Which nutrients do you actually need?

Posted by kathryn in Nutrition

A while ago a reader asked me the question: which nutrients are absolutely essential and which ones are optional extras? Her concern was, she didn’t like most of the lycopene containing fruit and veg. Was her diet and health missing out?

So here’s my answer.

The 4 nutrient types

Nutrients are substances which enable us to live and grow. We humans obtain these nutrients from the food we eat.

Food is broken down by our digestive system, the nutrients extracted and used in the myriad of biochemical processes occurring in your body.

For humans there are four basic levels of nutrients; four priorities of nutritional need. In order of importance they are:

1. Kilojoules
2. Macronutrients: protein, fat & carbohydrates
3. Micronutrients: vitamins & minerals
4. Antioxidants

So which of these do we actually need?

Nutritional Need Number 1: Kilojoules

The most basic level of nutritional need is kilojoules (or calories). Pure energy, to fuel your body’s biochemical processes and functioning.

Without an adequate kilojoule intake the risk and damage to your health is severe.

At it’s most fundamental level we need kilojoules to keep us alive.

For most people in developed countries, inadequate kilojoule intake is rare. Instead, for many people an excess of kilojoules is the problem.

Nutritional Need Number 2: Macronutrients

After kilojoules, the next most important nutritional need is sufficient quantities of the three macronutrients.

Macronutrients are the dietary components we consume in the largest quantities: protein, fat and carbohydrate.

While these three provide the bulk of kilojoules in your diet, they are each important for your health in a number of ways. Carbohydrates are the preferred energy source. Protein is a structural constituent, making up muscles, enzymes, organs, hormones. While fat provides energy and insulation, and is part of the structure of hormones, skin and hair.

These three are needed for the effective working of your body. A macronutrient deficiency causes severe health disruption. Therefore after adequate kilojoules, your second nutritional need is effective amounts of the three macronutrients.

Nutritional Need Number 3: Micronutrients

Next in the priority list of nutritional needs are the micronutrients: substances obtained from the diet in small quantities.

Vitamins and minerals are classified as micronutrients. Micronutrients can act as catalysts, antioxidants, hormones, plus they can form part of the structure of your body.

Micronutrient deficiences cause severe health problems. However these problems build up over a longer period of time. Neglecting one or more of the micronutrients has a less immediate impact than missing out on kilojoules or macronutrients.

Nutritional Need Number 4: Antioxidants

The last nutritional need is antioxidants.

Oxidation is a type of chemical reaction which occurs all the time in your body. While it’s necessary for life, the by-products of oxidation are damaging. These need to be mopped up and disposed of – which is where antioxidants shine.

Oxidative damage occurs over a long period of time and it’s believed to be a component of many degenerative health problems, such as heart disease, stroke, macular degeneration, cancer.

There are many, many different types of antioxidants. And at the moment we don’t know how many you need and which are the most important. Part of the problem is they work off each other. Complex synergies between antioxidants are suspected.

Which nutrients do you need?

Nutritional needs are a complex issue. And there’s still much we do not know on this subject. At it’s most basic level you need kilojoules and the macronutrients. Without these your health will unravel rapidly and sharply. In the short term, these are the nutrients you need.

However, without vitamins and minerals your health will also suffer. A deficiency of vitamin C causes scurvy which can be fatal. A lack of vitamin B12 leads to neurological damage. Even in less extreme examples low levels of the micronutrients mean your body is not functioning at it’s most efficient. You will be more tired and at greater risk of ill-health than you should be.

While if your diet lacks antioxidants it’s unlikely to cause you a problem today, this week, or even this year. However your health will suffer in the long term. A lack of antioxidants will increase your risk of disease and suffering in the future.

Moreover, while they’re not considered actual nutrients you also need water and fibre for the proper functioning of your body. Along with the macro-nutrients, these are also bulky components of many of the foods we eat.

In my opinion, to be healthy you need all of these nutrients, along with water and fibre. Simply staving off starvation and macro-nutrient deficiency is not enough. To be healthy both now and into the future, you also need those vitamins and minerals. And you need the antioxidants.

What to do?

If there is one particular food group you don’t like, then don’t force yourself. Leave it alone.

If you don’t like tomatoes and other lycopene containing foods then simply eat as widely as you possibly can from all the other antioxidant containing foods.

Through eating a wide range of foods, including plenty of vegetables and not eating too much, you’ll be getting the nutrients you need.

Tomato photograph by Vinduhl, jumping photograph by Sanja Gjenero, square meal photograph by Katiew, vitamin B12 molecule from Benjah-bmm27, strawberries photograph by chotda.

12 November, 2008