Your Guide to Iron: Why You're Tired and What to Do About It

Dr. C's Guide to Iron

Iron is the unsung hero of your body. It's what helps your red blood cells carry oxygen to every corner of you, from your brain to your toes. When you're low on iron, everything feels harder. You're tired, you can't think straight, and climbing a flight of stairs feels like summiting Everest. Let's fix that.

The Two Types of Iron (And Why One Is Way Better)

Not all iron is created equal. Your body is picky about which kind it likes.

Heme Iron: VIP

This is the iron from animals, and your body rolls out the red carpet for it. You'll absorb 15-35% of the iron from these foods, which is (sadly) the best our bodies can do. Find it in: 

• Red meat (beef, lamb)

• Chicken and turkey

• Mussels and sardines

• Organ meats, if you're brave.

Non-Heme Iron: The Economy Seat

This is plant-based iron, and your body is less enthusiastic about it. Best we can do is absorb 2-20%. But if you're vegetarian, vegan, or just trying to eat less meat, these are your go-to sources: 

• Fortified cereals and breads (check the label)

• Beans and lentils

• Spinach and dark leafy greens

• Tofu

• Cashews and sesame seeds

• Dried fruit (prunes, raisins are best)

• Sweet potatoes

Here's the thing: your body absorbs iron from meat about 10 times better than iron from plants. So if you're plant-based, we will need to be more strategic.

Iron's Best Friend: Vitamin C

For plant based iron to absorb at 15-20%, we need to pair it with vitamin C. Vitamin C is the only real way for our bodies to actually use it. 

Easy ways to add vitamin C:

• Drink orange juice with your iron-rich meal or supplement

• Add strawberries to your fortified cereal

• Throw bell peppers or tomatoes into your spinach salad

• Take a vitamin C tablet (80-100 mg) with your iron pill - if you know Dr C, you'll predict this is her least favorite option. 

Iron's Worst Enemies: The Absorption Blockers

Now for the bad news. Some of your favorite foods may be sabotaging your iron levels.

Tea and Coffee: The Worst Offenders

If you're trying to boost your iron, tea is basically the worst thing you can have. It blocks 80-90% of iron absorption. Coffee isn't quite as bad, but it still definitely blocks iron absorption, which is dismal to begin with. The way around this is to avoid consuming tea/coffee for at least 1 hour before and 1 hour after taking iron, whether in supplement or meal form. Yes, we know this is hard. But if you're exhausted from low iron, it's worth it.

Other Iron Blockers - space them out from iron by an hour. 

• Dairy products and calcium supplements (including greek yogurt)

• Whole grains, nuts, and beans: They contain phytates that block iron (but they also contain iron, so don't avoid them...just be smart about pairing.)

• Acid-blocking medications like prilosec: These reduce stomach acid, which you need to absorb iron.

Smart Strategies to Maximize Your Iron

• Timing is everything: Take iron supplements in the morning on an empty stomach with orange juice or a vitamin C tablet

• Don't overdo it: Taking iron multiple times a day or even just daily doesn't help because your body blocks absorption after the first dose (for about 48 hrs). Dr C finds that dosing iron every OTHER day works better and causes fewer side effects.

• Pair wisely: Eat iron-rich plant foods with vitamin C sources at the same meal

• Keep calcium separate: Don't take calcium and iron supplements together

• Skip the tea with breakfast: Save it for later in the day

When Pills Don't Cut It

IV Iron Infusions:

Sometimes oral iron just doesn't work. Maybe it makes a patient nauseous or constipated. Maybe the gut doesn't absorb it well (celiac patients, for example). Maybe you're losing iron faster than pills can replace it, like in women with very heavy periods. That's when IV iron comes in.

What is IV iron?

Instead of swallowing pills, you get iron delivered directly into your bloodstream through an IV. It's done in an outpatient clinic, and it bypasses all those absorption problems.

The different types:

Modern IV iron is much safer than the old formulations. Here are the options these days:

• Iron Sucrose/Venofer: Requires multiple visits (at least 3 infusions), but is the easiest to get approved through insurance, and is extremely well tolerated on the whole. 

• Low-Molecular-Weight Iron Dextran: Can give you a full dose (1,000 mg) in one visit, which is really efficient!

• Ferric Carboxymaltose (Injectafer): Usually just one dose (sometimes two).  Downside: it can temporarily lower your phosphate levels, which might make your muscles feel weak

• Ferric Derisomaltose (Monoferric): The new kid on the block. Can deliver up to 1,500 mg in just 30 minutes, with less risk of the phosphate problem.

• Ferumoxytol (Feraheme): One or two doses, works well. 

What to expect:

The infusion takes anywhere from 15 minutes to an hour depending on which type you get. You'll sit in a comfy chair, they'll monitor you for any reactions (rare with modern formulations), and then you're done. Most people feel fine, though some get a mild headache or muscle aches. Serious reactions are uncommon.

Who needs IV iron?

Your healthcare provider may recommend it if you: 

• Can't tolerate oral iron (the nausea and constipation are real)

• Have conditions that prevent iron absorption (celiac disease, inflammatory bowel disease, previous gastric surgery)

• Are losing iron faster than you can replace it orally

• Need your iron levels up quickly

When To Call Your Doctor

Reach out if you're experiencing: 

• Constant fatigue, weakness, or feeling winded easily

• Pale skin or pale inner eyelids

• Headaches or dizziness

• Cold hands and feet

• Brittle nails or hair loss

• Cravings for ice or non-food items (yes, this is a real symptom of iron deficiency!)

And definitely talk to your healthcare provider if you're taking iron supplements but not feeling better after a few weeks.

The Bottom Line

Getting enough iron is about more than just what you eat.... it's about how you eat it. Pair your iron with vitamin C, avoid tea and coffee around iron time, and if oral supplements aren't working, know that IV iron is a safe and effective option. Your energy levels will thank you.

Remember: Always get your iron levels checked with blood work before starting supplements. More isn't always better, and too much iron can cause problems too.

If you're craving ice chips, we're not judging, but we are scheduling your labs.

Aditi Correa, MD, MSCP

Your Partner in Health

References

1. Iron Deficiency. Pasricha SR, Tye-Din J, Muckenthaler MU, Swinkels DW. Lancet (London, England). 2021;397(10270):233-248. doi:10.1016/S0140-6736(20)32594-0.

2. Microcytic Anemia. DeLoughery TG. The New England Journal of Medicine. 2014;371(14):1324-31. doi:10.1056/NEJMra1215361.

3. AGA Clinical Practice Update on Management of Iron Deficiency Anemia: Expert Review. DeLoughery TG, Jackson CS, Ko CW, Rockey DC. Clinical Gastroenterology and Hepatology : The Official Clinical Practice Journal of the American Gastroenterological Association. 2024;22(8):1575-1583. doi:10.1016/j.cgh.2024.03.046.

4. Iron Deficiency Anemia: Evaluation and Management. Latimer K, Baci G, Layne M. American Family Physician. 2025;112(5):538-545.