Spring means marathon season! Or maybe marathon season is year-round? While I can’t imagine training for a marathon (I mean, how do you find the time?!), I do have a 6+ year running streak going. I know all too well bout the soreness and inflammation that can accompany a run. And as a runner who refuses to take days off, I know my fellow runners are very stubborn. Usually, it takes feeling soreness or pain before dialing into nutrition and recovery methods.
But it takes more than a balanced diet and a running coach-approved training plan during marathon training or a running streak to get you through the finish line. You need to hone in on all aspects of nutrition to maximize your recovery to keep you on the road or tread during these last few weeks of training. And, again, as a runner who refuses to take days off, I’ve tried all the supposedly best supplements for runners. And as a dietitian, I’m here to talk about the science behind the vitamins and supplements marketed to runners and decide which ones will work for us.

Macronutrients
Endurance athletes, like runners, utilize the lactic acid and oxidative system energy systems. These systems help the body replace ATP from body energy sources and use them for energy production. The muscle glycogen stores (carb stores) can provide energy for up to 15 miles, while the adipose tissue triglycerides (fat stores) can provide energy for up to 800 miles.
Unfortunately, getting energy from muscle glycogen stores requires breaking down muscle tissue which can lead to muscle soreness. If you do not recover properly, the broken-down muscle tissue can lead to muscle damage, but if you recover properly, you can create muscle growth. You can reduce the likelihood or severity of this type of soreness by properly fueling before long runs, devising a fueling plan during runs, and replenishing carbohydrates and proteins after runs and training sessions. Aim for 1.5 grams of carbohydrate per kilogram of bodyweight post-exercise and 20-30 grams of protein post-exercise to replenish the nutrients utilized during a long-distance run and aid in muscle recovery.
Vitamins for Runners
Most runners who eat a balanced diet get enough vitamins and minerals, and supplementation above the recommended values does not provide extra benefits. Even vitamins that are depleted more in exercise are likely to be compensated for by an increase in appetite from the increase in physical activity, or in this case, mileage. However, sometimes the right dietary supplements in combination with a healthy diet can maximize athletic performance and maintain overall health during a long training season. So, what are the best supplements for runners, and who can most benefit from them? Let’s get into it.
B Vitamins
The B vitamins are utilized for energy production, meaning they are involved in nearly all the processes to get energy to the body. Again, an increase in appetite that accompanies an increase in mileage should provide your body with enough of these naturally. However, some people may benefit from supplementation. Runners on restrictive diets, such as a vegan or low-calorie diet, are at a greater risk of Vitamin B deficiency.
Riboflavin, or B2, is needed for the production of red blood cells and is required in the reaction that breaks down protein for energy production. You can find riboflavin in milk, whole and enriched grains, and most meats. Vitamin B6, or pyridoxine, is required for more than 100 carb, fat, and protein metabolism enzymes. It also synthesizes hemoglobin, which makes it crucial for runners who utilize more oxygen and thus are at higher risk of anemia. B6 is found in meat, beans, legumes, nuts, eggs, and some breads and cereals.
Vitamin C
Vitamin C neutralizes free radicals so they cannot damage DNA. It is involved in collagen synthesis and may improve wound healing and strengthen connective tissue. While Vitamin C can be beneficial, large doses may blunt adaptions from exercise, which are needed to improve performance. Additionally, it can limit the storage of iron and increases the excretion of B6, meaning that consuming large amounts of Vitamin C in conjunction with foods high in B6 or iron leaves a person at risk of anemia. Stick to a low dose of vitamin C, such as 50-100mg, or consume it via whole foods. Vitamin C is in citrus fruits, such as oranges and papaya, as well as potatoes and dark green veggies.
Calcium
Calcium is responsible for the structure and regulation of our bones and teeth through its interaction with vitamin D, parathyroid hormone, and bone, as well as being involved in the transmission of nerves (think: heart muscle function), neurotransmitter release, and muscle contraction (remember calcium ion channels from high school science?). And as a runner, muscle contraction, heart function, and bone strength are essential!
And the body compensates for an inadequate dietary calcium intake by taking it from the bone, reducing overall bone mass, which is absolutely not something any runner can afford in a sport where stress fractures risk is already high. Adult runners need to be even more careful, as once you reach peak bone mass in your twenties, you cannot regain losses, and long-term calcium resorption from bone can lead to osteoporosis. Runners should get at least 1000 mg of calcium daily to protect bone health. If dairy products are not an option, look for foods fortified with calcium (a food is considered high in calcium if it has 200 mg per serving). If you still believe you aren’t getting enough calcium, get a supplement.
What to look for in a supplement:
- Calcium carbonate or calcium citrate will be best absorbed.
- A supplement with vitamin D will enhance calcium absorption, while one with aluminum or magnesium will reduce it.
Vitamin D
We can’t discuss calcium without getting into Vitamin D. Vitamin D is synonymous with bone but why? Bone is in a constant state of turnover where new bone develops and replaces older bone. Suppose an athlete’s activity is continuously repeated. In that case, as it is in running, with a steady pounding of feet on pavement, the breakdown of older bone outpaces the body’s ability to repair and replace it. As a result, the bone weakens and becomes vulnerable to stress fractures. Most runners know the dreaded stress fracture or stress reaction that can cause pain and sideline a runner for days to weeks.
Without vitamin D, only 10-15% of calcium is absorbed into the bone, so vitamin D intake is crucial for bone health. The amount of vitamin D needed depends on several factors, including skin color, where you live, how much time you spend in the sun, and how much skin is exposed to the sun. It is a fat-soluble vitamin, so you can’t just pee it out if you take too much. It is best to ask your doctor to test your vitamin D levels and to review the findings with a registered dietitian.
What to look for in a Vitamin D supplement
- Look for the D3 form
- A dosage of 1000-10,000 IU, depending on your individual needs.
Iron
In general, the prevalence of iron deficiency is higher in athletes and predominantly female athletes. This iron deficiency is likely due to athletes having higher iron needs but not consuming more iron than their non-athlete counterparts. Iron is crucial for delivering oxygen to blood and muscle cells; thus, exercise can increase the iron demand on the body. For example, when training at high altitudes, more oxygen needs to be delivered to cells; therefore, more iron is required to transport that oxygen. Additionally, repetitive foot contact in runners can lead to hemolysis, a breakdown of red blood cells that affects iron status. Finally, exercise can cause more significant iron losses through urine, feces, and sweat due to intense exercise or gastrointestinal inflammation.
Instead, focus on food. Iron in animal products, specifically red meat, is best absorbed. Runners should get in quality beef, steak, or pork three times a week and a rotation of poultry and fish on other days. The iron that is not as readily absorbed but still beneficial comes from leafy greens like spinach and kale. Iron is a particular vitamin, and a few easy changes can boost your levels without supplementation. Iron does not like to be absorbed with calcium, tannins in tea or wine, or the phytates in cereal. Try to have your steak without a glass of milk or wine. However, iron likes to be absorbed with vitamin C, so have a glass of orange juice with your bacon.
Anti-Inflammatory Supplements for Runners
While some studies show that antioxidant vitamins can reduce markers of muscle tissue damage, other studies have found no benefits, and others have found adverse effects of taking antioxidant supplements. So what should you do? First, when looking for a supplement, look for those with less than 100% of the RDA to prevent adverse effects. Second, look for ways to get the needed nutrients via whole foods or supplements derived from whole foods, such as cherry juice, before looking to supplements. Here are some examples of a few anti-inflammatory supplements that runners might be tempted to buy.
Omega-3 Fatty Acids
Claim: Builds muscle, improves endurance, reduce joint stiffness.
How it works: Omega-3 fatty acids, also known as fish oil, have been demonstrated to reduce inflammation by mediating the expression of genes and cell signaling that promotes an inflammatory response.
Food sources: Fatty fish (salmon, bluefish, mackerel, herring, tuna), nuts and seeds (flaxseed, walnuts, soybeans), and oils (canola, flaxseed, soybean).
BCAAs (Leucine, Isoleucine and Valine)
Claim: Delay fatigue, build muscle, improve performance
How it works: BCAAs can be used as fuel for endurance activity but have not been shown to delay fatigue. Eating carbs before, during, and after exercise appears to have the same effect as taking a BCAA supplement.
Food Sources: chicken, beef, shrimp, yogurt, egg, oatmeal, pinto beans
Beet Juice
Claim: improve stamina
How it works: Nitrates found in beets may increase nitric oxide levels, which assist in vasodilation, or the widening of blood vessels. Vasodilation allows for greater blood flow and more efficient use of oxygen, which may allow you to work out a bit harder and longer.
Food sources: Beets, cabbage, carrots, radishes, spinach
Tart Cherry Juice
Claim: Improve post-workout recovery, increase training capacity, reduce muscle pain
How it works: Antioxidants packed in cherry juice fight free radicals and may cause less muscle damage during exercise, which may reduce the time needed for recovery. Recent studies have found that consuming tart cherry juice may accelerate post-workout recovery by reducing muscle soreness. Most athletes and runners swear by tart cherry. It isn’t the easiest to drink but a quick chug at night, and you should feel better the next day! Prefer a powder or chew instead of juice? My blog post on the top tart cherry supplements should lead you in the right direction.
Food sources: tart cherries
And there you have it! The science behind some of the best supplements for runners. What do you think? Is one of these supplements right for you? If you have more questions or are interested in a personalized supplement plan, you can reach me at hillary@sportsnutritionally.com.
And remember that a well-balanced diet and the right supplements can help prepare you for a long run. However, you likely need a much more targeted approach during your race week than eating well. Consider working with a dietitian to devise a race day strategy.