Cashew

Other Names

acaiuacajaibaacajouacajuAcajuba occidentalisacajuibaalcayoibaanacardeanacardierAnacardium curatellifoliumAnacardium kuhlmannianumAnacardium microcarpumAnacardium occidentaleAnacardium occidentale var. americanumAnacardium occidentale var. gardneriAnacardium occidentale var. indicumAnacardium othonianumAnacardium rondonianumAnacardium subcordatumanacardoandiparippuateaabibocaajucacajuilcadjoucadjúcajjubicajoucajucajueirocajuícajuilcashew applecashew nutcashew treecashewnutcashocashuCassuvium pomiferumCassuvium reniformeCassuvium solitariumdaf durubadarakasedarkasoufisangajusgeru beejageru hannugoankugodambihijli badamikashujambujambu golokjambu medejambu metejambu monyetjambu terongjeedi pandujeedipappujibaranijocote maranonkacang medekacang metekadinniakajukandjukanjukashukashuvandiparippukasu mangakatchákazukazuwakoroshokushukusuilanka ambamabibomahabibomamuang himmalphanmani ya mbibomarañónmaranonmbibombibumbotzamerehmereymerlimkanjumkoroshomoyimsololikokomukejhumundhiri paruppumundiri pazhamngolosonkasunkazuwankolosonoix d'acajounuez de caobapajuilparangi andipomme cajoupomme de cajoupommier cajousal de venadosashuvoambarikayag guoyovotchan

Synopsis

Cashew (Anacardium occidentale L.): A Comprehensive Reference

1. Identity, Botanical Classification, and Common Forms

1.1 Botanical and Scientific Identity

The cashew tree, scientifically known as Anacardium occidentale L., is a tropical and subtropical evergreen tree belonging to the family Anacardiaceae. Native to northeastern Brazil, this species has gained global recognition for its valuable edible seeds, commonly called cashew nuts, and its unique accessory fruit, the cashew apple. The genus name Anacardium is derived from the Greek words for "similar to the heart" (ana = similar, kardia = heart), referencing the shape of the nut; the species epithet occidentale means "western," reflecting its New World origin. Common synonyms and regional names include cajueiro (Portuguese/Brazilian), anacardo (Spanish), and marañón (Central America). The kernel is botanically a seed rather than a true nut, and it grows attached to the base of the cashew apple, which is itself an enlarged, fleshy peduncle and is therefore termed a pseudofruit or "false fruit."

1.2 Plant Morphology and the Cashew "Nut"

The cashew is a cross-pollinating plant whose fruit consists of two parts: the nut, which is the true fruit in the botanical sense, and the apple. The tree is irregularly a shrub with resin canals. The very young cashew apple is green or purple, and later turns green. When ripe, the apple becomes red or yellow, or a mixture of both. The kidney-shaped kernel is enclosed within a double shell from which the highly caustic cashew nut shell liquid (CNSL) must be removed before the kernel is safe for consumption.

1.3 Common Commercial and Supplement Forms

Raw or roasted whole kernels: The most common food form. Because raw cashews sold commercially have already been steam-processed to remove CNSL, they are not strictly "raw" in the absolute sense.
Cashew nut butter and cashew milk: Processed food/beverage products used widely as dairy alternatives. Cashews are also part of many dairy alternatives, such as cashew milk, cashew-based cheeses, and cashew cream.
Cashew nut oil: Extracted from the kernel (distinct from CNSL), used in culinary and research contexts.
Cashew nut shell liquid (CNSL): CNSL is a product of little commercial value but with high technological potential due to its phenolic constitution and its various biological properties. CNSL obtained by maceration with hexane at room temperature is composed of a mixture of anacardic acid, cardol, and cardanol.
Leaf, bark, and root extracts: Used in traditional medicine and studied in pharmacological research, primarily as ethanolic or aqueous extracts.
Cashew gum: Cashew gum, among other products (fruit, accessory fruit peel, and leaf powder, fruit rind, fruit shell, leaves, stem bark, cashew apple juice), has been used traditionally as a source of food and medicine.

2. Traditional and Historical Use

2.1 Pre-Columbian and Indigenous American Use

Cashews originate from Brazil, where indigenous people were the first to discover and use them. They recognized the cashew's value, benefiting from the nut, the juicy cashew apple, and even the bark and leaves for various purposes. The nuts were not only a food source but also had medicinal uses in their cultures. Among the Anacardium plants, Anacardium occidentale leaf extract is traditionally used in treating various diseases in tropical America, especially in north-eastern Brazil.

A wine prepared using the cashew fruits was used for treating dysentery in different regions of the Amazon rainforest. The juice of the fruit as well as an herbal tea prepared with the bark are both widespread medications for treating diarrhea throughout the Amazon region. This remedy is used by the local people as well as curanderos (folk healers) alike. In the present-day herbal medicine of Peru, cashew leaf tea (known as casho) is used as a common remedy for diarrhea.

2.2 Brazilian Traditional Medicine

In Brazil, the leaves and bark of the cashew tree are used to treat psoriasis, eczema, dyspepsia, scrofula, venereal ailments, and genital problems. People in Brazil also use herbal formulations prepared with the leaves and bark to cure bronchitis, intestinal colic, cough, impotence, leishmaniasis, as well as skin problems associated with syphilis. In the herbal medicine of Brazil, the cashew fruit is taken internally to treat syphilis and also in the form of a diuretic, an energizer, and aphrodisiac.

2.3 West African and Nigerian Traditional Use

Cashew plants have been used for centuries as folk medicine in South America and West Africa. Quite a number of biological properties have been reported, among them antimicrobial, antioxidant, antiulcerogenic, and anti-inflammatory effects have drawn public attention. In Nigeria, these species have also been used to treat cardiovascular disorders. Different portions of A. occidentale (stem, leaves, fruits, and flowers) have elucidated diverse ethnopharmacological applications. It is common in popular medicine to treat diabetes, infections, as well as hemorrhage and diarrhea.

2.4 European Introduction and Global Spread

Portuguese explorers arrived in Brazil during the 16th century and quickly took note of the cashew tree's unique fruit. Fascinated by its unusual growing pattern — where the nut forms outside the fleshy fruit — and its culinary potential, Portuguese traders began spreading cashew trees to their colonies across the globe. By the late 1500s, cashew trees had been introduced to India and parts of East Africa, where they quickly adapted to the tropical climates. It was in these regions, especially the Indian state of Goa, that commercial cashew cultivation took root. Anacardium occidentale L. is used throughout the world to treat type 2 diabetes.

Anacardium occidentale L. (family Anacardiaceae), normally notorious as the cashew tree, is a widely distributed local Brazilian species. Currently, it is registered in the National Program of Medicinal Plants and Herbal Medicine of Italy's unique health system for therapeutic purposes.

3. Key Constituents and Active Compounds

3.1 Macronutrient Profile of the Kernel

The total dietary fiber, sugar, protein, lipid profile, sodium, and energy contents of 11 raw cashew kernel (Anacardium occidentale L.) samples from India, Brazil, Ivory Coast, Kenya, Mozambique, and Vietnam were determined. Total fat was the major component accounting for 48.3% of the total weight, of which 79.7% were unsaturated fatty acids (FA), 20.1% saturated FA, and 0.2% trans FA. Proteins, with 21.3 g/100 g, were ranked second followed by carbohydrates (20.5 g/100 g). The mean energy content was 2525 kJ/100 g.

3.2 Fatty Acid Profile

Fourteen fatty acids were identified, among which oleic acid was the most abundant with a contribution of 60.7% to the total fat, followed by linoleic (17.77%), palmitic (10.2%), and stearic (8.93%) acids. Approximately one-third of the saturated fat in cashews is stearic acid, which is relatively neutral on blood lipids. Neutral lipid from the kernel contributed 96% of the total lipids, while the remaining 4% was contributed by glycolipid and phospholipid. Unsaturated fatty acids like oleic and linoleic acid were found in a higher majority in triglycerides, while saturated fatty acids like lauric and myristic were the dominant glycolipids.

3.3 Sterols, Amino Acids, and Vitamins

The sterol profile and content, amino acids, vitamins, and minerals of raw cashew kernel samples from Brazil, India, Ivory Coast, and Vietnam were determined. β-Sitosterol, with 2380 ± 4 mg/kg fat, was the most occurring sterol. Glutamic acid, with 4.60 g/100 g, was the amino acid with the highest presence, whereas tryptophan with 0.32 g/100 g was the one with the lowest presence. As for its nutritional composition, phenolic lipids, saturated and unsaturated FA, tocopherols, squalenes, and phytosterols, as well as bioactive compounds such as β-carotene, lutein, zeaxanthin, α-tocopherol, γ-tocopherol, thiamin, stearic acid, oleic acid, and linoleic acid were identified and determined in cashew nuts.

Cashews are also good in many essential vitamins such as pantothenic acid (vitamin B5), pyridoxine (vitamin B-6), riboflavin, and thiamin (vitamin B-1). 100 g of nuts provide 0.147 mg, or 32% of the daily recommended levels of pyridoxine.

3.4 Mineral Content

Cashew nuts are abundant sources of essential minerals. Manganese, potassium, copper, iron, magnesium, zinc, and selenium are especially concentrated in them. Copper is particularly notable: Cashews are an excellent source of the essential mineral copper. This important mineral has a crucial role in the immune system, iron metabolism, and gene expression. Furthermore, copper is thought to play a significant role in cardiovascular health. According to research, a copper deficiency increases the susceptibility of LDL to oxidation, and it may increase the overall risk for cardiovascular disease.

3.5 Cashew Nut Shell Liquid (CNSL) Phenolic Compounds

Among phenolic compounds present in solvent-extracted CNSL, anacardic acids are by far the most abundant (58–64% w/w), followed by cardols (20–22% w/w) and cardanols (2–10% w/w). CNSL contains anacardic acid (2-hydroxy-6-n-pentadecylbenzoic acid) and cardanol (3-n-pentadecylphenol).

Anacardic acids (AAs) are alkyl phenols from the cashew (Anacardium occidentale Linn.), a tropical tree native to the northeast region of Brazil. AAs are abundantly present in many parts of the cashew plant and have received attention as a potential antioxidant substance. Cashew apple, cashew nut (raw and roasted), and CNSL contain a range of different alkyl phenols, including AAs, cardanols, and cardols. Higher amounts of AAs have been detected in CNSL (353.6 g/kg) followed by cashew fiber (6.1 g/kg), while the lowest (0.65 g/kg) amounts were found in roasted cashew nut.

3.6 Tannins, Flavonoids, and Other Phenolics

Cashew bark and leaves have a rich amount of tannins. Cashew nut kernel testa contains tannin as an interesting economical source of antioxidants that can be used for both food and nutraceutical purposes. The species also contains a rich amount of flavonoids with diverse physiological effects. Cashew trees have been used in folk medicine worldwide, particularly in America and Africa. A number of bioactive metabolites — including phenolics, flavonoids, anthocyanins, and carotenoids — and biological properties such as antimicrobial, antioxidant, antidiabetic, anticancer, and anti-inflammatory activities were found in different parts of cashew trees.

The cashew fruit is rich in minerals, vitamins, and some essential nutrients. It has high vitamin C, nearly five times higher than oranges, and also a high mineral content. The fruit comprises some volatile compounds, including esters, terpenes, and carboxylic acids.

3.7 Cashew Bark Compounds

Methanol (80%) extract of the inner stem bark of A. occidentale was quantitatively evaluated for antinutrients and few heavy metals. Several compounds like tannins (5.75%), oxalates (2.50%), saponins (2%), phytate (0.25%), and cyanide (0.03%) were also recorded.

4. Mechanisms of Action

4.1 Antioxidant Mechanisms

The antioxidant capacity of anacardic acid is more related to the inhibition of superoxide generation and xanthine oxidase than the scavenging of hydroxyl radicals, and the C15-alkenyl side chain is largely associated with their activity. Cashew fruit and nuts have been evaluated by the hypoxanthine/xanthine oxidase test, and they demonstrated high antioxidant capacity with 100% inhibition obtained by the liquid extract of the nut and 94% inhibition by the fiber. The anacardic acids had the highest antioxidant activity when compared to cardol and cardanol.

4.2 Anti-Inflammatory Mechanisms

Anacardic acids from CNSL present a series of biological activities including antitumor, anti-acne, antibacterial, antifungal, molluscocidal, and ability to inhibit the enzymes tyrosinase, prostaglandin synthase, and lipoxygenase. Inhibition of prostaglandin synthase and lipoxygenase represents a mechanistic basis for observed anti-inflammatory properties. The antimicrobial activity has been traced to the phenolic hydroxyl group: free anacardic acids maintain the in vitro antibacterial activity of the CNSL in the strains evaluated, and the phenolic hydroxyl is considered important for activity.

4.3 Glucose Transport / Antidiabetic Mechanism

Products of the cashew tree are used in traditional medicine for various ailments, including diabetes. The anti-diabetic properties of cashew plant parts were studied using differentiated C2C12 myoblasts (myotubes) and rat liver mitochondria. Hydroethanolic extract of cashew seed (CSE) and its active component, anacardic acid (AA), stimulated glucose transport into C2C12 myotubes in a concentration-dependent manner. Extracts of other parts (leaves, bark, and apple) of the cashew plant were inactive. A significant synergistic effect on glucose uptake with insulin was noticed at 100 μg/mL CSE. This evidence is limited to in vitro research and does not directly translate to clinical use.

4.4 Lipid-Modulating Mechanisms

Cashews are the third most-consumed tree nut in the United States and are abundant with monounsaturated fatty acids and polyunsaturated fatty acids, which are associated with reduced cardiovascular disease risk. Although a qualified FDA health claim exists for nuts and heart health, cashews have been exempt from its use because cashews exceed the disqualifying amount of saturated fatty acids. Approximately one-third of the saturated fat in cashews is stearic acid, which is relatively neutral on blood lipids, thereby suggesting that cashews could have effects that are similar to those of other nuts.

5. Scientific Evidence by Area of Health Application

5.1 Cardiovascular Risk Factors: Lipid Profile

Human clinical evidence (moderate quality). A 2017 randomized crossover, controlled-feeding trial (registered at ClinicalTrials.gov as NCT02769741) investigated the effect of daily cashew consumption in adults with or at risk of high LDL cholesterol. Results from this study provide support that the daily consumption of cashews, when substituted for a high-carbohydrate snack, may be a simple dietary strategy to help manage total cholesterol and LDL cholesterol.

A 2024 Brazilian randomized controlled three-arm trial (the "Brazilian Nuts Study") enrolled 68 adults with overweight/obesity. The eight-week randomized controlled-feeding study involved 68 adults with overweight/obesity (40 women, BMI: 33 ± 4 kg/m²). Participants were randomly assigned to one of the energy-restricted (−500 kcal/d) groups: control (CT, free-nuts), cashew nut (CN, 30 g/d), or cashew nut oil (OL, 30 mL/d). The CN group reduced liver enzymes (AST: −3.1 ± 5.3 U/L; ALT: −6.0 ± 9.9 U/L), while the OL group reduced LDL-c (−11.5 ± 21.8 mg/dL) and atherogenic index (−0.2 ± 0.5). Both intervention groups decreased neck circumference and apo B (CN: −6.6 ± 10.7 mg/dL; OL: −7.0 ± 15.3 mg/dL).

A 2020 systematic review and meta-analysis searched multiple databases (PubMed, Embase, Scopus, Web of Science, and Cochrane Library) to investigate the efficacy of cashew nut consumption on lipid profile and blood pressure, identifying randomized control trials (RCTs) examining effects on TG, HDL-C, LDL-C, TC, SBP, and DBP. The meta-analysis found that with mixed model regression analysis, no significant changes in mean weight, BMI, waist circumference, percent body fat, or glycaemic parameters, and non-significant reductions in plasma total cholesterol of 2.1% (−4.3 mg/dL; 95% CI −14.8, 6.1) and LDL-C of 4% (−4.7 mg/dL; 95% CI −14.3, 4.8) were observed. These reductions did not reach statistical significance, indicating that overall the evidence for cashew-specific LDL lowering remains inconclusive in pooled RCT data. Although there are more than 4 g of saturated fat per 50 g of cashew, it should be borne in mind that about 40–50% of the saturated fats in cashew are as stearic acid, which has no effect on plasma LDL-C concentrations.

5.2 Cardiovascular Risk Factors: Blood Pressure

Human clinical evidence (moderate quality). A 12-week parallel-arm RCT was conducted at the Madras Diabetes Research Foundation (India) involving 300 adults with type 2 diabetes (T2DM). In the parallel-arm randomized controlled trial, 300 adults with T2DM (mean ± SD age: 51 ± 9.3 y; BMI: 26.0 ± 3.4; 55% male) were randomly assigned to receive advice to follow a standard diabetic diet (control) or similar advice plus 30 g cashew nuts/d (intervention) for 12 weeks. Cashew nut supplementation in Asian Indians with T2DM reduced systolic blood pressure and increased HDL cholesterol concentrations with no deleterious effects on body weight, glycemia, or other lipid variables. This is a notable finding, though it applies specifically to a South Asian diabetic population and may not generalize broadly.

5.3 Glycemic Control and Type 2 Diabetes

Human clinical evidence (mixed, largely null for glucose endpoints). A 2020 PMC systematic review and meta-analysis of RCTs on nuts and glycemic control found that overall, there was no effect of nut consumption on fasting glucose (WMD: −0.52 mg/dL; 95% CI: −1.43, 0.38 mg/dL; I² = 53.4%). Sensitivity analysis showed that this result remained after individual removal of each study. On a nut-specific basis, for fasting glucose, the type of nut provided modified the main effect such that pistachios reduced fasting glucose, whereas almonds, cashews, peanuts, walnuts, and mixed nuts had no effect. However, for insulin sensitivity: consumption of peanuts or tree nuts significantly decreased HOMA-IR and fasting insulin; there was no effect of nut consumption on HbA1c or fasting glucose. The results suggest that nut consumption may improve insulin sensitivity.

A 2021 meta-analysis focused specifically on cashew nuts reviewed six clinical trials with 521 participants on body composition and glycemic indices. Combined effect sizes demonstrated no effect of cashew consumption on weight (WMD: 0.02, 95% CI: −1.04, 1.09, P > 0.05), BMI (WMD: 0.1, 95% CI: −0.72, 0.74, P > 0.05), and waist circumference (WMD: −0.13, 95% CI: −1.97, 1.70, P > 0.05). The authors noted that additional investigation with higher doses of cashew and longer trial duration will be needed.

In a separate 8-week RCT, 40 women were randomized to an energy-restricted diet without nuts or to an energy-restricted diet containing 45 g/d of nuts (15 g of Brazil nuts + 30 g of cashew nuts), which showed no significant differences in markers of glycemic status. The totality of current RCT data indicates that cashew nuts do not adversely affect blood glucose and may support modest improvements in insulin sensitivity, but no clinically meaningful independent effect on fasting glucose or HbA1c has been demonstrated.

5.4 Body Composition and Weight Management

Human clinical evidence (null effect on weight). The 2021 meta-analysis of six cashew-specific RCTs with 521 participants confirmed that cashew consumption combined effect sizes demonstrated no effect of cashew consumption on weight, BMI, or waist circumference. This is consistent with broader nut research: trials and cohort studies have shown that diets enriched with nuts do not increase body weight, BMI, or waist circumference, with a tendency to a slight reduction in all of these. One mixed-nut RCT incorporating cashews found that the eating of 45 g/d of mixed nuts (30 g of cashew + 15 g of Brazil nuts) plus energy restriction (–500 kcal/d) during 8 weeks decreased fat mass and VCAM-1 and, in parallel, increased lean mass, fat-free mass, muscle mass, truncal lean mass, and truncal fat-free mass, and selenium, compared to the control group in adult women with overweight and cardiometabolic risk. However, no differences were observed between groups for markers of lipid and glucose metabolism.

5.5 Copper and Zinc Mineral Status

Human clinical evidence (preliminary, single RCT). A recent RCT investigated the effect of cashew consumption on copper and zinc biomarkers in adolescents with obesity. The cashew nut group received 30 g/day of roasted cashew nuts for 12 weeks, and both groups received nutritional counseling. Anthropometric, dietary, and biochemical parameters (Zn, Cu, and superoxide dismutase [SOD]) were assessed at baseline and at the end of the study. The consumption of cashew nuts reduced plasma Cu levels in adolescents with obesity. On the other hand, nutritional guidance activities may influence increased plasma Zn levels and reduced Cu/Zn ratios in adolescents with obesity. The authors concluded that the consumption of cashew nuts, in combination with a healthy diet, may help regulate essential metals for antioxidant control and anti-inflammatory responses in obese individuals, though they acknowledged the need for further mechanistic study.

5.6 Anti-Inflammatory and Antioxidant Effects

Preclinical animal evidence (no completed human RCTs specifically on inflammation endpoints). A murine model of colitis demonstrated anti-inflammatory and antioxidant effects of orally administered cashew nuts. Anacardium occidentale L. is a tropical plant used for the treatment of inflammatory diseases. The goal of the present work was to investigate the anti-inflammatory and anti-oxidant potential of oral administration of cashew nuts in a mouse model of colitis. Induction of colitis was performed by intrarenal injection of dinitrobenzene sulfonic acid (DNBS). Cashew nuts were administered daily orally at 100 mg/kg in DNBS-injected mice. Positive outcomes were observed in histological markers of inflammation, but this remains preclinical animal evidence.

Regarding CNSL-derived anacardic acids specifically, animal research showed that anacardic acids from cashew nut shell liquid have antimicrobial and antioxidant activities and modulate immune responses and angiogenesis. As inflammatory lung diseases have been correlated to environmental pollutant exposure and no reports addressing the effects of dietary supplementation with anacardic acids on lung inflammation in vivo had been evidenced, researchers investigated the effects of supplementation with anacardic acids in a model of diesel exhaust particle-induced lung inflammation. This is preclinical research only. No human clinical trials have tested isolated anacardic acids for anti-inflammatory endpoints.

5.7 Antimicrobial Activity

In vitro evidence only. Anacardic acid, cardanol, and cardol, the main constituents of natural CNSL, were obtained by solvent extraction and assayed for antioxidant, larvicidal, and antiacetylcholinesterase activity. The antibacterial activity against the standard strains of Escherichia coli and Staphylococcus aureus were also observed, which were sensitive at concentrations equal to and greater than 78,125 ppm for CNSL and for the mixture of anacardic acids. These results are from cell culture and broth dilution assays and have not been validated in human infection trials.

5.8 Antidiabetic Properties of Bark and Leaf Extracts

Preclinical and in vitro evidence. Among the samples tested, the ethyl acetate fraction of cashew leaf extract exhibited the highest enzyme inhibition activity against α-amylase and α-glucosidase (IC50 values of 51.24 μg/mL and 99.29 μg/mL, respectively), cytotoxicity activity against HeLa cells (IC50 value of 79.49 μg/mL), and antibacterial activity. Inhibition of α-glucosidase is a recognized antidiabetic mechanism (the same target as the pharmaceutical acarbose), but this evidence is in vitro only. No human RCTs have assessed cashew leaf or bark extracts for antidiabetic endpoints.

6. Body Systems and Health Domains Associated with Cashew

Cardiovascular system: Lipid profile modulation (total and LDL cholesterol, apolipoprotein B), blood pressure, HDL cholesterol improvement in T2DM populations.
Metabolic/endocrine system: Insulin sensitivity, glucose homeostasis, glycemic index interactions.
Gastrointestinal system: Traditional antidiarrheal and antiulcer use of bark, gum, and leaf preparations; preclinical anti-colitis activity.
Immune and inflammatory pathways: Antioxidant activity of phenolic compounds (anacardic acid, cardol, cardanol); anti-inflammatory activity demonstrated in preclinical models.
Skeletal and muscular system: Magnesium, phosphorus, and calcium content relevant to bone health; preserving lean mass during energy restriction in mixed-nut studies.
Micronutrient homeostasis: Delivery of copper, zinc, magnesium, iron, and B vitamins; RCT evidence for effects on copper/zinc balance in adolescent obesity.
Skin and mucous membranes (external/traditional use): Bark and leaf preparations used traditionally for skin infections, psoriasis, eczema; anacardic acid has been proposed for skin care applications.

7. Dosage Forms and Doses Reported in Clinical Studies

The following dosages are those specifically reported in the cited clinical research and are not recommendations:

30 g cashew nuts/day for 12 weeks in a parallel-arm RCT of 300 adults with T2DM (Madras Diabetes Research Foundation), resulting in reduced systolic blood pressure and increased HDL cholesterol.
30 g/day of cashew nut or 30 mL/day of cashew nut oil for 8 weeks in a three-arm RCT involving 68 overweight/obese adults under energy restriction (−500 kcal/d) — the Brazilian Nuts Study.
45 g/day of mixed nuts (15 g Brazil nuts + 30 g cashew nuts) for 8 weeks in an RCT of 40 women on an energy-restricted diet.
30 g/day of roasted cashew nuts for 12 weeks in an RCT assessing copper and zinc status in adolescents with obesity.
100 mg/kg orally in mice in a preclinical mouse colitis model — not a human dose.
In most human RCTs reviewed in the 2021 meta-analysis, six clinical trials with 521 participants were included, spanning a range of cashew dosages and study durations, with no single standardized human dose established.

8. Safety Considerations and Notable Interactions

8.1 CNSL and Contact Dermatitis Hazard

CNSL contains anacardic acid/urushiol-like compounds; contact can burn skin, and incompletely processed cashews have historically triggered reactions, especially in people sensitive to poison ivy/oak (Anacardiaceae cross-reactivity). Cashew proteins (e.g., Ana o 2, Ana o 3) are potent allergens; heat can alter solubility/IgE binding but does not make cashews non-allergenic. Cashew trees are part of the Anacardiaceae family, which includes mango, poison ivy, sumac, pistachio, and Peruvian pepper. These plants all contain urushiol, an oil that is a potent skin irritant. Not only does the cashew nut shell oil contain urushiol, it includes a number of other harmful components, including anacardic acid, cardol, and cardanol.

Anacardic acid-induced contact dermatitis produces hyperpigmented skin lesions. Anacardic acid is closely related to urushiol, which causes contact dermatitis. Industrial-scale CNSL poisoning, while uncommon, has produced documented cases of toxic hepatitis and coagulation abnormalities: bilirubin levels and liver enzymes were mildly elevated; the toxic hepatitis resolved by day 3. Elevated prothrombin and partial thromboplastin time were also documented, potentially due to the inhibitory action of anacardic acid on clotting factors.

8.2 IgE-Mediated Food Allergy

Cashew-allergic patients most frequently show skin symptoms, followed by respiratory and gastro-intestinal symptoms. Studies have shown that a small amount of cashew nut allergen may cause severe clinical reactions, suggesting a high potency of this nut, comparable to that of other tree nuts and peanuts. One study published in the journal Allergy suggests that cashew nut allergies may be on the rise and that allergic reactions to cashews can be more severe than reactions to other tree nuts and peanuts.

8.3 Cross-Reactivity within Anacardiaceae

Allergic sensitisation towards cashew nut often happens without a clear history of eating cashew nut. IgE cross-reactivity between cashew and pistachio nut is well described. In a paediatric cohort study (n = 56): from the 56 subjects analysed, 36 were positive on dot blot for cashew nut (63%). Of these, 50% were mono-sensitised to cashew nuts, 19% were co-sensitised to Anacardiaceae species, and 31% were co-sensitised to tree nuts. Results demonstrate the in vitro presence of IgE cross-sensitisation in children towards multiple Anacardiaceae species. Putative novel allergens were identified in cashew, pistachio, and pink peppercorn, which may pose factors that underlie the observed cross-sensitivity to these species. The clinical relevance of this widespread cross-sensitisation is unknown.

The common allergen found in all these plants is urushiol, and hence there can be cross-reactivity with all the plants. In the case of the cashew, the apple has a higher concentration of urushiol than the nut. Hence, it has a greater likelihood of leading to allergic problems. These can occur via contact with the skin, resulting in the typical poison ivy-type rash of itchy bumps and blisters. Ingestion can cause irritation of the lips, tongue, mouth, and GI tract. Of special interest is that ingestion of cashew nut or cashew apple can lead to reappearance of a previously healed case of poison ivy/oak.

8.4 Aflatoxin Risk

As with other tree nuts, aflatoxins are a supply-chain risk managed via testing and limits (EFSA notes public-health assessments and maximum levels for nuts including cashews).

8.5 Saturated Fat and FDA Classification

Cashews are abundant with monounsaturated and polyunsaturated fatty acids, which are associated with reduced cardiovascular disease risk. Although a qualified FDA health claim exists for nuts and heart health, cashews have been exempt from its use because cashews exceed the disqualifying amount of saturated fatty acids. The mitigating factor is the predominantly stearic nature of the saturated fraction, which is metabolically distinct from lauric or myristic acid in its LDL effects.

8.6 General Population Safety Profile

Allergy and related adverse reactions to nuts were observed in 1–2% of adult populations, with substantial heterogeneity between studies. Overall, the current evidence supports dietary recommendations to consume a handful of nuts and seeds per day for people without allergies to these foods. In all published RCTs involving 30 g/day of cashew nuts consumed over 8–12 weeks, no serious adverse events attributable to the nuts were reported, and no deleterious effects on body weight or glycemia were observed.

References

Health Conditions

Health conditions that Cashew may help support.

No conditions available.

Body Systems

Body systems that Cashew may help support.

No body systems available.