When Is the Best Time of Day to Take Iron Supplements?
Having enough iron in the body is critical for riding strong and generally just living a healthy, energetic life.
“Iron is an essential mineral that is needed for growth and development and for supporting many facets of our health, from immune function to athletic performance,” Emma Laing, Ph.D., R.D.N., a spokesperson for the Academy of Nutrition and Dietetics and director of dietetics at The University of Georgia, tells Bicycling.
One important role of iron is making hemoglobin, a protein in the blood, that delivers oxygen to muscles, Carly Sedlacek, R.D., a registered dietitian from Cleveland Clinic’s Center for Human Nutrition, tells Bicycling. Your muscles need oxygen to perform their best, and the better your body is able to adapt and utilize oxygen, the more you may be able to boost your performance in workouts and races, she explains.
Conversely, not getting enough iron can trigger a host of performance-sabotaging issues, like fatigue, dizziness, weakness, lightheadedness, headache, reduced work capacity, irregular heart rate, shortness of breath, and poor concentration, according to Laing.
Though most folks are able to get enough iron through food, some 30 percent of the global population has iron-deficiency anemia, according to the research by the World Health Organization, cited in a medical journal.
Endurance athletes like cyclists typically require more iron than the average person, because their training causes a high rate of cell turnover and tissue repair, says Laing, adding that we also lose iron through sweat, poop, and menstrual blood. Athletes at elevated risk of low iron status include those who under-fuel, follow a vegan or vegetarian diet, train at high altitudes, experience heavy periods, or have a history of anemia, she says. Other folks at risk include pregnant people, young adults, growing children, regular blood donors, and those who suffer from food-insecurity, according to Laing.
Think you may be iron deficient? Visit a doctor to get your levels tested. If those results confirm you have low iron levels, and you aren’t able to get enough through diet alone, an iron supplement may be warranted.
We chatted with three experts to get the all the important intel on iron supplementation, including when the best time of day to take an iron supplement is for ideal absorption. Here’s what you need to know.
Should you take an iron supplement?
Like we mentioned, it’s important to first get your iron levels tested by a doctor and talk with them about the results to ID if an iron supplement is a smart choice for you.
That’s because there are serious health risks of consuming too much iron, including iron poisoning, says Laing. “Iron poisoning is most common among children as the result of accidental overdose,” says Laing, but it can happen to adults who take very high doses of iron supplements, she adds. Plus, ingesting high doses of iron from both foods and supplements can mess with the absorption of other nutrients and change the effect of some medications, says Laing.
Moreover, iron supplementation may not be good for folks with certain medical conditions, like hereditary hemochromatosis, which causes the body to store too much iron. And, high doses of iron can cause not-so-pleasant side effects like nausea, vomiting, constipation, diarrhea, and stomach pain.
Then there’s the financial piece: You probably don’t want to spend money on expensive supplements if they just aren’t necessary (and in fact, could be harmful), Crystal Scott, M.S., R.D., a registered dietitian with Top Nutrition Coaching, tells Bicycling.
The bottom line: Before popping iron supplements, it’s wise to make sure you actually need them. If you do, take them under the guidance of a physician or registered dietitian who specializes in sports nutrition, says Laing. They can help you determine things like an optimal dosing plan and how to mitigate side effects.
When is the best time of day to take iron supplements?
Timing matters when taking iron. To improve the absorption of your supplement, have it in the morning. That’s because hepcidin, a hormone responsible for decreasing iron absorption as a way to prevent your body from storing too much, typically rises throughout the day, says Laing. So by taking a supplement when levels of hepcidin are lower, you may be better able to absorb the iron.
Iron is also best absorbed on an empty stomach, so your best bet may be to take your supplement first thing in the morning, about 30 to 60 minutes before eating, says Laing. However, if pairing iron with an empty stomach causes GI upset, then you’ll likely need to take it with food or shortly after eating, Laing explains. (More on which specific foods to pair it with in a minute.)
Hepcidin is also released during exercise in response to inflammation in the body produced by a workout and tends to continue increasing for several hours after a workout, so you may also spur absorption by taking an iron supplement shortly after completing a ride before hepcidin fully peaks, explains Laing.
Because high doses of iron can trigger issues like diarrhea, constipation, vomiting, and stomach pain, avoid taking your supplement before a workout or big race—especially if you’re new to it and unsure how your body will respond. “Take it on an off day at first,” recommends Scott.
Keep in mind: Your healthcare provider may recommend you take your iron supplement several times per day in smaller doses versus one big dose, especially if you’re experiencing GI side effects, says Laing.
Should you take iron supplements with food?
While it’s smart to take iron first thing in the morning without food, to reduce the risk of GI issues, consider taking an iron supplement with food and stay well-hydrated, suggests Laing. Just be choosy about which foods you reach for.
Certain foods and drinks impede iron absorption—including teas, coffees, whole grains, legumes, nuts, seeds, dairy products, and calcium-fortified foods—so avoid these items when ingesting your supplement.
Instead, reach for vitamin C-rich foods, like lemon juice, oranges, berries, kiwi, tomatoes, and bell peppers, as these can help enhance iron absorption, says Laing. Scott recommends taking iron supplements with a few sips of orange juice.
How do you determine the correct dosage?
How much iron to take varies person to person and hinges on your medical history, says Sedlacek. The severity of your iron deficiency will influence the correct dosage for you, too, says Scott, and how well your GI system tolerates iron will also play a role, says Laing.
Again, chat with a doctor to figure out the best dosing for you. “A medical professional can give guidance based off of appropriate lab work,” says Scott.
They can also help you figure out a plan to mitigate any GI side effects. “Strategies like taking lower doses of iron several times per day versus one larger daily dose, choosing iron supplements that are coated or specially formulated to improve GI sensitivity, or alternating days when the iron supplements are consumed can improve GI tolerance,” says Laing.
How do you find a quality iron supplement?
Here’s the thing: Supplements aren’t regulated by the Federal Drug Administration, “so it’s important to do your research before choosing a supplement,” says Sedlacek. Scott suggests looking up supplement companies at NSF.org to see if their products have been third-party tested.
There are lots of different iron supplements to choose from, and supplements vary considerably by brand. You can get iron in a multivitamin supplement or by itself; in pill or liquid form; in a slow- or quick-release formula, and in various chemical states (for example, ferrous iron versus ferric iron), says Laing. Scott recommends opting for a ferrous iron supplement (either ferrous sulfate and ferrous gluconate), as that is more easily absorbed.
To see how much iron a product provides, scope the amount of “elemental iron” listed on the supplement facts panel, says Laing.
As with all things involving iron supplementation, it’s a good idea to talk with a healthcare professional for a recommendation on what specific supplement might be the best choice for you, says Sedlacek.
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