What are micronutrients and why are they so important?

In our last blog we learned our the three main macronutrients; protein, fats and carbohydrates. This time we’re going to look at micronutrients, their role within the body and importance for daily health as well as sports performance and what foods we should be focusing on in order to get what we need.

But firstly, what are they? A micronutrient is defined as chemical element or substance required in trace amounts for the normal growth and development of living organisms. If macronutrients are the fuel to our engines, then the micronutrients are the oil and water that keep the parts moving effectively. Micronutrients can be mostly put into the category of either a vitamin or mineral.

Most of us have heard about vitamins and are aware we need them, even if we aren’t quite sure why. Vitamins are either water soluble or fat soluble. The water soluble vitamins Vitamin C & B-complex vitamins, are lost through bodily fluids and should be consumed daily as part of a healthy diet to maintain their levels. Whereas fat soluble vitamins like A, D, E & K aren’t lost as easily and as a result are only needed sporadically within the diet to ensure adequate amounts.

But what do they do?
Vitamins are responsible for maintaining the healthy functioning of the body and are often associated with our immune function. And while there is a lot of overlap in what we need each vitamin for, here are some more specific areas that each vitamin is important for maintaining optimal function.

  • Vitamin C – Cell protection, healing, blood vessels, bone & cartilage. Found in; oranges, peppers, strawberries, currents, broccoli and sprouts.
  • Vitamin B-complex – Mostly associated with forms of energy release and nervous system function, recommended daily intakes should easily be met through a balanced diet. The most commonly talked about include B6 & B12.
  • Vitamin B6 – Allows the body to use and store energy from protein and carbohydrates as well as form haemoglobin which is responsible for oxygen transport. Found in pork, poultry, fish eggs and wholegrains.
  • Vitamin B12 – Allows the body to use folic acid, make red blood cells & releasing energy from food. Found in meat, fish, dairy and eggs.
  • Vitamin A – Immune system, vision & skin health including linings of nasal cavity. Found in; oily fish, eggs, green leafy veg, carrots and sweet potatoes.
  • Vitamin D – Regulation of calcium and phosphate, maintaining healthy bones, teeth and muscles. The body can create vitamin D from the skin’s exposure to sunlight. It can also be found in oily fish, red meats, liver and certain fortified foods. Vitamin D supplementation may be a good option for athletes during the winter months when exposure to daylight is reduced.
  • Vitamin E – Healthy skin & eyes as well as maintaining a healthy immune system. Found in plant oils, nuts and seeds.
  • Vitamin K – Involved in blood clotting and effective wound healing. Found in green leafy vegetables e.g. broccoli, spinach and kale.

Minerals include calcium, sodium, magnesium, potassium, chloride, phosphorus, iron and zinc. Their importance to a well functioning body include things like health & immune function, cognitive function fluid balance and are even involved in muscle contraction and energy production. While each may play only a small role, their link to so many processes within the body mean that a deficiency in one or more can prevent optimal function in many areas all over the body. Magnesium for example is utilises on over 300 chemical processes within the body, without which they’d all be affected.

Sticking with magnesium, in terms of exercise and performance, it’s linked to lowering lactic acid levels during exercise as well as muscle function. It is also lost through sweat, and therefore lost in larger quantities during harder bouts of exercise or training in hotter conditions.

Potassium, predominantly found in muscle tissue and works with sodium in the surrounding fluid to transport molecules in and out of the cells. Together with calcium ions, potassium and sodium are responsible for transmission of nerve impulses and muscle contraction and relaxation.

Many of the minerals we’ve mentioned are often referred to as electrolytes and play a key role in hydration. You can read more about the importance of hydration and electrolytes in our previous blog here. Because of the key role these minerals play in our fluid balance and muscle contraction, it’s imperative that we maintain good levels of each in our bodies in order to function well on a day to day basis, as well as during exercise. When training hard or racing, it’s especially important to maintain good electrolyte levels in order to sustain effort, since failing to replace these electrolytes will see loss in performance through reduced muscle efficiency, muscle spasms and cramps.

While foods are usually dominant in one of the macronutrients, with smaller amounts of the others, in the case of micronutrients certain ones are found only in certain foods. Hence the importance of a varied diet to ensure we get what we need. Foods that do contain large amounts of micronutrients are very valuable in our diet and we classify them as being nutrient dense foods. Examples of foods that provide us with key minerals are:

– Green leafy vegetables – magnesium, calcium,
– Nuts & seeds – magnesium, calcium, iron, zinc
– Brown rice – magnesium, phosphorus
– Potatoes – magnesium, Iron, Copper
– Fruit (bananas) – potassium, magnesium, phosphorus, zinc
– Pulses – potassium, copper, phosphorus, iron, zinc
– Meat/poultry – potassium, phosphorus, zinc
– Fish – magnesium, potassium
– Kale – Potassium, Calcium, Magnesium, Copper and Manganese.
– Avocado – Copper, magnesium, potassium, zinc

While a regular healthy diet should easily cover our daily requirements of micronutrients, this becomes more difficult when we eat processed foods since a lot of the nutrient content is lost during the process. This is a very good reason for choosing more natural whole grain options with foods. However, athletes and people who exercise regularly are putting additional demands on their body for growth and repair as well and extra strain on their immune system. It’s therefore imperative these individuals ensure they are consuming enough micronutrients so support and sustain optimal health and performance. Supplements are often seen as a useful addition to help prevent this. However, they should always be used to support an existing healthy eating protocol and not used in place of one. Supplements as their name suggest are there to ‘supplement’ our diet, and not replacement.

Cinar, Nizamlioğlu & Moğulkoc, (2006) The effect of magnesium supplementation on lactate levels of sportsmen and sedentary, Acta Physiologica Hungarica, Jun;93(2-3):137-44.

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