Nutrition: What is it and why is it Important?


Written by Nailah Aljasmi | 17th October 2019

As molecular biology, biochemistry, and genetics advance, nutrition has become more focused on metabolism and metabolic pathways – biochemical steps through which substances inside us are transformed from one form to another. (1.)

Nutritional science studies show how the body breaks food down (catabolism) and how it repairs and creates cells and tissue (anabolism).

Catabolism and Anabolism combined can also be referred to as the Metabolism. Nutritional science also examines how the body responds to food. (2.)

Photo by Lumin Learning

Fast facts on nutrition

  • The human body requires seven major types of nutrients.
  • Not all nutrients provide energy but are still important, such as water and fibre.
  • Micronutrients are important but required in smaller amounts.
  • Vitamins are essential organic compounds that the human body cannot synthesize.

What is Nutrition?

Nutrition is defined as the intake of food, considered in relation to the body’s dietary needs. Good nutrition – an adequate, well-balanced diet combined with regular physical activity – is a cornerstone of good health. Poor nutrition can lead to reduced immunity, increased susceptibility to disease, impaired physical and mental development, and reduced productivity. (3.)

Eating a healthy nutritious diet has been shown over and over to prevent a variety of diseases, including cancer. Good nutrition is vital to good health, disease prevention, and essential for healthy growth and development of children and adolescents. (4.)

There are 7 essential categories of nutrients: carbohydrates, fats, minerals, protein, vitamins, Fibre and water.

  1. Carbohydrates – the main source of our energy.
  2. Fats – one source of energy and important in relation to fat-soluble vitamins.
  3. Minerals – those inorganic elements occurring in the body and which are critical to its normal functions.
  4. Proteins – essential to growth and repair of muscle and other body tissues.
  5. Vitamins – water and fat-soluble vitamins play important roles in many chemical processes in the body.
  6. Roughage (Fiber) – the fibrous indigestible portion of our diet essential to the health of the digestive system.
  7. Water – essential to normal body function – as a vehicle for carrying other nutrients and because 60% of the human body is water.

These nutrient classes can be categorized as either;

  • Macro-nutrients (needed in relatively large amounts) –  The macro-nutrients are carbohydrates, fats, fibre, proteins, and water.
  • Micro-nutrients (needed in smaller quantities) – The micro-nutrients are minerals and vitamins.

1. Carbohydrates

Photo By Pixabay

The main fuel for the body, carbohydrate comes in two forms: ‘fast releasing‘, as in sugar, honey, malt, sweets and most refined foods, and ‘slow releasing‘, as in whole grains, vegetables and fresh fruit. The latter foods contain more complex carbohydrates and /or more fibre, both of which help to slow down the release of sugar. Fast- releasing carbohydrates tend to give a sudden burst of energy followed by a slump, while slow-releasing carbohydrates provide more sustained energy and therefore are preferable. (5.)

Some ‘fast-releasing’ carbs:

  • Candy
  • Short-grain white rice 
  • Rice cakes
  • White bread
  • Pretzels
  • Tapioca pudding
  • Cornmeal
  • Instant mashed potatoes
  • Energy bars
  • Dried fruits and fruit leathers
  • Sports beverages and soda
  • Instant oatmeal

Some ‘slow-releasing’ carbs:

  • Peanuts
  • Most beans
  • Lentils
  • Barley and oats
  • Tree nuts
  • Whole-wheat tortillas
  • Many fruits
  • Nonstarchy vegetables

Refined foods like sugar and white flour lack the vitamins and minerals needed for the body to use them properly and are best avoided. Some fruit, like bananas, dates, and raisins, contain fast- releasing sugar and are best kept to a minimum by people with glucose-related health problems.

2. Fats

Photo by Canva

The most misunderstood macronutrient. Fats are the largest, cleanest source of energy and they provide 9 calories per gram. When it comes to dietary fat, what matters most is the type of fat you eat. Contrary to past dietary advice promoting low-fat diets, newer research shows that healthy fats are necessary and beneficial for health. (6.)

Rather than adopting a low-fat diet, it’s more important to focus on eating beneficial “good” fats and avoiding harmful “bad” fats. Fat is an important part of a healthy diet. Choose foods with “good” unsaturated fats, limit foods high in saturated fat, and avoid “bad” trans fat.

  • “Good” unsaturated fats — Monounsaturated and polyunsaturated fats — lower disease risk. Foods high in good fats include vegetable oils (such as olive, canola, sunflower, soy, and corn), nuts, seeds, and fish.
  • “Bad” fats — trans fats — increase disease risk, even when eaten in small quantities. Foods containing trans fats are primarily in processed foods made with trans fat from partially hydrogenated oil. Fortunately, trans fats have been eliminated from many of these foods.
  • Saturated fats, while not as harmful as trans fats, by comparison with unsaturated fats negatively impact health and are best consumed in moderation. Foods containing large amounts of saturated fat include red meat, butter, cheese, and ice cream. Some plant-based fats like coconut oil and palm oil are also rich in saturated fat. (7.)

3. Minerals

Photo by Happy_Lark from Canva

Like vitamins, minerals are essential for just about every body process. We don’t manufacture essential minerals in the body. We need minerals to help us do three main things:

  • build strong teeth and bones
  • control body fluids inside and outside cells
  • turn the food we eat into energy.

We get them from our diet. The minerals come from rocks, soil, and water, and they’re absorbed as the plants grow or by animals as the animals eat the plants. Essential minerals are most potent when they come from food. But if you’re struggling with deficiencies, you may need to take supplements. (8.)

We need more of some minerals than others. For example, we need more calcium, phosphorus, magnesium, sodium, potassium and chloride than we do iron, zinc, iodine, selenium and copper. (9.)

  • Calcium – is a mineral that is necessary for life. In addition to building bones and keeping them healthy, calcium enables our blood to clot, our muscles to contract, and our heart to beat. About 99% of the calcium in our bodies is in our bones and teeth. Food sources include Kale, Spinach, Collard, Greens and most dairy products. (10.)
  • Phosphorus – works with calcium to help build bones. You need the right amount of both calcium and phosphorus for bone health. Phosphorus also plays an important structural role in nucleic acids and cell membranes. And it’s involved in the body’s energy production. Food sources include (Plant-based) sunflower seeds, beans, almonds, brown rice, (Animal-based) tuna, eggs, and dairy. (11.)
  • Potassium – Most of the body’s potassium is located inside the cells. It’s vital for the normal functioning of cells, nerves, and muscles. The body can use the large reservoir of potassium stored within cells to help maintain a constant level of potassium in the blood. Food sources include (Plant-based) – Beans, Avocado, Broccoli, and Sweet potato. (12.)
  • Sodium – Sodium is an essential nutrient involved in the maintenance of normal cellular functions and in the regulation of fluid and electrolyte balance and blood pressure (BP). Its role is crucial for maintaining ECF volume because of its important osmotic action and is equally important for the excitability of muscle and nerve cells and for the transport of nutrients and substrates through plasma membranes. Food sources include most natural foods. (13.)
  • Magnesium – Magnesium is a cofactor in more than 300 enzyme systems that regulate diverse biochemical reactions in the body, including protein synthesis, muscle and nerve function, blood glucose control, and blood pressure regulation. Magnesium is required for energy production, oxidative phosphorylation, and glycolysis. It contributes to the structural development of bone and is required for the synthesis of DNA, RNA, and the antioxidant glutathione.  Food sources include (plant-based) – Almonds, edamame, spinach, black beans, avocado, and banana. (Animal-based) – Salmon, Chicken, Yoghurt and Kefir. (14.)
  • Manganese – Structural component of antioxidant enzymes, facilitates bone development. Helps to make and break down amino-acids. Food sources include (plant-based) – tropical fruit, legumes, nuts, seeds and whole grains. (15.)
  • Iron – is important for the proper functioning of all cells in our bodies. The main role of iron in the body is in the red blood cells where it helps carry oxygen to the body’s cells and tissues. Iron is also important for our immune systems (to fight disease), brain function and muscle strength. Food sources include (Plant-based) – Lentils, spinach and raisins, (Animal-based) Beef and liver. (16.)
  • Zinc – performs a noteworthy role in the regulation of arterial blood pressure. It’s very important in the synthesis, storage, and secretion of insulin. Zinc has been identified as one of the most important essential trace metals in human nutrition and lifestyle. Zinc is not only a vital element in various physiological processes; it is also a drug in the prevention of many diseases. Food sources include (plant-based) – pumpkin seeds, chickpeas and cashews, (animal-based) – Oysters, beef and lamb. (17.)
  • Selenium – fights virus and heart diseases, helps radiation damage and inflammation. It’s a vital constituent of the antioxidant enzyme glutathione peroxidase, fights against cancer and premature ageing. Food sources include (plant-based) – brazil nuts, sunflower seeds and sesame seeds, (animal-based) – eggs, liver and tuna. (18.)
  • Copper – combines with certain proteins to produce enzymes that act as catalysts to help a number of body functions. To help provide the energy required by biochemical reactions. Others are involved in the transformation of melanin for pigmentation of the skin and still help to form collagen and elastin and thereby maintain and repair connective tissues. Food sources include (plant-based) – Kale, cashew and chickpeas, (animal-based) – beef and liver. (19.)
  • Chromium – is known to enhance the action of insulin, a hormone critical to the metabolism and storage of carbohydrate, fat, and protein in the body. Food sources include (plant-based) – chickpeas, broccoli, grapes, garlic, oranges and apples. (animal-based) – livers and oysters. (20.)
  • Iodine – is metabolized in the human body through a series of stages involving the hypothalamus, pituitary, thyroid gland and blood. Food sources include (plant-based) – Himalayan salt, seawater and seaweed, (animal-based) – milk, eggs and tuna. (21.) 
  • Molybdenum – is required for the function of four enzymes: sulfite oxidase, xanthine oxidase, aldehyde oxidase, and mitochondrial amidoxime reducing component (mARC). The kidneys are the main regulators of molybdenum levels in the body and are responsible for its excretion. Molybdenum, in the form of molybdopterin, is stored in the liver, kidney, adrenal glands, and bone. Food sources include (plant-based) – rice, banana, wheat, green beans, lentils, peas and tomatoes, (animal-based) – beef, tuna and chicken. (22.)

4. Proteins

Photo by Piyaset from Canva

Protein is important for growth and development and is also one of three macronutrients in food that provide calories, or “energy” for the body. Each gram of protein provides 4 calories. (23.)

Protein is found in foods from both plants and animals. Protein is made up of hundreds or thousands of smaller units, called amino acids, which are linked to one another in long chains. The sequence of amino acids determines each protein’s unique structure and its specific function.

There are twenty different amino acids that that can be combined to make every type of protein in the body. These amino acids fall into two categories:

  • Essential amino acids are required for normal body functioning, but they cannot be made by the body and must be obtained from food. Of the twenty amino acids, nine are considered “essential”.
  • Nonessential amino acids can be made by the body from essential amino acids consumed in food or in the normal breakdown of body proteins. Of the twenty amino acids, eleven are considered “nonessential”.

Because we don’t store amino acids, our bodies make them in two different ways: either from scratch or by modifying others. Nine amino acids—histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine—known as the essential amino acids must come from food. (24.)

The FDA recommends that adults consume 50 grams of protein a day, as part of a 2,000-calorie diet. A person’s daily value may be higher or lower depending on their calorie needs. However, the recommended protein intake is 0.8g per kilogram of body weight for a static non-active person. (25.)

Active individuals are required to have a higher daily intake of 1.4 -2.0 grams of protein per kg of body weight.

Endurance / Exercise / Cardio or Dance

1.4g x bodyweight

  • Football = 1.7g per day
  • Weightlifting = 2g per day

Protein is found in a variety of foods, including:

  • Beans and peas
  • Dairy products
  • Eggs
  • Grains and vegetables (these generally provide less protein than is found in other sources)
  • Meats and poultry
  • Nuts and seeds
  • Seafood (fish and shellfish)
  • Soy products

5. Vitamins

Photo by Crazypharmacist from Canva

Vitamins help your body grow and work the way it should. There are 13 vitamins—vitamins A, C, D, E, K, and the B vitamins (thiamine, riboflavin, niacin, pantothenic acid, biotin, B6, B12, and folate). (26.)

Vitamins have different jobs—helping you resist infections, keeping your nerves healthy, and helping your body get energy from food or your blood to clot properly. By following the Dietary Guidelines, you will get enough of most of these vitamins from food.

Vitamins and minerals are measured in a variety of ways. The most common are:

  • mg – milligram
  • mcg – microgram
  • IU – international unit

Micrograms are used to measure very small amounts—there are 1,000 micrograms in a milligram. The size of an international unit varies depending on the vitamin or drug it is used to measure. (27.)

There are 4 Fat-Soluble Vitamins

  1. Vitamin A – our bodies cannot manufacture it and therefore must be included in our diet. Vitamin A from food is stored in the liver until required by the body and is bound to protein before being transported to where it is needed. Vital for many physiological processes, including maintaining the integrity and function of all surface tissues (epithelia): for example, the skin, the lining of the respiratory tract, the gut, the bladder, the inner ear and the eye. Vitamin A supports the daily replacement of skin cells and ensures that tissues. It’s essential for vision under conditions of poor lighting, for maintaining a healthy immune system, for growth and development and for reproduction. Food sources include (plant-based) – carrots, pumpkins, green leafy vegetables, spinach, and sweet potato, (animal-based) – liver, eggs, milk and fish. (28.)
  2. Vitamin D – one of the many nutrients our bodies need to stay healthy. Among the vitamin’s main functions, it helps the body: Absorb calcium. Vitamin D, along with calcium, helps build bones and keep bones strong and healthy. Block the release of parathyroid hormone. This hormone reabsorbs bone tissue, which makes bones thin and brittle. Plays a role in muscle function and the immune system. The immune system is your body’s defence system. It helps protect it against infections and other illnesses. Food sources include (animal-based) – salmon, eggs, milk and cheese. (29.) 
  3. Vitamin E – it acts as an antioxidant, helping to protect cells from the damage caused by free radicals. Free radicals are compounds formed when our bodies convert the food we eat into energy. The body also needs vitamin E to boost its immune system so that it can fight off invading bacteria and viruses. It helps to widen blood vessels and keep blood from clotting within them. In addition, cells use vitamin E to interact with each other and to carry out many important functions. Food sources include (plant-based) – Vegetable oils like wheat germ, sunflower, and safflower oil, nuts, seeds and green vegetables, such as spinach and broccoli. (30.)
  4. Vitamin K – is a fat-soluble vitamin that comes in two forms. The main type is called phylloquinone, found in green leafy vegetables like collard greens, kale, and spinach. The other type, menaquinones, are found in some animal foods and fermented foods. Menaquinones can also be produced by bacteria in the human body helps to make various proteins that are needed for blood clotting and the building of bones. Prothrombin is a vitamin K-dependent protein directly involved with blood clotting. Osteocalcin is another protein that requires vitamin K to produce healthy bone tissue. Food sources include (plant-based) – kale, spinach, cabbage, and lettuce. (Animal-based k2) – Soy, Natto and Miso. (31.)

Water-Soluble Vitamins B’s and C’s

  • Vitamin B1 (Thiamine) – plays a critical role in energy metabolism and, therefore, in the growth, development, and function of cells. It’s a co-enzyme for metabolizing food for energy and nerve function. Food sources include (plant-based) – whole grains, beans and nuts. (Animal-based) – Beef, liver and pork. (32.)
  • Vitamin B2 (Riboflavin) – is an essential component of two major coenzymes, flavin mononucleotide (FMN; also known as riboflavin-5’-phosphate) and flavin adenine dinucleotide (FAD). These coenzymes play major roles in energy production; cellular function, growth, and development; and metabolism of fats, drugs, and steroids. Food sources include (plant-based) – rice, green leafy vegetables, beans, almonds, kidney beans. (animal-based) – Eggs, beef, milk, and salmon. (33.)
  • Vitamin B3 (Niacin) – niacin refers to nicotinic acid and nicotinamide (also called niacinamide). This nutrient helps the body convert food into glucose, used to produce energy Niacin contributes to the normal function of the nervous system and normal psychological function. It also contributes to the reduction of tiredness and fatigue.  Food sources include (plant-based) – sunflower seeds, green peas, mushrooms. (animal-based) – beef liver, chicken breast and tuna. (34.)
  • Vitamin B5 (Panthothenic Acid) – is a precursor in the synthesis of coenzyme A. Coenzyme A is essential to many biochemical reactions that sustain life.  Balances blood sugar, lowering high blood pressure and preventing heart failure. Helps convert nutrients to energy. Food sources include (plant-based) – avocados mushrooms, sweet potatoes, legumes and beans. (Animal-based) – fish, shellfish, milk, livers and kidney. (35.)
  • Vitamin B6 (Pyridoxine) – Pyridoxal 5’ phosphate (PLP) is the active coenzyme form and most common measure of B6 blood levels in the body. PLP is a coenzyme that assists more than 100 enzymes to perform various functions, including the breakdown of proteins, carbohydrates, and fats; maintaining normal levels of homocysteine (since high levels can cause heart problems); and supporting immune function and brain health. Food sources include (plant-based) – chickpeas, dark leafy greens, avocados, and bananas. (animal-based) – chicken, tuna, salmon and beef. (36.)
  • Vitamin B7 (Biotin) – is a vital part of a healthy metabolism and creating important enzymes. Biotin is often used to strengthen hair and nails and is also called Vitamin H (for hair). Food sources include (plant-based) – cauliflower, carrots and bananas. (animal-based) – salmon, eggs, dairy products and chicken. (37.)
  • Vitamin B9 (Folate) – the human body requires the folate in order to produce healthy red blood cells and prevent anemia. For the synthesis, repair, and methylation of DNA. Folate has an important role in cell division, and it is especially needed during infancy and pregnancy. Folic acid works closely with vitamin B12 in making red blood cells and helps iron function properly in the body. Vitamin B9 works with vitamins B6 and B12 and other nutrients in controlling the blood levels of the amino acid homocysteine Food sources include (plant-based) – avocado, spinach, dark leafy greens, spinach, asparagus, turnip, beets, and mustard greens, and brussels sprouts. (Animal-based) – salmon and milk. (38.)
  • Vitamin B12 (Cyanocobalamin) – You need vitamin B12, also known as cobalamin, to make red blood cells, which carry oxygen in the blood. The nutrient is also essential to the normal health, development and functioning of your brain, nerves and other body parts. Vitamin B12 is also needed to make DNA, your cells’ genetic “blueprint.”  (39.) Functions metabolically in two coenzyme forms, adenosylcobalamin and methylcobalamin, which function in the metabolism of propionate, amino acids, and single carbon. Physiologically, vitamin B12 functions in the regulation of homocysteine, haematological development, and the nervous system.  Food sources include (ONLY animal-based) – fish, meat, poultry, eggs, and dairy products. (40.)
  • Vitamin C (Ascorbic Acid) – is important in the health of the connective tissues of the body. Vitamin C is also a potent antioxidant. Some studies show that vitamin C may help reduce the symptoms and length of the common cold. Plays many roles in the chemistry of the human body. It’s needed to make collagen. This is a critical part of the body’s connective tissue. It also helps increase the absorption of iron from the intestines. This is needed to make haemoglobin. This is the oxygen-carrying pigment inside of red blood cells. Food sources include (plant-based) – strawberries, spinach, cauliflower, oranges, parsley and kiwi. (41.)

6. Roughage (Fiber)

Photo by Michal Bednarek from Canva

Roughage (Fibre) helps to regulate your digestion. Insoluble fibre provides bulk in your intestines and helps to keep food moving through your digestive tract. Insoluble fibre absorbs water and swells into a gel that helps to keep bowel movements soft and easy to pass. These attributes of fibre give it the ability to help relieve and prevent both constipation and diarrhoea.

Meeting your daily fibre needs may reduce your risk of developing certain forms of cancer including breast, colon, mouth, ovarian, stomach and prostate cancers. Fibre may bind to cancer-promoting toxins and remove them from your body. In addition, high-fibre foods contain phytochemicals, or plant chemicals, that act as antioxidants, helping to prevent damage from harmful free radicals in your body. Fibre may also ease inflammatory bowel diseases by reducing flare-ups in your intestines (42.)

Food sources include Plant-based: lentils, chickpeas, green peas, sweet potato, broccoli, avocado, banana, almonds, quinoa and raspberries (43.)

7. Water

Photo by VladimirFloyd from Canva

To function properly, all the cells and organs of the body need water. Cartilage, found in joints and the disks of the spine, contains around 80 per cent water. Long-term dehydration can reduce the joints’ shock-absorbing ability, leading to joint pain. Blood is more than 90 per cent water, and blood carries oxygen to different parts of the body. With dehydration, the skin can become more vulnerable to skin disorders and premature wrinkling. Water is needed in the processes of sweating and removal of urine and faeces. Water may also help with weight loss if it is consumed instead of sweetened juices and sodas. “Preloading” with water before meals can help prevent overeating by creating a sense of fullness. (44.)

Medical Disclaimer

This content is for informational and educational purposes only. It is not intended to provide medical advice or to take the place of such advice or treatment from a personal physician. All readers/viewers of this content are advised to consult their doctors or qualified health professionals regarding specific health questions. Neither Happiivue nor the publisher of this content takes responsibility for possible health consequences of any person or persons reading or following the information in this educational content. All viewers of this content, especially those taking prescription or over-the-counter medications, should consult their physicians before beginning any nutrition, supplement or lifestyle program.

Recommended For You

About the Author: Nailah Aljasmi

Marketing & Advertising Manager | Health and Wellbeing Educator | Nutrition Health Advocate