Women of reproductive age need 18 mg of iron daily, more than double the 8 mg recommended for men, largely because of menstrual blood loss. Even a normal period drains about 1 mg of iron per cycle, and heavy periods can strip away five to six times that amount. The good news: a combination of the right foods, smart timing, and, when needed, supplements can keep your iron stores from dropping.
How Your Period Depletes Iron
Every milliliter of blood contains iron locked inside red blood cells, so any blood loss is also iron loss. In women with normal periods, the median iron lost per cycle is roughly 0.87 mg. That may sound small, but it stacks on top of the iron your body already uses for daily functions like carrying oxygen and producing energy. Over months of inadequate replacement, those small losses compound into depleted stores.
Heavy menstrual bleeding, clinically defined as losing more than 80 mL of blood per cycle, changes the math dramatically. Women with heavy periods lose a median of about 5.2 mg of iron per cycle, with some losing nearly 9 mg. At that rate, diet alone often can’t keep up, and iron stores fall steadily toward deficiency.
Signs Your Iron Is Running Low
Iron depletion doesn’t always announce itself with obvious symptoms. Early on, you might just feel more tired than usual or notice you’re out of breath climbing stairs. As stores drop further, symptoms become harder to ignore: persistent fatigue and weakness, pale skin, cold hands and feet, dizziness, headaches, and a fast heartbeat even at rest. Brittle nails, a sore or swollen tongue, and restless legs at night are also common.
One of the more surprising signs is pica, a craving for non-food items like ice, dirt, or clay. Some people also develop unusual cravings for specific smells, like rubber or cleaning products. If any of these sound familiar, a simple blood test can check your ferritin (stored iron) levels and confirm whether you’re depleted.
Best Food Sources of Iron
Iron from food comes in two forms. Heme iron, found in animal products, is absorbed at about 15%. Non-heme iron, found in plants and fortified foods, is absorbed at roughly 7%. That difference matters when you’re planning meals around your period.
High-Iron Animal Sources
Oysters are one of the richest sources, delivering 8 mg in a 3-ounce serving. Beef liver provides about 5 mg per 3 ounces. More everyday options include beef (2 mg per 3 ounces), sardines (2 mg), and eggs (1 mg each). Even chicken, turkey, and canned tuna contribute about 1 mg per serving, which adds up over the course of a day.
High-Iron Plant Sources
White beans are a standout at 8 mg per cup. Lentils, spinach, and firm tofu each provide about 3 mg per half-cup serving. Chickpeas, kidney beans, dark chocolate (45% cacao or higher), canned tomatoes, baked potatoes, and cashews all deliver around 2 mg per serving. Whole wheat bread, raisins, green peas, and brown rice contribute about 1 mg each. A fortified breakfast cereal can provide up to 18 mg per serving, which covers a full day’s requirement on its own, though absorption from fortified foods varies.
How to Maximize Absorption
Getting iron onto your plate is only half the equation. What you eat alongside it determines how much actually reaches your bloodstream.
Vitamin C is the single most effective absorption booster. It works by binding to iron in your stomach and keeping it in a form your intestines can absorb efficiently. Practical pairings include squeezing lemon over lentils, adding bell peppers to a bean stir-fry, eating strawberries alongside fortified cereal, or drinking a small glass of orange juice with a spinach salad. This matters most for non-heme (plant) iron, where absorption rates are already low.
On the flip side, certain compounds interfere with iron uptake. Tannins, found in tea and coffee, form insoluble complexes with iron that your body can’t absorb. Phytates in whole grains and legumes do the same. Calcium also competes with iron for absorption. None of this means you need to avoid these foods entirely. Just separate them from your highest-iron meals by an hour or two. Drinking your morning coffee between meals rather than with breakfast, for example, can make a real difference over time.
When Supplements Make Sense
If your periods are heavy, your diet is restricted, or blood work shows low ferritin, a supplement can help close the gap. Two of the most common forms are ferrous sulfate and iron bisglycinate. Both are effective at raising ferritin levels. In one study comparing the two at 30 mg of elemental iron daily for 90 days, both significantly increased ferritin in people with low iron stores, and the improvement persisted six months after they stopped supplementing.
The practical difference between the two is mostly about side effects. Ferrous sulfate is cheaper and widely available but more likely to cause nausea, constipation, or stomach cramps. Iron bisglycinate tends to be gentler on the gut, which makes it easier to stick with long-term.
Alternate-Day Dosing Reduces Side Effects
If iron supplements upset your stomach, taking them every other day instead of daily is a well-supported alternative. A randomized, placebo-controlled trial in iron-depleted women compared 100 mg of iron taken daily for 90 days against the same total dose spread across alternate days over 180 days. Both groups ended up with nearly identical ferritin levels (about 44 μg/L). But the alternate-day group reported significantly fewer gastrointestinal side effects and, notably, had a lower rate of iron deficiency at the six-month mark (3% vs. 11%).
The reason this works relates to hepcidin, a hormone your body releases after absorbing iron. Hepcidin temporarily blocks further iron absorption for about 24 hours. By skipping a day, you let hepcidin levels drop, so a higher proportion of each dose actually gets absorbed. Taking your supplement every other day, ideally on an empty stomach with a source of vitamin C, gives you the best combination of absorption and tolerability.
Putting It All Together
A realistic daily strategy looks something like this: build at least two meals around iron-rich foods, pair plant-based iron sources with vitamin C, and keep tea, coffee, and calcium-rich foods away from your highest-iron meals. In the days leading up to and during your period, leaning into iron-dense choices like lentil soup with tomatoes, a spinach and white bean salad with lemon dressing, or a serving of oysters or beef can help offset what you’re losing.
If you suspect your stores are low, getting your ferritin tested gives you a clear baseline. For women with consistently heavy periods, food alone often isn’t enough to keep up with losses of 5 mg or more per cycle. In that case, an alternate-day supplement of 30 to 100 mg of elemental iron, taken with orange juice and away from coffee or dairy, is a practical and evidence-backed approach to rebuilding your reserves without the stomach trouble that makes so many people quit.