Edamame: the pods are the food, the trials are about soy

One cup of cooked edamame carries 18.5 g of protein and 457.6 µg of folate, which is 114 percent of the 400 µg Daily Value printed on American labels for adults. That figure was taken on edamame already cooked. That part is measurement, and it holds. The health evidence underneath is about soy in general. The heart claim rests on 43 controlled trials of soy protein at a median 25 g a day, which lowered LDL cholesterol by 4.76 mg/dL, about 3 to 4 percent. The iron figure comes from labelled soybeans eaten as soup or muffins. The breast cancer data comes from isoflavone intake in over 300 000 Chinese women, averaging 9.4 mg a day. None of these fed anybody green pods. So read them as what soy does, and keep in mind that a bowl of edamame is one soy food among many rather than the dose those studies used.

The numbers, per 100 g

How much is actually in it

• One cup of cooked edamame carries 18.5 grams of protein and more folate than a whole day needs. — one FNDDS food with three household measures (n = fdc_id 2707436) Evidence E source
  Protein 11.54 g per 100 g and folate 286 µg DFE per 100 g; 1 cup = 160 g = 18.5 g protein and 457.6 µg DFE, which is 114% of the 400 µg Daily Value for folate; 1 pod yields 2 g, so a single pod is 0.2 g protein

What a real portion looks like

• The threshold the United States attached to that claim is 25 grams of soy protein a day. — food labelling in the United States Evidence E source
  The daily intake level associated with reduced coronary heart disease risk is stated as 25 g or more per day of soy protein, and a food may carry the claim only if it holds at least 6.25 g of soy protein per reference amount customarily consumed

What your body absorbs

• Ten weeks of eating soy foods left iron and zinc status unchanged in young women. — non-smoking women aged 18 to 28 without chronic disease, anaemia, pregnancy or irregular menstrual cycles, randomised to soy food (n=31) or animal food (n=32) (n = 63) Evidence B source
  The soy diet supplied about 19 g protein and about 36 mg isoflavones a day; after the intervention there was no significant change in haemoglobin, transferrin saturation, serum iron, ferritin or transferrin receptor, and plasma zinc fell equally in both groups by 0.8 micromol/L
• Women with low iron stores absorbed about a quarter of the iron in soybeans, and absorbed more the lower their stores were. — 18 women, most with marginal iron deficiency; 11 ate the soup and 7 the muffins (n = 18) Evidence C source
  Mean iron-55 absorption was 27% from either soup or muffins against 61% from the reference dose, and red cell radioactivity correlated inversely with serum ferritin (r = -0.793, P < 0.001); the label was split about equally between protein (49.3 +/- 3.0%) and phytate

What cooking and storage change

• Boiling costs edamame between a third and nearly half its folate, and how much depends on how much water is thrown away. — group 11, Vegetables and Vegetable Products; 25 method rows carry a folate factor (n = 25 method rows) Evidence E source
  Cooked from frozen and drained retains 55% of folate, boiled under a cover of water and drained 60%, boiled in little water and drained 65%, and boiled in little water as other vegetables 70%

What it does to your health

• Soy protein lowers LDL cholesterol by about three to four percent, which is real and small. — adult men and women with baseline circulating LDL cholesterol from 110 to 201 mg/dL; of the 46 trials identified, 43 gave usable data and 41 gave LDL data (n = 43 controlled trials) Evidence A source
  At a median dose of 25 g a day over a median 6 weeks, LDL cholesterol fell 4.76 mg/dL (95% CI -6.71 to -2.80, P < 0.0001, I2 55%) and total cholesterol fell 6.41 mg/dL (95% CI -9.30 to -3.52, P < 0.0001, I2 74%) against non-soy protein controls, with no dose-response effect and no evidence of publication bias
• In 300 thousand Chinese women, moderate soy intake carried no more breast cancer than the lowest intake. — over 300000 women aged 30 to 79 from 10 regions of China enrolled between 2004 and 2008, with 2289 breast cancers over 10 years of follow-up (n = 300000) Evidence C source
  Mean soy isoflavone intake was 9.4 (SD 5.4) mg a day; the multivariable-adjusted relative risk for the top quartile (19.1 mg a day) against the bottom (4.5 mg a day) was 1.00 (95% CI 0.81 to 1.22), while the pooled dose-response gave a 3% lower risk (95% CI 1 to 5%) per 10 mg a day increment
• The United States allows food labels to link soy protein to lower heart disease risk, in hedged wording. — food labelling in the United States Evidence E source
  The regulation states that evidence demonstrates the addition of soy protein to a low saturated fat and cholesterol diet may also help reduce the risk of coronary heart disease; the claim must use the words may or might, and must name the substance as soy protein

Safety, limits and interactions

• In the same trial thyroid stimulating hormone and free thyroxine did not move either, in healthy young women over ten weeks. — the same 63 premenopausal women, 31 on soy foods and 32 on animal foods (n = 63) Evidence B source
  No significant changes in thyroid-stimulating hormone or free thyroxine after soy food intake, at about 19 g soy protein and about 36 mg isoflavones a day for 10 weeks

What people believe that the data does not support

• Europe looked at that same 25 gram cholesterol claim and refused it. — food labelling in the European Union Evidence E source
  Status Non-authorised; across the whole register 26 entries mention soy and every one of them is non-authorised, with zero authorised claims for soy of any kind

Who this works differently for

• Among women already diagnosed with breast cancer, soy eaten before diagnosis went with slightly better overall survival. — 12 articles covering 37275 women with breast cancer, reporting overall survival in 5770, breast cancer specific survival in 2386 and recurrence in 1500 cases (n = 37275) Evidence C source
  Pre-diagnosis soy and isoflavone intake gave a hazard ratio of 0.84 (95% CI 0.71 to 0.98) for overall survival and 0.89 (0.74 to 1.07) for breast cancer specific survival; post-diagnosis intake showed no significant association, at 0.80 (0.62 to 1.04) and 0.83 (0.64 to 1.07)

The bottom line

Edamame is one of the easier things to put on a plate, and the folate and protein numbers carry it on their own. On the fears about soy that have actually been measured, the answers are reassuring and unspectacular. Ten weeks of two to three servings of soy foods a day, about 19 g of soy protein and 36 mg of isoflavones, left haemoglobin, serum iron, ferritin and transferrin receptor unchanged in young women, and left thyroid-stimulating hormone and free thyroxine unchanged too. Hold that second result inside its own boundaries. Those were 63 healthy women aged 18 to 28 with no thyroid disease, measured over ten weeks, and the thyroid readings were a secondary outcome in a trial built to look at minerals. People who already have an underactive thyroid, or who take replacement for one, were not in it, and this page holds no card about them. One more gap is worth naming out loud, because people arrive on this page looking for it. We hold no card on soy and allergy either, so this page cannot answer that question at all, and its silence is not an all-clear. Among more than 300 000 Chinese women followed for ten years, the top quartile of isoflavone intake carried the same breast cancer risk as the bottom, a relative risk of 1.00. In women already diagnosed, soy eaten before diagnosis went with better overall survival at a hazard ratio of 0.84. That is an association pulled out of observational studies, not an effect of soy, and nobody was randomised to eat it. Soy eaten after diagnosis showed nothing significant either way. Iron is the real trade-off. Women with low iron stores absorbed 27 percent of the iron in soybeans against 61 percent from a reference dose, with the label split about evenly between the protein and the phytate. Soy is a poor place to go looking for iron even though it contains some. Two regulators read the same 25 g soy protein cholesterol claim and split. The United States authorises it in hedged wording, requiring the words may or might and at least 6.25 g of soy protein per serving. Europe refused it, along with every one of the 26 soy entries in its register. Cook the pods in as little water as you can: cooked from frozen and drained keeps 55 percent of the folate, boiled under a cover of water 60 percent, and boiled in little water 65 to 70 percent. Those percentages are what boiling costs a raw pod. They are already inside the 457.6 µg at the top of this page, which was measured on the cooked food, so do not take them off it a second time.

Sources

1. eda-p1-10 · reference dataset
   Edamame, cooked · Protein 11.54 G на 100 г [fdc_id 2707436] · 1 pod, yields 2 г 0.2 G · 1 cup 160 г 18.5 G || Folate, DFE 286 UG на 100 г [fdc_id 2707436] · 1 pod, yields 2 г 5.7 UG · 1 cup 160 г 457.6 UG
   USDA FNDDS 2021-2023, Edamame, cooked (fdc_id 2707436) · checked 2026-09-22
2. eda-p1-08 · regulatory provision
   The daily dietary intake level of soy protein that has been associated with reduced risk of coronary heart disease is 25 grams (g) or more per day of soy protein.
   21 CFR 101.82, Health claims: Soy protein and risk of coronary heart disease · checked 2026-09-22
3. eda-p1-02 · randomised controlled trial
   After intervention, no significant changes were observed in hemoglobin, transferrin saturation, serum iron, ferritin, or transferrin receptor (TFR) concentrations.
   Journal of Women's Health, 2011 · checked 2026-09-22
4. eda-p1-04 · controlled feeding study with stable isotope labelling
   The mean (55)Fe absorption from either soup or muffins was 27% and that from the reference dose was 61%.
   The American Journal of Clinical Nutrition, 2003 · checked 2026-09-22
5. eda-p1-11 · reference dataset
   folate_total_ug · група 11 Vegetables and Vegetable Products · 3019 VEG,GREENS,COOKED FROM FROZEN,DRAIN — 55% · 3005 VEG,GREENS,BOILED,WATER COVER DRAIN — 60% · 3004 VEG,GREENS,BOILD,LITTLE WATER DRAIN — 65% · 3774 VEG,OTHER,BLD,LITTLE WATER,DRAINED — 70%
   USDA Table of Nutrient Retention Factors, Release 6 (2007) · checked 2026-09-22
6. eda-p1-01 · systematic review and meta-analysis of controlled trials
   Soy protein at a median dose of 25 g/d during a median follow-up of 6 wk decreased LDL cholesterol by 4.76 mg/dL (95% CI: -6.71, -2.80 mg/dL, P < 0.0001; I2 = 55%, P < 0.0001)...Soy protein significantly reduced LDL cholesterol by approximately 3-4% in adults.
   The Journal of Nutrition, 2019 · checked 2026-09-22
7. eda-p1-05 · prospective cohort study with dose-response meta-analysis
   The multivariable-adjusted relative risk was 1.00 (95% confidence interval [CI] 0.81-1.22) for the fourth (19.1 mg/day) versus the first (4.5 mg/day) soy isoflavone intake quartile.
   European Journal of Epidemiology, 2020 · checked 2026-09-22
8. eda-p1-07 · regulatory provision
   Scientific evidence demonstrates that diets low in saturated fat and cholesterol may reduce the risk of CHD. Other evidence demonstrates that the addition of soy protein to a diet that is low in saturated fat and cholesterol may also help to reduce the risk of CHD.
   21 CFR 101.82, Health claims: Soy protein and risk of coronary heart disease · checked 2026-09-22
9. eda-p1-03 · randomised controlled trial
   No significant changes were observed in bone resorption, thyroid-stimulating hormone (TSH), or free thyroxine after soy food intake.
   Journal of Women's Health, 2011 · checked 2026-09-22
10. eda-p1-09 · regulatory register entry
    POL-HC-7961 Soy protein Soy helps to control cholesterol. l. 25 g soy protein daily as part of a diet with few saturated fatty acids helps to maintain healthy cholesterol levels. Non-authorised
    EU Register on nutrition and health claims, заява POL-HC-7961, знімок 2026-09-21 · checked 2026-09-22
11. eda-p1-06 · systematic review and meta-analysis of observational studies
    The summary HR (95% CI) for the association (highest vs. lowest) of pre-diagnosis soy and isoflavones consumption with OS and BCSS was 0.84 (0.71-0.98) and 0.89 (0.74-1.07), respectively.
    European Journal of Nutrition, 2019 · checked 2026-09-22