Macronutrients
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Macronutrient is defined as a nutrient that is needed in large amounts and has lots of functions
in our bodies.
Three of the essential nutrients our bodies need are called macronutrients.
These macronutrients are also the energy producing nutrients.
The Three macronutrients are Carbohydrates, Fats, and Protein.
CARBOHYDRATES
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are the sugars, starches and fibres in your diet.
Are made up of three common chemical elements: carbon, hydrogen and oxygen.
When these elements are bonded together they form what are called sugar units or saccharides.
The way these elements are bonded together determines the type of sugar/saccharide unit
achieved. It also dictates the level at which the carbohydrates are able to be broken down.
Simple patterns or Complex patterns.
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The three saccharide groups are:
1. Monosaccharides
2. Disaccharides
3. Polysaccharides
1. Monosaccharides
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are the smallest carbohydrate molecules, they are made up of one single sugar unit.
Single sugar units/monosaccharides are easily digested and absorbed across the
intestinal wall and available for energy.
There are three monosaccharides: glucose, fructose and galactose. Glucose and
fructose stand alone but galactose is always bonded to glucose.
Glucose – is our body’s major source of energy.
Fructose – is found naturally in honey and fruits
Galactose – always bonded with glucose and this bonding can be problematic for
individuals that don’t have the enzyme necessary to break the bond that allows
digestion. (see next overhead)
2. Disaccharides
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Disaccharides are made up of double sugar units.
The body uses enzymes to breakdown down these sugar units, once the action of the
enzymes occurs the disaccharides are turned into monosaccharides so they can be
digested and absorbed into the body as a source of energy.
There are three different disaccharides: sucrose, maltose, and lactose.
Sucrose – is the sugar we use in our baking or in our coffees it is also found in many
foods like molasses and maple syrup. It is made up of two bonded monosaccharides –
glucose and fructose.
Lactose – is found in milk, again it is made up of two bonded monosaccharides –
glucose and galactose.
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Maltose – is found in some grain products but is also produced when the body breaks
down starch. It is made up of to identical and bonded monosaccharides - glucose and
glucose.
3. Polysaccharides
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Polysaccharides are made up of many bonded monosacchrides.
Again it is necessary for our body to breakdown these bonded units in order for us to
digest them. This is done by the secretion of enzymes used to break the bonds that
connect the monosacchrides.
 There are two types of polysaccharides: starch and fibres
 Starch – starch is found in grains and pastas as well as starchy vegetables. Starch is
made up of many bonded glucose molecules. Starch is actually formed in plants
through the process of photosynthesis. Starch is a plants fat source, in other words a
plant stores its excess energy as starch.
 Fibres – are only found in plants. During the digestion process there is no enzyme that
is successful in breaking down these polysaccharides. Because they are not successfully
digested, fibres provide almost zero energy to our bodies. Some of the most significant
fibres are Cellulose, gums and pectin.
Why is fibre important in our diets
 Helps promote normal digestion and elimination of body wastes.
 Fibre not only moves things through the intestinal track more quickly because of its absorption
of water, this absorption also makes us feel full and reduces our desire to over eat.
 Fibre also reduces the risks of gastro intestinal track diseases like colon cancer
 Dietary fibre can prevent appendicitis and helps control diabetes.
 Fibrous diets may be a proponent in lowering the risk of heart disease and artery disease.
Two Types of Fibre
1. Soluble fibre – these fibres are easily dissolved in water and becomes gel-like as it travels
through the intestines to be eliminated – Some sources are oat bran, legumes, and citrus fruits.
2. Insoluble fibre – these do not dissolve and are often pushed through our systems whole –
some sources are wheat bran, pea pods, wheat stalks, corn.
Simple and Complex Carbohydrates
(Chart on Page 78)
1. Simple Carbohydrates: these are described as simple because the bonds are easily broken down
by our enzymes. All monosaccharides and disaccharides are considered simple carbohydrates.
Some simple carbohydrates are candy, syrups, and soft drinks
2. Complex Carbohydrates: these are described as complex because of the complexity and
intricate bond structures. All polysaccharides are considered complex carbohydrates. Some
complex carbohydrates are breads, cereals, pastas and vegetables.
So why know this??????
 Because complex carbohydrates require more work for our bodies to digest and convert to
energy and are also much more nutritious for us.
The Functions of Carbohydrates
1. Our bodies major source of energy – in order for our bodies to get energy from
carbohydrates(CHO), the CHO has to be converted to Glucose during digestion. Recall that
glucose is a monosaccharide.
The Process
 Glucose is absorbed by the cell then splits in half – this splitting results in the release of
energy.
 Once splitting occurs the left over fragments can re-join and make more glucose or they
can breakdown even further where even more energy is released. Once the fragments
further breakdown they can no longer re-join to make more glucose. The cell must then
find more glucose to absorb in order to get more energy.
Glucose Absorbed by cell and splits resulting in:
1) fragments can be put back together to make glucose again
or
2)
fragments can be broken down even further, where they release more energy – here they are
no longer capable of gathering to make more Glucose.
2. Necessary cells require CHO – Three cells in our bodies absolutely require carbohydrates.
The three cells are red blood cells, brain cells, and nerve cells. Because of their requirement
of CHO these cells are called obigate CHO users.
3. Spares the use of Protein – Protein has its own functions related to tissue building and cell
construction it doesn’t really have time to waste making energy for you…but it will. If you
deprive your body of CHO it will use protein and your lean body tissue to form glucose for
energy. Ingesting CHO ultimately spares the use of protein so it can stay busy doing what it is
meant to do.
4. Helps break down FAT – excess glucose is stored as fat in the body…but this process cannot
be reversed. Once glucose is turned to fat it cannot become glucose again. Fat cannot
breakdown properly without CHO, in order to produce energy, carbohydrates need to combine
with fat…if CHO is not available fat remains as ketone bodies(unusual products of fat
breakdown) in the blood. Ketosis is the result. Ketosis is a very unusual acid-base imbalance.
If Ketosis is present during pregnancy it can cause brain damage to the unborn fetus.
Helps make us feel full – creates bulk – it is CHO’s that help keep our intestinal track healthy and
disease free. Review : Why is fibre important in our diets
Sources:
Simple Carbohydrates
1. Natural sugars: fresh fruit, honey, lactose in milk
2. Refined sugars: chocolate, candy, soft drinks, baked goods, some cereals.
Buyers beware: just because a product says fat free it doesn’t mean your body won’t take the added
calories from sugar and make fat.
Complex Carbohydrates
1. Starchy foods: potatoes, rice, pastas, breads, cereals
2. Fibres: whole grain breads and cereals, bran, vegetables, fruits, dry beans, legumes and lentils.
What is the required intake of CHO for our diet???
 We should be receiving 45-60 percent of our daily intake of calories should come from CHO’s
and most of this should be from complex carbohydrates instead of simple carbohydrates.
Problems with excess Carbohydrates
1. Excess of simple CHO – can result in weight gain, but consumption of complex CHO does not
pose any major problems. To reduce overall calorie intake in a diet reducing fat works better.
Recall Calorie Calculations.
2. Dental Caries – excess refined sugar in a diet can cause some problems with cavities.
Research has produce clear evidence in a correlation between excess sugars and tooth decay.
There are other CHO that can cause problems as well – on of the biggest cavity causing
products is actually raisins. Any product that sticks to teeth is likely to result in an increase in
tooth decay.
3. CHO do not cause hyperactivity as previously suggested – much research has tried to draw
a connection between sugars and hyperactivity – but no correlation really exists.
4. Diabetes Mellitus – is a disease where ones body does not use insulin properly. Type I is
insulin dependant while Type II can be treated effectively with diet restructuring and an
exercise plan. In the late stages of Type II insulin may be necessary. Individuals that are
overweight have a higher likelihood of developing Type II Diabetes.
5. Hypoglycemia – this is described as a low blood glucose level. This again is a problem with
insulin levels – overproduction of insulin results in low blood sugar which impacts the central
nervous system.
6. Lactose Intolerance: individuals that suffer here do not have the enzyme necessary to
breakdown this disaccharide and are therefore unable to digest the lactose.
FATS
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Another word that is often interchanged in the scientific world with respect to fat is lipids.
Lipids covers a group of compounds that include oils, cholesterol etc…
The three components connected to lipids are triglycerides, phospholipids, and sterols.
1. Triglycerides
- are one of the major fats found in foods and the body, they actually make up 95% of the lipids
in our diet and in our body.
- triglycerides are made up of three fatty acids attached to one glycerol molecule.
-- fatty acid
-- fatty acid
-- fatty acid
glycerol
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these fatty acid chains can be long, short saturated or unsaturated. Fatty Acid is made up of
single bonded carbon atoms that have hydrogen atoms attached to them.
Saturated Fatty Acid – Is a chain of single bond carbon atoms which are saturated with as
many hydrogen atoms the carbon atoms can hold. Saturated fats are normally recognized by
their solid form at room temperature, examples of saturated fats are butter, margarine, lard also
any fat in meat is also solid at room temperature and is a saturated fat. There are also 3
vegetable oils that are saturated fats – coconut oil, palm oil and tropical vegetable oils.
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Monunsaturated Fatty Acids – are set up the same as saturated fatty acids only with one
double bond between the carbon atoms. Monounsaturated fats are liquid at room temperature –
olive oil, canola oil and peanut oil.
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Polyunsaturated Fatty Acids – similar to monounsaturated fatty acids only in this fatty acid
there is more than on double bond. These fatty acids are not made by the body and are
therefore essential fatty acids. They assist the development of skin, reproductive system, liver
and kidneys. Polyunsaturated fats are very liquid at room temperature, some examples of this
fat are sunflower oil, safflower oil, corn oil and soybean oil.
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Nearly all fats have a combination of all three types of Fatty acids, but since most fats will
have a concentration in one fat more than the others, we can classify some fats as either
monounsaturated, saturated, or polyunsaturated fat.
Hydrogenation – the double carbon bonds in unsaturated fats are broken down and more
hydrogen is added making it act more like a saturated fat. This occurs because during the
hydrogenation process some of the unsaturated fatty acids change their molecular shape and
therefore become trans-fatty acids. Trans –fatty acids act like saturated fats in our body. So what
was originally a potentially healthier substitute, through hydrogenation turns extremely unhealthy.
So why hydrogenate???
Hydrogenation does two things
1. helps the fat become more solid at room temperature.
2. Reduce the likelihood of the fat to spoil.
Trans-fat and saturated fat is known for causing heart disease.
2. Phospholipids
– appear like fatty acids, but have one end as
Phosphorus. Phospholipids are soluble in water and fat
and are therefore considered emulsifier.
-- phosphorus
-- unsaturated FA
-- FA
glycerol
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An example of phospholipids is Lecithin. Lecithin is naturally made by the liver so it isn’t an
essential nutrient, but it is also found in many of the foods we eat (egg yolks). Lecithin is
extremely important in the structure of cell membranes.
3. Sterols
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the molecular structure of sterols is very complex.
Cholesterol is an example of a sterol. Our bodies use cholesterol in the creation of sex
hormones and bile acids.
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Cholesterol in not an essential nutrient because our bodies produce cholesterol and our body
therefore does not need to receive it in our diets.
some foods that contain cholesterol are: milk, cheese, eggs, hamburgers, butter, organ meats,
crab and lobster.
How is Fat Digested??
 Fat forms droplets and rises to the top of chyme (stomach contents). Since it rises to the top it
is the last to travel from the stomach to the small intestines.
 Fat sends a satiety(fullness) message to our brains, but not as quickly as CHO or PRO because
it is the last to be digested.
 When fat reaches small intestine bile is secreted to emulsify fat so it can be ready for
absorption.
 Bile helps break the fat into tiny dropets which increases the surface area and this allows the
pancreatic enzyme to break down the triglyceride.
 Short chain FA’s and Glycerol are water soluble and therefore they diffuse into intestinal wall
cells and enter into circulatory system.
 Long chain FA’s and monoglycerides enter into intestinal wall cells and reconnects with
glycerol or with a monoglyceride and makes a triglyceride again and is not water soluble. In
order for absorption to occur it must combined with cholesterol, phospholipids and proteins,
this results in the formation of chylomicrons. Chylomicrons are water soluble and are able to
pass into lymphatic system and then into circulatory system to be used.
 Lipoproteins – is a combination of fat and protein that assists in the transportation of fat in the
body.
 Two types of lipoproteins are
1. Low-Density Lipoproteins ( LDL) – carry
cholesterol throughout the blood stream to
body cells.
2. High-Density Lipoproteins (HDL) –pick up cholesterol from around the body and
transfer it to other lipoproteins for transport back to the liver to be discarded from the
body.
 Enzymes are used by the body to break down the different types of fat and turn it into glycerol
and fatty acids. Once this process is complete the cells can pick up these compounds and break
them down even further.
 Most cells can store only a limited amount of triglycerides, but fat cells have almost unlimited
space. And when necessary the fat cells can send out the stored triglycerides for use in other
cells.
How can Fat be Harmful?
Excess fat in diets can cause major problems with an individual’s heart health.
Coronary Heart Disease (CHD) is one of the largest problems associated with Fat. Fatty compounds
in the blood can attach themselves to the walls of arteries forming plaque. Blood clots can also form
at the site of these plaque build up resulting in the possibility of heart attack or stroke.
Uncontrollable Heart-Health Factors
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Age – you are more at risk as you age
Gender – men are more at risk then women – connected to hormones
Race – African Americans are twice as likely to heart problems
Family History – heredity plays a role in heart health
Controllable Heart-Health Factors
Change in life style behaviours can have a huge impact on an individual’s heart health.
Smoking – 2 to 4 times at higher risk for dying from a heart attack. Related to how hard the
heart must work to get oxygen. By quitting the body is often able to repair most of the damage
that has been done.
- High Blood Pressure (hypertension) – connected to excess force that is placed on the arteries
to pump the blood throughout the body.
Normal Blood Pressure is 120/80
120 – stands for the systolic pressure (the pressure
on the arteries when the heart muscle contracts).
80 – stands for the diastolic pressure (the pressure on
the arteries when the heart is between beats)
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High blood pressure adds to CVD by putting added stress on the heart and it can damage the walls
of the arteries. High Blood pressure cannot be cured but it can be controlled through diet, exercise
and stress management. Medication may also be necessary to control high blood pressure.
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High Blood Cholesterol – large amounts of serum cholesterol (artery-clogging plaque) is a
risk factor for CVD. Here heredity may also be involved.
Levels of high and low density lipids has an impact here. High density lipids are considered the
“good cholesterol” because these lipids work to take fatty acids back to the liver to be
discarded from the body. But low density lipids are given the bad reputation because they
carry the cholesterol that is deposited in our body tissue.
Doctors can have your blood checked by sending you to a lab for a blood lipid profile.
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Diabetes Mellitus – this disease causes blood vessels to become damaged or blocked with fat,
thus impacting blood flow.
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Excess Weight – the more tissue that is built from fat the more blood vessels become
necessary to nourish this increase of tissue, thus resulting in more work for the heart. Excess
Weight increases a persons risk for diabetes, high blood pressure, and high blood cholesterol.
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Inactivity – results in excess weight problems. Lack of activity results in less energy being
consumed, when energy is not consumed it is stored as fat.
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Stress and Personality – individuals who are not emotionally balances seem to be at higher
risk for poor heart health. But this can be changed by developing the skills to better cope with
all situations.
The Function of Fat in our Bodies
 Fat is the second nutrient that provides our bodies with energy. Many high aerobic exercises
count of fat to be available as an energy source.
 Fat helps to cushion and protect our internal organs
 Fat works as an insulator for our body…during colder weather we use fat to help keep us
warm. It is the fat in seal lions that keep their internal temperatures normal, fat works very
much the same way for humans.
 Fat also helps to cushion our joints and muscles.
PROTEIN
 Protein is an energy nutrient composed of carbon, hydrogen, oxygen and nitrogen (nitrogen is
the component that makes this nutrient different from the other energy producing nutrients).
 The building blocks of protein molecules are called Amino Acids. Proteins are usually made
up of varying combinations of 20 different amino acids. The different combinations of amino
acids can result in up to 30,000 different proteins that our bodies use.
 Denaturation is the process where protein molecules change their shape and take on new
characteristics. The Change can occur do to heat, acids, bases and alcohol changes that
happen to the food. (Example: Cooking an Egg)
 The process of denaturation results in a constant change to the protein molecules. (Egg will
never get runny after being cooked)
 Of the 20 amino acids that are required to make up protein only 9 are essential amino acids.
9 of the amino acids are not able to be produced by our bodies and must be found in our
foods.
 The other 11 amino acids can be synthesized by our bodies. These 11 are called nonessential
amino acids.
 Protein is available in both animal and plant food sources.
Animal Sources of Protein
 Animal food sources are called complete proteins because they supply our bodies with the 9
essential amino acids that can not be produced.
 Animal flesh from beef, veal, pork, lamb, poultry, fish, etc… is considered the best and largest
source of protein available to us.
 Other animal sources include eggs, milk, yogurt, cheese and ice cream.
Plant Sources of Protein
 Most plant sources of protein are called incomplete proteins because they do not supply all of
the 9 essential amino acids our bodies require.
 Protein is found in grains, nuts, seeds and legumes.
 Examples of some very important legumes are kidney beans, soybeans, chick peas, green peas,
etc…
Reasons individuals may avoid meat products
 Religious Reasons – some religious groups avoid meat and follow a strict vegetarian diet.
 Health Reasons – individuals that must avoid fat and cholesterol may chose to stay away from
animal sources. Also illness that can be transmitted from animals may make people stay away
from meat products. (Example: Mad Cow Disease)
 Socioeconomic Reasons – Many individuals feel that feeding cow’s grain crops that could
potentially reduce famine across the globe is ridiculous and they chose not to consume meat for
this reason.
 Environmental Reasons – Grazing animals is hard on soil and land. Individuals that use this
reasoning also make connections to the over use of natural resources like water and energy to
sustain the diet and health of the grazing herd.
 Humanitarian Reasons – individuals that use this form or reasoning believe that an animal’s
right to life is just as important as ours.
It is important for individuals that chose to avoid meat to find the protein substitutes necessary to get
all 20 amino acids…most importantly the 9 essential nutrients that we must get from our food sources.
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Vegetarians are able to get their complete proteins by eating complementary
proteins.
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Complementary proteins are two incomplete proteins that together would achieve the
complete 9 essential amino acids required by the body.
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Which plant proteins are complementary?? Legumes are the one product that can be
combined with tree nuts, seeds or grains to become a complete protein (See Chart 7-8
on pg. 117 in textbook).
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By combining Peanuts (legume) with whole wheat bread (grain) complementary
proteins are established.
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That are three ways that individuals can receive all the essential amino acids
necessary to build protein.
1. Simply make sure you eat animal food sources, which are already made up of
complete sets of amino acids.
2. Eat an incomplete with a complete protein. Even small amounts of complete
proteins will make a meal that is abundantly made up of incomplete proteins a
good source of all nine essential amino acids.
3. Eat two complementary proteins – two incomplete proteins that complement
each other. Legumes with nuts, seeds or grains will supply an individual with
the nine essential amino acids required from a diet.
Unlike the other two energy nutrients our bodies do not store Protein. It is important
therefore to intake some form of complete protein everyday.
An individuals need for protein is based on age, gender, body size and health.
Age: children and teens are still growing and building body tissue, therefore they need more
protein than adults need.
Gender: When women are pregnant they need more protein than men do. Pregnant women
are after all building new tissue to make a new human life. Lactation also requires protein.
But on average men would normally out weigh women for protein needs because they have
more lean body tissue than women do.
Body Size: The larger our bodies the more tissue we have to maintain and therefore the
larger need for protein.
Health: proteins are required for the creation of antibodies necessary to fight infections and if
we damage tissue through injury protein is necessary to rebuild that damaged tissue.
Functions of Protein
1. Protein is needed to build and maintain tissue. Every cell in our bodies use protein
as a building block (protein makes up 18-20% of your body) See Chart 7-3 on pg. 112
for placement of protein on the body.
2. Protein is used to help make important compounds like enzymes, antibodies, and
hormones. Recall how the body uses enzymes to break down and absorb the
nutrients from our foods.
3. Protein helps regulate mineral and fluid balance between cells. Without the proper
fluid balance the heart, lungs, brain and every cell could not function properly.
4. Protein also regulates the acid-base balance in our blood. It makes sure that the
acidity in our fluid stays balanced.
5. Protein also helps carry some vital substances our blood needs. Substances like
lipoproteins, iron, oxygen and other nutrients as well. Health will begin to deteriorate
if our body cannot receive these vital substances.
6. Protein is also our third source of energy. When Fat or Carbohydrates are not
available as an energy source the body will turn to protein for its energy supply. If
there is excess protein our body will use the excess as an energy source, remember
our bodies do not store protein.
How much protein do our bodies need??? Studies have suggested that 10% of our daily intake of
calories should come from protein. If we were to consume a diet of 2400 calories, we would need to
make sure 240 of them were from protein foods.
Protein Imbalances
DEFICENCY
When an individual does not consume enough protein there are several possible complications that
will arise due to what is called protein-energy malnutrition(PEM). PEM results when an individual
is not consuming enough calories. The result is diarrhea and thus a loss of necessary nutrients needed
for the body to function properly.
There exist two types of PEM diseases:
1. Kwashiorkor – found in many poor countries in older siblings that have been weaned
from mothers breast because of the introduction of a newborn. These poor countries
have a limited supply of protein based foods and therefore children develop bloated
abdomens, and very skinny arms and legs. (World Vision Ads).
We must remember that protein intake is connected to antibody production and a healthy immune
system. In these poor countries many children die do to lack of protein because the body system
cannot fend off illness.
2. Marasmus : is considered a wasting disease because muscles and tissues in an infant
(most often found in infants) begins to waste away. It results in weakness, thinness and
makes infants prone to infections and disease. There bodies are starving from lack of
protein.
TOXICITY
When an individual intakes too much protein the body reacts in different ways:
1. Liver and Kidney Problems: remember Protein is made up of nitrogen and our bodies
must discard nitrogen waste. When our bodies have an excess of protein they also
have an excess of nitrogen waste. The organs responsible for removal of waste are the
liver and kidney. Over working these organs can result in their premature aging.
2.
Loss of Calcium: High protein diets have been directly linked to loss of calcium on
the bones. Loss of calcium can result in other problems as well – excessive loss can
lead to osteoporosis.
3.
Obesity: Many high protein foods are also high fat foods. Meats, whole milk, cheeses,
even peanut butter are all high fat foods that if eaten in abundance can increase body
fat and ultimately lead to obesity.
WATER
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Our body weight is made up of 50-70% water.
Every cell in our body uses water, it will help determine the cells shape, size and firmness.
Function of Water
1.
Facilitates Chemical Reactions: all the chemical reactions needed in the production
and distribution of enzymes, amino acids, as well as the action of breaking down our
energy nutrients, requires water.
2.
Transports Nutrients and Waste Products: Since water is a Solvent it helps dissolve
water-soluble substances. Many amino acids, minerals and vitamins can be dissolved
and absorbed by the body with the help of water. Waste products are also carried away
from the body with the assistance of water. Examples – when we perspire, exhale and
even feces all contain water.
3.
Lubricates Surfaces: As a lubricant water helps in the
mastication/digestion/absorption of food products. Fluid keeps your eyes and joints
healthy, and also helps fat in the cushioning of vital tissue and organs.
4.
Regulation of Body Temperature: Blood and perspiration are the two elements that
help regulate our body’s temperature. By perspiring our bodies are able to reduce the
internal heat caused by over exertion. The expanding or constricting of blood vessels
near the skins surface will help to cool or heat our body.
Importance of Fluid Balance
Balloon Analogy
 To much water in the cell = burst
 To little water in the cell = collapse
Water is found in the body either:
1. Intracellular – within the cell
2. Extracellular – outside the cell
If we recall the mineral presentations on sodium, chloride and potassium (the three electrolytes).
These minerals help balance the fluid level in cells.