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Lecture 1

LIFESCI 2N03 Lecture Notes - Lecture 1: The Chances, Starch, Phospholipid

Life Sciences
Course Code
Gang Wu

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Lecture 1 Review:
Foods with high energy density provide more kcalories than food with low
energy density. In the breakfast example the toast with the fruit salad, sausage
, etc. although oered thee times as much food as the donut and coee; it had
less energy density which means it overall provided less kcal.
Why do people eat particular foods:
Social interactions
Health bene$ts
Why is nutrition important?
Some diseases are causes by nutrient de$ciency
Some diseases are in&uenced by nutrition
Nutrition plays a role in some diseases
What is nutrition?
The science of foods and the nutrients they contain and of their actions within
the body which includes the social, economic, cultural and psychological
implications of food and eating.
What is a Nutrient?
Any substance in food that the body can use to obtain energy, synthesize
tissues and regulate physiological/physical functions
Essential: amino and fatty acids
Macro: proteins, carbohydrates , fats
Micro: minerals and vitamins
Types of nutrients
Energy- yielding nutrients contain kcalories and are associated with energy
Non-energy yielding nutrients contain no calories and are not associated with
Energy yeilding contains: proteins, carbs, fats
Non- energy yielding: vitamins, minerals and water
Organic nutrients refers to nutrients that contain carbon
Minerals and water are inorganic compounds
Proteins, lipids(fats), carbs and vitamins are organic compounds
That is they contain carbon, hydrogen oxygen
Only proteins contain Nitrogen
Mineral contain just minerals
Water contains hydrogen and oxygen.
Unit of measurement

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Kcalories= Kcal
Carbohydrates 4 kcal/g
Fats 9 kcal/g
Proteins 4 kcal/g
Essential nutrients: nutrients that we must ingest through food because the body
cannot make them
Macronutrients: nutrients required in large amounts
Micronutrients: Nutrients required in small amounts
In order to harness energy food must undergo metabolisms- which refers to
the process where food is broken down to yield energy or to form body
When macronutrients are metabolized, they can be used immediately or
stored for later.
Either way, they are eventually used to regulate all activities in the body, like
sending electrical signals to the brain and nerves, physical activity or
synthesizing body compounds.
Supplies energy to cells
It is stored in the liver and skeletal muscles
Sources include complex or simple carbohydrates that are found in fruits,
vegetables, starches and grains
Over ingestion of carbohydrate can lead to type 2 diabetes
Building blocks of phospholipids and glycolipids
Derivatives serves as hormones and second messengers
Assists in protein modi$cation by attaching to fatty acids
Stored in the adipose tissue
Source: meat, diary products, avocado, coconut, olives
Diseases: obesity, coronary disease, high blood pressure(atherosclerosis)
Structure and energy, stored in every tissue
Can be food in meats diary products, vegetables, legumes, grains, $sh
Disease: lack of protein leads to kwashiorkor: swelling, fat deposition into liver
Marasmus: muscle wasting and fat depletion
Excess protein can lead to: cancer, heart disease osteoporosis.
Kwashiorkor: lack of protein but su<cient carbs and fat
Marasmus: lack of energy-yeilding nutrients( fats carbs, proteins)
Range of energy intake that should come from each micronutrient
Carbs 45-60%
Fats 20-35%
Protein 10-35%
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