Vitamins are organic compounds vital for growth and development. Your body cannot synthesize them, so you need a regular dose to maintain your good health. Your regular diet supplies vitamins in small quantities, but as a triathlete, you need a higher amount of these micronutrients for your training.

There are two types of vitamins: water soluble and fat soluble. Water-soluble vitamins as the name denotes, dissolve in water and carried throughout the tissues and excreted in the urine. Fat-soluble vitamins, on the other hand, are absorbed by the body with the aid of dietary fats and stored in the fatty tissues.



The water-soluble vitamins are composed of B vitamin complex and Vitamin C. As the food breaks down in the small intestines, water carries them directly into the bloodstream except for Vitamin B6 or pyridoxine which stays mostly in the muscle tissues.

It is worthy to note that the B vitamin complex has a direct relationship with your training performance since they are involved in energy production, blood formation, and muscle maintenance. Vitamin C, on the other hand, stimulates your healing process by alleviating your aches and pains and body stiffness.

For instance, vitamins B1 (thiamine), B2 (riboflavin) and B3 (niacin) help you prolong stamina by supplying energy during your exercise regimen while vitamin B6 (pyridoxine), B9 (folate) and B12 (cobalamin) maintain the nervous, circulatory and muscular systems for fast recovery from stress, strain and damaged muscles after your exercise.

Vitamin B1 – Thiamine

Thiamine is needed in the formation of adenosine triphosphate (ATP) to metabolize food for energy. It maintains the healthy functions of the nervous system, brain, muscles, heart, stomach, and intestines. It helps contract your muscles and conducts nerve signals which affect your movement as you run, swim and cycle.

Eat foods rich in thiamine such as seaweeds, sunflower seeds, macadamia nuts, lentils, soybeans, green split peas, pinto beans, mung beans, wheat germ, beef steak, pork, trout, Bluefin tuna, eggs, enriched or fortified whole grain products such as bread, cereals, and pasta.

Vitamin B2 – Riboflavin

Riboflavin allows other B vitamins to function properly. As part of the B complex, it helps in producing energy for the body by converting proteins into amino acids and carbohydrates into glucose. It’s an essential vitamin in producing red blood cells, boosting energy levels and keeping a healthy digestive system.

An excellent supply of vitamin B2 comes from the liver of lamb, beef, veal, turkey, and chicken. Other rich sources are mollusks, beef, lamb, eggs, milk, organic feta cheese, almonds, lean lamb, fermented soy, mackerel, beef and lamb kidneys, seaweeds, goat cheese, whole-grains, enriched bread and cereals, mushrooms, and spinach.

Vitamin B3 – Niacin

Vitamin B3 helps maintain a healthy cardiovascular system, nervous system, and digestive system. Specifically, it supports the conversion of food into energy, the balance of blood cholesterol levels, proper brain and nerve functions, skin health, reduction of joint pains, and prevention of diabetes.

Excellent sources of niacin are beef liver, chicken breast, turkey, beef, lamb, tuna, salmon, sardines, seaweed, peanuts and enriched bread and cereals, brown rice, corn, mushrooms, asparagus, leafy greens, butternut squash, winter squash, sweet potatoes, green peas, and okra.

Vitamin B6 – Pyridoxal Phosphate

Vitamin B6 serves as a coenzyme in hemoglobin synthesis and functions,  and also in the metabolisms of amino acid, glucose, and fats. It produces the two hormones serotonin and norepinephrine for proper brain functions. Serotonin regulates your mood while norepinephrine helps your body to cope with stress.

Rich sources include tuna, salmon, beef, poultry, pork, turkey, eggs, liver and other organs, potatoes, and other starchy vegetables, avocados, bananas, and fortified breakfast cereals, chickpeas, and pistachios.

Vitamin B9 – Folate

Folate or folic acid needs for making DNA and new cells, especially red blood cells and the synthesis and repair of DNA and RNA. It works with other B vitamins to produce and use new proteins for metabolism. It also supports nerve and immune functions. Deficiency of this vitamin can cause anemia.

Foods rich in vitamin B9 are spinach, beef liver, black-eyed peas, asparagus, broccoli, mushrooms, Brussel sprouts, mustard greens, kidney beans, chickpeas, Romaine lettuce, avocado, wheat germ, bulgur wheat, oranges, lentils, hazelnuts, peanuts, flax, walnuts, almonds, and sunflower seeds.

Vitamin B12 – Cyanocobalamin or Cobalamin

Vitamin B12 supports the metabolism of carbohydrates, fats, and proteins. A cofactor in the synthesis of new cells particularly the DNA, it keeps the nerves and red blood cells healthy; prevents megaloblastic anemia which makes you tired and weak, and helps in the absorption of folic acid or vitamin B9.

Best sources of vitamin B12 are liver and kidneys, clams, sardines, beef, pork chops, turkey, chicken, tuna, trout, herring, salmon, sardines, mussels, mackerel, clams, crab meat, shrimp, crabs, fortified breakfast cereals, eggs, milk, Ricotta cheese, Mozzarella cheese, Cottage cheese, Swiss cheese, poultry, yogurt, and nutritional yeast.

Vitamin C – Ascorbic Acid

A powerful antioxidant, vitamin C needs for protein production to maintain healthy skin, tendons, ligaments and blood vessels. It boosts immune functions; repairs cartilage and bones; heals wounds; enhances iron absorption for the production of red blood cells and slows down aging. It also lessens the duration and effects of colds and flu by strengthening immunity against viruses and bacteria.

Vitamin C can be found only in fruits and vegetables such as blackcurrant, red pepper, kiwi fruit, guava, green bell pepper, turnip greens, lettuce, oranges, strawberries, papaya, broccoli, kale, parsley, pineapple, cantaloupe, grapefruit, mango, raspberries, blueberries, cranberries, Brussel sprouts, cauliflower, spinach, cabbage, winter squash, tomatoes, sweet and white potatoes.



Bile acids from the liver are carried into the small intestine to emulsify fats. When dietary fats break down, they help in the absorption of fat-soluble vitamins. The fats transport them from the small intestines into the bloodstream and store in the liver. So, you need to consume an adequate amount of fats with your diet to fully utilize the benefits of these vitamins.

Vitamin A – Retinoids and Carotenoids

Vitamin A is an antioxidant which fights cell damage and needed for healthy vision, skin, bone and immune system. It helps to fight inflammation; organs such as lungs, kidneys, and heart to function properly; and the bones to heal and recover from fracture and stress.

Vitamin A from animal sources is called retinoid and includes meat, fortified margarine/milk, poultry, cream, butter, eggs, cheese and liver. Carotenoid or beta-carotene, from plants, includes dark green vegetables such as broccoli and spinach; yellow to orange fruits such as apricots, cantaloupe, peaches, and papaya; root vegetables such as carrots, winter squash, sweet potatoes, and pumpkin.

Vitamin D

Vitamin D, also known as the sunshine vitamin is needed for the absorption of calcium to promote healthy bones. It also influences the quality of sleep which is vital for you as an athlete, more exposure to sunlight ensures deep and undisrupted sleep during the night. Deficiency in vitamin D makes you tired and fatigue after a workout.

Rich sources include egg yolks, beef liver, fortified milk, fatty fish like tuna, mackerel, and salmon; and fortified products such as soya milk and cereals. An excellent source of vitamin D is exposure to early morning sunlight which enables the skin to manufacture vitamin D.

Vitamin E

Vitamin E is an antioxidant which protects cells from damage caused by free radicals. It promotes strong immunity and healthy skin and eyes. It maintains blood vessels and keeps blood from clotting to prevent cramps in the legs and feet during and after your training.

Rich sources are goose meat, plant oils like soybean oil, corn oil, cottonseed oil, safflower oil, sunflower oil, hazelnut oil, wheat germ oil; nuts like almonds, peanuts, hazelnuts and Brazil nuts; fish and shellfish like Atlantic salmon, abalone and rainbow trout; fruits and vegetables like avocado, raw sweet red pepper, turnips green, and mango.

Vitamin K

Vitamin K helps in the synthesis of proteins needed for the coagulation of the blood which regulates blood clotting.  Blood clotting can occur to triathletes especially in the veins of the lower leg and thigh.  It also protects cartilage and ligaments and promotes healthy bones.

Excellent sources of vitamin K include green and/or leafy vegetables such as:

  • Kale
  • Spinach
  • Brussels Sprouts
  • Green Leaf Lettuce
  • Collards
  • Parsley
  • Broccoli
  • Cabbage
  • Turnip Greens
  • Swiss Chard
  • Mustard Greens
  • Romaine
  • Cauliflower

And as long as you’re not vegan, you’ll find a great source in fish, meat, liver, and eggs.

If you’re struggling to get your diet to fully cover all the vitamin needs for your marathon or triathlon training then make sure you get a reliable and trusted supplement. Check out our page on powdered supplement shakes for all types of running athletes.


Hey everyone, I’m Sandra Ryan and I’ve been contributing to this website for almost a year now.

My professional background is in finance where I work at a small bank outside Austin, TX, as an accounting technician. I’m still gradually working towards becoming an accountant by attending night classes, but my real passion is sport.

I’ve been involved in martial arts since I was about 8 years old when I had to figure out ways to outdo my 3 older brothers who were in constant WWE style fights. Nothing ever happened more than bruises and the occasional cut, but once I started Taekwondo I just couldn’t get enough.

I have won many state championships over the years, but have started to take a bit of step back from competitive fighting. Mainly down to a few leg strain injuries that basically mean that I cannot perform at my absolute best anymore.

My hunger for competition has been replaced by running marathons and in the past 2 years also competing in triathlons. So far I have completed 7 marathons and 2 triathlons and my aim is to complete an Ironman in the next couple of years.

When the opportunity came up to contribute to a website with training tips I immediately loved the idea. You’ll see a lot of my blog posts on triathlon training, and if you have questions, just leave some comments.

We will be happy to hear your thoughts

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