Black beans with meat: the iron pairing, measured meal by meal

Putting meat next to beans is an old trick for iron, and it has a measured basis. In a randomized trial in 45 healthy young women, adding 1.8 oz (50 g) of pork to a phytate-rich test meal raised nonheme iron absorption by 44 percent and 75 g raised it by 57 percent, while 25 g made no significant difference. Those were single isotope-labeled meals built on rice and peas, so the trial measured absorption from one plate, without black beans and without tracking iron status. The NIH Office of Dietary Supplements points the same way: meat, poultry and seafood help nonheme iron, and the phytate in beans works against it. Whether the effect adds up over weeks is less settled. In an 8-week trial in 52 iron-deficient women who also took an iron supplement, beef meals improved iron status no more than plant-based meat meals, and the authors concluded the meat factor did not contribute substantially alongside a supplement. A cup of the dish (260 g) gives about 460 calories, 27.6 g protein, 18.2 g fiber, 5.1 mg iron and 715 mg sodium, from one standard USDA recipe that real pots will differ from in meat and salt.

As people eat it, per 3.5 oz (100 g)

How much is actually in it

• Black beans with meat (USDA survey food) provides 177 calories, 10.6 g protein, 7 g fiber, 1.95 mg iron and 275 mg sodium per 3.5 oz (100 g). — — Evidence E source
  Per 100 g: energy 177 calories; protein 10.61 g; fiber 7 g; iron 1.95 mg; sodium 275 mg

What a real portion looks like

• One cup of black beans with meat (260 g) supplies about 460 calories, 27.6 g protein, 18.2 g fiber, 5.1 mg iron and 715 mg sodium. — — Evidence E source
  Per 1 cup (260 g): 460 calories; protein 27.6 g; fiber 18.2 g; iron 5.1 mg; sodium 715 mg; unspecified quantity 130 g

What your body absorbs

• In an RCT in 45 young women, adding 50 g or 2.6 oz (75 g) of pork to a phytate-rich meal raised nonheme iron absorption by 44% and 57%, while 25 g had no significant effect. — 45 healthy women, mean age 24 y, single test meals (n = 45) Evidence B source
  +44% (50 g meat, P<0.001); +57% (75 g meat, P<0.001); 25 g not significant (P=0.13)
• In an 8-week RCT in 52 iron-deficient women, taking an iron supplement with a beef meal improved iron status no more than with a plant-based meat meal. — nonpregnant females of reproductive age with serum ferritin below 25 ug/L, 8 weeks (n = 52) Evidence B source
  Ferritin +10.7 +/- 9.6 ug/L over time in both arms; treatment-by-time interaction P>0.05 for all indicators
• In crossover RCTs in 30 young and 25 older adults, two ounce-equivalents of pork delivered 7.36 g essential amino acids versus 3.02 g from black beans, with greater bioavailability from pork. — young adults (n = 30) and older adults (n = 25), single meals (n = 55) Evidence B source
  EAA content: pork 7.36 g vs black beans 3.02 g; bioavailability pork > black beans, p<0.0001; age did not change the result
• According to the NIH Office of Dietary Supplements, meat, poultry and seafood enhance absorption of the nonheme iron in beans, while phytate in beans has the opposite effect. — — Evidence E source
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What cooking and storage change

• In a trial in 21 women, cooking pork at 120 C instead of 70 C did not reduce its boost to nonheme iron absorption from a phytate-rich meal. — 21 women, 25 +/- 3 y, single test meals (n = 21) Evidence B source
  Absorption +0.9% (70 C, P=0.06), +0.7% (95 C, P=0.1), +2.0% (120 C, P<0.001) versus meal without meat

What it does to your health

• In a crossover RCT in 17 adults with type 2 diabetes, black beans with rice lowered the postprandial glucose area under the curve compared with rice alone at matched 50 g carbohydrate. — 17 men and women with type 2 diabetes aged 35-70 years, single breakfast meals (n = 17) Evidence B source
  Incremental AUC significantly lower for black bean/rice versus rice; net glucose lower at 90, 120 and 150 min
• In a crossover RCT in 35 older adults, a breakfast tortilla with 135 g black beans was as filling as one with 80 g beef, with no difference in 24-hour energy intake. — older adults, age 72.4 +/- 6.66 y, single test meals (n = 35) Evidence B source
  Appetite AUCs, ad libitum pizza intake and 24-h energy intake did not significantly differ

Safety, limits and interactions

• In a crossover RCT in 23 calcium stone formers, diets with beef or with legume-based plant protein gave the same urinary calcium oxalate risk index. — normocalciuric patients with a history of calcium kidney stones, 8 women and 15 men, mean age 50.7 y (n = 23) Evidence B source
  Urinary calcium, oxalate, magnesium, citrate, phosphorus, volume and TRI did not differ between diets

What people believe that the data does not support

• The EU did not authorize the claim that a white kidney bean (Phaseolus vulgaris) extract helps to reduce body weight, and no Phaseolus vulgaris claim is authorized. — — Evidence E source
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Who this works differently for

• In an RCT in 110 moderately anemic Guatemalan toddlers eating refried black beans for 10 weeks, hemoglobin rose 7.3 to 11.4 g/L with no overall difference between plain, ferrous sulfate and heme iron beans. — children aged 12-36 months with Hb 100-115 g/L, five 156-g cans of refried black beans per week for 10 weeks (n = 110) Evidence B source
  Hb +7.3 to +11.4 g/L across groups, no significant difference; post hoc heme iron subgroup +13.1 +/- 7.7 g/L

The bottom line

Cooking the meat hard does not seem to cost you the iron benefit. In a trial in 21 women, pork cooked at 70, 95 or 120 C raised nonheme iron absorption from a phytate-rich meal by 0.9, 0.7 and 2.0 percent against a meatless meal, and only the 120 C version reached significance. The meat also carries more usable protein. In crossover trials in 30 young and 25 older adults, two ounce-equivalents of pork held 7.36 g of essential amino acids against 3.02 g in the same measure of black beans, and more of the pork version reached the blood. The beans hold their own on fullness and blood sugar. In 35 older adults, a breakfast tortilla with 4.8 oz (135 g) of black beans was as filling as one with 2.8 oz (80 g) of beef, with no difference in what they ate over the next 24 hours. In 17 adults with type 2 diabetes, black beans with rice gave a lower blood glucose curve than rice alone at the same 50 g of carbohydrate. That was one breakfast, and there was no meat in it. Who should be careful. Sodium is the plain number to watch, at 715 mg per cup in the USDA recipe. For people who have had calcium kidney stones, a crossover trial in 23 such patients found beef and legume protein diets gave the same urinary stone risk index, though each diet ran only a few days and the index stands in for stones. In 110 moderately anemic Guatemalan toddlers eating refried black beans for 10 weeks, hemoglobin rose by 7.3 to 11.4 g/L in every group, and beans fortified with heme iron did no better overall than plain ones. The EU has refused a weight-loss claim for white kidney bean extract and has authorized no claim for this bean species at all. Nobody we found has studied this dish itself.

Sources

1. bbwm-daily-r4-01 · food composition dataset
   Black beans with meat, FNDDS code 41102170, fdc_id 2707366: Energy 177 KCAL, Protein 10.61 G, Fiber, total dietary 7 G, Iron, Fe 1.95 MG, Sodium, Na 275 MG per 100 g
   USDA FoodData Central survey (FNDDS) 2024-10-31, food code 41102170, fdc_id 2707366 · checked 2026-10-02
2. bbwm-daily-r4-02 · food portion dataset
   Black beans with meat, FNDDS code 41102170, fdc_id 2707366: 1 cup 260 g; Quantity not specified 130 g
   USDA FoodData Central survey (FNDDS) 2024-10-31, food code 41102170, fdc_id 2707366, portion 1 cup = 260 g · checked 2026-10-02
3. bbwm-daily-r4-03 · randomized controlled trial
   Twenty-five grams meat did not increase nonheme-iron absorption significantly (P = 0.13), whereas absorption increased 44% (P < 0.001) and 57% (P < 0.001), respectively, when 50 and 75 g meat were added to the basic meal.
   Am J Clin Nutr, 2003 · checked 2026-10-02
4. bbwm-daily-r4-05 · randomized controlled trial
   Findings suggest that the "meat factor" does not contribute substantially to improvements in iron status in women of reproductive age with iron deficiency when consumed with an iron supplement for 8 wk.
   Am J Clin Nutr, 2025 · checked 2026-10-02
5. bbwm-daily-r4-06 · randomized controlled trial
   Two oz-eq portions of pork (7.36 g EAA) and eggs (5.38 g EAA) resulted in greater EAA bioavailability than black beans (3.02 g EAA) and almonds (1.85 g EAA) in young and older adults, separately or combined (p < 0.0001 for all).
   Nutrients, 2023 · checked 2026-10-02
6. bbwm-daily-r4-11 · agency fact sheet
   In addition to ascorbic acid, meat, poultry, and seafood can enhance nonheme iron absorption, whereas phytate (which is present in grains and beans) and certain polyphenols in some nonanimal foods (e.g., cereals, legumes) have the opposite effect [4].
   NIH Office of Dietary Supplements, Iron Fact Sheet for Health Professionals · checked 2026-10-02
7. bbwm-daily-r4-04 · randomized controlled trial
   Increasing the cooking temperature of meat did not impair nonheme iron absorption compared with cooking at 70 degrees C.
   J Nutr, 2003 · checked 2026-10-02
8. bbwm-daily-r4-08 · randomized controlled trial
   Incremental area under the curve values were significantly lower for the pinto and black bean/rice meals compared to rice alone, but not for kidney beans.
   Nutr J, 2012 · checked 2026-10-02
9. bbwm-daily-r4-09 · randomized controlled trial
   Appetite sensation AUCs, ad libitum pizza intake, and 24-h energy intake did not significantly differ between the test meals.
   J Nutr, 2025 · checked 2026-10-02
10. bbwm-daily-r4-10 · randomized controlled trial
    Urinary calcium, oxalate, magnesium, citrate, phosphorus, volume, and TRI did not differ between diets.
    J Am Diet Assoc, 2001 · checked 2026-10-02
11. bbwm-daily-r4-12 · EU claims register entry
    POL-HC-8466 Standardised aqueous extract from white kidney bean (Phaseolus vulgaris L.) Helps to reduce body weight -/- Non-authorised
    EU Register on nutrition and health claims, claim POL-HC-8466, snapshot 2026-09-21 · checked 2026-10-02
12. bbwm-daily-r4-07 · randomized controlled trial
    Hb concentrations increased by the order of 7.3-11.4 g l(-1) during the intervention, but without significant differences across treatments.
    Public Health Nutr, 2005 · checked 2026-10-02