Nutrients are substances in our food and beverages that provide essential nourishment for our body’s growth and repair.

So what are these nutrients?

Water

Our bodies are 50-80% water. Water is classified as an essential nutrient, as our bodies need in amounts that exceed our ability to produce it. It fills the spaces in and between cells and helps form structures of large molecules such as protein and glycogen. We need water for digestion, absorption and transportation, of nutrients, elimination of waste and to regulate our temperature. We get about 20% of water intake from foods, and the rest comes from the water and other beverages we drink.

The Macronutrients

Sometimes called “macro’s”, macronutrients are the nutrients that our bodies need in relatively large amounts as they are our body’s building blocks, and which provide our bodies with energy (calories/kilojoules):

Carbohydrates

The primary role of carbohydrates is to provide energy to our cells. Each gram of carbohydrate provides 4 calories or 17 kilojoules of energy. The carbohydrates in the foods we eat are digested, and broken down into glucose before entering the bloodstream. Glucose from carbohydrates is our body’s preferred fuel source. Cells in our bodies, such as our lean muscle cells, take in the glucose from our blood and, via a process called cellular respiration, use that glucose to make adenosine triphosphate (ATP) , a “fuel molecule”, which is in turn used to fuel a variety of metabolic tasks throughout our body. Any excess glucose from the carbohydrates we eat can be stored in our liver as glycogen, or converted to triglycerides and stored as fat. To read more about Carbohydrates, check out THIS blog post.

Protein

Our body needs protein for maintenance and growth. It is found in all cells in our body, in our muscles, organs, hair and skin. Each gram of protein provides 4 calories or 17 kilojoules of energy. Proteins are composed of different amino acids linked together in different combinations by peptide bonds. The protein we eat is broken down into individual amino acids in our digestive tract. To read more about Protein, check out THIS blog post.

Fats

Fats are the most energy-dense nutrient, providing 9 calories or 37.7 kilojoules per gram. All foods containing fat generally have a mix of different types of fats:

Saturated fats: These fats are mainly found in animal products, but there are also plant sourced saturated fats (coconut oil, palm oil).

Unsaturated fats: These fats are liquid at room temperature and can be monounsaturated or polyunsaturated.

Trans fats: Trans fats are a “man made” fat, produced when unsaturated fats which are liquid at room temperature, are hydrogenated to make them solid. These fats are extremely unhealthy and have been shown to raise LDL (bad) cholesterol.

Micronutrients

Vitamins and minerals are micronutrients, essential elements needed by the human body, but in much smaller amounts than the macronutrients.

Vitamins

Water-Soluble Vitamins: Vitamin C and all of the B Vitamins (thiamin/B1, riboflavin/B2, niacin/B3, pantothenic acid/B5, pyridoxine/B6, biotin/B7, folic acid/B9, and cobalamin/B12) are water-soluble. As their name implies, water-soluble vitamins dissolve in water. Our diet needs to provide us with a regular supply of these Vitamins, as they are not stored in our bodies and are excreted in our urine.

Fat-Soluble Vitamins: Vitamins A, D, E, and K are our fat-soluble vitamins. These Vitamins can be stored in our liver and body fat, and our body can draw on these stores as and when needed.

Minerals

Micro-minerals: Micro-minerals are common minerals like calcium, phosphorus, magnesium, sodium, and potassium.

Trace Minerals: Trace minerals, including iron, manganese, copper, zinc, and selenium, are needed in smaller amounts than the Micro-minerals.

Phytonutrients

Phytonutrients are natural chemicals found only in plant foods (fruit, vegetables, nuts, legumes, grains, herbs, spices, tea and coffee) that have beneficial effects on the human body. They are not formally classified as Nutrients, but due tot their powerful health benefits I think they should be!

There are more than 25,000 different phytonutrients. Many have been the subject of scientific studies to understand their beneficial impacts on the human body. I will be writing a lot more about phytonutrients soon, but in the meantime check out THIS POST about anthocyanins, a powerful phytonutrient that provide the vibrant red-orange and purple-blue-violet pigments in fruit, veggies and other plant foods like grains and legumes.

Now that we have covered the different types of nutrients, here are some things you need to know about nutrients:

Alcohol is NOT a nutrient!

Alcohol provides energy (calories/kilojoules) but is not classified as a nutrient because it does not contribute in any way to the growth, maintenance or repair of the human body. For more information on the impact of alcohol on the human body, check out THIS POST.

Some nutrients are classified as Essential

Essential nutrients are nutrients that our body can’t make itself, or cannot make I the amount it needs. So we have to get these essential nutrients through the food we eat. Essential nutrients include water, the various categories of carbohydrates, fats and proteins, and certain vitamins and minerals. For example, protein is comprised of 20 amino acids, nine of these cannot be synthesised by the human body and must be obtained from the protein we eat.

Nonessential nutrients are those that can be made in our body or obtained from non-food sources. For example, bacteria in our gastrointestinal tract can produce vitamin K and biotin/B7, our liver can produce cholesterol that is produced by the liver, and our skin can synthesise Vitamin D from sunlight.

There are also substances known as Antinutrients

Antinutrients are nature or synthetic compounds that impede our body’s absorption of nutrients. Almost all foods contain small amounts of anti nutrients. Antinutrients in our foods can be reduced by cooking, fermenting or sprouting.

Examples of antinutrients include:

Phytic acid, a compound found in the hulls of nuts, seeds and grains. Phytic acid binds to minerals such as calcium, magnesium, iron, copper and zinc, which prevents these minerals from being absorbed in our digestive tract.
Oxalic acid and oxalates, found in many plant foods including rhubarb, spinach and purslane. Oxalates bind to calcium, hampering with our body’s ability to absorb it.
Glucosinolates, found in brassica vegetables such as cabbage, broccoli, Brussels sprouts, radishes and cauliflower, interfere with the body’s absorption of iodine, which can in turn impact our thyroid function.

How much of each nutrient do I need?

We need the right nutrients in the right amounts for optimal health. But how can we find out what nutrients we need?

The NRVs (Nutrient Reference Values) are a set of recommendations compiled by the National Health & Medical Research Council for nutritional intake based on currently available scientific knowledge.

You can visit the NHMRC website (https://www.nrv.gov.au/nutrients) and trawl through each individual nutrient, or you can use one of these really simple but very cool nutrient calculators: https://www.eatforhealth.gov.au/webform/daily-nutrient-requirements-calculator

We don’t eat nutrients, we eat foods and meals that contain an array of nutrients

So once we know what our nutrient need are, it can be helpful to then work out how we can get the nutrients we need for optimal health through our diet.

One way of doing that is to use a food serves calculator, like this one: https://www.eatforhealth.gov.au/webform/average-recommended-number-serves-calculator