Lentils: the iron on the label and the iron you get

A cup of cooked lentils lists 5.7 mg of iron, which is 32 percent of the Daily Value, and that number is close to meaningless on its own. When 19 women ate 330 g of lentil dal labelled so the iron could be traced, they absorbed 2.2 percent of it. The same iron load given as ferrous sulfate gave 23.6 percent. Multiply the two numbers and the iron actually taken up from that cup is on the order of a tenth of a milligram, which is an illustration rather than a measurement, and it is the right order of magnitude to carry in your head. Absorption rose as iron stores fell, measured as serum ferritin and hepcidin, so that single average hides a reader who is running low taking up more of it than a reader who is replete. The cholesterol story is real and it is borrowed. Half a cup of pulses a day lowered LDL by 0.14 mmol/L across 38 trials at moderate to high certainty, but the dose-response gradient was shown for beans, and the authors say trials on lentils are still needed. Lentils ride here on the class result, not on their own.

The numbers, per 100 g

How much is actually in it

• Britain and America agree about lentils almost exactly, which they do for almost nothing else. — 8 USDA records with 8 Foundation Foods samples (FDC 2644283) against CoFID Lentils, red, split, dried, raw (code 13-657) (n = 8 samples) Evidence E source
  Iron 7.158 mg per 100 g in USDA against 7 in CoFID, a 2% gap, with the USDA Foundation samples running 6.52 to 7.94 so the British value falls near the middle; protein 23.569 g against 25.6, an 8% gap, with USDA samples at 22.125 to 24.375; copper 0.838 mg against 0.72, a 14% gap, with USDA samples at 0.761 to 0.881

What a real portion looks like

• A cup of cooked lentils lists nearly a third of a day's iron, and delivers a small fraction of that. — one FNDDS food with two household measures (n = fdc_id 2707423) Evidence E source
  Iron 3.1 mg per 100 g of cooked lentils; 1 cup = 185 g = 5.7 mg, which is 32% of the 18 mg Daily Value; quantity not specified = 92 g = 2.9 mg. Applying the 2.20% absorption measured for a lentil meal, the iron actually taken up from that cup is on the order of 0.1 mg

What your body absorbs

• Mean iron absorption from a lentil dal was 2.20% against 23.6% from the same iron load given as ferrous sulfate, in 19 women over a single meal. — 19 non-pregnant women, 6 of them anaemic with haemoglobin below 12.0 g/dL, each eating 330 g of dal made from lentils enriched to 85.1% with iron-57 (8 mg native iron-57) and a reference meal of ferrous sulfate (7 mg plus 1 mg iron-58) (n = 19) Evidence B source
  Mean iron absorption from the dal was 2.20% ± 3.40% against 23.6% ± 13.2% from the same iron load as ferrous sulfate (P < 0.001); absorption from both sources was inversely associated with serum ferritin (r = -0.50 and -0.81) and serum hepcidin (r = -0.45 and -0.60); in the 6 anaemic women absorption was 1.20% from the dal and 18.3% from ferrous sulfate

What cooking and storage change

• Draining the cooking water costs lentils a quarter of their iron, and keeping it costs a fifth. — group 16, Legumes; 19 method rows carry an iron factor (n = 19 method rows) Evidence E source
  Legumes cooked 2 to 2.5 hours then boiled and drained retain 75% of iron, whether afterwards baked, fried or not; the same cooking with the water used retains 80%, as do boiled then baked, boiled then fried, and the shorter 45 to 75 minute cooking with draining

What it does to your health

• A median 130 g of pulses a day, about half a cup, lowered LDL cholesterol by 0.14 mmol/L over a median of 6 weeks across 38 trials. — 2095 participants across 38 trials giving 52 trial comparisons of pulses as a class rather than of lentils, median duration 6 weeks and median dose 130 g a day, which is 0.5 to 0.67 of a cup (n = 2095) Evidence A source
  LDL cholesterol fell 0.14 mmol/L (95% CI -0.19 to -0.08), non-HDL cholesterol 0.22 mmol/L (-0.30 to -0.14), apolipoprotein B 0.08 g/L (-0.13 to -0.03) and HDL 0.03 mmol/L (-0.05 to -0.01), with no effect on other lipids; results were similar across pulse types, and beans showed a linear dose-response up to 1 cup a day; GRADE certainty was moderate to high for all outcomes except apolipoprotein B, which was very low
• Across forty-one trials pulses lowered fasting glucose and insulin, and moved glycosylated blood proteins only inside low glycaemic index diets, in standardised units that do not convert to an HbA1c figure. — 41 trials in 39 reports, in people with and without diabetes, split into pulses alone (11 trials), pulses within low glycaemic index diets (19 trials) and pulses within high-fibre diets (11 trials) (n = 41 trials) Evidence A source
  Pulses alone lowered fasting blood glucose (SMD -0.82, 95% CI -1.36 to -0.27) and insulin (-0.49, -0.93 to -0.04); within low glycaemic index diets they lowered glycosylated blood proteins measured as HbA1c or fructosamine (-0.28, -0.42 to -0.14); within high-fibre diets they lowered fasting glucose (-0.32, -0.49 to -0.15) and glycosylated proteins (-0.27, -0.45 to -0.09)

What people believe that the data does not support

• No pulse anywhere carries an approved health claim for lowering cholesterol, which the authors of the strongest trial evidence point out themselves. — food labelling Evidence E source
  The review states that although clinical practice guidelines recognise dietary pulses for reducing cholesterol and coronary heart disease risk, intake is low and there are no health claims for any pulse for cholesterol reduction; our own registry snapshots agree, with only a content claim under 21 CFR 101.65 mentioning lentils in the United States and no entry of any kind for lentils in the EU Register

The bottom line

Keep the cooking water. The USDA retention table works on food groups rather than on lentils, and it gives legumes boiled and drained 75 percent of their iron against 80 percent when the water is used. That is a five point difference sitting next to a tenfold difference in absorption, so a dal that keeps its liquid is the better habit and a small one. What would move the bigger number, soaking, sprouting, or eating something acidic or vitamin C rich alongside, was not tested in that trial, so we cannot tell you how much any of it helps. For blood sugar the evidence is wide and loose. Forty-one trials found pulses lowered fasting glucose and insulin, and lowered glycosylated blood proteins, measured as HbA1c or fructosamine, when they sat inside a low glycaemic index diet. The authors state plainly that variation between studies was high and unexplained, that the result shifted with diabetes status, dose, pulse type, physical form and background diet, and that the effects are reported in standardised units nobody can convert into an HbA1c figure. It is from 2009 and trials as short as seven days counted. Read it as a direction. No regulator anywhere allows a pulse to claim it lowers cholesterol. The reviewers who produced the strongest trial evidence point this out themselves, and our own snapshots of the American and European registers agree: nothing for lentils in Europe, and only a content claim in the United States. An absent claim is not a verdict on the food. It usually means nobody with money to spend on a dossier stood to gain from filing one. One small pleasure of this food for anyone who reads labels across countries. Britain and America disagree about almost every fresh product and they agree about lentils, 7.158 mg of iron per 100 g against 7, with the American samples running 6.52 to 7.94. A dried lentil is a stored seed with no ripeness, no season and no water content to drift, which is exactly why the same comparison for pumpkin came apart by 82 percent. One thing this page does not tell you: we hold no evidence cards on who should be careful with lentils, so there is no safety section here, and that is a gap in what we have read rather than an all-clear.

Sources

1. len-p1-05 · reference dataset comparison
   USDA Lentils, dry [FDC 2644283, foundation] iron 7.158 mg, Foundation samples 6.52-7.94 n=8; protein 23.569 g, samples 22.125-24.375; copper 0.838 mg, samples 0.761-0.881 n=8 || CoFID Lentils, red, split, dried, raw [13-657] Iron (mg) 7 · Protein (g) 25.6 · Copper (mg) 0.72
   USDA FoodData Central, Foundation Foods (FDC 2644283) and CoFID 2021, Public Health England / OGL v3.0 (code 13-657) · checked 2026-09-22
2. len-p1-06 · reference dataset
   Lentils, NFS · Iron, Fe 3.1 MG per 100 g [fdc_id 2707423] · 1 cup 185 g 5.7 MG · Quantity not specified 92 g 2.9 MG
   USDA FNDDS 2021-2023, Lentils, NFS (fdc_id 2707423) · checked 2026-09-22
3. len-p1-03 · randomised crossover trial with stable-isotope labelling
   We found that the mean iron absorption from the dal was 2.20% ± 3.40% and was significantly lower than the 23.6% ± 13.2% observed from the same iron load given as ferrous sulfate (P < 0.001).
   The Journal of Nutrition, 2015 · checked 2026-09-22
4. len-p1-07 · reference dataset
   iron_mg · group 16 Legumes · 541 LEGUMES,CKD 2/2.5HRS,BOILED,DRAINED — 75% · 543 LEGUMES,CKD 2/2.5HRS,BLD,DRND,BKD — 75% · 545 LEGUMES,CKD 2/2.5HRS,BLD,DRND,FRIED — 75% · 542 LEGUMES,CKD 2/2.5HRS,BLD,WATER USED — 80% · 523 LEGUMES,CKD 45/75MIN,BLD,DRND,BKD — 80%
   USDA Table of Nutrient Retention Factors, Release 6 (2007) · checked 2026-09-22
5. len-p1-01 · systematic review and dose-response meta-analysis of randomised controlled trials
   Thirty-eight trials (52 trial comparisons, n=2095) with a median of 6 weeks and dose of 130 g/d (0.5-0.67 cup/d) showed that whole dietary pulses decreased low-density lipoprotein-cholesterol (mean difference, -0.14 mmol/L [95% CI, -0.19 to -0.08])
   Journal of the American Heart Association, 2026 · checked 2026-09-22
6. len-p1-02 · systematic review and meta-analysis of randomised controlled trials
   Pulses alone (11 trials) lowered fasting blood glucose (FBG) (-0.82, 95% CI -1.36 to -0.27) and insulin (-0.49, 95% CI -0.93 to -0.04)...Inter-study heterogeneity was high and unexplained for most outcomes
   Diabetologia, 2009 · checked 2026-09-22
7. len-p1-04 · regulatory position stated in a systematic review
   Although dietary pulses are recognized by major clinical practice guidelines to reduce cholesterol and coronary heart disease risk, intake is low. There are no health claims for any pulse for cholesterol reduction, which could support uptake.
   Journal of the American Heart Association, 2026 · checked 2026-09-22