NUTR2001: Comprehensive Report on Macronutrients and Human Health

This report, prepared for the NUTR2001 Human Nutrition 1 course, comprehensively examines the role of macronutrients in human health. It begins with an executive summary and table of contents, followed by detailed discussions on proteins, carbohydrates, and lipids. For each macronutrient, the report elucidates their composition, biological functions, dietary sources, recommended daily intake (RDI), factors contributing to states of excess and insufficiency/deficiency, and associated signs and symptoms. The protein section covers amino acids, their role in growth and maintenance, sources like meat and dairy, and deficiency signs such as edema and hair thinning. The carbohydrate section details monosaccharides, energy provision, dietary sources like grains and fruits, and the impact of excess and deficiency. The lipid section explores fatty acids, membrane structure, energy storage, dietary sources like nuts and oils, and the effects of imbalances. The report concludes by emphasizing the importance of balanced macronutrient intake for overall health, referencing various scientific publications to support its findings.

Running head: NUTR2001: HUMAN NUTRITION 1
The Role of Macronutrients in Health
Name of the Student
Name of the University
Author Note

1NUTR2001: HUMAN NUTRITION 1
Executive summary
Nutrients are referred to as environmental substances that provide energy and are essential for
the conduction of different bodily functions. Based on their role, they are required by the
body in either small or large amounts. Three major macronutrients are carbohydrates,
proteins and lipids. This report elucidated the composition, dietary sources, biological
functions, and signs and symptoms of these macronutrients.

2NUTR2001: HUMAN NUTRITION 1
Table of Contents
Introduction................................................................................................................................4
Protein........................................................................................................................................4
Composition...........................................................................................................................4
Functions................................................................................................................................4
Dietary sources.......................................................................................................................5
Recommended Daily Intake (RDI)........................................................................................5
Factors contributing to states of excess..................................................................................5
Factors contributing to states of insufficiency and deficiency...............................................5
Signs and symptoms...............................................................................................................5
Carbohydrate..............................................................................................................................6
Composition...........................................................................................................................6
Functions................................................................................................................................6
Dietary sources.......................................................................................................................6
Recommended Daily Intake (RDI)........................................................................................7
Factors contributing to states of excess..................................................................................7
Factors contributing to states of insufficiency and deficiency...............................................7
Signs and symptoms...............................................................................................................7
Lipids..........................................................................................................................................8
Composition...........................................................................................................................8
Functions................................................................................................................................8
Dietary sources.......................................................................................................................8

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Recommended Daily Intake (RDI)........................................................................................9
Factors contributing to states of excess..................................................................................9
Factors contributing to states of insufficiency and deficiency...............................................9
Signs and symptoms...............................................................................................................9
Conclusion..................................................................................................................................9
References................................................................................................................................11

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Introduction
Macronutrients refer to energy providing chemical compounds that are consumed by
living organisms in large amount. There are four major categories of macronutrients namely,
protein, lipids, carbohydrate, and alcohol (Solon-Biet et al., 2015). While water makes up a
significantly large amount of the entire mass consumed as share of a normal diet, it fails to
deliver any nutritional value. Some common macronutrients are glucose, sucrose, ribose,
amylose, alanine, asparagine, glycine, butyric acid, arachidic acid, palmitic acid, oleic acid,
and palmitoyl. The human body and the different physiological activities are multifaceted.
Thus, they require these macronutrients to function in an optimal manner. This report will
elaborate on three macronutrients namely, protein, carbohydrates, and lipids.
Protein
Composition
Proteins are indispensable nutrients for the human body, and have been identified as
one of the major building blocks of the tissues. They also act in the form of a major fuel
source. Proteins are polymer chains that are made up of amino acids, which in turn
are connected together by means of peptide bonds (Rodwell et al., 2015). At the time of
human digestion, these proteins get broken down inside the stomach to reduced polypeptide
chains through the action of protease and hydrochloric acid.
Functions
Protein are required for growth and maintenance of the human body. Proteins are
generally can found in all cells and act as the principal structural component of the muscles,
hair, body organs, and skin. They act in the form of precursors to co-enzymes, immune
response, nucleic acid, hormones, cellular repair, and different essential molecules.
Furthermore, they also play an important role in the formation of blood cells.

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Dietary sources
Meat, products obtained from milk, soy, eggs, and fish are dietary sources of protein.
Cereals and whole grains are another major source of proteins. In addition, vegetarian sources
of proteins comprise of nuts, seeds, legumes, and fruits. Legumes such as, soybeans, lentils,
mung beans, lima beans, chickpeas, and kidney beans comprise of greater concentration of
amino acid, when compared to cereals and whole grains (Farvid et al., 2014).
Recommended Daily Intake (RDI)
The Australian guidelines suggest that the RDI for protein must be 0.75 g/kg for adult
females, 0.84 gm.kg for adult males, and approximately 1 g/kg for breastfeeding and
pregnant females, and for males and females over 70 years (Better Health, 2019).
Factors contributing to states of excess
Showing adherence to high-protein diet such as, Paleo diet or Caveman diet increase
the consumption of protein. Furthermore, people who are employed in physically demanding
jobs, pregnant and breastfeeding women, and athletes consume excess protein on a regular
basis (Rosenbloom, 2014).
Factors contributing to states of insufficiency and deficiency
Protein-energy malnutrition (PEM) generally manifests in the form of a pathological
condition that occurs when a person does not consume the necessary dietary protein (van der
Pols-Vijlbrief et al., 2014). Deficiency might occur due to oxidative stress or changes in the
gut microbiome and lead to the development of kwashiorkor and marasmus.
Signs and symptoms
Common signs of protein malnutrition include pitting oedema, distended abdomen,
enlarged liver, dermatitis, loss of teeth, thinning of hair, anorexia, wasted appearance, loss of

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muscle mass, hypothermia, anaemia, dehydration, and decreased consciousness. People might
also display signs of tachypnoea, ocular manifestations, dry skin, and hypovolemic shock.
Carbohydrate
Composition
Carbohydrates are biomolecules that comprise of hydrogen (H), carbon (C),
and oxygen (O) atoms, typically with a ratio of hydrogen–oxygen atom as 2:1. Natural
saccharides are commonly made up of simple carbohydrates, referred to as
monosaccharide, having the general formula (CH2O)n, where n stands for three or more. A
monosaccharide comprises of the structure H–(CHOH)x(C=O)–(CHOH)y–H (Moran et al.,
2014).
Functions
There are five chief functions of carbohydrates that are energy storage, energy
production, sparing protein, building macromolecules, and helping lipid metabolism. The
principal role of carbohydrates is the supply of energy to different body cells. Numerous cells
prefer glucose energy source. Some glucose gets transformed to ribose and deoxyribose that
act as building blocks of DNA, RNA, and ATP. Glucose also gets produced from amino
acids, thereby sparing protein breakdown.
Dietary sources
Carbohydrates account for more than half the calories that are consumed by adults.
Most dietary carbohydrates are obtained from plants. Grains such as, oats, wheat, rice, barley
and cornmeal, buckwheat, sorghum, quinoa, and triticale contain carbohydrates. Furthermore,
it is also present in bread, milk, beans, popcorn, soft drinks, cookies, potatoes, spaghetti,
corn, and cherry pie. Furthermore, all fruits and fruit juices comprise of carbohydrates as

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natural sugars, such as fructose and glucose (Gatesoupe et al., 2014). These fruit sugars
contribute approximately the entire calories that are present in these food items.
Recommended Daily Intake (RDI)
In Australia, infants aged 0-6 months are expected to consume 60 g/day, which is less
than 95 g/day carbohydrates that must be consumed by infants aged 7-12 months (NHMRC,
2019). This is accredited to the fact that the size of infant brain is relative to the entire body
and consumes more than 60% of the total intake of energy. Furthermore, a balanced diet
consumed by an adult should comprise of 310 grams of carbohydrate (Mydailyintake.net,
2019).
Factors contributing to states of excess
Craving for sweets and junk food increases the daily consumption of carbohydrate for
an adult. Traditional food that emphasises on the consumption of rice and bread also
increases its consumption. Furthermore, easy availability of carbohydrate-rich food source is
another major factor.
Factors contributing to states of insufficiency and deficiency
Adherence to low-carb diet results in a deficiency of this macronutrient (Gardner et
al., 2018). Furthermore, poor availability of grain, fruits, and cereals, and an increased
dependence on protein-rich food might also lead to lead to carbohydrate insufficiency.
Signs and symptoms
Symptoms of deficiency include nausea, lethargy, dehydration, dizziness,
constipation, and loss of appetite. In contrast, excess carbohydrate consumption leads to
obesity, type 2 diabetes, and dental caries.

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Lipids
Composition
The term lipid refers to esters, fatty acids and possible esters of fatty acids. These
biomolecules are soluble in nonpolar solvent and comprise of hydrophobic and hydrophilic
ends. They comprise of two major building blocks namely, isoprene and ketoacyl groups.
Functions
The glycerophospholipids have been identified as major structural constituent
of biological membranes, and generally leads to the formation of the plasma membrane and
intracellular membranes of different organelles. While glycerophospholipids are known as
the major constituent of biological membranes, non-glyceride lipids such as sterols and
sphingomyelin (principally cholesterol present in animal cell membranes) are present in the
biological membranes. A biological membrane comprises of a lamellar phase made up of
lipid bilayer (Luckey, 2014). Triglycerides are stored in the adipose tissue, are act as
reservoir of energy storage, in both plants and animals. They provide energy owing to the fact
that the carbohydrates are present in completely reduced structures. When compared to
glycogen that significantly contributes to as much as half of the energy, carbons of
triglyceride are all attached to hydrogens, dissimilar to carbohydrates. Furthermore, lipid
signalling has also been identified as a significant component of cell signalling. This
generally occurs through the activation of nuclear or G protein-coupled receptors. In addition,
"fat-soluble" vitamins namely, vitamin A, E, D, and K, which are also referred to as isoprene-
based lipids, act as important nutrients that are stored in the fatty tissues and liver.
Dietary sources
Major sources of monounsaturated fat comprise of nuts (cashews, almonds, pecans,
and peanuts), almond and peanut butter, avocado, and vegetable oil. Also referred to as
essential fats, polyunsaturated fats are present in salmon, herring, trout, and plant-based foods

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such as, tofu, walnuts, sesame seeds, pumpkin seeds, sunflower seeds, soft margarine, and
soy beans. Baked goods like pastries and cookies, processed snacks, vegetable shortening,
and fried foods like doughnuts and French fries are other sources of dietary lipids
(Byelashov, Sinclair & Kaur, 2015).
Recommended Daily Intake (RDI)
According to the Heart Foundation (2018) an Australian adult should consume <10%
of total energy of saturated fat, <1% of total trans-fat, 4-10% of Omega-6 polyunsaturated fat,
1 gm/day of combined EPA/DHA, and 250-500mg/day of Omega-3 polyunsaturated fat.
Factors contributing to states of excess
Consuming a diet that is rich in dairy food and different types of meat increases the
level of cholesterol present in the bloodstream. Lack of exercise, in addition to consumption
of egg yolk, ice cream, red meat and processed food leads to hyperlipidaemia or fat excess.
Factors contributing to states of insufficiency and deficiency
Unavailability of fat-rich food products and consumption of a diet that does not
contain linoleic acid (LA) and alpha-linolenic acid (ALA leads to insufficiency of dietary
lipids.
Signs and symptoms
Hyperlipidaemia is characterised by atherosclerosis, chest pain, stroke, angina,
deposition of fat in the skin and swelling of different organs like the pancreas, liver or spleen
(Navar-Boggan et al., 2015). Essential fatty acid (EFA) deficiency is manifested by signs and
symptoms that include alopecia, scaly dermatitis, thrombocytopenia, and intellectual
disability in children.

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Conclusion
To conclude, macronutrients are the major source of calories that act as fuel for the
essential life processes. They are required in large quantities in the body and comprise of
carbohydrates, water, fat and protein. Thus, apart from water, the aforementioned three
macronutrients help in repair, growth, and development of new cells and tissues in the body,
thus regulating major life processes.

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References
Better Health. (2019). Protein. Retrieved from
https://www.betterhealth.vic.gov.au/health/healthyliving/protein
Byelashov, O. A., Sinclair, A. J., & Kaur, G. (2015). Dietary sources, current intakes, and
nutritional role of omega‐3 docosapentaenoic acid. Lipid technology, 27(4), 79-82.
Farvid, M. S., Cho, E., Chen, W. Y., Eliassen, A. H., & Willett, W. C. (2014). Dietary protein
sources in early adulthood and breast cancer incidence: prospective cohort
study. Bmj, 348, g3437.
Gardner, C. D., Trepanowski, J. F., Del Gobbo, L. C., Hauser, M. E., Rigdon, J., Ioannidis, J.
P., ... & King, A. C. (2018). Effect of low-fat vs low-carbohydrate diet on 12-month
weight loss in overweight adults and the association with genotype pattern or insulin
secretion: the DIETFITS randomized clinical trial. Jama, 319(7), 667-679.
Gatesoupe, F. J., Huelvan, C., Le Bayon, N., Sévère, A., Aasen, I. M., Degnes, K. F., ... &
Kaushik, S. J. (2014). The effects of dietary carbohydrate sources and forms on
metabolic response and intestinal microbiota in sea bass juveniles, Dicentrarchus
labrax. Aquaculture, 422, 47-53.
Heart Foundation. (2018). Dietary Fat and Heart Healthy Eating Position Statement.
Retrieved from
https://www.heartfoundation.org.au/images/uploads/main/For_professionals/
Dietary_Fats_Position_Statement_2017.pdf
Luckey, M. (2014). Membrane structural biology: with biochemical and biophysical
foundations. Cambridge University Press.

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Moran, L. A., Horton, R. A., Scrimgeour, K. G., & Perry, M. D. (2014). Principles of
biochemistry.
Mydailyintake.net. (2019). Daily Intake Levels. Retrieved from
http://www.mydailyintake.net/daily-intake-levels/
National Health and Medical Research Council. (2019). Carbohydrate. Retrieved from
https://www.nrv.gov.au/nutrients/carbohydrate
Navar-Boggan, A. M., Peterson, E. D., D’Agostino Sr, R. B., Neely, B., Sniderman, A. D., &
Pencina, M. J. (2015). Hyperlipidemia in early adulthood increases long-term risk of
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Rodwell, V., Bender, D., Botham, K. M., Kennelly, P. J., & Weil, P. A. (2015). Harpers
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Solon-Biet, S. M., Mitchell, S. J., de Cabo, R., Raubenheimer, D., Le Couteur, D. G., &
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van der Pols-Vijlbrief, R., Wijnhoven, H. A., Schaap, L. A., Terwee, C. B., & Visser, M.
(2014). Determinants of protein–energy malnutrition in community-dwelling older
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