Nutrition is the study of nutrients in food, and how our bodies use them to keep us alive and healthy. It includes the nutrients that are important for our health, how we can achieve a healthy nutritional balance through diet, and the biochemical and physiological processes that make nutrients useful. It also focuses on using diet to prevent disease.
The seven nutrients essential to our health are protein, carbohydrates, fibre, fats, minerals, vitamins, and water (more on these below). The amount of nutrients we need depends on our age, how much we exercise, whether we have diseases, medications we are taking, and if we are pregnant.
In this article, we’ll cover the key topics on nutrition, including why it is important, the risks of poor nutrition, what makes a healthy diet, information on the essential nutrients and vitamins, and more.
Table of contents
- Why is nutrition important?
- What is good nutrition?
- What is the relationship between poor nutrition and disease?
- What is functional nutrition?
- 7 essential nutrients
- What is the difference between vitamins and minerals?
- How to measure nutritional status
- How does genetics affect nutrition?
- How does nutrition affect mental health?
- How does nutrition affect the immune system?
- What is a mode of nutrition?
Why is nutrition important?
Good nutrition is achieved through diet, and is incredibly important for our overall health. It helps us accomplish the following:
- Maintain a healthy weight
- Support our growth
- Improve our mental health
- Maintain good energy levels
- Drastically reduce our risk for certain diseases
- Help us to live longer and healthier lives
Without good nutrition, we can become weak, sick, and even die. We need the proper nutrients and the right amounts to grow, and perform our day-to-day mental and physical tasks.
What is good nutrition?
Image from Harvard Health
As with every science, nutrition is a work in progress, and scientists are constantly discovering new information. We have a good depth of knowledge on nutrition, but it remains a highly disputed science, particularly on the subject of diets, with many diet creators claiming theirs to be the best.
Thankfully, there are simple rules you can follow to achieve good nutrition, without worrying about following particular diets (although this can be a healthy option).
Eat plenty of fruits and vegetables
Fruits and vegetables are some of the most nutritious foods we can eat, so getting your daily allowance is an effective way to achieve good nutritional health. It’s recommended to eat two serves of fruit and five serves of vegetables per day, with a serve being roughly 75g in weight (this ranges from half a cup to a cup for most)1. This includes non-fresh food such as tinned fruit and frozen vegetables—just look for items with no added salt or sugar.
Eat a variety of foods
Different food groups provide us with different vitamins and minerals, so we must have a well-balanced diet by eating a variety of foods. This not only keeps us in good health, but also protects us from chronic disease.
To achieve a well-balanced diet, we should eat food from the five main groups:
- Vegetables and legumes
- Grains such as rice, cereal, bread, and pasta (whole grain is healthier)
- Lean meat, poultry, fish, eggs, tofu, nuts and seeds, beans
- Milk, yoghurt, and cheese
Avoid processed food
Processed food often contains high levels of salt, sugar, and unhealthy fat, which lead to serious health issues such as cancer, heart disease, obesity, high blood pressure, and diabetes. They also tend to have few healthy nutrients, and are high in calories.
Processed food can also be delicious, making them addictive. It’s ok to eat processed food occasionally, but it should be a treat rather than a regular part of your diet. Popular processed foods include:
- Breakfast cereal
- Cakes and biscuits
- Soft drinks
- Chips, sausage rolls, and pies
- Bacon, sausage, ham, salami, and other processed meats
- Frozen meals
Eat the right types of fats
Not all fat is created equal. There are four types of fats that we need to think about: trans, polyunsaturated, saturated, and monounsaturated. Trans is awful for our health, polyunsaturated is fine in moderation, and saturated and monounsaturated fats are the two healthiest. We cover more information on these fats below, in the 7 essential nutrients section.
Limit red meat
When consumed in large amounts, red meat such as beef, lamb, and pork increases cardiovascular disease, coronary heart disease, and risk of stroke2. The Heart Foundation recommends limiting red meat to less than 350g per week.
Limit sugar intake
Consuming high amounts of sugar increases the risk of heart disease, obesity, high blood pressure, diabetes risk, and inflammation. It may also increase your risk of cancer, depression, make you look older, and quickly drain your energy.
Sugar-heavy foods include:
- Soft drinks
- Chocolate and candy
- Low-fat yoghurt
- Breakfast cereal
- Fruit juice
- Protein bars
Try to swap out some of these foods with fruit—you’ll still get the taste of sweetness, but it’ll be much healthier for you.
What is the best diet?
If you’d prefer to follow a particular diet, these have shown to be the best for your health:
- Low-carb, whole food diet—this diet helps you lose weight, lower your risk of disease, and be healthier all-round. As the name suggests, It focuses on eating fewer carbs and more whole foods.
- Mediterranean diet—this diet has proven to be incredibly healthy, particularly for our heart. It includes plenty of vegetables, fruits, fish, poultry, whole grains, legumes, and extra virgin olive oil.
- DASH diet—this diet was initially created to reduce the risk of heart disease. It includes plenty of vegetables, fruit, lean protein, and also restricts red meat, salt, added sugars, and fat.
What is the relationship between poor nutrition and disease?
Eating a balanced-diet that is rich in nutrients is incredibly important for our health. If we have a poor diet that includes lots of processed food, sugar, salt, and trans fats, we’re at risk of developing a vast number of illnesses and chronic health problems. These include an increased risk of:
- Heart disease and stroke
- Type-2 diabetes
- High blood pressure
- High cholesterol
- Certain cancers
- Reduced brain function
- Tooth decay
What is functional nutrition?
Functional nutrition is a personal approach to nutrition that focuses on the patient, rather than the disease. It takes a person’s genetics and lifestyle into account to achieve the best possible nutrition based on their individual needs, and to improve their physical, mental, and spiritual health.
Functional medicine also acknowledges how organs in the body work together to achieve optimal health. It plays a more significant role in practices such as massage therapy, acupuncture, chiropractic services, and more.
7 essential nutrients
We need seven different nutrients to keep our minds and bodies functioning correctly, which we get from our food. Here are the details.
Protein is a macronutrient that makes up around 20% of our weight. It’s a “building block” that allows our bodies to do the following key processes:
- Build new cells
- Repair damaged cells
- Oxygenate us
- Aid digestion
- Regulate our hormones
Carbs are a quick source of energy that power our cells. Our body breaks them down into glucose, which enters our cells with the help of insulin, and provides us with energy. Too many carbs can be stored as fat, and also cause insulin resistance which leads to hunger cravings.
There’s two types of carbs:
- Sugar (simple carbs)—these are a quick source of energy, but can damage our metabolism over time, and make us unhealthy.
- Starch (complex carbs)—starch is made up of longer chains of glucose, so takes more time for your body to break down, which provides a slower release of energy. They also contain fibre, which aids digestion.
Fibre is a type of carbohydrate that is critical for helping us to digest our food. There’s two types of fibre:
- Soluble fibre—this type of fibre dissolves in water, and creates a gel-like substance that improves digestion.
- Insoluble fibre—this type of fibre attracts water to your stool, which creates a healthier bowel, and may even reduce your risk of diabetes.
Fats can also provide us with energy, and help us to absorb vitamins, build cell membranes, allow our muscles to move, and our blood to clot. They also aid inflammation (as part of our bodies natural defence). There are four main types of fat:
- Saturated fat—these fats can have many benefits to your health, including increased energy, improved bone health, better lung health, and even reducing cholesterol levels.
- Trans fats—these fats are terrible for our heart health. They’re found in many fast foods, baked goods, and other low-quality food sources.
- Monounsaturated fats—these are one of the healthiest fats, with anti-inflammatory properties, and promotion of cell growth and repair. They’re found in foods such as avocados, olive oil, and macadamias.
- Polyunsaturated fats—this type of fat is ok in moderation, but a balance must be struck between these and monounsaturated fats. They’re commonly found in oils such as soy, and sunflower.
Minerals are micronutrients that support the body’s functions, such as your metabolism, bones, heart, inflammatory response, and staying well-hydrated. Minerals-rich foods include seafood, leafy vegetables, citrus fruits, whole wheat foods, eggs, milk, cheese, nuts, and more.
Vitamins are also micronutrients that support our body’s functions, and help to prevent disease. They promote eye health, skin health, and bone health, boost our immune system, and might also lower our risk for certain cancers.
Water is our last essential nutrient. It’s critical for a considerable number of reasons—body temperature regulation, digestion, removing toxins, reducing inflammation, protecting our tissues, helping us absorb nutrients, and much more.
Learn more about the 7 Essential Nutrients, and How Your Body Uses Them.
What is the difference between vitamins and minerals?
Vitamins are organic compounds that come from plants and animals, and minerals are inorganic compounds from the earth. Plants and animals absorb and eat minerals, so we get both vitamins and minerals from our food.
Vitamins have a diverse number of biochemical functions in our bodies, including our metabolic processes. These are the essential vitamins:
- Vitamin A
- Vitamins B1, B2, B6, B7 and B12
- Vitamin C
- Vitamin D
- Vitamin E
- Vitamin K
- Folic acid
Vitamins can be either fat-soluble or water-soluble. This means that they can be absorbed in our bodies with fat, or with water.
Minerals help with muscle contraction, blood coagulation, heart and brain function, forming bones, and producing enzymes and hormones. There are 16 essential minerals:
For more in-depth information, check out our article What Is The Difference Between Vitamins & Minerals.
How to measure nutritional status
Nutritional status is a key indicator of health. It’s your body’s physiological state based on the number and quality of nutrients that you can absorb, and defines whether you’re healthy, malnourished, or underweight.
Here are the most common and effective ways to measure nutritional status, as part of a nutritional assessment.
This tests the levels of macronutrients and micronutrients in your body, using blood samples. These tests are broken down by vitamins and minerals—vitamin tests, mineral tests, calcium tests, etc.
Nutrition response testing is an alternative method that involves muscle testing, to identify weakness or dysfunction.
Assessing a person’s diet is another useful way to measure their nutritional status. By tallying up what has been eaten over a 24-hour period, you can get a good idea of whether they’re eating the right foods, and in the right amounts.
A dietary assessment can include number of meals per day, salt intake, changes in appetite, and alcohol and caffeine consumption.
Anthropometry is the study of measuring the human body. The human species has measurements that fall within a certain range, and when these ranges are breached (e.g. a large belly), it can indicate poor nutritional status.
Anthropometry includes measuring a person’s height, length, weight, body mass index (BMI), head circumference, skin fold thickness, and arm circumference, which are usually taken from one date to another.
As with our body measurements, chemicals inside our bodies must also sit within a particular range to keep us healthy. We can measure certain proteins, cells, and other chemicals to identify nutritional status.
Clinical assessment is the physical examination of a patient, to identify problems. Nutritional deficiencies show on the body in a number of ways, including muscle wasting, pale skin, fatigue, swelling, ulcers, bleeding gums, and more. By identifying these issues, we can diagnose issues and understand how they’re best treated.
To get more information on this topic, check out our comprehensive article on the 5 Most Reliable Ways To Measure Nutritional Status.
How does genetics affect nutrition?
Genetics affects your tolerance to certain foods. Common examples are lactose intolerance (dairy) and gluten intolerance (wheat, barley, and rye). People who are intolerant should avoid these foods, or risk a number of unpleasant symptoms. In functional nutrition, a person’s genetics are taken into consideration when creating a healthy diet for them.
Genetics may also affect your body’s nutritional processes, including absorption, metabolism, receptor action, and excretion3. Finally, it may affect your food preferences, which can influence whether you get enough nutrients.
How does nutrition affect mental health?
Eating a balanced diet that is rich in fruits and vegetables has shown to have a positive effect on your mental health and wellbeing. The stomach produces a large number of neurotransmitters (dopamine and serotonin are two common examples), and as a result, is often referred to as the “second brain.” The brain and stomach share a close relationship, and by eating healthy food, you’re promoting the production of “good” bacteria which increases the number of neurotransmitters in your body, and improves your mood. Unhealthy food, on the other hand, can cause inflammation and hinder the production of neurotransmitters, which worsens your mood4.
How does nutrition affect the immune system?
As with other areas of your health, good nutrition can improve your immune system. It does this by creating a healthier microbiome, and improving your gut barrier function, inflammatory processes, and white blood cell function. With a better immune system, there’s a decreased risk for disease and allergy5.
What is a mode of nutrition?
Modes of nutrition are the ways that living things get their food. There’s two modes of nutrition: autotrophic, and heterotrophic. Autotrophs make their own food (hence the word “auto”), with the most common example being plants that turn sunlight into food through photosynthesis. Heterotrophs get their food from other sources by eating them, and include pretty much every animal (including us).
- Nicole Mills, 2019, What you need to get your recommended intake of fruits and vegetables, ABC News
- Meat & Heart Healthy Eating, Heart Foundation
- National Research Council (US) Committee on Diet and Health, Washington (DC), Genetics and Nutrition - Diet and Health - NCBI Bookshelf, National Academies Press
- Alice Gomstyn, Food & Your Mood: How Food Affects Mental Health, Aetna
- Jillian Kubala, MS, RD, 2021, Diet and the immune system: What is the link?, Medical News Today