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. Supplements can cause side effects and interact with medicines. Read mushroom safety and interactions before you use any mushroom product.
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.| Nut | What the source found | Strength of evidence | Population and design |
|---|---|---|---|
| Pecans | Adults 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 limited | 56 adults at risk of heart disease; small randomized trial |
| Cashews | One 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] | Mixed | Randomized crossover trials; review |
| Brazil nuts | In 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 |
| Macadamias | In 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 evidence | Randomized crossover |
Reading the details
- Cashews and the FDA claim. Two trial reports state that cashews are excluded from the FDA's qualified health claim for tree nuts because of their saturated fat. [11][12] The FDA's list also has a separate 2017 entry titled "Macadamia Nuts and Reduced Risk of Coronary Heart Disease". We read the title only. [16]
- 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
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
- NHS (UK). Food allergy. Read 2026-10-23.
- MedlinePlus. Food allergy. Read 2026-10-23.
- 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).
- MedlinePlus. Selenium in diet. Read 2026-10-23.
- 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).
- GBIF Secretariat. Carya illinoinensis (Wangenh.) K.Koch, accepted name, family Juglandaceae. Read 2026-10-23 (GBIF species match API).
- GBIF Secretariat. Anacardium occidentale L., accepted name, family Anacardiaceae. Read 2026-10-23 (GBIF species match API).
- GBIF Secretariat. Bertholletia excelsa Bonpl., accepted name, family Lecythidaceae. Read 2026-10-23 (GBIF species match API).
- GBIF Secretariat. Macadamia integrifolia Maiden & Betche, accepted name, family Proteaceae. Read 2026-10-23 (GBIF species match API).
- 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).
- 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).
- 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).
- 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).
- 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).
- Macadamia nut effects on cardiometabolic risk factors: a randomised trial. J Nutr Sci 2023. Read 2026-10-23 (abstract via Europe PMC).
- U.S. Food and Drug Administration. Qualified Health Claims: Letters of Enforcement Discretion (list of claim titles and dates; letters not read). Read 2026-10-23.
- 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).