It's no secret that foods such as fruits, veggies, and whole grains are integral components of a healthy diet. But what makes these eats so good for you, exactly? It's all thanks to their essential nutrients, aka compounds you need to survive but your body can't make on its own. Specifically, essential nutrients are important for overall health because we need them for a healthy functioning body. Not only are essential nutrients vital for overall good health, but, according to the World Health Organisation, they're also key for growth, reproduction, and disease prevention.

Essential nutrients are classified as either macronutrients or micronutrients. Quick refresher: Macronutrients are consumed in relatively large quantities and include carbohydrates, protein, and fat – all of which provide your body with energy (via calories). Micronutrients, on the other hand, are needed in small amounts and consist of vitamins and minerals. And then there's water, an essential nutrient that's in a league of its own.

Now, if you've been keeping count, you've likely realised that there are six essential nutrients: carbohydrates, protein, fat, vitamins, minerals, and water. But why are these bad boys in particular considered essential? Read on for a deep dive into essential nutrients, below.

Carbohydrates
Despite the seemingly perpetual low-carb craze, carbohydrates are actually pretty darn good for your body. For one, when digested, carbs break down into a type of monosaccharide (aka sugar molecule) called glucose. Sound familiar? That's because glucose is the body's main source of energy; meaning, it (and, thus, carbs) help vital organs, such as the kidneys, function properly.

Protein
When it comes to nutrition, protein gets a lot of attention – and for good reason. See, protein is required to keep seemingly every part of your body running smoothly. In fact, it's often considered the body's "building blocks," as it provides structure to cells and tissues (e.g. muscles, organs). What's more, protein also allows the body to repair cells and make new ones, making the nutrient especially crucial during periods of development. But that's not all: The essential macronutrient is also needed to transport other compounds (think: oxygen), clot blood to prevent excessive bleeding, and contract muscles during movement.

Fat
Though fat often gets a bad rap, it actually has numerous vital functions in the body. Fat stores and provides energy, gives structure to cells, and supports the absorption of fat-soluble vitamins (e.g. vitamins A, D, E, and K). Plus, when digested, it is responsible for the sense of satisfaction and fullness.

There are only two types of fats that are considered essential for humans. Our bodies can create some fatty acids, meaning these fats are not essential in our diet. However, the body can't make omega-3 and omega-6 fatty acids, so you need to get them via food. These fats support healthy heart rhythms and blood cholesterol levels, making them beneficial for cardiovascular health.

Vitamins
Now, it's time to talk about the essential micronutrients, beginning with vitamins. They are vital components of a healthy diet as the body can't make them on its own. There are 13 essential vitamins, which are categorised into two groups – fat-soluble and water-soluble vitamins – depending on how they're handled by the body.

Fat-soluble vitamins, such as vitamins A, D, E, and K, are involved in functions such as vision, immunity, and bone health. Meanwhile, water-soluble vitamins include vitamin C – a major player in immunity and collagen production – and the B vitamins – which are needed to repair DNA, produce energy, and support brain function.

Minerals
Minerals are classified into two groups based on how much the body needs. First up are macrominerals, including calcium, magnesium, phosphorus, sodium, potassium, and chloride, which are needed in larger amounts. On the flip side, microminerals, also called trace minerals, are needed in smaller amounts. Microminerals include iron, zinc, copper, iodine, and selenium. Like vitamins, each mineral specialises in different functions within the body. But overall, these micronutrients are involved in the growth of our bones and teeth, as well as the function of our hearts, brains, and muscles. They also support fluid balance, nerve cell communication, and blood health.

Water
Yes, you read that right: Water is considered one of the six essential nutrients. That's because water is required for vital bodily processes, including the regulation of body temperature and blood volume. It's also needed to carry nutrients and oxygen between cells, lubricate the joints, and excrete waste via sweat and urine. What's more, water is the most abundant substance in your body; it makes up to a whopping 60 per cent of your body weight.