Nopales: a cactus vegetable whose weight claims do not hold

Nopales, the flat pads of the prickly pear cactus, are sold as a weight loss food far more often than the evidence allows. A meta-analysis of 5 randomized trials of Opuntia ficus-indica supplements found no significant change in body weight, a mean difference of -1.8 lb (95% CI -5.5 to 1.8; metric: -0.83 kg, -2.49 to 0.83), and the trials disagreed sharply with each other (I2 of 93%). Those trials tested supplements made from the plant. One 12-week trial in 123 overweight adults on a calorie-reduced diet did report 8.4 lb (3.8 kg) lost on 3 g a day of a proprietary Opuntia fiber complex, against 3.1 lb (1.4 kg) on placebo. That single result conflicts with the pooled one, and the product was a concentrated fiber made for capsules. In the US, supplements do not go through FDA approval the way medicines do, so anyone who takes medication, is pregnant or has a chronic illness should talk to a doctor before taking one. The EU did not authorize a claim that dehydrated cactus leaves improve blood lipids, which means the evidence was judged insufficient when it was assessed. As a plain food, raw nopales hold 164 mg calcium per 3.5 oz (100 g) in a single USDA record with no spread across samples, and part of that calcium is bound as oxalate. The only absorption data come from ovariectomised rats, so how much of it a person actually absorbs is unknown.

The numbers, per 3.5 oz (100 g)

How much is actually in it

• Dehydrated nopal had a measured glycemic index of 32.5 in seven healthy adults. — 7 healthy adults, 50 g available carbohydrate from glucose or dehydrated nopal (n = 7) Evidence C source
  Glycemic index 32.5 +/- 4; insulinemic index 36.1 +/- 6
• Raw nopales contain 164 mg calcium per 3.5 oz (100 g) in USDA data. — USDA SR Legacy, Nopales, raw (FDC 168571) (n = -) Evidence E source
  Calcium 164 mg/100 g; magnesium 52 mg/100 g; vitamin C 9.3 mg/100 g

What your body absorbs

• In ovariectomised rats, laboratory data suggest calcium from nopal soluble fiber was absorbed better (93.9%) than from whole nopal powder (78.3%). — 35 ovariectomised Wistar rats (n = 35) Evidence D source
  Apparent calcium absorption 93.87% (soluble fiber) vs 83.81% (calcium citrate) vs 78.26% (whole nopal powder)

What cooking and storage change

• For greens boiled in a little water and drained, USDA retention factors give 60% vitamin C and 95% calcium retained. — USDA R6 group Vegetables and Vegetable Products, VEG,GREENS,BOILD,LITTLE WATER DRAIN (n = -) Evidence E source
  Vitamin C 60% retained, calcium 95%, magnesium 95%

What it does to your health

• In a crossover RCT in 14 healthy volunteers, nopal fiber held more water in the small bowel than wheat bran (AUC difference 7.1 L/min). — 14 healthy volunteers, 7.5 g fiber three times over 24 h, crossover with psyllium and wheat bran (n = 14) Evidence B source
  Small bowel water AUC difference vs wheat bran 7.1 (95% CI 0.6 to 13.8) L/min
• In a 2.5-month RCT in 62 adults with mild high cholesterol, a dietary portfolio including dehydrated nopal lowered LDL-C by 18.05% more than a low saturated fat diet alone. — 62 overweight adults with mild hypercholesterolemia, portfolio of nopal, soy protein, chia, inulin and oats, 2.5 months (n = 62) Evidence B source
  LDL-C -18.05% (P = 0.003), TC -17.08% vs low saturated fat diet

Safety, limits and interactions

• Across 5 randomized trials of Opuntia ficus-indica supplements, reported adverse events were gastric intolerance and flu symptoms. — Adults in 5 randomized clinical trials of Opuntia ficus-indica supplements (n = 5 trials) Evidence A source
  Adverse events: gastric intolerance, flu symptoms (frequency not given in abstract)
• In the same IBS trial, the highest dose of nopal fiber, 30 g/day, caused more loose stools than placebo. — 60 adults with IBS (Rome IV), 1 week, nopal fiber up to 30 g/day (n = 60) Evidence B source
  More loose stools at 30 g/day (p = 0.027); size not given in abstract
• In a 16-week RCT in 29 obese prediabetic adults, an Opuntia ficus-indica extract showed no difference from placebo in blood safety parameters. — 29 obese prediabetic men and women aged 20-50, OpunDia 200 mg/day or placebo, 16 weeks (n = 29) Evidence B source
  No between-group differences in comprehensive metabolic panel after 16 weeks

What people believe that the data does not support

• A meta-analysis of randomized trials found no significant effect of Opuntia ficus-indica on body weight (mean difference -1.8 lb (-0.83 kg)). — Adults in 5 randomized clinical trials of Opuntia ficus-indica supplements (n = 5 trials) Evidence A source
  Body weight MD -1.8 lb (95% CI -5.5 to 1.8; metric: -0.83 kg, -2.49 to 0.83), I2 = 93%
• In a 24-week non-randomized trial, 5 g/day of nopal powder did not change bone mineral density in women aged 40 to 60. — 69 women aged 40-60 (56 nopal powder 5 g/day, 13 habitual diet), 24 weeks (n = 69) Evidence C source
  No significant change in BMD (P = .885 nopal group)
• In a 12-week RCT in 123 overweight adults on a calorie-reduced diet, an Opuntia-derived fiber complex at 3 g/day led to 8.4 lb (3.8 kg) weight loss vs 3.1 lb (1.4 kg) on placebo. — 123 overweight and obese adults, hypocaloric diet, 3 g/day Litramine IQP G-002AS or placebo, 12 weeks (n = 123) Evidence B source
  Weight change -3.8 +/- 1.8 kg vs -1.4 +/- 2.6 kg (P < 0.001)
• The EU rejected a health claim that dehydrated prickly pear cactus leaves (NeOpuntia) help improve blood lipids. — EU health claims register (n = -) Evidence E source
  Claim status: non-authorized

Who this works differently for

• In a one-week RCT in 60 people with IBS, 20 g/day of nopal fiber gave adequate symptom relief in 87% vs 33% on placebo. — 60 adults with IBS (Rome IV), 1 week, nopal fiber 10, 20 or 30 g/day vs dextrose placebo (n = 60) Evidence B source
  Adequate relief 87% (20 g/day) and 80% (30 g/day) vs 33% placebo; IBS-SSS >50% drop 67% vs 20%
• In a non-randomized study, people with type 2 diabetes who ate a high-carbohydrate breakfast with 300 g steamed nopal had a lower glucose area under the curve (287 vs 443). — 14 patients with type 2 diabetes, single test meals with or without 300 g steamed nopal; 7 healthy adults for glycemic index (n = 14) Evidence C source
  Glucose AUC 287 +/- 30 with nopal vs 443 +/- 49 without

What is still unknown

• A systematic review found the effect of eating Opuntia cladodes on blood lipids was small, and studies often confused cladodes with the fruit. — 11 human studies of Opuntia fruit (6), cladode (4) or commercial products (1) (n = 11 studies) Evidence C source
  Cladode: small effect; one subgroup HDL-C increase

The bottom line

The gut findings are the most interesting and the least like a meal. In a one-week randomized trial in 60 adults with irritable bowel syndrome, 20 g a day of extracted nopal fiber powder gave adequate symptom relief to 87% against 33% on placebo, with only 15 people in each arm. That was a one-week test of a fiber powder, not a guide to how much to take, and we have no card on an upper limit for it. At 30 g a day the same powder caused more loose stools, and the abstract does not give how many more. In 14 healthy volunteers, nopal fiber held more water in the small bowel than wheat bran on MRI, 7.1 L/min more (95% CI 0.6 to 13.8), a physiological measurement that says nothing yet about symptoms. Blood sugar data are small and short. Dehydrated nopal had a glycemic index of 32.5 in seven healthy adults. In a non-randomized study of 14 people with type 2 diabetes, a high-carbohydrate breakfast eaten with 11 oz (300 g) of steamed nopal gave a glucose area under the curve of 287 against 443 without it, after one test meal. For cholesterol, a 2.5-month randomized trial in 62 overweight adults with mildly raised cholesterol found LDL fell 18.05% more on a portfolio diet than on a low saturated fat diet alone. Nopal was one of five foods in that portfolio, so its own share is unknown. A systematic review judged the effect of eating the pads on blood lipids small, and noted that studies often mixed up the pads with the fruit. Nopal powder at 5 g a day for 24 weeks did not change bone density in 69 women aged 40 to 60, in a trial without randomization and with only 13 controls. Boiling costs some vitamin C. The USDA factor for greens boiled in a little water and drained keeps 60% of vitamin C and 95% of calcium, a group value never measured on nopales themselves. On safety, the supplement trials reported gastric intolerance and flu symptoms, without saying how often. A 200 mg daily extract taken for 16 weeks by 29 obese adults with prediabetes showed no difference from placebo on a full metabolic blood panel. We found no data on nopales in pregnancy, in children, in kidney disease or alongside glucose-lowering drugs. That gap is not a sign of safety. The 300 g test meal above lowered blood glucose in people with type 2 diabetes, so anyone who takes medicine for diabetes should talk to a doctor before adding large servings of nopal or a nopal supplement to meals.

Sources

1. nop-daily-r5-07 · controlled clinical trial
   The glycemic index of nopal was 32.5±4, insulinemic index was 36.1±6, GIP index was 6.5±3.0, and GLP-1 index was 25.9±18.
   J Acad Nutr Diet, 2014 · checked 2026-09-28
2. nop-daily-r5-13 · food composition data
   Nopales, raw (FDC 168571, SR Legacy, Vegetables and Vegetable Products): calcium 164 mg per 100 g = 13% DV; magnesium 52 mg = 12% DV; vitamin C 9.3 mg = 10% DV; Foundation samples 0, CoFID match none
   USDA FoodData Central, SR Legacy 2018, FDC 168571 · checked 2026-09-28
3. nop-daily-r5-15 · animal study
   The results shown in Figure 2a indicate that the apparent calcium absorption was significantly higher (p ≤ 0.05) in the group fed with soluble fiber (93.87% ± 3.15%) compared with that observed in the groups fed with diets supplemented with calcium citrate (83.81% ± 2.12%), O. ficus-indica powder (78.26% ± 3.46%) and insoluble fiber (77.96% ± 5.16%) and the ovariectomized group (OVX) fed with AIN-93M (78.13% ± 6.31%).
   Nutrients, 2020 · checked 2026-09-28
4. nop-daily-r5-14 · retention factor data
   USDA-RETN-R6:3004 VEG,GREENS,BOILD,LITTLE WATER DRAIN, group Vegetables and Vegetable Products (11): vitamin_c_mg 60%, calcium_mg 95%, magnesium_mg 95%
   USDA Table of Nutrient Retention Factors, Release 6 (2007), code 3004 · checked 2026-09-28
5. nop-daily-r5-05 · randomized crossover trial
   SBWC increased for all fibers; nopal stimulated more water than wheat bran [AUC mean (95% CI) difference: 7.1 (0.6, 13.8) L/min, P = 0.03].
   Am J Clin Nutr, 2020 · checked 2026-09-28
6. nop-daily-r5-11 · randomized controlled trial
   Subjects who consumed the LSFD + DP interventions had a significantly higher reduction of LDL-C (-18.05%, P = 0.003) and TC (-17.08%, P = 0.02) compared to volunteers who consumed an LSFD for the same period.
   Clin Nutr, 2021 · checked 2026-09-28
7. nop-daily-r5-02 · meta-analysis of RCTs
   Adverse events included gastric intolerance and flu symptoms.
   Nutrition, 2015 · checked 2026-09-28
8. nop-daily-r5-04 · randomized controlled trial
   More patients receiving 20 g/day nopal fiber (67%) had a > 50% reduction in IBS-SSS compared to placebo (20%, p = 0.027), whereas the 30 g/day dose induced more loose stools (p = 0.027).
   Neurogastroenterol Motil, 2021 · checked 2026-09-28
9. nop-daily-r5-09 · randomized controlled trial
   There were no between-group differences found with the OGTT time points, area under the curve, blood chemistry variables (insulin, hsCRP, adiponectin, proinsulin, Hb1Ac), diet analysis variables (carbohydrates, fat, protein and total kcals), body composition variables (fat mass, fat free mass, percent body fat and total body weight), or blood chemistry safety parameters (comprehensive metabolic panel) pre-to-post 16-week intervention.
   J Ethnopharmacol, 2010 · checked 2026-09-28
10. nop-daily-r5-01 · meta-analysis of RCTs
    Meta-analysis revealed a nonsignificant difference in body weight between OFI and controls (mean difference = -0.83 kg; 95% confidence interval, -2.49 to 0.83; I(2) = 93%).
    Nutrition, 2015 · checked 2026-09-28
11. nop-daily-r5-08 · controlled clinical trial
    These results indicate that advanced maturation NP does not have influence in bone health, BMI, and body composition in adult women.
    J Med Food, 2020 · checked 2026-09-28
12. nop-daily-r5-10 · randomized controlled trial
    The mean body weight change from baseline was 3.8 ± 1.8 kg in IQ vs. 1.4 ± 2.6 kg in placebo (P < 0.001).
    Obesity (Silver Spring), 2013 · checked 2026-09-28
13. nop-daily-r5-12 · regulatory decision
    POL-HC-6279 NeOpuntia®, containing dehydrated leaves of the prickly pear cactus (Opuntia ficus-indica) NeOpuntia® helps to improve blood lipid parameters associated with cardiovascular risks, especially the HDL-cholesterol. -/- Non-authorised
    EU Register on nutrition and health claims, claim POL-HC-6279, snapshot 2026-09-21 · checked 2026-09-28
14. nop-daily-r5-03 · randomized controlled trial
    Significantly more patients reported adequate relief of symptoms after 20 g/day (87%, p = 0.008) and 30 g/day (80%, p = 0.025) of nopal fiber compared to placebo (33%).
    Neurogastroenterol Motil, 2021 · checked 2026-09-28
15. nop-daily-r5-06 · controlled clinical trial
    For those patients with type 2 diabetes who consumed the HCB+nopal, there was significantly lower area under the curve for glucose (287±30) than for those who consumed the HCB only (443±49), and lower incremental area under the curve for insulin (5,952±833 vs 7,313±1,090)
    J Acad Nutr Diet, 2014 · checked 2026-09-28
16. nop-daily-r5-16 · systematic review
    Separately, the effect of CLD consumption on lipids was small with one study reporting a significant increase in plasma HDL-C in a subgroup of participants (>45 years of age) following consumption of a patented CLD powder product.
    Complement Ther Med, 2020 · checked 2026-09-28