Micronutrients are essential nutrients, needed to sustain life but in small quantities and include vitamins, minerals, antioxidants and phytonutrients. Most of us are aware that vitamins and minerals are vital to our health. A balanced healthy diet should give us all of the micronutrients require so, where possible, our main source of micronutrients should be natural, whole food, especially fresh, seasonal fruits and vegetables. It is recommended to eat a ‘Rainbow Diet’; fruits and vegetables representing the colours of the rainbow. Each colour is created by a group of phytonutrients, so to get the benefit of the health giving properties of nature’s bounty, go for the reds, oranges, yellow, greens, blues and purples!
Micronutrients play an important role in energy production, oxygen transport, maintenance of bone health, adequate immune function and protection of the body against oxidative damage, which occurs through exercise. They also assist with tissue growth and repair and recovery from exercise. Exercise stresses many of the metabolic pathways where micronutrients are required.
The most important micronutrients to consider in an athletes diet are:
Calcium is the most abundant mineral in the body. Calcium has a wide range of functions in the body such as maintaining healthy bones and teeth, muscle contraction, nervous system function, stabilization of blood pressure, contribute to normal brain function, blood clotting, secretion of hormones and helps maintain a regular heartbeat.
Calcium is important for runners in order to achieve and maintain optimum bone density.
1000mg of calcium a day is recommended for adults, which may not be that hard to reach as one glass of milk can give you 300mg.
Maximise your calcium intake by including calcium containing recovery snacks such as Greek yoghurt and almonds or hard-boiled eggs. Plant sources of calcium include cherries, broccoli and spinach.
Vitamin D plays a critical role in the absorption of calcium, so it is usually added to dairy products to aid absorption. Living in the northerly latitude of Ireland, Vitamin D deficiency is quite common. This important nutrient is actually a hormone and is synthesised by our skin through UV rays. Given that we don’t see the sun that often and when we do, we use sunscreen, it’s easy to see why we can be deficient. Vitamin D is not only beneficial for the absorption of calcium and bone health, more and more research is demonstrating its powerful effect on immunity and preventing illness. Good dietary sources of Vitamin D are eggs, oily fish and fortified dairy foods.
Vitamin B1 Thiamin, B2 Riboflavin, B3 Niacin, B5 Pantothenic, B6 Pyridoxin, B7 Biotin, B9 Folate and B12 all play a role in energy metabolism, which is what you need as an endurance runner. These nutrients help the release of energy from carbohydrates, proteins and fats, folate plays an important role in cell division and red blood cell production, which is how we transport oxygen, so you see, from an endurance runner perspective, these vitamins are pretty important. You can get your B vitamins from eating a balanced diet as wholegrains, legumes, vegetables, meats and fish are all good sources.
Iron is one of the most important minerals consumed by athletes. Regular intensive workouts can decrease your iron stores in the body, which can result in iron deficiency anaemia, a condition that impairs the body’s ability to transport oxygen. Iron is also lost through sweating and foot strike hemolysis, which is caused by repeated pounding of the feet on hard surfaces, destroying red blood cells, which causes iron losses. Iron is involved in many processes in the body, including the formation of red blood cells; oxygen and carbon dioxide transport and is also involved in energy production. Iron cannot be produced in the body, therefore, it must be supplied by the food we eat. Haem iron, which is easily absorbed, is found in animal sources particularly in lean red meat, such as beef, liver, pork, poultry and seafood. Non-haem iron is found in plant-based sources, such as cereal grains, nuts and certain green vegetables and is not as easily absorbed as haem iron. Vitamin C helps the absorption of iron from plant sources so, if you’re vegetarian, be mindful of the relationship.
Zinc is a trace element found in all tissues and fluids in the body. It is very important in enhancing a person’s immune function, by reducing the risk of the common cold and infectious diseases. It also has roles associated with growth and development, healing wounds and enhancing senses. Foods rich in zinc include beef, lamb, spinach, nuts and mushrooms, with the RDA for both males and females is 15mg/day.
Magnesium plays a role in muscle and nerve function and the creation of ATP (the energy currency which causes muscles to fire) and is also an electrolyte, which we mentioned in the water section. Low blood levels of magnesium can result in muscle fatigue. Sources of magnesium are dark green leafy vegetables, nuts, seeds and fish.
Antioxidants play a very important role for your diet, particularly if you exercise frequently. They are vitamins minerals and enzymes, which can be either consumed or naturally produced by the body. The main role of antioxidants is to protect the body’s cells from the effects of free radicals. These are molecules produced as a by-product of energy production. Therefore, the amount of free radicals increases during periods of exercise. Free radicals can lead to oxidative stress, which strains muscle tissues, and can play a role in many diseases, such as cancer and heart-related diseases. By adding an intake of antioxidants to your diet, muscle damage and fatigue can be prevented, and can improve aerobic capacity after intense training sessions.
The best way to ensure you eat enough antioxidants, is to eat a wide variety of foods in a healthy, balanced diet. The best sources of antioxidants can be found in:
Nitrates are becoming increasingly popular for endurance athletes. These are ions, containing nitrogen and oxygen, which can either be produced in the body or ingested. Their consumption has grown interest in athletes, as studies have reported that they can be used as a potential aid to enhance exercise performance. Even small amounts digested have been shown to increase plasma nitrite/nitrate levels, and reduces the amount of oxygen lost during exercise. It has also been reported that nitrate consumption can aid to treat individuals with high blood pressure and oxidative stress. Vegetables, such as celery, beetroot, spinach and rocket have a large nitrate content of over 2,500mg per kg, which can be added to a wide variety of meals.