Cashew nuts: the heart claim that was refused, and a calorie count that is too high

Cashews are sold as a heart food. The strongest evidence here says nothing so encouraging. Across the three randomised trials of cashew supplementation that could be pooled, LDL cholesterol moved by a standardised mean difference of -0.18. The confidence interval ran from -0.75 to 0.39, wide enough to hide a real effect in either direction, and only three of the six trials in that review could be pooled at all. Total cholesterol behaved the same way, at -0.02 (95% CI -0.32 to 0.28). A controlled feeding trial makes the point in plainer terms. Forty-two weight-stable adults ate 42 g of cashews a day for four weeks on a fully controlled diet, and none of the primary cardiovascular risk factors moved, neither blood lipids nor blood pressure. The number worth carrying away is about energy instead. In 18 healthy adults on controlled diets, with faeces and urine collected in full, a 28 g serving delivered 137 kcal on average. That is 16 percent below the figure printed on labels (p < 0.0001), measured in one nut and one small group of people.

The numbers, per 100 g

How much is actually in it

• In the cashews used for the USDA feeding trial, fat supplied 29.8% of energy, carbohydrate 21.5% and protein 11.4%. — a laboratory sample of roasted cashews, no human participants Evidence D source
  Fat 29.8% of energy, carbohydrate 21.5%, protein 11.4%, total sterols 77.5 mg/100 g

What your body absorbs

• A 28 g serving of cashews delivers 137 kcal on average, which is 16% less than the figure printed on food labels. — 18 healthy adults, 9 men and 9 women, mean age 56.9 years, 4-week feeding phases (n = 18) Evidence B source
  137 kcal per 28 g serving (SEM 3.4, range 105 to 151), 16% below the Atwater-derived label value, p < 0.0001
• Adding cashews to a controlled diet lowered fat digestibility from 97.8% to 96.1% and energy digestibility from 94.9% to 92.9%. — 18 healthy adults on fully controlled diets, one week of complete faecal and urine collection per phase (n = 18) Evidence B source
  Energy 92.9% vs 94.9% (p < 0.0001); fat 96.1% vs 97.8% (p = 0.0009); protein 90.1% vs 91.2% (p = 0.0012)

What cooking and storage change

• Roasting does not disarm the cashew allergen: the seed storage proteins that cause cashew reactions stay heat stable across thermal processing methods. — 32 articles on processed tree nuts, mostly in vitro work on isolated proteins (n = 32 studies) Evidence D source
  Heat stability of nsLTPs and seed storage proteins reported across processing methods, in contrast to PR-10 proteins in hazelnut and almond

What it does to your health

• Pooled across three randomised trials of cashew supplementation, LDL cholesterol moved by a standardised mean difference of -0.18 (95% CI -0.75 to 0.39), which includes no effect. — 531 adults in six randomised trials, three of them pooled (n = 531) Evidence A source
  SMD -0.02 (95% CI -0.32, 0.28) total cholesterol; -0.18 (95% CI -0.75, 0.39) LDL
• Feeding 42 g of cashews a day for 4 weeks under full dietary control changed none of the primary cardiovascular risk factors in 42 weight-stable adults. — 42 adults, randomised crossover controlled feeding, two 4-week phases (n = 42) Evidence B source
  No significant change in blood lipids, blood pressure, augmentation index, glucose, endothelin, adhesion molecules or clotting factors; PCSK9 fell with no change in LDL
• In 142 adolescents with obesity, 30 g of roasted cashews daily for 12 weeks reduced waist circumference, lipid peroxidation and total antioxidant capacity, while neck circumference rose. — 142 adolescents with obesity, 77 in the cashew group and 65 in the control group, 12 weeks (n = 142) Evidence B source
  Decreases in waist circumference, thiobarbituric acid reactive substances and total antioxidant capacity at 60 minutes in the cashew group; neck circumference increased
• A drink holding 30 g of cashews and 15 g of Brazil nuts raised postprandial fat oxidation to 47.53 mg/min against 27.93 mg/min for the control drink. — adult women with overweight or obesity at cardiometabolic risk, acute phase measured over 3 hours (n = not stated in the abstract) Evidence B source
  Postprandial fat oxidation piAUC 47.53 (SD 5.78) vs 27.93 (SD 6.98) mg/min, p = 0.048; after 8 weeks no significant between-group difference

Safety, limits and interactions

• Among children allergic to cashew, 5% react with objective symptoms to as little as 7.4 mg of cashew protein. — 31 children with a positive double-blind placebo-controlled food challenge to cashew nut, out of a clinical database of children tested for food allergy (n = 31) Evidence C source
  Eliciting dose for 5% of the allergic population 7.4 mg cashew protein for objective symptoms; thresholds for any symptom 2 to 6 times lower
• A year of eating 3 to 4 ounces of cashews daily preceded oxalate nephropathy, confirmed on kidney biopsy, in a 78-year-old man whose creatinine rose from 2.05 to 6.0 mg/dL. — one 78-year-old man with stable chronic kidney disease (n = 1) Evidence D source
  Serum creatinine 6.0 mg/dL against a baseline of 2.05 mg/dL, with extensive calcium oxalate crystal deposition on biopsy
• In a low-dose oral immunotherapy programme covering 46 cashew-allergic toddlers among 189 treated allergies, 95.3% of dosing reactions were mild and one reaction in the whole cohort needed epinephrine. — 124 children aged 9 to 24 months treated for 189 food allergies, cashew nut being the second most common allergen at 46 cases (n = 124) Evidence C source
  Allergic dosing reactions in 89 children and 117 treatment courses; 95.3% Sampson grade I to II; 10 severe reactions, 1 requiring epinephrine

What people believe that the data does not support

• The European claim that 30 g of nuts a day helps maintain heart health was refused, and its wording excludes cashews from the nuts it covers in the first place. — regulatory decision, not a study population Evidence E source
  —

Who this works differently for

• Thirty grams of roasted cashews a day for 12 weeks lowered plasma copper (p = 0.004) and raised superoxide dismutase (p = 0.030) in adolescents with obesity. — 81 adolescents aged 10 to 14 with obesity who completed the trial, 54 in the cashew group and 27 in the control group, Fortaleza, Brazil (n = 81) Evidence B source
  Decrease in plasma copper (p = 0.004) and increase in superoxide dismutase (p = 0.030) in the cashew group; the between-group difference for copper was significant (p = 0.004)
• Among Japanese preschoolers with food allergy who had never eaten tree nuts, sensitisation to the cashew allergen Ana o 3 peaked at 12.2% in the 5 to 6 year group. — 248 preschool children under 7 with diagnosed food allergies and no prior tree nut consumption, four hospitals in Chiba Prefecture (n = 248) Evidence C source
  Ana o 3 sensitisation 12.2% at ages 5 to 6; Jug r 1 sensitisation 34.0% at ages 3 to 4

The bottom line

Eat cashews because you like them and they travel well. The European claim that 30 g of nuts a day helps maintain heart health was refused, and its wording names the nuts it covers and leaves cashews out of them, so the shelf promise never applied to this nut even on paper. In the same controlled trial that measured the calories, adding cashews to the diet pulled fat digestibility from 97.8 to 96.1 percent and energy digestibility from 94.9 to 92.9 percent, which is the whole diet being measured rather than the nut in isolation. Outside that one trial we did not find studies on how cashews are absorbed. Two Brazilian trials in adolescents with obesity are the closest thing to a positive result, and both are hard to read. In 142 adolescents, 30 g of roasted cashews a day for 12 weeks shrank waist circumference and lowered lipid peroxidation, while neck circumference went up and total antioxidant capacity fell. The abstract gives directions without effect sizes, and both arms also received nutrition education. In the companion trial, among the 81 adolescents who completed it out of 143 who started, plasma copper fell (p = 0.004) and superoxide dismutase rose (p = 0.030). A drink holding 30 g of cashews with 15 g of Brazil nuts raised postprandial fat oxidation to 47.53 mg/min against 27.93 for the control drink (p = 0.048) in women with overweight or obesity. The nuts were mixed, the abstract never says how many women took part, and after 8 weeks the difference between groups was gone. Allergy is the caution that carries real numbers. Among 31 children with a positive double-blind placebo-controlled challenge to cashew, 5 percent reacted with objective symptoms to 7.4 mg of cashew protein. Those were children already referred for challenge testing, so that distribution describes diagnosed allergy rather than children in general. Roasting does not help. A review of 32 articles, mostly in vitro work on isolated proteins, found the seed storage proteins behind cashew reactions stayed heat stable across thermal processing methods. A single-centre programme of low-dose oral immunotherapy treated 124 toddlers, with cashew the second most common allergen at 46 cases. Of the dosing reactions there, 95.3 percent were mild, and one reaction in the whole cohort needed epinephrine. That programme had no control group, and those were reactions to measured doses given inside a treatment programme rather than to cashew met by accident. Among 248 Japanese preschoolers who already had a diagnosed food allergy and had never eaten tree nuts, sensitisation to the cashew allergen Ana o 3 peaked at 12.2 percent in the 5 to 6 year group. Sensitisation is not the same as a clinical allergy. One 78-year-old man with stable chronic kidney disease ate 3 to 4 ounces of cashews daily for a year, and a biopsy found oxalate nephropathy with his creatinine at 6.0 mg/dL against a baseline of 2.05. A single case cannot say how often that happens or at what intake, and he had kidney disease before the nuts.

Sources

1. cshw-r3-05 · in vitro food composition analysis
   Fat content was 29.8% of energy, carbohydrate content was 21.5% of energy and protein content was 11.4% of energy.
   Nutrients, 2018 · checked 2026-09-24
2. cshw-r3-03 · randomised controlled trial
   The average available energy (calorie) content of a 28 g serving of cashew nuts was 137 kcal (±3.4 kcal SEM) and ranged from 105 to 151 kcal. The mean value of 137 kcal/serving is 16% lower (p < 0.0001) than what is typically found on food labels.
   Nutrients, 2018 · checked 2026-09-24
3. cshw-r3-04 · randomised controlled trial
   Digestibility of energy, fat, protein, and carbohydrate was lower for the cashew-containing diet compared to the control diet (92.9% vs. 94.9%, p < 0.0001 for energy; 96.1% vs. 97.8%, p = 0.0009 for fat; 90.1% vs. 91.2%, p = 0.0012 for protein; 92.9% vs. 94.9%, p < 0.0001 for carbohydrate; for the cashew-containing diet vs. the control diet, respectively).
   Nutrients, 2018 · checked 2026-09-24
4. cshw-r3-09 · systematic review of in vitro and clinical studies
   The majority of the in vitro studies investigating the allergenicity of nonspecific lipid transfer proteins (nsLTPs) and seed storage proteins in hazelnut, almond, cashew nut, Brazil nut, walnut, pecan nut and pistachio nut show heat stability towards different thermal processing methods.
   Allergy, 2013 · checked 2026-09-24
5. cshw-r3-01 · systematic review and meta-analysis of RCTs
   There were no significant changes for total cholesterol (TC) (standardized mean difference [SMD]: -0.02, 95% CI: -0.32, 0.28), triglycerides (TG) (SMD: -0.01, 95% CI: -0.22, 0.20), high-density lipoprotein (HDL) cholesterol (SMD: 0.09, 95% CI: -0.16, 0.34), or low-density lipoprotein (LDL) cholesterol (SMD: -0.18, 95% CI: -0.75, 0.39).
   Complement Med Res, 2020 · checked 2026-09-24
6. cshw-r3-02 · randomised controlled trial
   Consumption of 1.5 servings of cashew nuts/d, the amount associated with the FDA qualified health claim for tree nuts and cardiovascular disease, did not positively or adversely affect any of the primary risk factors for cardiovascular disease.
   Am J Clin Nutr, 2019 · checked 2026-09-24
7. cshw-r3-12 · randomised controlled trial
   The main post-intervention findings in the CNG showed decreases in waist circumference (WC), thiobarbituric acid reactive substances (TBARS) and total antioxidant capacity (TAC) at 60 minutes in the CNG, while neck circumference (NC) increased.
   Nutr Res, 2025 · checked 2026-09-24
8. cshw-r3-13 · randomised controlled trial
   In the postprandial period, fat oxidation was higher in the MNG than in the CTG (piAUC: 47.53 ± 5.78 mg/min vs. 27.93 ± 6.98 mg/min; p = 0.048).
   Nutr Metab Cardiovasc Dis, 2026 · checked 2026-09-24
9. cshw-r3-06 · retrospective cohort of food challenges
   The protein dose at which 5% of the allergic population is likely to respond with objective reactions was 1.6 mg for peanut, 1.1 mg for cow's milk, 1.5 mg for hen's egg, 7.4 mg for cashew nut, and 0.29 mg for hazelnut.
   J Allergy Clin Immunol, 2013 · checked 2026-09-24
10. cshw-r3-07 · case report
    He underwent a kidney biopsy, which showed acute tubular injury associated with extensive calcium oxalate crystal deposition. On revisiting his history, it was discovered that the patient had been consuming 3-4 oz of cashew nuts daily for the last 1 year.
    Kidney Med, 2026 · checked 2026-09-24
11. cshw-r3-08 · prospective clinical trial without randomisation
    Most reactions (95.3%) were mild (Sampson I-II) and resolved spontaneously (55.6%) or with antihistamines (29.9%). Ten reactions were severe (Sampson III-IV), of which one required epinephrine.
    Front Allergy, 2026 · checked 2026-09-24
12. cshw-r3-10 · regulatory register entry
    POL-HC-7666 Nuts - peanuts and tree nuts (almonds, hazelnuts, pecans, pistachios and walnuts), excluding brazil, macadamia and cashew nuts Eating 30g of nuts per day as part of a balanced diet helps maintain heart health. Non-authorised
    EU Register on nutrition and health claims, claim POL-HC-7666, snapshot 2026-09-21 · checked 2026-09-24
13. cshw-r3-11 · randomised controlled trial
    After the intervention, the CASN group presented a decrease in plasma Cu (p = 0.004) and an increase in SOD (p = 0.030).
    Nutrients, 2024 · checked 2026-09-24
14. cshw-r3-14 · prevalence study
    Jug r 1 sensitization peaked at 34.0% in the 3-4-year group, while Ana o 3 sensitization peaked at 12.2% in the 5-6-year group.
    Int Arch Allergy Immunol, 2025 · checked 2026-09-24