Chapter 1 - Science of Nutrition Flashcards
Classes of Nutrients
- Carbohydrates
- Lipids(fats and oils)
- Proteins
- Vitamins
- Minerals
- Water
Nutrition
the science of food
- The nutrients and substances therein - Their action, interaction and balance in relation to health and disease - The process by which the organism ingests, digests, absorbs, transports, utilizes and excretes food substances
Nutrients
substances essential for health that the body cannot make or it can only make in small insufficient quantities
- Provide energy, materials for building body parts and factors needed to regulate chemical processes in the body
Characteristics of Nutrients
- Have a specific biological function
- Cause a decline in human biological function if removed from the diet
- Restore normal human biological functions that was impaired by its absence when returned to diet before permanent change
- Cause a decline in human biological function if removed from the diet
Categories of Nutrients
- Those that provide energy(in kcal)
- Those that enable growth and development
- Those that regulate body processes
- Those that enable growth and development
Macronutrients
nutrients needed in gram quantities in our diets
- E.g. proteins, carbs and fats
- Textbook includes water
Micronutrients
nutrients needed in milligram or microgram quantities in a diet
- Vitamins and minerals
Carbohydrates
- Composed of elements such as carbon, hydrogen and oxygen
- main source of fuel for cells- Two types of carbs:
○ Complex: sugars which chemically bond to form large polysaccharides like starch or glycogen
○ Simple: small carbohydrate structures like sugars - Yields 4 calories per gram
- Two types of carbs:
Lipids
- made up of carbon, hydrogen and oxygen
- Lipids yield 9 calories per gram
- lipids are a triglyceride which are the major form of energy storage in the body
- Composed of 3 fatty acid chains attached to a glycerol molecule
○ Either saturated(solid at room temp) or unsaturated(liquid at room temp) based on the chemical structure of fatty acid tails
Protein
- Composed of carbon, oxygen and hydrogen but also contain nitrogen
- The main structural component in the body
○ Major parts of bone, muscle, components in blood, cell membranes, enzymes and immune factors - Provide 4 calories per gram of energy to cells but not a primary source of energy
- The main structural component in the body
Vitamins
- Contain elements such as carbon, hydrogen, nitrogen, oxygen, phosphorous, sulfur and others
- Main function is to enable chemical reactions
- Some of which release energy from carbs, lipids and proteins
- Themselves provide no usable energy for the body
2 groups:
- fat soluble
- water soluble
Fat Soluble Vitamins
- A
- D
- E
- K
As a result fat soluble vitamins are more likely to build up in the body and create toxicity
Water Soluble:
- C
- B Vitamins:
○ Thiamin
○ Riboflavin
○ Niacin,
○ B-6
○ Pantothenic Acid
○ Biotin
○ Folate
○ B-12
- B Vitamins:
Water soluble vitamins are more easily destroyed by cooking and easily excreted from the body
Minerals
- Structurally simple inorganic substances which lack carbon atoms bonded to hydrogen atoms in chemical structure
- Because they are elements they cannot be destroyed during cooking
- Can leak into cooking liquid and be discarded if food is drained
- They yield no energy but are required due to playing key roles in functioning nervous, skeletal systems and in water balance
2 groups:
- major
- trace
Major Minerals
needed daily in gram amounts
- Sodium
- Potassium
- Chloride
- Calcium
- Phosphorus
Trace Minerals
needed in amounts of less than 100 mg daily
- Iron
- Zinc
- Copper
- Selenium
Water
- An inorganic molecule which is needed in the largest quantity
Function of Water in our body:
- Acts as a solvent and lubricant
- transports nutrients to cells
- Helps regulate body temperatures
Phytochemicals
physiologically active compounds in plant components such as fruits, vegetables, legumes and whole grains may provide health benefits
zoochemical
physiologically active compounds found in foods of animals that may provide health benefits
Functional foods
foods rich phytochemicals and zoochemicals which provide health benefits beyond those supplied by traditional nutrients
- May decrease disease risk and/or promote optimal health
Alcohol
- provides 7 kcal of energy per gram
- not a nutrient as it does not provide a function
Use of Energy in the body
- Build new compounds
- Move muscles
- Transmit nerve impulses
- Balance ions within cells
Measure of Energy
Calorie: the amount of heat energy it takes to raise a gram of water 1 degree C used to represent energy in food
Kilocalorie: the amount of heat energy it takes to raise the temperature of 1L of water by 1 degree C
The actual measurement used in everyday life
What Influences Food Choice
- Appetite: psychological influences encouraging us to find and eat food, often in the absence of obvious hunger
- Hunger: physiological drive for food
