Do Ultrarunners Need More Vitamins Than Other Athletes?

In a constant search for energy and performance, athletes tend to focus on the big macronutrients: carbohydrate, protein, and fat. They manipulate the percentage of calories from each, going from the classic endurance athlete’s high carbohydrate strategy to a Paleo-esque high-protein strategy, or even a high-fat ketogenic strategy. However, the foods we eat supply more than just energy. They are also our primary sources of vitamins and minerals. These micronutrients don’t provide energy, but play crucial roles in almost every bodily function. The question for ultrarunners is whether or how the rigors of ultradistance running change an athlete’s micronutrient needs.

Examining the Ultramarathon Runner’s Micronutrient Needs

CTS athletes and coaches worked with Registered Dietitian Jennifer McDaniel for years. We turned to Jen with our micronutrient questions. In addition to being an RD and a Licensed Dietitian (LD), Jen earned her Master’s degree in Nutrition and Physical Performance and is a Board Certified Specialist in Sports Dietetics (CSSD).

CTS: Are there increased micronutrient demands for ultrarunners?

Jennifer McDaniel: Ultra distance athletes might have increased micronutrient needs due to the nature of the sport (i.e. excessive losses of nutrients in sweat and urine).

Stronger evidence suggests that ultra runners may be at higher risk for micronutrient deficiency if they’re not eating enough calories to sustain their training, if they follow diets that eliminate whole food groups (i.e. vegan athletes, ketogenic athletes), or if they lack variety in the diet. Vegans can certainly get all the macronutrients and micronutrients they need; consuming inadequate energy is what increases their risk of deficiencies.

CTS: Does taking a multivitamin make sense for ultrarunners as an insurance policy, in case they are not getting enough from their diet? 

JM: Yes, no, well… maybe… it depends! The need for a multivitamin will depend on factors such as the athlete’s diet, certain medical conditions, where and when they train, etc. The priority of nutrition optimization will always be food first, supplements second. Supplements are just what they sound like…to be used as a “supplement” to the diet. Obtaining a nutrition evaluation from a sports dietitian is the ideal way to assess whether an athlete’s diet is in need of supplementation.

Eating a well-balanced diet rich in fruits, veggies, whole grains, legumes, lean meats, and low-fat dairy generally meets nutrient needs, provided the athlete is eating enough calories. The high caloric intake necessary to fuel an ultrarunner’s training works in their favor. An ultrarunner who consumes adequate energy and lots of whole foods very often meets their micronutrient needs – even elevated needs – because of the sheer volume of fruits, vegetables, grains, legumes, etc. they eat. All else being equal, if you eat good food and enough of it, many nutritional needs take care of themselves.

That said, a multivitamin can certainly help cover any gaps in the diet and is likely safe for most athletes. If you choose to seek out a supplement, go for one that has a wide array of vitamins and minerals and supplies no more than ~50-100% of the RDA of each.

CTS: Are there particular micronutrient deficiencies ultrarunners or other ultraendurance athletes may be prone to? Iron comes to mind for ultrarunners because of hemolysis from repeated foot strikes.

JM: Ultraendurance athletes may be more prone to low sodium levels, due to losses in sweat. Sodium plays an important role in body fluid balance, as well as nerve and muscle function. Whether or not an athlete needs to consume more sodium depends on how much she is getting in the diet, as well as sweat rate and training volume. High mileage in warm weather would certainly require more sodium replacement than a quick run in cool weather.

Iron depletion is more common among ultraendurance athletes for a couple of reasons, including losses through sweat and the GI tract, and foot strike hemolysis. Iron is important because it delivers oxygen to the muscles and tissues. Ultraendurance athletes should be sure to consume enough iron in the diet from foods like meats, dried beans, fortified grains, and leafy greens. Athletes should remember, however, that it’s best to have iron levels checked by a doctor before starting to take an iron supplement.

As with sodium, ultraendurance athletes may be at higher risk for magnesium deficiency due to losses in sweat and urine. Magnesium is important for muscle contraction and strength. Some studies suggest that magnesium needs many be up to 20% higher for endurance athletes. Nuts and seeds, legumes, tofu, and whole grains are good sources of magnesium.

Some studies have shown ultra-distance athlete to be low in certain B-vitamins (thiamin & riboflavin). However, the study that looked at inadequate thiamin speculated the low levels might have been because athletes had a high consumption of refined carbohydrate foods. Again, this reinforces the idea that all athletes do best by eating good whole foods, and eating enough of them.

CTS: Besides the normal ‘eat more fruits and vegetables, more colorful foods, lean proteins, and whole grains’ advice, are there particular foods or categories of foods that ultrarunners or ultraendurance athletes benefit from?

JM: A list of beneficial foods for ultra athletes could be endless. However, here are my top 5 choices!

Tart cherry juice: 

Foods or beverages that speed recovery, like tart cherry juice, are good choices. The antioxidants found in this beverage can help reduce inflammation in the joints and muscles, and boost immune function. Some inflammation is normal and part of the process of adapting to training stress. Moderate antioxidant intakes – especially from foods – aren’t going to hinder those processes, but there isn’t good evidence suggesting massive antioxidant doses are beneficial for athletes. Current dosage recommendations for tart cherry juice include 1 oz. serving 2 x a day.

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Whole grains (oats, farro, quinoa, brown rice):

Ultra athletes require more carbohydrate compared to shorter distance runners or non-athletes. In addition to carbohydrate content, whole grains provide more fiber, vitamins, minerals, and antioxidants compared to refined grains. For ultra-distance athletes who feel like they can never get full, the fiber and texture of whole grains make them more satisfying.

Chia seeds:

Ultra athletes require long-last energy, and the composition of chia seeds offers this benefit. When mixed with external or internal fluids, chia seeds absorb up to 8-10 times their size in water. This gel-like consistency slows the breakdown into glucose (sugar). This means these seeds can help fuel the body for longer periods of time and combat dehydration. In addition, chia seeds contain plant-based sources of omega-3 fatty acids, which may help reduce inflammation and joint pain.


Walnuts contain more omega-3 fatty acids, compared to other nuts. They also are a rich source of fiber, vitamin E (important for athlete who train at altitude), and B-vitamins. And they are the ideal snack for stomping out between-meal hunger.


If you’re looking to omega-3 fatty acids to help reduce inflammation, fatty fish like salmon is your most efficient food source of this nutrient. Salmon is also a food source of vitamin D (~ 100 IU per oz. of fish). Despite time spent outdoors, many athletes are D-deficient. Vitamin D plays a role in bone density, immunity, muscle integrity and exercise-related inflammation.

CTS: Are there foods or food combinations ultraendurance athletes should minimize or avoid because of their effect on micronutrient levels? 

JM: There’s some evidence that caffeine, polyphenols (found in coffee and tea), and tannins (found in wine, coffee, and tea) may limit absorption of dietary iron. This is true for all people ­– not just endurance athletes. Any risk from this would be seen with higher consumption of these compounds. Thus, ultra endurance athletes at higher risk for iron deficiency (such as menstruating females) may benefit from limiting caffeine consumption, or from avoiding caffeine at mealtimes.

CTS: Are there any significant differences between the micronutrient needs of women vs. men, specific to endurance or ultraendurance athletes? 

JM: Female ultra-distance athletes are more likely to have higher vitamin and mineral needs related to hormone and bone health. With regular strenuous training, levels of sex hormones (such as estrogen) are often compromised, causing potential bone loss. If a female athlete also has low energy availability (not enough energy on board to support normal physiological functions), then the needs for nutrients like calcium, magnesium, and vitamin D may be higher.

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In addition, iron requirements may be higher due to menstruation and losses that occur in long distance exercise, (i.e. the sweat and GI tract, and foot strike hemolysis). As mentioned above, women should have iron levels checked by a doctor before considering iron supplementation.

CTS: Jennifer included the following takeaway.

JM: Recommendations for changing micronutrient intake, either through diet or supplements, must be individualized for each athlete. In some cases, excessive intake could be harmful. As a result, it’s difficult to make sweeping generalizations when it comes to taking in more of a nutrient. I highly encourage ultraendurance athletes to seek out a registered dietitian and/or a doctor to help dial in their nutrition strategy and make sure they are fueling their bodies as well as possible.

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Comments 1

  1. Once a year I have a micronutrient test done through Questlabs or AnyLabTestNow. This very detailed analysis and the recommendations of the Ph.D’s in the labs have been very helpful identifying micronutrient groupings, their purposes, individual MN deficiencies and foods and/or supplements to correct them.

    As a Master’s athlete and Ultra Endurance cyclist (age 65), the micronutrient side of the equation is critical to performance and health. Most deficiencies take several weeks to a few months to correct and stabilize. My own research shows the RDA for micronutrients is simply the absolute lowest levels to avoid certain population wide diseases and chronic illnesses, and not recommendations for athletic performance, superior health, longevity or compressed morbidity. The new mantra is MDA (maximum daily amount).

    Micronutrient groupings by function/purpose/ratio are very important to identify because they work in a relationship to perform various tasks. It’s why an Electrolyte complex with all electrolytes in balanced ratios is far, far more important that just taking more Sodium for example to keep your body’s chemicals in balance (think: sodium, chloride, calcium, magnesium, potassium, phosphate). Exercise over an hour or so shifts the balance of Electrolytes and then depletes them deteriorating performance as your body starts to shut down because of increased blood acidity and inability to deal with metabolic waste.

    For what it’s worth, I know CTS is not big on Hammer products for some reason, but their Endurolytes and Anti-Fatigue caps changed the game for me. Excellent ratios of all Electrolytes and a few other trace minerals essential for keeping the cells working the way they are supposed to. I’ve seen training partners ( a few salty sweaters and others) get really run down when their electrolytes start to be depleted. Then, within 10 minutes of quaffing some Endurolytes, they are back in the game.

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