Four Nutrients Runners Can't Get Enough Of

By Jen Rawson, RD

Runners are a unique breed. Few other people get up to run before the sunrise, run through freezing weather and snow storms, or turn down Saturday night plans to run for hours on a Sunday morning. 

Another uniqueness to runners is their nutrient requirements. Here is a list of the top 4 nutrients runners should ensure to get enough of.

1. Iron 

Iron is an essential component for carrying oxygen around the body, which means a deficiency can result in not enough oxygen being delivered to the brain and muscles resulting in fatigue and decreased performance.

Some groups of runners are at higher risk of developing iron deficiency. Women already have higher iron requirements than men and some sources estimate that the iron needs of women runners may be up to 70% higher than the Estimated Average Requirement. The iron in plant-based foods is not as readily absorbed as iron from animal sources, making vegetarian athletes at a higher risk of developing an iron deficiency. Long-distance runners lose iron through footstrike hemolysis, which is the rupturing of red blood cells through the repetitive striking of the foot on the ground, making them also at increased risk of deficiency.

Recommended Daily Allowance (18-50 years of age):

8mg/day for men

18mg/day for women

Food sources of Iron:

  • Meat, fish, poultry
  • Beans, lentils, chickpeas
  • Fortified grain products (bread, oats, cereal)
  • Leafy green vegetable (spinach, kale)
  • Root vegetables (potatoes, turnips, beets)
  • Soybean, tofu, tempeh
  • Pumpkin seeds

2. Vitamin D 

Vitamin D increases the absorption of calcium and therefore plays an important function in the maintenance of bone health. However, vitamin D also has a role in muscle contraction and strength making it of even greater interest to the sports community.

Vitamin D is often referred to as the sunshine vitamin because our body can naturally produce it with exposure to sunlight. However, some populations are at a greater risk of vitamin D deficiency due to limited sun exposure or absorption including those who live in a northern latitude (such as Canada), people with darker skin colour, and people over 65 years old. A 2013 report released by Stats Canada indicated that approximately 32% of Canadians had insufficient levels of Vitamin D. Inadequate levels of Vitamin D puts runners at risk of stress fractures, muscle injuries and decreased strength and performance.

When it comes to Vitamin D and runners, what is currently understood is that while a deficiency in Vitamin D can have a negative impact on performance, there is no evidence to support a performance-enhancing effect of taking additional vitamin D beyond adequate levels.

Recommended Daily Allowance (18-50 years of age)

600 IU for men & women

Food Sources of Vitamin D:

  • Egg yolks
  • Fatty Fish (tuna, mackerel, salmon)
  • Milk and fortified yogurt
  • Fortified plant-based beverages (soy milk, almond milk)
  • Fortified orange juice

3. Calcium

Calcium is well known for its role in maintaining bone health, however, it is also needed for muscle contraction, nerve signals and maintaining our heartbeat. If our calcium needs are not met through diet, our body will take calcium from our bones weakening them and putting us at risk of developing a fracture.

People most at risk of developing calcium deficiency are those who are not eating adequate calories to support their daily requirements or avoiding dairy products without intaking other high calcium sources.

Recommended Dietary Allowance (18-50 years of age)

1000mg for men & women

Food Sources of Calcium: 

  • Milk and milk alternatives (yogurt, cheese, kefir)
  • Fortified plant-based beverages (soy milk, almond milk, rice milk)
  • Dark green vegetables (broccoli, kale, collard greens, spinach)
  • Tofu
  • White and navy beans
  • Almonds
  • Fish with soft bones

4. Antioxidants

Exercise causes oxidation in our bodies which produces free radicals. An excess of free radicals leads to oxidative stress which can damage our cell membranes and prolong recovery. Antioxidants are compounds found in food (such as Vitamin E, Vitamin C, Carotenoids, etc) that mop up these free radicals and therefore prevent or reduce oxidative stress.

While it may seem that taking antioxidant supplements to reduce oxidative stress and speed up recovery would be a good idea, much of the research is conflicting with studies showing no benefit and some even showing a detrimental effect. The research supports that runners can intake sufficient antioxidants through a well-balanced diet and that food, rather than supplements, should be the focus for athletes.

Recommended Dietary Allowance: 

The current literature is not sufficient to determine definitive recommendations concerning antioxidant requirements for athletes and exercising individuals.

Food Sources of Antioxidants:

  • Leafy green vegetables (spinach, kale, swiss chard, arugula, collard greens)
  • Berries (blackberries, cherries, blueberries, raspberries)
  • Citrus fruits (oranges, grapefruits, lemon)
  • Nuts and seeds (almonds, peanuts, sunflower seeds, brazil nuts)
  • Orange vegetables (carrots, squash, bell peppers, sweet potato)
  • Cocoa and green tea

Some runners may have requirements that exceed the Recommended Dietary Allowance (RDA) for some vitamins or minerals and being deficient in nutrients can have negative impacts on their performance and overall health. Most runners can meet their dietary requirements through a well-balanced diet by choosing foods high in the nutrients of concern. Taking supplemental vitamins and minerals may be indicated for some but should always be done in consultation with your Doctor and Dietitian based on lab results, dietary patterns, and individual needs. When it comes to vitamin and minerals, more is not always better and supplementing without due cause can result in side effects or impaired performance.