Iron is the gap most women on plants actually have, and the one they are most often told they do not. The blood count comes back “normal”, the tiredness stays, and nobody checked ferritin. Plants carry plenty of iron. The trouble is that it is non-haem iron, absorbed at 5 to 12 percent against 15 to 35 percent from meat, and that the same meal often contains the things that switch absorption off. The fix is less about eating more iron than about eating it correctly.
The signs iron is low before the blood count moves
Iron stores fall first, for months, while haemoglobin holds. Low stores alone are enough to make you feel like this:
- Tired by mid-afternoon in a way that coffee does not fix; heavy legs on a run that used to be easy.
- Cold hands and feet in a warm room; pale inner eyelids and nail beds.
- Breathless on the second flight of stairs; a heart you can hear on the pillow.
- Restless legs at night, a pull toward ice or crunchy cold things.
- Hair thinning at the parting, nails that spoon or split, mouth corners that crack.
- Concentration that drifts and a low mood that lifts the week iron is corrected.
Women who menstruate heavily, who run, who are pregnant or who donate blood are the usual cases. Running breaks red cells in the feet; heavy periods remove 20 to 40 mg of iron a month that has to be replaced at a few percent absorption.
The blood test, and what the numbers mean
Ask for all four. Ferritin alone is misleading when there is any inflammation, which is why CRP goes with it.
| Test | Low | Comfortable | Note |
|---|---|---|---|
| Ferritin (stores) | below 15 µg/L is empty; below 30 is low | 50 µg/L or more if you train or are tired | the number that explains tiredness long before anaemia |
| Haemoglobin | below 120 g/L in women | 130 to 150 g/L | anaemia starts here; stores have usually been empty for months |
| Transferrin saturation | below 16 percent | 20 to 45 percent | how much iron is circulating to the marrow |
| CRP | above 5 mg/L inflates ferritin | low | read ferritin with this beside it |
A ferritin of 22 with a haemoglobin of 128 is “within range” on the printout and the reason a woman cannot finish a workout. Treat the ferritin.
How much you need
| Reference | Amount |
|---|---|
| EFSA PRI, women 18 to 50 | 16 mg a day |
| US RDA, women 19 to 50 | 18 mg a day |
| EFSA PRI, after menopause | 11 mg a day |
| Pregnancy | 27 mg a day (US) |
| Tolerable upper intake, supplements | 45 mg a day (US) |
Because plant iron absorbs at 5 to 12 percent, some authorities suggest vegetarians aim for up to 1.8 times these figures. In practice the absorption rules below matter more than chasing 30 mg.
Iron-rich vegan foods, milligrams per portion
| Food | Portion | Iron |
|---|---|---|
| Lentils, cooked | 200 g | 6.6 mg |
| Firm tofu | 150 g | 4.0 mg |
| Chickpeas, cooked | 200 g | 3.0 mg |
| Spinach, cooked | 100 g | 3.5 mg (low absorption, high oxalate) |
| Pumpkin seeds | 30 g | 2.5 mg |
| Oats, dry | 50 g | 2.2 mg |
| Tahini | 30 g | 2.7 mg |
| Tempeh | 100 g | 2.7 mg |
| Edamame, shelled | 150 g | 3.4 mg |
| Dark chocolate, 70 percent | 30 g | 3.5 mg |
| Blackstrap molasses | 1 tablespoon | 3.6 mg |
| Fortified oats or cereal | 40 g | 4 to 8 mg, check the label |
| Dried apricots | 50 g | 1.4 mg |
A day that reaches 18 mg without trying: fortified oats with pumpkin seeds and berries at breakfast, a lentil and tomato bowl at lunch, tofu with peppers at dinner, a square of dark chocolate.
The absorption rules, which matter more than the milligrams
Add vitamin C to the same plate. 50 to 100 mg, which is half a red pepper, a kiwi, a handful of strawberries or the juice of a lemon, can double or triple non-haem absorption. Tomato in the lentils, lemon on the tofu, an orange after breakfast. This is the single highest-return habit on this site.
Keep tea and coffee an hour away. The tannins and polyphenols in a cup of black tea taken with the meal cut absorption by half or more. Coffee at breakfast with the fortified oats is the classic way to waste the oats. Drink it an hour before or an hour after.
Keep calcium off the iron meal. A calcium supplement or a large glass of calcium-fortified milk at the same sitting blocks iron. Put calcium at a different meal.
Reduce phytate. Soak dried beans overnight and discard the water, choose sprouted or fermented options (tempeh, sourdough, sprouted lentils), and let bread rise properly. Each step frees iron the phytate was holding.
Cook in cast iron. Acidic foods simmered in a cast-iron pan pick up measurable iron. Tomato-based lentils in a cast-iron pot is a two-for-one.
Spread it out. Absorption per meal is capped by hepcidin, the hormone that closes the gut’s iron gate for several hours after a load. Three iron-containing meals beat one enormous one.
The supplement: when, which, how
Supplement when ferritin is below 30 µg/L, or below 50 with symptoms and a reason (heavy periods, running). Not before a test: iron overload from a genetic cause is common enough that blind supplementing is a bad bet, and iron is one of the few nutrients that can genuinely hurt in excess.
- Form: ferrous bisglycinate 25 mg elemental iron is gentle on the stomach and well absorbed; ferrous sulfate 65 mg elemental (200 mg tablet) is the standard and cheaper.
- Dose and timing: one tablet, on alternate days, in the morning, with a glass of orange juice or a vitamin C tablet, an hour away from coffee, tea, calcium and other minerals. Alternate-day dosing raises absorption because hepcidin falls back between doses; the research on this is from Stoffel and colleagues in The Lancet Haematology, 2017.
- How long: expect ferritin to climb by roughly 10 to 20 µg/L a month. Retest at three months. Continue until ferritin sits above 50, then rely on the food rules.
- Constipation or nausea usually means the sulfate form; switch to bisglycinate rather than giving up.
The one-week fix
- Book ferritin, haemoglobin, transferrin saturation and CRP for this week, before changing anything, so you have a baseline.
- Move coffee to an hour after breakfast. This alone is worth several milligrams a day.
- Put a lemon, a pepper or a kiwi on every iron meal.
- Cook one pot of lentils with tomatoes in a cast-iron pan on Sunday; it covers three lunches.
- If the test comes back under 30, start alternate-day bisglycinate the morning the result arrives.
What the research says
- Haider and colleagues, Critical Reviews in Food Science and Nutrition, 2018, meta-analysis of 27 studies, adult vegetarians and vegans against non-vegetarians on their habitual diets: vegetarians had lower serum ferritin than non-vegetarians, with the clearest gap in women. The contrary finding: haemoglobin differed little or not significantly in several of the pooled studies, so lower stores did not always mean anaemia. doi.org/10.1080/10408398.2016.1259210
That is exactly the pattern in the clinic: stores down, blood count still passing, woman still tired. Test ferritin.
Questions women ask
My haemoglobin is normal. Can I still be low in iron? Yes, and it is the most common situation on this site. Ask for ferritin.
Is spinach a good iron source? It carries iron but the oxalate in it blocks most of the absorption. Lentils, tofu and pumpkin seeds are better bets; eat spinach for the folate and the pleasure.
How long before I feel the difference? With a corrected dose, energy and the cold hands usually improve inside three to four weeks; ferritin takes three months to show it on paper.