Skip to content
AlternativeMed

Other Nuts: Pecans, Cashews, Brazil Nuts and Macadamias

Pecans, cashews, Brazil nuts and macadamias as foods: what small trials found, why Brazil nuts need a selenium caution, and tree nut allergy and cross-reactivity.

Content last updated . This page has not been medically reviewed.

Safety first. Natural products can cause side effects and interact with medicines. Read functional food safety before you use anything on this page.

Plants and parts eaten

The edible part of each is the seed or kernel: pecan, Carya illinoinensis (Wangenh.) K.Koch, family Juglandaceae [6]; cashew, Anacardium occidentale L., Anacardiaceae [7]; Brazil nut, Bertholletia excelsa Bonpl., Lecythidaceae [8]; macadamia, Macadamia integrifolia Maiden & Betche and related species, Proteaceae. [9]

What small trials found

These are trials of whole nuts as food. They mostly measure blood tests, not heart attacks. The wider picture for nuts is on nuts and seeds for heart health.
NutWhat the source foundStrength of evidencePopulation and design
PecansAdults eating 68 g of pecans a day, added to or swapped into their diet, had lower fasting total cholesterol, LDL and triglycerides at 8 weeks, with no change in the control group. [10]Promising but limited56 adults at risk of heart disease; small randomized trial
CashewsOne feeding trial (51 adults, 28 to 64 g a day for 28 days, versus potato chips) found lower total and LDL cholesterol. [11] A later trial (42 adults, 42 g a day for 4 weeks) found no difference in blood lipids or blood pressure. [12] A 2020 review of trials (392 people) found no effect on lipids but about 3.4 mmHg lower systolic blood pressure. [13]MixedRandomized crossover trials; review
Brazil nutsIn a pilot trial, one Brazil nut a day for 6 months raised blood selenium in older adults with mild memory impairment, and some thinking tests improved versus control. [14]Promising but limited (very small; 20 finished)Biomarker and cognitive tests
MacadamiasIn 35 adults with abdominal obesity, about 15% of daily calories from macadamias for 8 weeks caused no significant change in weight or blood sugar and non-significant cholesterol reductions. [15]Insufficient evidenceRandomized crossover

Reading the details

  • Cashews and the FDA claim. In its July 2003 letter on nuts and coronary heart disease, the FDA said it did not intend to use enforcement discretion for a nut claim on Brazil nuts, macadamia nuts, cashew nuts and some pine nuts, because they exceeded the saturated-fat limit for health claims. [18] Two cashew trial reports repeat this exclusion. [11][12] The FDA's 2017 letter on macadamia nuts then allowed a qualified claim for macadamia anyway, about 1.5 ounces a day replacing other sources of saturated fat, and it states the saturated-fat limit as above 4.0 g per 50 g of nuts. [16] USDA's current table lists cashews at about 7.8 g saturated fat per 100 g, roughly 3.9 g per 50 g, which is just under that limit. [19] So the 2003 exclusion may rest on older figures; we did not find an FDA statement updating it for cashews, and we cannot say whether a cashew claim is allowed today.
  • Brazil nut selenium varies. A 2025 trial noted that Brazil nuts have "high variability" in selenium. [17] The pilot trial above estimated 288.75 micrograms a day from one nut a day, which is higher than the EFSA upper level, so do not treat that trial as advice. [14]
  • Which amounts to eat is for a clinician or dietitian. This page quotes amounts only from trials and official bodies.

Not covered

We did not read sources on mold toxins, heavy metals or choking in these nuts. Parents should see foods for babies and toddlers. For other nuts see walnuts, almonds and pistachios.

Frequently asked questions

How much Brazil nut is too much?

We cannot give a personal number because selenium content varies. EFSA set 255 micrograms a day as the adult upper level and named regular Brazil nut consumers as a group that may exceed it. [5][17] Ask a clinician.

What happens if you eat too much selenium?

MedlinePlus lists hair loss, nail problems, nausea, irritability, fatigue and mild nerve damage. [4]

If I am allergic to cashews, am I allergic to pistachios?

Not always, but a case series found cross-reactivity between the two. [3] Ask an allergy clinician.

Do pecans lower cholesterol?

One small 8-week trial found lower fasting cholesterol and triglycerides. [10] Larger trials on pecans were not found in what we read.

Are cashews good for the heart?

Results are mixed: one feeding trial found lower LDL, a later one found no change. [11][12]

More details: evidence, limits and cautions

The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.

Safety first: allergy and Brazil nut selenium
Allergy. Tree nuts include pecans, cashews and Brazil nuts. [1] MedlinePlus says allergies to peanuts, tree nuts and shellfish tend to last a lifetime. [2] In a small Japanese case series, a few pieces of cashew triggered severe anaphylaxis, and tests suggested cross-reactivity between cashew and pistachio. [3] Call 911 for trouble breathing or swelling of the lips, mouth or throat. See food allergy basics.

Selenium. Brazil nuts are a very good source of selenium, and too much selenium causes selenosis, with hair loss, nail problems, nausea and fatigue. [4] The European Food Safety Authority (EFSA, 2023) set an upper level of 255 micrograms a day for adults, including pregnant and lactating women, and said adult consumers are unlikely to exceed it except regular users of high-dose supplements or regular consumers of Brazil nuts. [5] Ask a clinician or pharmacist before eating Brazil nuts regularly, especially if you also take a selenium supplement. See selenium.

References
  1. NHS (UK). Food allergy. Read 2026-10-23.
  2. MedlinePlus. Food allergy. Read 2026-10-23.
  3. Clinical features of four cases with cashew nut allergy and cross-reactivity between cashew nut and pistachio. Allergol Int 2009. Read 2026-10-23 (abstract via Europe PMC).
  4. MedlinePlus. Selenium in diet. Read 2026-10-23.
  5. EFSA Panel on Nutrition, Novel Foods and Food Allergens. Scientific opinion on the tolerable upper intake level for selenium. EFSA Journal 2023;21:e07704. DOI 10.2903/j.efsa.2023.7704. Read 2026-10-23 (abstract via Europe PMC).
  6. GBIF Secretariat. Carya illinoinensis (Wangenh.) K.Koch, accepted name, family Juglandaceae. Read 2026-10-23 (GBIF species match API).
  7. GBIF Secretariat. Anacardium occidentale L., accepted name, family Anacardiaceae. Read 2026-10-23 (GBIF species match API).
  8. GBIF Secretariat. Bertholletia excelsa Bonpl., accepted name, family Lecythidaceae. Read 2026-10-23 (GBIF species match API).
  9. GBIF Secretariat. Macadamia integrifolia Maiden & Betche, accepted name, family Proteaceae. Read 2026-10-23 (GBIF species match API).
  10. Pecan-Enriched Diets Alter Cholesterol Profiles and Triglycerides in Adults at Risk for Cardiovascular Disease in a Randomized, Controlled Trial. J Nutr 2021. Read 2026-10-23 (abstract via Europe PMC).
  11. Cashew consumption reduces total and LDL cholesterol: a randomized, crossover, controlled-feeding trial. Am J Clin Nutr 2017. Read 2026-10-23 (abstract via Europe PMC).
  12. Consumption of cashew nuts does not influence blood lipids or other markers of cardiovascular disease in humans: a randomized controlled trial. Am J Clin Nutr 2019. Read 2026-10-23 (abstract via Europe PMC).
  13. The effects of cashew nut intake on lipid profile and blood pressure: A systematic review and meta-analysis of randomized controlled trials. Complement Ther Med 2020. Read 2026-10-23 (abstract via Europe PMC).
  14. Effects of Brazil nut consumption on selenium status and cognitive performance in older adults with mild cognitive impairment: a randomized controlled pilot trial. Eur J Nutr 2016. Read 2026-10-23 (abstract via Europe PMC).
  15. Macadamia nut effects on cardiometabolic risk factors: a randomised trial. J Nutr Sci 2023. Read 2026-10-23 (abstract via Europe PMC).
  16. U.S. Food and Drug Administration. Qualified Health Claims: Letters of Enforcement Discretion (list of claim titles and dates; the 2017 macadamia letter was read in full). Read 2026-10-23.
  17. Improving the selenium supply of vegans and omnivores with Brazil nut butter compared to a dietary supplement in a randomized controlled trial. Eur J Nutr 2025. Read 2026-10-23 (abstract via Europe PMC).
  18. U.S. Food and Drug Administration. Letter of enforcement discretion: Nuts and Coronary Heart Disease (qualified health claim), July 14, 2003 (archived copy). Read 2026-10-23.
  19. U.S. Department of Agriculture. FoodData Central: Nuts, cashew nuts, raw (SR Legacy, FDC 170162). Saturated fat 7.783 g per 100 g, from our USDA data file. Read 2026-10-23.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.