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Nutrition

By Vishi08 Mar 13, 2014 3301 Words
1

WHAT IS NUTRITION?
Latin derivative, nutritio, nourish
• “All  the  processes  involved  in  the  taking  in  and  utilization  of  food  substances  by   which growth, repair, and maintenance of activities in the body as a whole or in any of its parts are accomplished. Includes ingestion, digestion, absorption, and metabolism (assimilation). Some nutrients are capable of being stored by the body  in  various  forms  and  drawn  upon  when  the  food  intake  is  not  sufficient.” Tabers Cyclopedic Medical Dictionary

What is food?
• “Any  material  that  provides  the  nutritive  requirements  of  an  organism  to  maintain  growth  and   physical  well  being.”
Tabers Cyclopedic Medical Dictionary
Is food important?......obviously, YES.
What role does food play in the world?

Economic Prosperity/Security

Social Welfare
In the US there is a food stamp
program for those who are
unemployed etc. This raises
political issues based on
taxes.

Geopolitics
Many countries that cannot grow
food and are dependant on
importing food, which has led to
armed conflict. Groups vie to
control the food because if you
can control the food then you
have bargaining and political
power.

LS 2N03 – Human Nutrition for Life Sciences
D.M. Pincivero, 2013

Most Canadians are extremely privileged
and are not aware of food shortages
around the world because food is so
abundant at fairly reasonable prices.

Armed Conflicts
Bargaining and political power often
leads to armed conflict.

2

FOOD, SCIENCE AND WORLD PEACE
Norman Borlaug (Mar 25, 1914 – Sept 12, 2009)
1970 Nobel Peace Prize
• Invented a new strain of wheat (dwarf) which was disease resistant and generated high yields to combat world hunger.
• Exported the new strain to Central America, Middle East, India, Pakistan, Africa
He developed a new strain of wheat which was disease and wind damage resistant. The very long tall wheat, can topple over and breaks before the grains can be yielded. The dwarf wheat is less prone to buckling and breakage and therefore increases the yield.

Dealt with a lot of hunger problems and food shortages in countries that have trouble growing wheat.

WHY ISNUTRITION IMPORTANT?
Nutrition can prevent disease.
a. Diseases caused by nutrient deficiency:
scurvy, goiter, rickets 1:1 relationship
b. Diseases influenced by nutrition:
chronic diseases such as heart disease
c. Diseases in which nutrition plays a role:
osteoarthritis, osteoporosis

LS 2N03 – Human Nutrition for Life Sciences
D.M. Pincivero, 2013

What do we know about obesity? It has gone up, it is staying up.

NUTRITION AND OBESITY IN CANADA

3
In Canada, US, etc. - there is a big increase in the % of the population that is characterized as obese and it is consistent across age spectrum. it is known as an "epidemic". Different from most diseases, as most are caused by person to person transfer of microorganism. You can't give someone obesity. The increase in numbers are over a very short time. Lots of health related and economic

problems caused by obesity. It is
important because of its strain on the
health care system.

Why  do  we  eat  the  way  we  do?......we’re  influenced 1) Physiological hunger

Driven by hormones and the nervous system.
We feel sensations of hunger and we seek to alleviate perceptions by eating. It is instinctive.

2) Sensory stimulation
 Food flavour:
 Texture:

taste and smell We associate pleasurable experiences with eating food. “feel”  of  food  – crisp, chewy, smooth

Studies suggest humans prefer the texture of food rather than the taste. Ex. Skim Milk vs. 2% - the fat content is very different, 2% is thick, where as skim is like water. Titanium dioxide used to be added to skim milk to give it texture, but is not healthy to ingest.

3) Personal preferences
Food we select is based upon experiences and what we are raised with and exposed to. Over time as our perceptions become shaped we form our own experiences we develop personal preferences.

4) Habits: 3 meals/day
There is no scientific evidence for 3 meals a day. It is just a habit we have developed here in Canada based on our life style but there is no evidence to suggest that it is how humans are supposed to eat.

5) Ethnic heritage or tradition
Dictated by food availability in certain geographic locations.



One of the strongest influences on our eating habits/patterns

a) Cultural beliefs and traditions
b) Religion – established rules

Ex. Rhinoceros Beetle - source of vitamin A and protein. It
is a delicacy and tradition in some countries however we
would not eat it in Canada.

LS 2N03 – Human Nutrition for Life Sciences Certain religions have rules: what and when we should be eating D.M. Pincivero, 2013

4

6. Social interactions
Many times you interact with friends and family it is usually around a meal. You dictate your relationships with people based on food.
Ex. Dates - dinner = big commitment, lunch = less commitment

7. Availability, convenience, and economy
Something that is good for us is usually $$$, unhealthy food is usually cheap and more available.

8. Positive and negative associations: commercial advertising

Eat something, makes you sick = negative memory, you wont have that food again. Eat something and something positive happens = positive memory. You formulate memories and depending on what we are doing and associate it with foods. Commercial advertising is also very positive, Ex. Dr. Oz.

9. Emotions:    comfort….instinctive  for  newborns




Comfort food: Food provides comfort during periods of psychological distress. Can be instinctive, ie. breast feeding in new borns.

Food cravings
Beta-endorphins (popular theory for feelings of pleasure) Give us a "high" after eating certain foods. Pica: craving for non-food  items  (dirt,  clay)…pregnancy

10. Values
Vegetarianism: some people choose it out of moral values for not killing animals. When you kill an animal for food, you fuel that sector of the economy. You contribute to more killing and global warming etc.

11. Body weight and image
In the short-term it is a strong motivating factor in the long term it is not very effective. DIETS!! Diets address self image but most do not work.

12. Nutrition and health benefits
Tied to education. People become informed on benefits but it might not be enough to create a change in eating habits.
Tied to traumatic health events. People get "scared straight", person is engaging in destructive behaviour and some key event (ie. heart attack, stroke) happens that will have a direct threat to their way of life which causes the person to change attitudes and behaviours to improve overall health.

LS 2N03 – Human Nutrition for Life Sciences
D.M. Pincivero, 2013

5

SPORTS SUPPLEMENTS
Global market value, 2009: US$4.6 billion (does not include sports drinks, United States largest consumer, two-thirds in world)
1) Sports drinks
• Provides  carbohydrates  and  fluid…..enhance  exercise  performance  and  recovery. • In Canada 2009, valued at $423 million When we exercise we lose water and it stays lost unless we replace it. Sport drinks replace water and the carbohydrates • Gatorade and Powerade

"sugar water"

that we burn. Ingesting carbs during exercise has proved to
be beneficial.

2) Sports food
• Typically found in a bar format
• Nutrient dense and leverages the functional food proposition; that is, it provides health benefits that go beyond their nutritional value Functional food: selection of food selected for maximizing health benefits

• Whey and soy are dominant ingredients
• In Canada, 2009, sales at $85.4 million
3) Sports supplements
Objectives
• Build muscle tissue, increase energy stores/utilization, decrease body fat. Some raise metabolic rates - ephedrine
Forms:
• Tablets, powders, ready-to-drink
Typical ingredients:
• Soy protein, whey protein, creatine, L-carnitine and amino acids (does not include sports drinks)
Market share:
Canada, 2009:
• $114 million
Whey protein is much more popular than
soy protein: whey is superior to soy
because of its quality and digestibility.
Creatine: Contributes to energy turnover of
muscle cells during exercise
Carnitine: Dipeptide that enables muscle
cells to break not fatty acids for energy.
Fatty acids = more energy dense than carbs.
Amino Acids: Protein essential macro
nutrients.

LS 2N03 – Human Nutrition for Life Sciences
D.M. Pincivero, 2013

Protein is designed to be taken after
exercise, that is when our cells are
most sensitive.

6

Nutrient
• Any substance in food that the body can use to obtain energy, synthesize tissues, or regulate physiological/physical functions.
Anything that are cells are doing require macro and micro nutrients, and the food that we take in provides those nutrients.

Essential nutrient An essential nutrient is not a important nutrient. • A substance that must be ingested because the body cannot make it or adequate amounts of it.
Cells have the capacity to make some nutrients (ie. Vitamin D) unfortunately we cannot make them in the winter.
Ex. Vitamins, amino acids, certain fatty acids (Omega 3), carbohydrates

Macronutrient
• A nutrient that is needed in relatively large amounts in the diet (carbohydrates, fats and proteins)
Nutrients that provide energy to our body

Micronutrient
• A nutrient that is needed in relatively small amounts in the diet (vitamins and minerals). Do not carry energy but provide the body with key small molecules to break down macronutrients (ie. glycolysis)

Organic
• In chemistry, any compound that contains carbon, except carbon oxides.

Inorganic
• Any substance that does not contain carbon, except certain simple carbon compounds (carbon dioxide).
“Organic”  food
• Food growth without use of fertilizers, hormones, antibiotics, etc.

LS 2N03 – Human Nutrition for Life Sciences
D.M. Pincivero, 2013

7

“Organic”  food
• Must meet standards of the Canadian Organic Products Regulations. • Crop production
• Livestock production
• Processing
• Cleaners, disinfectants, sanitizers
• Health care products
Organic = conditions in which the plant was cultivated. The soil

Example: Soil and crop nutrition must meet certain regulations as well. •
Over 100 different substances regulated

“Bone  meal: Permitted only if guaranteed free of specified risk materials including the skull, brain, trigeminal ganglia (nerves attached to the brain), eyes, tonsils, spinal cord and dorsal root ganglia (nerves attached to the spinal cord) of cattle aged 30 months or older; and the distal ileum (portion of  the  small  intestine)  of  cattle  of  all  ages.” This suggests non-organic foods probably contains those things. Antioxidant

• A nutrient that that combines with or neutralizes free radicals, preventing oxidative damage to the cell.
Free radicals are damaging your DNA and causing cells to be pre-cancerous. As we get older we lose the ability to deal with free radicals. Certain foods are better at handling diseases than medicine.

Phytochemicals (micronutrients)
• “plant  chemical”.
• Complex chemicals that vary from plant to plant
• Example: orange has over 170 distinct phytochemicals
• Function: fight bacteria and viruses, UV lights, free radicals • Health benefits: cancer prevention (free radical and hormone neutralizing), lowering of LDL cholesterol Cardio-protective: reduces blood pressure

Oxidative Metabolism:
O2 + electrons + protons (ATP)
= H2O
When something goes wrong:
O2 picks up lone eO2- (super oxide anion)
- highly reactive
- binds with cell membranes,
DNA and disrupts membrane
structure
Enzyme that deal with it is
superoxide dismutase. As we
our ability to make the enzyme
deceases.

LS 2N03 – Human Nutrition for Life Sciences Organic vs. Inorganic D.M. Pincivero, 2013

Our cells lose the ability
to deal with the free
radicals as we age.
Cancer: breast,
endometrial, and prostate
cancer are tied to being
affected by what we eat.
Trans-fat, sat-fat = bad.,
mono-saturated and poly
= beneficial.

8

MACRONUTRIENTS

O2 + electrons + protons = ATP for energy to fuel cellular processes (ie. sleeping two muscles must work: cardiac and diaphragm muscles)
Our cells break up ATP to harness energy however we need to replace whatever we use. We have to constantly make ATP because we are constantly using it. We combust fats, nutrients and carbs to make ATP.

1) Carbohydrates
• “hydrate  of  carbon”

Purpose: Supplies energy to the cell
Storage:

Particularly applicable to neurons and RBC (prefer carbs than other macro nutrients). Low carb diet could impair those processes. So our body breaks down protein in our muscles.

Liver and skeletal muscles. We have a storage capacity, as we burn through the carbs they stay depleted unless we replace what was lost.

Example food sources:

Simple or complex CHO
Mostly plants, and rarely in animal products (milk)

Problems/diseases specific to CHO:

- We store carbohydrates as glycogen
- In plants: carbs are found as starch, sugars, and
dietary fibre

Diabetes mellitus

We ingest fibre but we can't break it down.

2) Lipids
• Fats, oils, cholesterol, phospholipids
Purpose:
1) Building block of phospholipids and glycolipids Structure and stability to cell membranes 2) Protein modification by attaching to fatty acids
3) Fuel Dense form of energy - we can make a lot of ATP to burn fat 4) Derivatives serve as hormones and intracellular messengers Take in and form a number of different molecules

Storage:
White adipose tissue and brown adipose tissue (fatty tissue found around our internal organs) Adipose tissue made up of fat cells.

Example food sources:

Meat, dairy etc.

Problems/diseases specific to lipids:
Excessive intake leads to many diseases (ex. coronary)
Unsaturated = healthy
Trans/Saturated Fat = bad

LS 2N03 – Human Nutrition for Life Sciences
D.M. Pincivero, 2013

9

3) Protein
Purpose:
Amino acids are the building blocks. AA are assembled in different order and yields different structure and function. Provide structure and energy if necessary. If carbs are not available some amino acids can be converted into glucose (glucogenic).

Storage:

No central storage location.
They are found in all of our tissues. AA are circulating through our body.

Example food sources:
Meat, fish, dairy, legumes
Animal based sources are better that plant based foods - greater amount and quality. We are eating skeletal muscles which are made up of protein. Some plants are high in protein: soy, lentils

Problems/diseases:
Kwashiorkor: lack of dietary protein, fat deposition into liver, swelling Marasmus: muscle wasting and fat depletion
Excess: heart disease (increased fat), cancers (colon, kidney, prostate, breast), osteoporosis (increased Ca+ excretion)

Non-protein nitrogenous compounds


Composed of amino acids, but not considered to be protein
All are peptides - connecting two or three animo acids together

Examples:






Glutathione Works with vitamin C as an anti-oxidant
Carnitine Molecule mitochondria uses to break up fatty acids for energy Carnosine Dipeptide (two AA) that has anti-oxidant properties Creatine Sports supplement used as an energy supplement, high energy molecule Choline Component of cell membranes and neurotransmitters

LS 2N03 – Human Nutrition for Life Sciences
D.M. Pincivero, 2013

10

MICRONUTRIENTS
Very small molecules that we do not get energy from them, but they enable us to extract energy from macronutrients. Various enzymes that are involved in breaking up macronutrients require micronutrients.

Vitamins
• Organic compounds that contain carbon, hydrogen and other atoms (nitrogen, oxygen, phosphorus)
Function:
• Energy extraction from macronutrients
• Calcium balance
• Blood clotting
2 groups:
1) Water soluble: B vitamins (8) and vitamin C Subject to filtration by the kidney 2) Fat soluble: A, D, E, K
Absorbed with dietary lipids
More prone to toxicity

Minerals
• An inorganic nutrient that is needed for growth and regulation of normal physiology • 16 minerals
Macrominerals: Major minerals required in the diet in larger amounts than the trace minerals. • Na, K, Cl, Ca, P, Mg, S
Trace minerals: Required in small amounts in the diet.
• Fe, Zn, Cu, Mo, Mn, Se, I, Fl
WATER

LS 2N03 – Human Nutrition for Life Sciences
D.M. Pincivero, 2013

11

What is Energy?


An ability to cause changes in, or perform, work, heat and/or mass.



Common definition: ability to perform work.

Forms of energy:






Mechanical
Electrical
Thermal
Chemical
Nuclear

-

moving physical objects
moving charges (electrons)
increasing temperature (randomness)
binding/unbinding of bonds
binding/unbinding of nucleons

calorie
• is the amount of energy needed to raise the temperature of 1 gram of water by 1 degree C. 1,000 calories = 1 kcalorie = 1 Calorie
Energy density: amount  of  energy  in  a  food  source  relative  to  its’  mass. Delivers a lot of calories per until mass (g).

Nutrient density: amount  of  nutrients  in  a  food  source  relative  to  its’  energy  content. Opposite to energy density.
Delivers a lot of macro and micro nutrients per kcalorie
Where is this food energy?.......chemical bonds (ATP)

Which nutrients provide energy?.......macronutrients fats, proteins, carbohydrates How does our body use this food energy?.......metabolism to support life ***ENERGY BALANCE EQUATION***
Energy IN = Energy OUT + E STORAGE
Macro

= Macro Nutrient Combustion + CHO (liver, skeletal muscles)
Lipids (adipose)
TYPE OF FOOD
Proteins
PHYSICAL ACTIVITY LEVEL, DISEASE, DRUGS
(effects whether we store or combust macro)

LS 2N03 – Human Nutrition for Life Sciences
D.M. Pincivero, 2013

12

How much energy do the macronutrients provide?
Carbohydrates

=

4 kcal/gram

Protein

=

4 kcal/gram

Lipids (fats)

=

9 kcal/gram

Example: One half avocado
• 101 grams, 2 g protein, 9 g carbohydrates, 15 g fat = 161 kcalories Doesn’t  add  up!!!! = (2 x 4) + (9 x 4) + (15 x 9) = 179 kcalories Why not?.....hint…..a  carb  is  a  carb is a carb?
Monounsaturated fat is good for you however they still carry a large amount of calories. Not all carbs are the same:
161 = amount of energy available to our cells
179 = total calories in food item: what is available to us + fibre The remaining calories are in fibre which our digestive system cannot break up and absorb

LS 2N03 – Human Nutrition for Life Sciences
D.M. Pincivero, 2013

13

DIETARY REFERENCE INTAKES



Standards defined for energy nutrients, other dietary components, physical activity Recommendations apply to healthy people
 May be different for specific groups

LS 2N03 – Human Nutrition for Life Sciences
D.M. Pincivero, 2013

14

DIETARY REFERENCE INTAKES
Estimated Average Requirement (EAR)
• The average daily intake level of a nutrient that will meet the needs of half of the people in a particular category.
Used to establish the RDA

Recommended Dietary Allowances (RDA)
• The average daily intake level required to meet the needs of 97 – 98% of people in a particular category. Based on age and requirement
Listed on nutritional labels

Example:
Protein intake for a 19 year old woman = 46 grams/day (10-35%) Number in parenthesis is AMDR
Absolute vs. relative (0.8 grams/kg/day)
This suggests protein should make up 10-35% however the problem is our protein intake should be determined by our body size. Physical activity is also a determinant.

Adequate Intake (AI)

Recommended average daily intake level for a nutrient

Based on observations and estimates from experiments

Used when the RDA is not yet established: e.g., calcium, vitamin D, vitamin K, fluoride Difference between AI and RDA is the amount of evidence to support RDA AI is reported for some, and RDA for other. Either or.

Example:

Vitamin K for 15 year old male = 75 ng/day
Blood clotting factor synthesis, bone protein formation
Food sources: liver, green leafy vegetables, cabbage family

Tolerable Upper Intake Level (UL)

Highest average daily intake level that is not likely to have adverse effects on the health of most people

Consumption of a nutrient at levels above the UL is not considered safe •
Protects against over-consumption
Amount of micronutrient that can be ingested without experiencing toxicity like symptoms

Example:
Vitamin C - water soluble
Taking it near the UL = not beneficial, because most of it will be excreted Anti-oxidant, prevent iron absorption, amino acid metabolism 55 year old woman = 2000 mg/day
Toxicity: abdominal cramps, diarrhea, haemolytic anemia
Children are most prone to vitamin toxicity

LS 2N03 – Human Nutrition for Life Sciences
D.M. Pincivero, 2013

15

DIETARY REFERENCE INTAKES

LS 2N03 – Human Nutrition for Life Sciences
D.M. Pincivero, 2013

16

Estimated Energy Requirement (EER)

Average dietary energy intake (kcal) to maintain energy balance •
Based on age, gender, weight, height, level of physical activity

Acceptable Macronutrient Distribution Ranges (AMDR)

Describes the portion of the energy intake that should come from each macronutrient •
Expressed as ranges (percentage of total energy) with upper and lower boundary.

Nutrition Assessment
Individual Level

Deficiency or excess over time leads to malnutrition

Symptoms of malnutrition

Diarrhea

Skin rashes

Fatigue

Others


Creating  a  “total  picture”  of  the  individual Body weight is the best predictor of cardiovascular health!! – Historical information
• Health status
• Diet history – intake over several days; portion sizes; computer analysis – Anthropometric measurements
• Height and weight – track to identify trends
– Physical examinations
– Laboratory tests

LS 2N03 – Human Nutrition for Life Sciences
D.M. Pincivero, 2013

17

NUTRITION INFORMATION
Registered Dietitian
• http://www.dietitians.ca/
College of Dietitians of Ontario
• http://www.cdo.on.ca/en/
Scientific information database: PubMed
• http://www.ncbi.nlm.nih.gov/pubmed
Credible websites
• See Table H1-2 (page 32)
• Health Canada (www.hc-sc.gc.ca)
• Canadian council of Food and Nutrition (www.ccfn.ca)
• University, hospital, health network websites

LS 2N03 – Human Nutrition for Life Sciences
D.M. Pincivero, 2013

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