Transcript Slide 1

Option A: Human nutrition and
health
Define nutrient.
A Nutrient is a
chemical
substance
found in foods
that is used in
the human
body.
http://www.faqs.org/nutrition/images/nwaz_02_img0168.jpg
List the type of nutrients that are
essential in the human diet:
Amino acids are the
building blocks of protein . The
body has twenty different amino
acids that act as these building
blocks.
Nonessential amino acids are those
that the body can synthesize for
itself, provided there is enough
nitrogen, carbon, hydrogen, and
oxygen available.
Essential amino acids are those
supplied by the diet , since the
human body either cannot make
them at all or cannot make them in
sufficient quantity to meet its
needs.
Under normal conditions, eleven of
the amino acids are nonessential
and nine are essential.
Fatty Acids
Saturated fatty acids can align closely
together so lipids containing primarily
saturated fatty acids are usually solid at room
temperature (aka Fat).
The C=C double bond(s) in unsaturated fatty
acids causes the molecule to "bend" (a fatty
acid with one C=C bond is monounsaturated, a fatty acid with several C=C
bonds is poly-unsaturated.
Because they are "bent", unsaturated fatty
acids are less able to interact and lipids
contain primarily unsaturated fatty acids are
liquid at room temperature (oils).
•
Trans fatty acids are manufactured fats
created during a process called
hydrogenation, which is aimed at
stabilizing polyunsaturated oils to
prevent them from becoming rancid
and to keep them solid at room
temperature. They may be particularly
dangerous for the heart and may pose
a risk for certain cancers.
Hydrogenated fats are used in stick
margarine, fast foods, commercial
baked goods (donuts, cookies,
crackers), processed foods, and fried
foods.
Cis and trans are terms that refer to the arrangement of chains of carbon atoms across
the double bond. In the cis arrangement, the chains are on the same side of the double
bond, resulting in a kink. In the trans arrangement, the chains are on opposite sides of
the double bond, and the chain is straight.
•
•
Omega-3 fatty acids are a form of
polyunsaturated fat that the body
derives from food. Omega-3s (and
omega-6s) are known as essential
fatty acids (EFAs) because they are
important for good health. The body
cannot make these fatty acids on its
own so omega-3s must be obtained
from food. These different types of
acids can be obtained in foods such
as cold-water fish including tuna,
salmon, and mackerel. Other
important omega 3 fatty acids are
found in dark green leafy vegetables,
flaxseed oils, and certain vegetable
oils.
Omega-3 fatty acids have been found
to be beneficial for the heart. Positive
effects include anti-inflammatory and
anti-blood clotting actions, lowering
cholesterol and triglyceride levels, and
reducing blood pressure. These fatty
acids may also reduce the risks and
symptoms for other disorders
including diabetes, stroke, rheumatoid
arthritis, asthma, inflammatory bowel
disease, ulcerative colitis, some
cancers, and mental decline.
Minerals
These foods are all “mineral dense” foods. Find out which
minerals are in each food.
http://hachten.com/monavie/wp-content/images/19-fruits.jpg
Vitamins
A vitamin is an organic compound
required as a nutrient in tiny amounts by
an organism
http://www.childrenfirst.nhs.uk/teens/images/healthyeating/vitamins.jpg
• This might be a useful table to help
you fill in the Minerals lists.
http://www.healthalternatives2000.com
/minerals-nutrition-chart.html
Make a table!
Vitamin
A
B1
B2
B3
B12
C
D
E
Name
Use
Deficiency
disease
Too
much
RDA
Good
source
Water
Roughage / Fibre
Consists mainly of Cellulose
which is insoluble and
indigestible by animals. Forms
bulk which allows the gut to
move the food.
Not enough fibre causes
constipation in the short term,
and may lead to spastic colon in
long term and cancers of the gut
due to build up of poisons.
Go once a day!
Good sources: Fruit and
vegetables.
http://fitness.resourcesforattorneys.com/images/dietary-fiber.jpg
Outline the consequences of protein
deficiency malnutrition.
• Protein deficiency is shortage of one or
more essential amino acids.
• The consequences are lack of blood
plasma proteins and subsequent tissue
fluid retention, with swelling of the
abdomen.
• Development of children is likely to be
both mentally and physically retarded.
Kwashiorkor – a protein deficiency
• Kwashiorkor is a condition that
affects children who belong to
areas that have experienced
shortage of food. This is usually
places where famine has struck.
Among the lesser educated
classes of society also
Kwashiorkor is a fairly common
problem since the lack of
awareness about a balanced diet
often leads to a an inadequate
consumption of proteins.
Try this website for some amazing
pictures:
http://www.jamesnachtwey.com/
Explain the causes and consequences of phenylketonuria (PKU) and how
early diagnosis and a special diet can reduce the consequences.
• Phenylketonuria (PKU) is an autosomal
recessive genetic disorder characterized by a
deficiency in the hepatic enzyme phenylalanine
hydroxylase (PAH) This enzyme is necessary to
metabolize the amino acid phenylalanine ('Phe')
to the amino acid tyrosine. When PAH is
deficient, phenylalanine accumulates and is
converted into phenylpyruvate (also known as
phenylketone), which is detected in the urine.
Watch this YouTube clip :
http://www.youtube.com/watch?v=KUJVujhHxPQ
• It can be managed by a patient controlling their
diet with little or no side effects, just
inconvenience with managing the treatment. If
however the condition was left untreated, it can
cause problems with brain development, leading
to progressive mental retardation, brain damage,
and seizures.
• There is currently no cure for this disease,
although some treatments are available with
varying success rates. PKU is generally
detected through newborn screening with a heal
prick test done at 10 days of age.
Evaluate the health consequences
of diets rich in the different types of
fatty acid.
Dietary studies are difficult to control sufficiently to gain really reliable data.
Where data are produced it may not be possible to conclude causal
relationships from correlation. Care must be taken to think critically about
nutrition-based news stories and articles.
Distinguish between minerals and
vitamins in terms of their chemical
nature.
• Minerals are elements in ionic
form.
• Vitamins are organic
compounds.
Outline two of the methods that have been used to determine the
recommended daily intake of vitamin C.
Some of the experiments used to determine
necessary levels of vitamin consumption were
done using conscientious objectors during the
second world war. This raises ethical
questions about trials in which the
experimental subjects could be harmed or
suffer.
Look at this website for detailed description of
what they did! It is fascinating.
http://ije.oxfordjournals.org/cgi/content/full/35/3/
556
•
•
•
During World War II, 36 conscientious
objectors participated in a study of human
starvation conducted by Ancel Keys and his
colleagues at the University of Minnesota. The
Minnesota Starvation Experiment, as it was
later known, was a grueling study meant to
gain insight into the physical and psychological
effects of semi-starvation and the problem of
re-feeding civilians who had been starved
during the war.
During the experiment, the participants were
subjected to semi-starvation in which most lost
>25% of their weight, and many experienced
anemia, fatigue, apathy, extreme weakness,
irritability, neurological deficits, and lower
extremity edema.
In 2003–2004, 18 of the original 36 participants
were still alive and were interviewed. Many
came from the Historic Peace Churches
(Mennonite, Brethren, and Quaker), and all
expressed strong convictions about
nonviolence and wanting to make a meaningful
contribution during the war. Despite ethical
issues about subjecting healthy humans to
starvation, the men interviewed were
unanimous in saying that they would do it all
over again, even after knowing the suffering
that they had experienced.
• Life
magazine
photograph of
conscientious
objectors
during
starvation
experiment.
Life Magazine - July 30, 1945. Volume 19, Number 5, p. 43. Credit: Wallace
Kirkland/Time Life Pictures/Getty Images
Animal trials on Vitamin C
• Guinea pig trials: observed the effect of
vitamin C concentration on collagen
structure. After periods of varying vitamin
C supplementation and measurement of
blood and urine vitamin C levels, guinea
pigs were sacrificed and the structure of
collagen fibres observed. Guinea pigs
with restricted vitamin C showed weaker
collagen.
• Think ethics! What is vivisection?
Can it be justified?
http://www.woodwindsanimalhotel.com/images/guinea-pig.jpg
What is rebound malnutrition?
• Rebound malnutrition can occur when a
normally adequate intake of a vitamin
follows a period of excessive intake and
excretion.
List the sources of vitamin D in
human diets.
• Vitamin D can be produced by skin as a
response to sunlight.
It also can be found (in a slightly different
form) in foods: fatty fish, fish oils, liver,
eggs and some mushrooms.
In some countries, milk is supplemented
with vitamin D.
Finding balances……
Vitamin how
D is synthesized
Suggest
you might in
But too much
Ultraviolet
Suggest
how
the
skin
the
skin
with
exposure
ensure you get enough to
radiationitself
can from
cause
Skin
protects
skin
Vitamin D sunlight.
in a
Cancer
cancer.
Norwegian winter.
Now using your food diary…..
Go to http://www.myfoodrecord.com/mainnat.html
1. For the 24 hours you recorded in homework do a diet
analysis.
2. Make up an ‘ideal’ MacDonalds Day diet, of breakfast,
lunch afternoon snack and dinner. Each meal must be
different!
Answer the following questions:
• What was your diet good for?
• What mineral, vitamin or other nutrient was lacking in
your diet?
• What suggestions could you make to improve your diet?
Compare the energy content per 100 g of
carbohydrate, fat and protein.
Food type
Energy per
100g (kJ)
carbohydrates
1,760
protein
1,720
fats
4,000
Compare the main dietary sources of energy in
different ethnic groups.
The 5 most grown carbohydrate sources are:
Crop
Wheat
Production
(Million ha)
624
Rice
608
Maize
705
Barley
155
Sorghum
60
http://www.darfu4b.da.gov.ph/images/New%20Folder/cassava_pic.JPG
Maize
http://en.wikipedia.org/wiki/File:MaizeYield.png
Wheat
http://upload.wikimedia.org/wikipedia/commons/1/10/WheatYield.png
Rice
http://en.wikipedia.org/wiki/File:RiceYield.png
Explain the possible health consequences of diets rich in
carbohydrates, fats and proteins.
Outline the function of the appetite control centre
in the brain.
Hormones/Nervous impulse
Hormones are produced
by the pancreas and
small intestine after
eating and by adipose
tissue in response to fat
storage. These pass to
an appetite control centre
in the brain, which makes
the person feel that they
have eaten enough.
Horn, Robert. Appetite and Metabolism and Obesity.
MedBio.info. [Online] 2006. [Cited: June 24, 2009.]
Appetite is controlled in the
hypothalamus of the brain.
Control is both nervous and
hormonal: some hormones
trigger appetite-stimulating
neurons, others trigger
appetite-inhibiting neurons.
An empty stomach releases the
hormone gherin, which triggers
appetite-stimulating hormones,
leading to hunger. When food
enters the stomach, gherin
production is stopped, reducing
hunger.
1. Food entering the intestine stimulates
release of PYY3-36 hormone.
2. Carbohydrate and protein digestion stimulate
release of insulin hormone from the
pancreas.
3. Fat storage stimulates release of leptin
hormone from the pancreas. This is
enhanced by insulin.
These three hormones trigger appetite-inhibiting
neurons in the appetite control centre.
There are strong links to malfunction of any of these pathways and obesity,
as the individual eats more than is required.
Calculate body mass index (BMI) from the
body mass and height of a person.
BodyMass ( Kg )
• BMI =
2
Height ( m )
Limitations of the BMI using this table:
• Race, gender and age are not considered
• No distinction is made on body fat/water/muscle composition
Work out the BMI for the following:
Height (m)
Body Mass (kg)
1.70
54
BMI
Category
We is getting’ fat…….
• Increased levels of obesity world-wide…
Childhood obesity has more than tripled in the
past 30 years.
An estimated 17 percent of children and
adolescents (ages 2-19 years) are obese in the
U.S.
Obese children are at risk for numerous health
problems during their youth and into adulthood.
Children who are obese are more likely to have
high blood pressure, high cholesterol, and
Type 2 diabetes.
Why?
http://www.getamericafit.org/images/american-obesity-trends.gif
http://www.yisongyue.com/silly/misc/ObeseMouse.jpg
http://media.photobucket.com/image/obese/grimrecords/Obese.jpg?o=4
http://images.mirror.co.uk/upl/m4/dec2009/2/0/obese-flight-passenger-pic-kieran-daly-94182647.jpg
http://maxcdn.fooyoh.com/files/attach/images/591/206/098/005/chinese_obese_7caa7.jpg
http://resources3.news.com.au/images/2011/03/23/1226026/741679-obese-todler.jpg
http://joannaburns.files.wordpress.com/2008/11/mcdonalds.jpg
http://3.bp.blogspot.com/_DQXAKB1OvOw/TSQJ2R1rAzI/AAAAAAAAANg/Y4QDJNUUtkE/s1600/fat_american_walking_dog_from_car-1.jpg
http://health.lifegoesstrong.com/sites/default/files/imagecache/reg/article_media/fat_office_worker.jpg
increasing
use
ofactive
vehicles
Cheap
A change
High
from
energy
foods
to
for transport,
sedentary
Large
portion
occupations.
sizes
At the other extreme….
http://medicallywiseinfo.co
m/wpcontent/uploads/2010/03/
Anorexia-nervosa0.jpg
http://www.womenshealth
zone.net/eatingdisorders/anorexianervosa/effects/img/1287.
gif
Comparison of Human Milk and Formula
NUTRIENT FACTOR
BREAST MILK CONTAINS
Fats
•Rich in brain-building omega 3s, namely DHA and AA
-Automatically adjusts to infant's needs; levels decline as baby gets older
-Rich in cholesterol
-Nearly completely absorbed
-Contains fat-digesting enzyme, lipase
FORMULA CONTAINS
-No DHA
-Doesn't adjust to infant's needs
-No cholesterol
-Not completely absorbed
-No lipase
Protein
-Soft, easily-digestible whey
-More completely absorbed; higher in the milk of mothers who deliver preterm
-Lactoferrin for intestinal health
-Lysozyme, an antimicrobial
-Rich in brain-and-body- building protein components
-Rich in growth factors
-Contains sleep-inducing proteins
-Harder-to-digest casein curds
-Not completely absorbed, more waste, harder on
kidneys
-No lactoferrin, or only a trace
-No lysozyme
-Deficient or low in some brain-and body-building
proteins
-Deficient in growth factors
-Does not contain as many sleep-inducing proteins.
Carbohdrates
-Rich in lactose
-Rich in oligosaccharides, which promote intestinal health
-No lactose in some formulas
-Deficient in oligosaccharides
Immune Boosters
-Rich in living white blood cells, millions per feeding
-Rich in immunoglobulins
-No live white blood cells-or any other cells. Dead
food has less immunological benefit.
-Few immunoglobulins and most are the wrong kind
Vitamins and
Minerals
-Better absorbed, especially iron, zinc, and calcium
-Iron is 50 to 75 percent absorbed.
-Contains more selenium (an antioxidant)
-Not absorbed as well
-Iron is 5 to 10 percent absorbed
-Contains less selenium (an antioxidant)
Enzymes and
Hormones
-Rich in digestive enzymes, such as lipase and amylase
-Rich in many hormones: thyroid, prolactin, oxytocin, and more than fifteen others
-Varies with mother's diet
-Processing kills digestive enzymes
-Processing kills hormones, which are not human to
begin with
-Always tastes the same
Cost
-Around $600 a year in extra food for mother
-Around $1,200 a year
-Up to $2,500 a year for hypoallergenic formulas
-Cost for bottles and other supplies
-Lost income when baby is ill
Breast is best……..
(Discuss the benefits of breast feeding)
Look at some of these sites:
http://www.pregnancyandchildren.com/pregnancy/pregnancy
_breast_milk_versus_formula.htm
http://www.webmd.com/parenting/baby/your-babys-feedingbreast-vs-bottle
http://www.007b.com/breast_versus_bottle.php
http://www.burpingbaby.net/breast_vs_bottle.htm
Make a table of the pros and cons of breast- and
bottle-feeding:
Issue
Breast feeding
Bottle feeding
Costs
Free? US$600 per year on extra
food for mother
US$1200- 2000 on formula and
equipment for one year.
Loss of earnings while baby is ill
Immunity
Legality
Privacy
Drugs
Alcohol
Disease
(Mother’s)
Diabetes (type II)
• Go to this site:
http://en.wikipedia.org/wiki/Diabetes_mellitus_type_2
1. Outline the causes and symptoms of type II diabetes.
What is polyuria, polydipsia and polyphagia?
2. What are the differences in susceptibility between
ethnic groups and suggest a reason why? (especially
Native Australians, Native Americans, Latinos, Pacific
Islanders.
3. Explain the dietary advice that should be given to a
patient who has developed type II diabetes.
Discuss the ethical issues concerning the eating of
animal products, including honey, eggs, milk and meat.
Look at this great page…..
http://debatepedia.idebate.org/en/index.php/Debate:_Vegetarianism#Dominion:_Do_
humans_NOT_have_dominion_over_animals_.28and_a_right_to_eat_them.29.3F
Discuss the concept of food miles and the reasons
for consumers choosing foods to minimize
Go to this website – this is where I found these 2 posters…
http://hawthornevalleyfarm.org/fep/food.html
Evaluate the benefits of reducing dietary
cholesterol in lowering the risk of coronary heart
disease.
Take a look at these websites:
1. An editorial introduction to the debate:
http://drpeterdingle.blogspot.com/2010/09/cholesterol-debate.html
2. Link between cholesterol and heart disease- A bit long but detailed:
http://www.cholesterol-and-health.com/Does-Cholesterol-Cause-HeartDisease-Myth.html
3. Functions of cholesterol:
http://www.cholesterol-and-health.com/Steroid-Hormones.html
http://www.cholesterol-and-health.com/Cholesterol-Cell-Membrane.html
http://www.cholesterol-and-health.com/Memory-And-Cholesterol.html
http://www.cholesterol-and-health.com/Bile-Acids.html
http://www.cholesterol-and-health.com/Vitamin-D.html
4. For the alternative viewpoint look at this site:
http://www.bhf.org.uk/heart-health/conditions/high-cholesterol.aspx