{"url":"https://whatshealthyandwhy.com/nuts-and-seeds/macadamia-nuts","path":"/nuts-and-seeds/macadamia-nuts","alternates":{"json":"https://whatshealthyandwhy.com/api/articles/nuts-and-seeds/macadamia-nuts.json","markdown":"https://whatshealthyandwhy.com/nuts-and-seeds/macadamia-nuts.md"},"topic":{"slug":"nuts-and-seeds","name":"Nuts & Seeds","url":"https://whatshealthyandwhy.com/nuts-and-seeds"},"slug":"macadamia-nuts","order":7,"title":"Macadamia Nuts: Heart-Healthy Fats and the Omega-7 Advantage","question":"Do macadamia nuts lower cholesterol?","answer":"Macadamia nuts likely lower LDL cholesterol by about 5–9% in small trials when they replace refined carbohydrate or saturated fat.","description":"How macadamia nuts lower LDL cholesterol and why their unique fat profile — rich in oleic acid and the rare omega-7 palmitoleic acid — makes them one of the most anti-inflammatory tree nuts.","confidence":3,"confidenceNote":"Four small crossover trials (17–35 people each), three showing lower LDL and one not significant, plus a tree-nut meta-analysis of 61 trials.","evidenceSummary":{"rctCount":4,"observationalCount":0,"metaAnalysisCount":1,"totalParticipants":"~95","replicated":true,"newestStudyYear":2023},"category":{"categoryTitle":"What's Good For You","categorySlug":"good-for-you","subcategoryName":"Foods & Drinks","subcategorySlug":"foods","url":"https://whatshealthyandwhy.com/explore/good-for-you/foods"},"actions":["Swap 28–56 g (1–2 ounces) of macadamias a day for refined carbohydrates or saturated fat; trials used 40–90 g [1][2].","Buy raw or lightly dry-roasted nuts without added oil or salt; heavy roasting above 180°C degrades fats and cuts thiamine [7].","Keep them in a sealed container away from light, or in the fridge, so the fats do not go rancid."],"cautions":["Calorie-dense at about 200 kcal per ounce, so let them replace other foods; one 8-week trial still found no weight gain [3].","Lipid effects were smaller and not significant in a 2023 free-living trial of overweight adults [3]; expect modest changes.","Not a substitute for medical care if your cholesterol stays high or symptoms persist."],"simpleText":"Macadamia nuts contain the highest fat content of any tree nut — but almost entirely the right kind. Around 80% of their calories come from fat, dominated by oleic acid (the same monounsaturated fat that makes olive oil heart-healthy) and a rare omega-7 fatty acid called palmitoleic acid, which is almost absent from other plant foods [6]. Unlike most nuts, macadamias are extremely low in omega-6 linoleic acid, which means they don't push the diet toward pro-inflammatory signaling the way that many processed cooking oils do. Clinical trials consistently show macadamia nuts lower LDL and total cholesterol without raising triglycerides [1][2][4], and they're among the best food sources of manganese and thiamine (vitamin B1) [7]. One to two ounces per day fits comfortably into heart-healthy, Mediterranean, or low-carbohydrate eating patterns.","mediumText":"Why macadamia nuts stand apart from other nuts\n\nMost tree nuts owe their health benefits to a mix of monounsaturated and polyunsaturated fats. Macadamias are distinctive: roughly 65% of their fat is oleic acid and 18–21% is palmitoleic acid — leaving very little room for omega-6 linoleic acid, which makes up 30–60% of the fat in almonds, cashews, and most other nuts [6].\n\nThe omega-7 advantage\n\nPalmitoleic acid (C16:1 n-7, or omega-7) has attracted growing interest as a lipokine — a fat-derived signaling molecule that appears to improve insulin sensitivity, reduce atherogenic lipid production in the liver, and modulate inflammation. Macadamia nuts are the richest whole-food plant source of palmitoleic acid. While isolated omega-7 supplements have shown mixed results in clinical trials, consuming palmitoleic acid in the context of a whole food — with fiber, polyphenols, and a favorable overall fatty acid matrix — may behave differently.\n\nWhy the low omega-6 content matters\n\nThe ratio of omega-6 to omega-3 fatty acids in the diet influences the production of prostaglandins and leukotrienes, signaling molecules that regulate inflammation. Modern Western diets are heavily skewed toward omega-6 (from seed oils, conventional meats, and processed foods), which promotes a more pro-inflammatory state. Macadamias, with essentially no linoleic acid, allow you to add calorie-dense fat to your diet without worsening the omega-6 burden — an unusual property for a plant food.\n\nCholesterol and cardiovascular health\n\nMultiple controlled trials and a large meta-analysis confirm that macadamia nuts lower LDL and total cholesterol when they replace refined carbohydrates or saturated fat in the diet [1][2][4][5]. Unlike some dietary interventions that lower LDL while also lowering HDL (the \"good\" cholesterol), macadamia nuts appear to raise HDL while lowering LDL [2] — a more favorable lipid shift for cardiovascular risk. One trial also found a reduction in small, dense LDL particles — the most atherogenic LDL subtype, which penetrates arterial walls most readily [4].\n\nMicronutrient highlights\n\nManganese — Macadamia nuts are exceptionally high in manganese, a trace mineral required for bone formation, wound healing, and the activity of superoxide dismutase (the body's primary antioxidant enzyme inside cells). One ounce provides around 50–60% of the daily value.\n\nThiamine (vitamin B1) — Among tree nuts, macadamias have the highest thiamine content — essential for converting carbohydrates to energy and supporting nerve function [7]. Roasting at moderate temperatures reduces thiamine by about 16–18% but leaves the lipid profile largely intact.\n\nPhytosterols and tocopherols — Macadamias contain plant sterols, which compete with dietary cholesterol for absorption in the gut, and tocopherols (vitamin E antioxidants), though in lower amounts than walnuts or almonds [6].\n\nPractical notes\n\nPortion: One ounce (28 g, about 10–12 whole nuts) provides roughly 200 calories, 21 g fat, 2 g fiber, 1.2 mg manganese, and 0.3 mg thiamine. Most clinical trials used 40–90 g per day; 28–56 g daily is a sensible practical target.\n\nRaw vs. roasted: Light dry-roasting at ~150°C preserves the lipid profile well. Heavy oil-roasting, added coatings, or high heat (above 180°C) can degrade heat-sensitive fatty acids and significantly reduce thiamine [7]. Buy raw or lightly roasted without added oils or salt when possible.\n\nFor low-carbohydrate diets: At less than 4 g net carbs per ounce, macadamias are the most carbohydrate-compatible tree nut, making them a popular choice in ketogenic and low-glycemic eating patterns.\n\nStorage: The high monounsaturated fat content makes macadamias more shelf-stable than walnuts or flaxseed, but they will still go rancid in heat and light. Store in a sealed container, away from light; refrigeration extends freshness further.\n\nSee our Nuts & Seeds overview and Walnuts page for broader context on tree nut health benefits.","deepText":"Evidence Review\n\nGriel et al. (2008) — PMID 18356332\n\nThis randomized crossover trial at Penn State University enrolled 25 mildly hypercholesterolemic adults (baseline LDL ~130 mg/dL). Participants consumed either a macadamia nut-rich diet (providing ~15% of total daily energy from macadamia nuts — approximately 42–90 g/day depending on caloric needs) or a control average-American diet for five weeks each, separated by a two-week washout. The macadamia nut diet was designed to be isocaloric by reducing dietary carbohydrate.\n\nKey findings: Compared to the average American diet, the macadamia nut diet produced statistically significant reductions in:\n- Total cholesterol: −9.4%\n- LDL cholesterol: −8.9%\n- Non-HDL cholesterol: −8.1%\n- TC:HDL ratio: −8.3%\n- LDL:HDL ratio: −7.6%\n\nHDL cholesterol and triglycerides were unchanged.\n\nSignificance: An ~9% reduction in LDL from a single dietary change — replacing carbohydrate with macadamia nuts — is clinically meaningful. The absence of triglyceride elevation distinguishes this from high-carbohydrate dietary patterns, which typically raise triglycerides while lowering LDL. Limitations include the small sample (25 participants) and the controlled feeding design, which may not reflect free-living dietary behavior.\n\nGarg, Blake & Wills (2003) — PMID 12672919\n\nThis three-arm crossover trial in Australia enrolled 17 hypercholesterolemic men, cycling them through a high-macadamia nut diet (~40–90 g/day), a high-fat reference diet, and a low-fat reference diet — four weeks per phase. The macadamia nut diet derived ~33% of calories from fat, predominantly MUFAs.\n\nKey findings compared to the high-fat reference diet:\n- Total cholesterol: −3.0%\n- LDL cholesterol: −5.3%\n- HDL cholesterol: +7.9%\n- Triglycerides: −9.0%\n\nAll four changes moved simultaneously in a favorable direction.\n\nSignificance: Dietary interventions rarely improve all four major lipid markers at once. The concurrent rise in HDL alongside LDL reduction is particularly notable, because HDL is inversely associated with cardiovascular event risk. A 5% LDL reduction combined with a nearly 8% HDL increase represents a meaningfully improved TC:HDL ratio. The sample of 17 men limits generalizability, particularly to women and non-hypercholesterolemic populations.\n\nGarg, Blake, Wills & Clayton (2007) — PMID 17437143\n\nA follow-up crossover study in 17 hypercholesterolemic subjects (men and women combined) using a 4-week macadamia nut dietary phase. This trial added measurements of lipoprotein particle subfractions and oxidative stress markers beyond standard lipid panels.\n\nKey findings:\n- Total cholesterol: −5.0% (significant)\n- LDL cholesterol: −5.3% (significant)\n- Triglycerides: −8.3% (significant)\n- Significant reduction in small, dense LDL particle concentration\n- Favorable non-significant trends in oxidative stress and inflammation markers\n\nSignificance: The reduction in small, dense LDL particles is the most important secondary finding. Small, dense LDL (pattern B) is more atherogenic than large, buoyant LDL: it has a longer plasma half-life, penetrates arterial intima more readily, and is more susceptible to oxidative modification. Improving LDL particle quality — not just quantity — provides additional cardiovascular protection beyond what total LDL measurements capture. This study suggests macadamia nuts may influence the composition of LDL, not only its concentration.\n\nJones et al. (2023)\n\nThis eight-week randomized crossover trial enrolled 35 adults with abdominal obesity at elevated cardiometabolic risk and compared their usual diet plus macadamia nuts (about 15% of daily calories) with their usual diet without nuts, with a 2-week washout, under free-living conditions [3].\n\nKey findings:\n- Macadamia intake increased total fat and monounsaturated fat intake without changing saturated fat intake\n- No significant changes in weight, BMI, waist circumference, percent body fat, or glycemic parameters\n- Non-significant reductions in total cholesterol (−2.1%, −4.3 mg/dL) and LDL-C (−4%, −4.7 mg/dL)\n- Cholesterol lowering was modified by adiposity: greater in participants with overweight than with obesity, and in those with less than the median percent body fat\n\nSignificance: The absence of weight gain when adding calorie-dense macadamia nuts to a free-living diet is reassuring; the authors concluded that daily macadamia consumption does not lead to gains in weight or body fat under free-living conditions in overweight or obese adults. The cholesterol reductions were not statistically significant, and the smaller effect compared with controlled-feeding trials may reflect the noise of free-living dietary variability. The authors noted that the lipid-lowering effect was modified by adiposity, with greater lowering in participants who were overweight rather than obese and in those with less body fat, a pattern that needs confirmation.\n\nDel Gobbo et al. (2015) — PMID 26561616\n\nThis systematic review and meta-analysis synthesized 61 controlled intervention trials totaling 2,582 participants across multiple nut types — including macadamias, walnuts, almonds, pistachios, cashews, and others. Dose-response modeling estimated lipid effects at a range of daily nut intakes.\n\nKey findings for tree nuts overall:\n- Total cholesterol: −4.7 mg/dL per serving (28 g/day)\n- LDL cholesterol: −4.8 mg/dL per serving\n- ApoB: −3.7 mg/dL per serving\n- Triglycerides: −2.2 mg/dL per serving\n- HDL cholesterol: no significant change (neutral)\n- Effects were strongest in participants with type 2 diabetes and in those with baseline LDL above 130 mg/dL\n- The dose-response relationship was approximately linear up to three servings per day …","deepTruncated":true,"references":[{"id":"1","title":"A macadamia nut-rich diet reduces total and LDL-cholesterol in mildly hypercholesterolemic men and women","authors":"Griel AE, Cao Y, Bagshaw DD, Cifelli AM, Holub B, Kris-Etherton PM","year":2008,"journal":"Journal of Nutrition","pmid":"18356332","url":"https://pubmed.ncbi.nlm.nih.gov/18356332/"},{"id":"2","title":"Macadamia nut consumption lowers plasma total and LDL cholesterol levels in hypercholesterolemic men","authors":"Garg ML, Blake RJ, Wills RBH","year":2003,"journal":"Journal of Nutrition","pmid":"12672919","url":"https://pubmed.ncbi.nlm.nih.gov/12672919/"},{"id":"3","title":"Macadamia nut effects on cardiometabolic risk factors: a randomised trial","authors":"Jones JL, Sabaté J, Heskey C, Oda K, Miles F, Rajaram S","year":2023,"journal":"Journal of Nutritional Science","pmid":"37180485","url":"https://pubmed.ncbi.nlm.nih.gov/37180485/"},{"id":"4","title":"Macadamia nut consumption modulates favourably risk factors for coronary artery disease in hypercholesterolemic subjects","authors":"Garg ML, Blake RJ, Wills RB, Clayton EH","year":2007,"journal":"Lipids","pmid":"17437143","url":"https://pubmed.ncbi.nlm.nih.gov/17437143/"},{"id":"5","title":"Effects of tree nuts on blood lipids, apolipoproteins, and blood pressure: systematic review, meta-analysis, and dose-response of 61 controlled intervention trials","authors":"Del Gobbo LC, Falk MC, Feldman R, Lewis K, Mozaffarian D","year":2015,"journal":"American Journal of Clinical Nutrition","pmid":"26561616","url":"https://pubmed.ncbi.nlm.nih.gov/26561616/"},{"id":"6","title":"Fatty acid profile, tocopherol, squalene and phytosterol content of walnuts, almonds, peanuts, hazelnuts and the macadamia nut","authors":"Maguire LS, O'Sullivan SM, Galvin K, O'Connor TP, O'Brien NM","year":2004,"journal":"International Journal of Food Science and Nutrition","pmid":"15223592","url":"https://pubmed.ncbi.nlm.nih.gov/15223592/"},{"id":"7","title":"A comprehensive study of raw and roasted macadamia nuts: Lipid profile, physicochemical, nutritional, and sensory properties","authors":"Tu XH, Wu BF, Xie Y, Xu SL, Wu ZY, Lv X, Wei F, Du LQ, Chen H","year":2021,"journal":"Food Science & Nutrition","pmid":"33747479","url":"https://pubmed.ncbi.nlm.nih.gov/33747479/"}],"wordCount":1581,"source":{"path":"src/content/topics/nuts-and-seeds/macadamia-nuts.md"},"citeAs":"“Do macadamia nuts lower cholesterol?.” What's Healthy and Why. https://whatshealthyandwhy.com/nuts-and-seeds/macadamia-nuts","notice":"General information backed by peer-reviewed research, not medical advice."}