Nutrition 251
Nutrition: The science of food, The substances within, the process in which an organism ingests, digests and excretes food
Nutrients:
Characteristics of an essential nutrient:
Has a specific biological functioning
Absence: decline in biological functioning
Adding missing substance back: restores normal aspects (if done before permanent damage)
Functional categories of nutrients:
Primarily provides energy
Important for growth and development
Keep body functions running smoothly
Carbohydrates:
Composed of carbon, hydrogen and oxygen
Primarily obtained from fruits, vegetables, grains, and beans
Provides 4cal/gram
Two main types
Simple sugars
> Table sugar (sucrose)
>Blood glucose
-Complex
>Starch
> Glycogen
>Fiber
Proteins:
Composed of carbon, oxygen, hydrogen, and nitrogen
Main structural component of the body
Provide 4 Cal/g
Formed from peptide bonding of amino acids
lipids (fats and oils) vitamins:
Also composed of carbon, oxygen, and hydrogen
Insoluble in water (don’t like it)
^ Need to be in a carrier to go throughout the body
Provides 9 Cal/g
Fat- Lipids that are solid at room temperature
Oil- Lipids that are liquid at room temperature
Minerals:
Inorganic substances
Do not contain carbon atoms bound to hydrogen ‘Not destroyed by cooking
Water:
Needed in the largest quantity
Several Vital function
Solvent, lubricant, transports nutrients, regulated body temp
Sources: food and drink, byproduct of metabolism
Calorie:
- Amount of heat energy needed to raise the temperature of 1 gram of water 1 degree Celsius
kilocalorie (kcal):
Amount of heat energy needed to raise the temperature of 1000 grams of water 1 degree Celsius
Triglycerides:
A major form of fat in food and body
A major energy source for the body
Composed of 3 fatty acids attached to a glycerol backbone
saturated fat:
Mainly solid at room temp
Mainly found in animal sources
Raise blood cholesterol levels
Can lead to cardiovascular disease
unsaturated fat:
Mainly liquid at room temp
Mainly found in plant sources
Healthier than saturated fats
Phytochemicals:
Active compounds found in plants
Hunger:
They physical food we need
Appetite:
The psychological desire we have to eat food
Case-control study:
Individuals who have a condition are compared to those who don't
Double-blind study:
Studies and researches don’t know who is in which group
Terms to know →
Macronutrients:
We need them in large quantities
Carbohydrates
Lipids
Protein
Water
Micronutrients:
Need in smaller quantities
Vitamins
Minerals
registered dietitian nutritionist:
The "RDN" credential is a legally protected title that can only be used by practitioners who are authorized by the Commission on Dietetic Registration of the Academy of Nutrition and Dietetics
Important concepts to note →
• Differences between macronutrients and micronutrients
Macronutrients include carbohydrate, protein and fat; micronutrients include vitamins and minerals
• Types of carbohydrates (CHO)
Two Main Types
Simple
Table sugar (sucrose)
Blood glucose
Complex
Starch
Glycogen
Fiber
• Types of lipids (saturated vs unsaturated)
The term lipid encompasses both fats, referring to solids, and oils, referring to liquids, and determination of saturation is dependent on dominant fatty acids
• Groups of vitamins
13 vitamins, 2 groups
Fat-soluble:
Vitamins A, D, E, and K
More likely to accumulate and cause toxicity
Water-soluble:
Vitamin C and the B-vitamins
More likely destroyed by cooking
Excreted from the body more readily
• Groups of minerals
Major minerals needed in gram amounts daily
Trace mineral needed in <100 mg daily
• Essential nutrients
Essential nutrients must be provided by the diet, while nonessential nutrients may be made within the body in sufficient amounts
• Functions of nutrients
Primarily provides energy
Important for growth and development
Keep body functions running smoothly
• Proper nutrition and impact on disease
balance in relation to health and disease
• Energy sources and uses, physiological fuel values of nutrients and alcohol, calculating energy available from food.
Energy is needed to perform body functions and do work.
Provided by carbohydrates, proteins, and fats
Alcohol also provides energy (not a nutrient)
Measured in kilocalories
16 grams of carbohydrate, 7 grams of protein and 9
grams of fat
• Assessing nutritional status
o Anthropometric (height, weight)
o Biochemical (blood, serum levels)
o Clinical or Medical (functional/social/mental status, health conditions, medical history) o Dietary
o Environmental (smoking, substance abuse, foster care)
Chapter 2: Tools of a Healthy Diet
Definitions/terms to know →
Dietary Reference Intakes:
The Dietary Reference Intakes (DRIs), established by the FNB include the EARS, RDAs, AIs, ULs, and EERs
Estimated Average Requirement:
Established to meet the needs of half of the people of a certain life stage
50% of population needs met by EARs
Recommended Dietary Allowance:
Nutrient amount sufficient to meet the needs of nearly all healthy individuals (97-98%)
Based on established EARs
Set to prevent chronic disease (rather than just prevent deficiency)
RDA is higher than average human needs
Adequate Intake:
Intake recommendation set when there insufficient data to establish an EAR
Should still cover 97-98% of the population
Can be used for individuals
Estimated Energy Requirement:
Used to estimate energy needs according to:
Height
Weight
Biological sex
Age
Physical activity pattern
Listed values are set at the average daily energy (kcal) need for each life-stage group
EERs are estimates because energy needs depend on many variables (e.g., physical activity level,pregnancy, growth, lactation, etc)
Acceptable Macronutrient Distribution Range:
Set for macronutrients and essential fatty acids
Carbohydrate: 45-65% of kcal
Fat: 20-35% of kcal
Protein: 10-35% of kcal
Nutrient Density:
a tool for assessing nutrient quality of an individual food
Daily values:
Generic standards developed by the Food and Drug Administration (FDA)
Daily Reference Values:
Type of daily value
Reference Daily Intakes:
Type of daily value
Nutrient Content Claims:
Describe the nutrient content of a food
Amount is clearly specified
Health Claims:
Describe the relationship between a disease and a nutrient, food, or food constituent
FDA regulated – require significant scientific agreement to support the claim
Requirements exist for nutritional value beyond just the nutrient in the claim
Structure Function Claims:
FDA does not approve or authorize
Describe how a nutrient affects the body structure or function
Can NOT focus on disease risk
Should be accurate and not misleading
Energy Density:
compares a food’s kcal per gram weight of food
Energy dense foods – high in kcal, low weight; may help those with poor appetite maintain or gain weight
Low energy dense foods – large amounts of water, few kcals
Important concepts to note →
• Know each of the 5 DRIs (EAR, RDA, AI, UL, EER)
o Remember most of these are set for all age groups (0 years of age +)
• Know the AMDRs for each nutrient.
• Nutrient density slides, calculation example
• Daily Values (DRV, RDI)
o Know the difference between the 2 types
o Set for 4 different age groups and used for nutrition facts panels on food labels
• Nutrition labels (what are the different items we see on labels), nutrition facts panel.
• Know the 3 different claims that are used on food labels (Nutrient Content Claims, Health Claims, Structure Function Claims)
Describe the nutrient content of a food
Describe the relationship between a disease and a nutrient, food, or food constituent
Describe how a nutrient affects the body structure or function
o Know the common claims and values per serving
• Energy density slides
o There won't be a calculation on the exam
o You will want to know concepts and identify nutrition energy dense foods
o Know the energy density of common foods (Table 2-4)
• Dietary guidelines for Americans (DGAs) (slides 43 – 52)
o You don’t need to know the changes from the 2015-2020 DGAs but know how they are used, the four overarching guidelines of the DGAs, the importance of these
recommendations, the new age groups being reached, nutrients being limited/alcohol guidelines if consumed
• DGAs in practice (slides 53 – 70)
o Know the MyPlate concepts and recommendations for each food group
o Different categories for vegetables
o Dairy servings
Chapter 4: Digestion and Absorption
Definitions/terms to know →
Adenosine TriPhosphate (ATP):
a nucleotide that serves as the primary energy currency for cells in all living organisms
Lower Esophageal Sphincter (LES):
Food reaches the lower esophageal sphincter and enters the stomach; valve shuts when food is in the stomach
pyloric sphincter:
controls the release of chyme into the small intestine
mechanical digestion:
Physical breakdown of food into smaller pieces
chemical digestion:
Chemical breakdown of large nutrients into their component parts
Segmentation:
a back and forth movement in the small intestine breaks food into smaller pieces
Peristalsis:
the movement of food toward the anus
Enzymes:
proteins that speed up chemical reactions
Amylases:
break down starch into sugars
Lipase:
digests fat
Proteases:
partially digests proteins
Lysozymes:
kills bacteria
Peptidases:
breaks down partially digested proteins
Disaccharidases:
break down disaccharides into monosaccharides
hydrochloric acid (HCl):
Lowers the stomach pH
Inactivates ingested proteins
Kills harmful bacteria and viruses
sodium bicarbonate:
neutralizes acidic chyme
Bile:
emulsifies fats
Feces:
The material in a bowel movement
Probiotics:
Live microorganisms that colonize the large intestine “food” for the bacteria in the colon
Found in fermented foods (yogurt, kefir, miso) and supplements
Prebiotics:
Non-digestible food ingredients
Inulin: chicory, wheat, onions, garlic, asparagus, bananas, Resistant starch
Unprocessed whole grains, seeds, legumes, unripe fruit, pasta, potatoes, rice
Important concepts to note →
• Organization of the human body (slides 1 – 10)
• Know the digestive system and the 2 major components: GI tract (7 parts) + accessory organs (pancreas, liver, gallbladder)
• Know the GI tract anatomy (4 layers) and the sphincters (LES and pyloric)
• Know the GI function: Digestion, mixing/propulsion, digestive enzymes and secretions • Review the “Moving through the GI Tract” slides and thoroughly examine the details taking place at each site: mouth, esophagus, stomach, small intestine, large intestine (slides 22 – 43) o Note the mechanical and chemical digestion taking place in each site.
o Know the different secretions, their function and where they are being secreted (mouth, stomach, small intestine, pancreas, liver, gallbladder): amylases, proteases, lipases, lysozymes, intrinsic factor, hydrochloric acid (HCl), mucous, gastric cells (parietal, chief, G cells), bile (emulsifier), sodium bicarbonate (neutralizes)
o Small intestine: 3 segments, lumen folds (villi and microvilli)
o Large intestine: 3 important functions
o Review major hormones and their functions
• Important points to remember about digestion and absorption:
o Digestion:
▪ Mouth → Carbohydrate and lipid digestion starts
▪ Stomach → Protein metabolism starts, lipid digestion continues
▪ Small intestine → CHO, lipid and protein digestion continues and is completed o Absorption:
▪ Stomach → Water, 20% alcohol
▪ Small intestine → Water, CHO, lipids, proteins, 80% alcohol
▪ Large intestine → Water, some minerals (electrolytes), some fatty acids
• Review nutrient absorption from body to circulatory systems → Either cardiovascular or lymphatic (slides 47 – 51)
o 4 different transport methods from the small intestine to the circulatory system (passive diffusion, facilitated diffusion, active transport, endocytosis (phagocytosis, pinocytosis)) o Which nutrients are absorbed into each system?
• Review the 7 different GI disorders → Causes, examples, contributing factors, symptoms, lifestyle changes, treatment, prevention (Slides 52 – 64).