Distance Runners: 5 Nutrients Your Body Needs

by Danielle Omar, MS, RD

When I’m working with a client who is training for a marathon the first thing I notice is how restrictive they are with their food. This is a problem because when you don’t eat enough while training, you tend to be hungry all the time, which can lead to poor food choices. Over time, poor food choices can lead to nutrient deficiencies. Deficiencies in important nutrients can not only compromise a runner’s training efforts, but can also cause problems long after the race is over.


Taking in the appropriate amount of protein, carbs, and fats to fuel training is the most important aspect to remember, but there are also specific nutrients distinct to a marathoner’s needs. This is true especially for distance runners, who is taxing her body’s nutrient stores more than what you’ll see with other types of exercise.

My Top 5 Most Important Nutrients for Marathon Runners

1) Iron

“Iron is a nutrient that most runners don't think too much about, but it’s essential in delivering oxygen to the muscles during exercise,” says Heather Caplan, Registered Dietitian and blogger at //heathercaplan.com/">Dietitian on the Run. If you’re getting fatigued early in your run or have a hard time recovering, iron could be the culprit. No matter what your fitness level is, it’s a good idea to get your iron levels checked before beginning your marathon training to avoid any problems down the road. When getting tested, ask your doctor to check both hemoglobin and ferritin levels. Oftentimes with endurance athletes, their hemoglobin will be normal, but their ferritin, which indicates iron stores in the body, may be low.

When training, make sure to include various sources of iron in your diet. Red meat, poultry, spinach, beans, oysters, clams and mussels, enriched grains and cereals, tofu, and pumpkin seeds are all great sources.

2) Omega 3

The list of incredible performance-enhancing aspects related to Omega 3 just keeps growing. Traditionally known for supporting brain health, research shows Omega 3 fats offer real advantages to athletes, especially runners. Anti-inflammatory benefits include alleviating and preventing joint pain, improved response to muscle fatigue and injury, and reduced exercise-induced asthma. There are three types of Omega 3 fats, ALA, DHA, and EPA. Fatty fish and algae are rich dietary sources of DHA and EPA. ALA is found in plant sources such as nuts/nut oils and flax seed. Much of the anti-inflammatory benefits come from DHA and EPA.

Consuming salmon, herring, or sardines just a few days per week is a great way to get these Omega-3s into your diet, but supplementation may be necessary for those who do not like or tolerate fish.


3) Glutamine

I love glutamine as a recovery aid after intense training. Glutamine is a non-essential amino acid important for fueling the cells of your immune system. During stress or intense exercise, your body may need more glutamine than it can make. Research shows that athletes, and especially marathon runners, are at a higher risk for upper respiratory tract infections after long endurance races or an intense training period. Supplementation with 5 to 20 grams of glutamine after a marathon has been shown to help reduce the incidence of these infections and support optimal immune system function.

4) Calcium

While running is one of the best ways to //www.cal-ez.com/bone-health">build stronger bones, it can have the opposite effect if you’re not getting enough calcium in your diet, especially for women. Too little calcium can deplete bone mass, which for runners can lead to an increase in stress fractures. Adequate calcium intake is key for prevention of stress fractures and other bone-related injuries. A good source of calcium provides at least 100 mg of calcium per serving. If you’re looking at a nutrition facts panel, choose foods that contain 10% or more of the Daily Value for calcium.

Dark leafy greens, dried beans, broccoli, figs, and sardines are great natural sources of calcium. There is one caveat though; you need to make sure you are absorbing the calcium you’re taking in. To do so, you need some Vitamin D!


5) Vitamin D

For the endurance athlete, adequate Vitamin D levels can have a huge impact on performance. Not only does Vitamin D assist with calcium absorption for bone health, it also helps to control inflammation, support immune system function, and increase muscle strength. Vitamin D is not readily found in foods, but can be synthesized from exposure to sunlight. If you’re not already deficient, 15 to 30 minutes of sun exposure each day will meet your daily needs for vitamin D.

Even though they spend a lot of time training outside, studies show 75% of marathon runners are deficient in Vitamin D. This is why it’s a smart idea to get your Vitamin D level (along with iron) checked before starting any marathon training. If deficient, it will be difficult to bring your stores to normal levels with diet or sunlight alone.

Cal-EZ supports bone health and can assist in bringing Vitamin D stores back to optimal levels by providing 100% of the RDA of calcium and 167% of the RDA for Vitamin D. It has no taste and mixes easily with water. I like to blend it with my post-run smoothie or stir it into oatmeal or yogurt!

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