Nutrients and Homeostasis
Dec 25, 2015
Macromolecules vs. Macronutrients
Macromolecules are large, complex molecules that make up polymers
4 MACROMOLECULES:• Carbohydrates• Proteins• Fats• Nucleic Acids
Macronutrient is a type of food required in large amounts in the human diet
6 GROUPS OF NUTRIENTS: • Carbohydrates• Proteins• Fats• Vitamins• Minerals• Water
What are Carbohydrates?• Should make-up ~50-60% of daily calories• Purpose:
– Provide the body with short term energy– Preferred energy source– Our body converts all carbohydrates to glucose (simple
sugar)– Carbohydrates not used will be stored by your body as fat
• Two types:– Simple– Complex
What are Simple Carbohydrates?• Easily broken down• Provides quick energy• Simple sugars are probably the largest source of
cellular energy • Examples:
– Glucose– Fructose– Lactose
Fruit is a type of simple carbohydrate, like cake. But, why is fruit a better option for fuel than cake? What are some
differences?
What are Complex Carbohydrates? • Broken down more slowly
– More fiber– Feel fuller, for longer
• Majority of carbohydrates in your diet should be complex carbohydrates!
• Examples:– Whole grains– Legumes – Seeds
Proteins• Purpose:
– Promotes muscle and connective tissue growth– Formation of antibodies to strengthen immune system– Foundation of hormones, enzymes, and blood cells
• 10-35% of your daily calories should come from protein
• Two Types:– Complete– Incomplete
Complete vs Incomplete Proteins
• Complete Protein– Contains amounts of 9 essential amino acids– Examples: fish, meat, poultry, eggs, milk, cheese,
yogurt, soy• Incomplete Protein
– Lack 1+ essential amino acids – Examples: beans, peas, nuts and whole grains
What are Fats?• Fats are a type of lipid, a fatty substance that does not
dissolve in water (hydro-phobic)• 20-30% of your daily calories should come from fat• Purpose:
– Essential for absorption of some vitamins– Long term energy storage → keeps you FULL! – Protects body organs/cell membranes
• The “building blocks of fats” are called fatty acids • Two types:
– Saturated– Unsaturated
What are Saturated Fats?• Straight, fatty acid chain with all single bonds• Easier for body to break down, but not as useful • Solid at room temp• Most ANIMAL fats
– Examples:• White, visible fat found in meats• Lard, Crisco, butter• Coconut and palm oils• Dairy products
✦ Whole milk✦ Cream✦ Hard cheeses
• High intake is associated with an increased risk of heart disease and high cholesterol
What are Unsaturated fats?• Kinked, fatty acid chain
with a double bond• Harder for body to break
down, but more useful• Liquid at room temp• Most PLANT fats
– Examples:• Olive, vegetable, and canola
oil• Nuts/nut butters• Fish oils• Avocado • Associated with a reduced risk of
heart disease
Function of Nucleic Acids
•Stores genetic information •Gene – specific piece of DNA that codes for a specific protein
And now for your viewing delight… .. http://www.youtube.com/watch?v=nt9u7CfVoc4
Vitamins & Minerals
• Vitamins are compounds that help regulate many vital body processes that include digestion, absorption, metabolism, and circulation
• We will break this down into three types:– Water Soluble Vitamins– Fat Soluble Vitamins– Minerals
What does it mean for something to be SOLUBLE??
Vitamins & MineralsWater-soluble vitamins
• Dissolve in water and pass easily into the blood during digestion• The body does not store these so they need to be replenished
regularly • Includes vitamins C, B1 ,B2, Niacin, B6, Folic acid, and B12
Fat-soluble vitamins • Absorbed, stored, and transported in fat• Body stores these vitamins in fatty tissue, liver, and kidneys • Excess buildup can be toxic → including vitamins A, D, E, and K
Minerals• Substances that the body cannot manufacture• Needed for forming healthy bones and teeth• Important minerals include calcium, phosphorus, magnesium, and iron
Why is Water Important?• Water makes up, up to 65% of our body • Water helps maintain bodily functions
• Lubricates joints and mucous membranes• Helps us swallow and digest foods • Absorbs other nutrients and eliminates waste• Sweat helps us maintain a normal body temperature
• It’s important to drink at least 8 cups of water/ day to maintain health
How Many Calories Do I Need?• What is a calorie?
– unit used to measure the energy value of foods– men and women have different caloric needs
How Many Calories Do I Need?
• To burn 1 pound of fat you must burn 3,500 calories– 1 pound a week = 500 calories a day burned– 2 pounds a week = 1,000 calories a day burned
• So, how do we figure out how to eat the right amount of calories?– Reading nutrition labels– Calculating calories in/out
• Product labeling shows a food’s nutritious value
• Some common used terms are light, less, free, more, rich, rich in, lean, or excellent source of…
• Many food products have open dates on their label• Examples are
expiration date, freshness date, pack date, and sell-by date
Understanding Nutritional Labels • Start with the serving
size– Provided in units like
cups, grams, or pieces…
• Try to pay attention to the serving size (how many servings there are in the food package)– Example: A package of
pop-tarts is TWO servings
Understanding Nutritional Labels • Next, look at the calories (& calories from fat)
– We usually consume more calories than we need WITHOUT meeting our RDA for vitamins/nutrients
• Rule of thumb – for a 2000 calories diet– 40 calories is low– 100 calories is moderate– 400+ calories is high
Understanding Nutritional Labels • Finally, Daily Values (DV)• Foot note at the bottom of all labels shows the DVs for a 2,000
and 2,500 calorie diet– Notice cholesterol and sodium do not increase
• These are values to use as a benchmark when eating (based on a 2,000 calorie diet):
Nutrient DV DV% Goal
Total Fat 65 g = 100%DV Less than
Sat. Fat 20 g = 100%DV Less than
Cholesterol 300 mg = 100%DV Less than
Sodium 2400 mg = 100%DV Less than
Total Carbohydrates 300 g = 100%DV At least
Dietary Fiber 25 g = 100%DV At least
Understanding Nutritional Labels • Daily Values Percentages (DV%) are
recommendations for a 2,000 calories diet ONLY
• Helps determine if a serving of food is high or low in a nutrient
• Rule of thumb: 5% is low, 20% is high • Example – This mac & cheese food makes up
18% of the fat for a 2,000 calorie diet
Notice how much fat you will still have for your diet if you eat 1 serving….or 2….