functions (the "go" nutrient)
- Primary source of energy in the body (glucose & glycogen) - Protein sparing - Fat metabolism primer - Primary fuel for the CNS - Fiber lowers blood cholesterol, improves blood sugar tolerance, promotes regularity - Essential component of a weight maintenance or weight loss eating regimen
Probiotics vs prebiotics
- Probiotics = promote a green lawn in your gut - Prebiotics = fertilizer for your lawn
3. Moderation
- Providing enough, but not too much of any one food or nutrient - PORTION CONTROL
Low fat/low cholesterol diet
- Purpose: to reduce body fat levels and/or treat medical conditions that interfere with how the body uses fat such as diseases of the liver, gallbladder or pancreas - Limits fat to 50 grams or no more than 30% calories derived from fat. - Low in total fat and saturated fat - Approximately 250-300 mg cholesterol
Gallbladder
- Receives bile from the liver via common hepatic duct - Concentrates and stores bile - Releases bile into small intestine via common bile duct
Case-control studies - retrospective
- Researchers compare people who do and do not have a given condition such as a disease, closely matching them in age, gender, and other key variables so that differences in other factors will stand out - These differences may account for the condition in the group that has it Ex: women using combined hormone replacement therapy (HRT) have a reduced incidence of coronary heart disease (CHD)
Cross-sectional studies
- Scientists observe how much and what kinds of foods a group of people eat and how healthy those people are - These studies take place at a single point in time - The study results identify factors that might influence the incidence of a disease in various populations Ex: the people of the Mediterranean region drink lots of wine, eat plenty of fat from olive oil, and yet have a lower incidence of heart disease than North Americans
3. Structure/function claims
- Structure/function claims describe how a nutrient or dietary compound affects the structure or function of the human body - S/F claims cannot state that the nutrient or dietary compound can be used to treat a disease or condition - "Calcium builds strong bones" - "Fiber maintains bowel regularity" - Do not have to be pre-approved by the FDA - Disclaimer only for dietary supplements, not foods
Adequate Intake (AI)
- The average daily intake level assumed to be adequate - Used when an EAR cannot be determined - Aim for this amount if there is no RDA
Tolerable Upper Intake Level (UL)
- The highest average daily intake level likely to pose no health risks - Do not exceed this amount on a daily basis
What is nutrition?
- The science of food, the nutrients, and other substances therein - Nutrient action, interaction, and balance in relation to health and disease, and - The process by which the organism ingests, absorbs, transports, utilizes, and excretes food substances
Energy needs vary according to
1. Age 2. Gender 3. Activity level
Does your diet have proportionality?
1. Are grains the main choice at all your meals? 2. Do you often forget to eat veggies? 3. Do you typically eat fewer than 3 servings of fruit/day? 4. Do you often have fewer than 3 cups of milk, yogurt, and/or calcium-fortified milk alternatives each day? 5. Is the portion of meat, chicken, or fish the largest item on your dinner plate?
Key diet planning principles
1. Balance 2. Variety 3. Moderation 4. High nutrient density 5. Low energy density (with exceptions)
5 specific dietary guidelines
1. Follow a healthy eating pattern across the lifespan 2. Focus on variety, nutrient density, and amount 3. Limit the following: kcals from added sugars and saturated fats (<10% kcals); sodium (<2,300 mg); alcohol (♀: 1 drink/d; ♂: 2 drinks/d); trans fats; dietary cholesterol and caffeine (<400 mg/d) 4. Shift to healthier food and beverage choices 5. Support healthy eating patterns for all
Label claims can reveal potential health benefits
1. Nutrient content claims: claims on the food label that describe the level or amount of a nutrient in the food 2. Health claims: claims on food labels that describe a relationship between a food, food component, dietary ingredient, or dietary supplement and a disease or health-related condition. 3. Structure/function claims: claims on food labels that describe the role of a nutrient or dietary compound that is proposed to influence the structure or function of the human body
The accessory organs
1. Salivary glands 2. Liver 3. Gallbladder 4. Pancreas
Kilocalorie (kcal)/calorie
Amount of heat necessary to raise the temperature of one kilogram of water one degree Celsius
Fat/lipid functions (the "concentrated go" nutrient)
Body Fat (adipose tissue): - A concentrated energy source and reserve - Serves as a component of all cell membranes - Provides insulation and cushions the vital organs Dietary fat: - Spares protein stores - Provides essential fatty acids - Acts as a transport medium for fat soluble vitamins, essential fatty acids, and certain phytochemicals - Provides sustained relief from hunger - Increases the flavor and palatability of foods
Celiac disease continued
Cause: An abnormal reaction to the protein gluten, found in wheat, rye and barley Symptoms: - Reoccurring abdominal bloating - Cramping and/or gas - Diarrhea - Foul-smelling stools - Weight loss - Anemia - Bone or joint pain
Intestinal permeability
Cause: - Unknown: chronic stress, intestinal infections, excessive alcohol, poor diet and certain meds Symptoms: - Flatulence, indigestion, constipation, bloating and abdominal pain - Difficulty breathing, chronic joint and muscle pain, confusion, mood swings, poor memory, and anxiety - Asthma, recurrent infections and chronic fatigue syndrome Treatment: - Diet first!! - Eliminate processed foods and sugars - More research is needed to find an effective treatment
Celiac disease continued
Complications associated with celiac disease: - Increased risk for osteoporosis, diminished growth, seizures and nutrient deficiencies - Diagnosis is made with a blood test and tissue biopsy of the small intestine. Treatment - Follow a gluten-free diet. - Include milk, meat, eggs, fruits, vegetables, rice, potatoes, beans, millet, amaranth and other gluten free items. - Moderate amounts of oats (up to ¼ c) may be tolerated - Eliminate all foods that contain wheat, barley and rye.
Gut microbiomes help...
Develop a mucosal barrier, reduce pH in the colon and secrete antibacterial compounds: - These activities reduce attachment of and destroy potentially harmful bacteria - They also reduce the risk of a 'leaky gut'
Dysphagia
Difficulty swallowing - ↑ risk for aspiration - When food or liquid enters the lungs by accident and can cause aspiration pneumonia and other problems
2. Variety
Eating a wide selection of foods WITHIN and AMONG the major food groups
5. Low energy density
Energy density: a measurement of the kilocalories in a food compared with the weight (grams) of the food - Most high-fat foods are energy dense Low-energy-dense foods: - Can promote weight loss - You can eat larger portions for the same number of kilocalories when consuming low energy density foods which may improve satiety and decrease hunger *Energy density: high in energy, but still nutrient dense
Types of nutrition research studies
Epidemiological/observational studies: - Cross-sectional studies - Case-control studies - Cohort studies Controlled scientific experiments: - Laboratory-based animal studies - Human intervention (clinical) trials
What are the six classes of nutrients?
Macronutrients: 1. Carbohydrates 2. Fats (lipids) 3. Protein 4. Water Micronutrients: 5. Vitamins 6. Minerals
Common minerals
Major minerals: - Sodium - Chloride - Potassium - Calcium - Phosphorus - Magnesium - Sulfur Trace minerals: - Iron - Zinc - Iodine - Selenium - Copper - Manganese - Fluoride - Chromium - Molybdenum
Mouth
Mechanical digestion*** - Major food manipulation - Chewing = taste perception and bolus formation Chemical Digestion - Saliva contains salt, water, salivary amylase and mucus - Saliva also protects the teeth, and linings of the mouth, esophagus, and stomach from harmful substances - Absorption (of very little glucose)
Stomach
Mechanical digestion*** - Major function - Food becomes chyme Chemical digestion: - Acidic environment prevents bacterial growth - Gastric juice (water, enzymes, hydrochloric acid) - Limited digestion of carbos, fats and proteins Absorption: - Some alcohol and water - Pyloric sphincter
Small intestine
Mechanical digestion: - Less mechanical breakdown - Food still called chyme Chemical digestion*** - Pancreatic juice - Enzymes and bicarbonate - Basic environment - Bile is made in the liver and stored in the gallbladder - release is triggered when fat arrives in the SI - Intestinal enzymes Absorption*** - Primary site of nutrient absorption - Ileocecal valve
Mechanical vs chemical digestion
Mechanical digestion: Breaking down food through chewing, grinding, squeezing, and moving food through the GI tract by peristalsis and segmentation - Circular muscles - Longitudinal muscles - Diagonal muscles (stomach only) - Sphincters Chemical digestion: Breaking down food through enzymatic and chemical reactions - Salivary enzymes - Gastric enzymes, chemicals and hormones - Pancreatic enzymes and hormones - Intestinal enzymes
2. Health claims
Must be pre-approved by the FDA
What are nutrients?
Nutrients are essential compounds in foods that serve as building blocks for body components and sustain body processes
Organic vs inorganic structure
Organic (it's alive): - A substance containing carbon-carbon bonds or carbon-hydrogen bonds - More complex nutrients - Carbohydrates, lipids, proteins, and vitamins Inorganic: - Not containing carbon or pertaining to living things - Simpler nutrients - Minerals and water
The GI tract & accessory organs
Organs of the GI tract: 1. Mouth 2. Esophagus 3. Stomach 4. Small intestine 5. Large intestine - Sphincters allow food to pass from one organ to the next - Accessory organs outside the GI tract aid in digestion: Salivary glands, liver, pancreas, gallbladder
Mechanical digestion and propulsion of food
Peristalsis and segmentation
Support your gut microbiome
Probiotics: live microorganisms that inhabit the digestive system that are believed to provide health benefits Educate and regulate our immune system: - 60-80% of your immune system is in your GI tract Modify our mood: - Gut microbes create 95% of serotonin in the body
1. Balance
Providing foods in proportion to one another and in proportion to the body's needs - Iron: meat and meat alternatives - Calcium: milk and milk products
Controlled scientific experiments
Purpose: - Test the cause-and-effect relationships between variables - Experimental vs. control - The two groups are similar with respect to the variable being studied - Blind vs. double-blind - Randomization Strengths: - Can control conditions - Can determine effects of a variable - Can apply some findings to certain groups in the population Weaknesses: - Cannot apply results from animals directly to humans - Cannot generalize study findings on to all human beings - Cannot use certain treatments for clinical or ethical reasons
Epidemiological/observational studies
Purpose: - To research the incidence, distribution, and control of disease in a population - Researchers observe a LARGE group of subjects - No experimental interventions are performed Strengths: - Can narrow down the list of possible causes of a disease - Can raise questions to pursue through other research Weaknesses: - Cannot control variables that may influence the development or the prevention of a disease - Cannot prove cause and effect
Cohort studies - prospective
Researchers analyze data collected from a selected group of people (a cohort) at intervals over a certain period of time - Framingham Heart Study - Nurses Health Study
Laboratory-based animal studies
Researchers feed animals special diets that provide or omit specific nutrients and then observe any changes in health Ex: mice fed a high-fat diet eat less food than mice given a lower-fat diet so that they receive the same number of calories - but the mice eating the fat-rich diet become severely obese
Bicarbonate ions
Secretion pathway: Secreted by pancreas through the pancreatic duct into the small intestine Action: Raise pH and neutralize stomach acid
Intestinal juice
Secretion pathway: Secreted by the crypts into small intestine Action: Contains enzymes that digest carbohydrate, protein, and lipid
Bile
Secretion pathway: Secreted by liver into gallbladder for storage; released from gallbladder into small intestine via common bile duct Action: Emulsifies large globules of lipid into smaller droplets
Hydrochloric acid (HCl)
Secretion pathway: Secreted by parietal cells into stomach Action: Denatures protein; activates pepsinogen - pepsin
Intrinsic factor
Secretion pathway: Secreted by parietal cells into stomach Action: Needed for vitamin B12 absorption
Saliva
Secretion pathway: Secreted by salivary glands into mouth Action: Moistens food, eases swallowing; contains the enzyme salivary amylase
Mucus
Secretion pathway: Secreted throughout the GI tract, including in the stomach and intestinal glands Action: Lubricates and coats the internal mucosa to protect it from chemical or mechanical damage
Secretin
Stimulus: Acid chyme in duodenum Secreted from: Duodenum Action: Stimulates the pancreas to release bicarbonate ions
Cholecystokinin (CCK)
Stimulus: Fats and proteins in duodenum Secreted from: Duodenum Action: Stimulates the gallbladder to secrete bile and the pancreas to secrete bicarbonate ions and enzymes
Gastrin
Stimulus: Food in the stomach Secreted from: Gastric cells Action: Stimulates parietal cells to release HCl
Estimated Energy Requirement (EER)
The average daily energy intake predicted to meet the needs of healthy adults
Acceptable Macronutrient Distribution Range (AMDR)
The recommended range of carbohydrate, fat, and protein intake expressed as a percentage of total energy
Human intervention/clinical trails
The type of study used to find definitive answers to a hypothesis of interest Method: - Subjects are assigned to one of two groups - A planned intervention is provided to the experimental group - After a specified period of time it is determined whether certain predetermined factors differ between the two groups
Vitamins (the "glow nutrient")
Water-soluble vitamins (9): Eight B vitamins: - Thiamin - Riboflavin - Niacin - Vitamin B6 - Vitamin B12 - Folate - Biotin - Pantothenic Acid Plus: - Vitamin C Fat-soluble vitamins (4): - Vitamin A - Vitamin D - Vitamin E - Vitamin K
