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Prescription 2015: Macadamia Nuts

August 3, 2015 Written by JP    [Font too small?]

These days, many nutritionists are no longer recommending a low fat diet as the be-all and end-all for promoting health. I agree! It’s absolutely fine, and, even advisable, for most people to eat moderate to large amounts of healthy fats. Foods such as avocados, grass fed meat, nuts, omega-3 eggs, seeds and wild fish can be enjoyed regularly without any sense of guilt or lingering uncertainty. But, the thing to keep in mind is that the components of any given diet do not exist in isolation. The health effects of dietary fat are influenced by the composition of your overall diet. For instance, a potato chip snack which is high in carbohydrates and fat will affect your body much differently than avocado slices wrapped in prosciutto. A typical serving of the latter may contain an equivalent amount of fat, but is much lower in carbohydrates and a richer source of protein.

My “prescription” today is to eat more omega-7 fatty acids in the form of macadamia nuts or oil. However, there are a few caveats to this suggestion. For starters, some people are allergic to macadamias. Mrs. Healthy Fellow cannot get anywhere near them! Also, pet owners need to be aware that dogs can have toxic reactions to these nuts. If you decide to stock them in your kitchen or pantry, be very careful to keep fido away. And, as alluded to above, if you add macadamia nuts or oil to your diet, do so as the expense of high glycemic, refined carbohydrates. A few examples: Try using macadamia nuts in place of croutons in a salad, popcorn at the movies or as a breading ingredient instead of grain-based flours.

Some of my long time readers may be wondering why I am recommending macadamia as a source of omega-7 fatty acids instead of sea buckthorn oil (SBO). I’ve been a proponent of SBO for many years and, I still am. There’s solid evidence supporting the various health benefits of SBO, ranging from a reduction in dry eye symptoms to the reversal of vaginal atrophy in postmenopausal women. Simply put, I continue to endorse SBO supplements for these conditions and others. Having said that, macadamia nuts are more easily accessible as a food source – rather than a supplement. This translates into vastly different amounts of omega-7s in a typical serving. As an example, two 500 mg soft gels of SBO provide approximately 300 – 400 mg of palmitoleic acid, an omega-7 fat. A tablespoon of macadamia oil contains up to 3,500 mg of palmitoleic acid. Beyond that, these two distinct sources of omega-7s are profoundly different in nutritional and phytochemical composition.

Macadamias are unique in the tree nut category, in that they contain a minimal amount of omega-6 fatty acids (4%) and an abundance of monounsaturated fat (79%). A 2014 review in the journal Lipids Health and Disease reports that diets rich in monounsaturated fats, including olive oil, reduce all-cause mortality by 11%, cardiovascular mortality by 12% and stroke by 17%. What’s more, five studies appearing in other prestigious journals support the notion that consuming macadamia nuts reduces cardiovascular risk factors. In most of the trials, a dose of about 1.5 – 3 ounces/day of macadamias was used. Some of the benefits noted were decreased LDL (“bad”) cholesterol, increased HDL (“good”) cholesterol and a reduction in biomarkers relating to inflammation, oxidative stress and thrombosis. Additionally, no weight gain was documented when the nuts were used as isocaloric replacements for other foods. In fact, one trial actually revealed a decline in body weight in young women who were fed a macadamia nut diet over a three week period.

When choosing macadamia nuts or oil keep the following in mind: Raw macadamias are higher in antioxidants, though lightly roasting the nuts still maintains much of their goodness. Macadamia oil has a maximum shelf life of about 12 months. So, be sure not to hang on to it for more than that. Rancid oil is never healthy, no matter what the source. All of this is to say that if you’re not allergic, or a dog, you can heartily eat macadamias as part of a holistic wellness program. Enjoy!

Note: Please check out the “Comments & Updates” section of this blog – at the bottom of the page. You can find the latest research about this topic there!

To learn more about the studies referenced in today’s column, please click on the following links:

Study 1 – Macadamia Nut Allergy: 2 Case Reports and a Review of the Literature (link)

Study 2 – Allergy to Macadamia Nut (link)

Study 3 – Weakness, Tremors, and Depression Associated with Macadamia Nuts in (link)

Study 4 – Potential Plant Poisonings in Dogs and Cats in Southern Africa (link)

Study 5 – Effects of Oral Sea Buckthorn Oil on Tear Film Fatty Acids in Individuals(link)

Study 6 – Effects of Sea Buckthorn Oil Intake on Vaginal Atrophy in (link)

Study 7 – Healthful New Oil from Macadamia Nuts (link)

Study 8 – Monounsaturated Fatty Acids, Olive Oil and Health Status: A Systematic (link)

Study 9 – A Macadamia Nut-Rich Diet Reduces Total and LDL-Cholesterol in Mildly (link)

Study 10 – Macadamia Nut Consumption Modulates Favourably Risk Factors for (link)

Study 11 – Serum Lipid Effects of a Monounsaturated (Palmitoleic) Fatty Acid-Rich (link)

Study 12 – Macadamia Nut Consumption Lowers Plasma Total and LDL Cholesterol (link)

Study 13 – Serum Lipid Effects of a High-Monounsaturated Fat Diet Based on (link)

Study 14 – Influence of Roasting Conditions on Health-Related Compounds in (link)

Study 15 – Aging Effects on Macadamia Nut Oil Studied by Electrospray Ionization (link)

Study 16 – The Antioxidant Activity and Oxidative Stability of Cold-Pressed Oils (link)

Macadamia Nut Diet Reduces LDL Cholesterol & Triglycerides

Source: Arch Intern Med. 2000 Apr 24;160(8):1154-8. (link)

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Posted in Food and Drink, Heart Health, Nutrition

9 Comments & Updates to “Prescription 2015: Macadamia Nuts”

  1. JP Says:

    Updated 08/03/15:


    Nutr J. 2015 Jun 28;14(1):64.

    Tree Nut consumption is associated with better adiposity measures and cardiovascular and metabolic syndromehealth risk factors in U.S. Adults: NHANES 2005-2010.

    INTRODUCTION: Previous research has shown inconsistencies in the association of tree nut consumption with risk factors for cardiovascular disease (CVD) and metabolic syndrome (MetS).

    OBJECTIVE: To determine the association of tree nut consumption with risk factors for CVD and for MetS in adults.

    METHODS: NHANES 2005-2010 data were used to examine the associations of tree nut consumption with health risks in adults 19+ years (n = 14,386; 51 % males). Tree nuts were: almonds, Brazil nuts, cashews, filberts [hazelnuts], macadamias, pecans, pine nuts, pistachios, and walnuts. Group definitions were non-consumers <  ¼ ounce/day and consumers of ≥ ¼ ounce/day tree nuts using data from 24-h dietary recalls. Means and ANOVA (covariate adjusted) were determined using appropriate sample weights. Using logistic regression, odds ratios of being overweight (OW)/obese (OB) (body mass index [BMI] >25/<30 and ≥30, respectively) and having CVRF or MetS, were determined.

    RESULTS: Tree nut consumption was associated with lower BMI (p = 0.004), waist circumference (WC) (p = 0.008), systolic blood pressure (BP) (p = 0.001), Homeostatic Model Assessment-Insulin Resistance (p = 0.043), and higher high density lipoprotein-cholesterol (p = 0.022), compared with no consumption, and a lower likelihood of OB (-25 %), OW/OB (-23 %), and elevated WC (-21 %).

    CONCLUSIONS: Tree nut consumption was associated with better weight status and some CVRF and MetS components.

    Be well!


  2. JP Says:

    Updated 08/03/15:


    Nutr Metab Cardiovasc Dis. 2014 Aug;24(8):845-52.

    Nut consumption, serum fatty acid profile and estimated coronary heart disease risk in type 2 diabetes.

    BACKGROUND AND AIMS: Nut consumption has been associated with decreased risk of coronary heart disease (CHD) and type 2 diabetes which has been largely attributed to their healthy fatty acid profile, yet this has not been ascertained. Therefore, we investigated the effect of nut consumption on serum fatty acid concentrations and how these relate to changes in markers of glycemic control and calculated CHD risk score in type 2 diabetes.

    METHODS AND RESULTS: 117 subjects with type 2 diabetes consumed one of three iso-energetic (mean 475 kcal/d) supplements for 12 weeks: 1. full-dose nuts (50-100 g/d); 2. half-dose nuts with half-dose muffins; and 3. full-dose muffins. In this secondary analysis, fatty acid concentrations in the phospholipid, triacylglycerol, free fatty acid, and cholesteryl ester fractions from fasting blood samples obtained at baseline and week 12 were analyzed using thin layer and gas chromatography. Full-dose nut supplementation significantly increased serum oleic acid (OA) and MUFAs compared to the control in the phospholipid fraction (OA: P = 0.036; MUFAs: P = 0.024). Inverse associations were found with changes in CHD risk versus changes in OA and MUFAs in the triacylglycerol (r = -0.256, P = 0.011; r = -0.228, P = 0.024, respectively) and phospholipid (r = -0.278, P = 0.006; r = -0.260, P = 0.010, respectively) fractions. In the cholesteryl ester fraction, change in MUFAs was inversely associated with markers of glycemic control (HbA1c: r = -0.250, P = 0.013; fasting blood glucose: r = -0.395, P < 0.0001). CONCLUSION: Nut consumption increased OA and MUFA content of the serum phospholipid fraction, which was inversely associated with CHD risk factors and 10-year CHD risk. Be well! JP

  3. JP Says:

    Updated 08/03/15:


    J Acad Nutr Diet. 2015 Feb;115(2):225-30.

    Dietary fat increases vitamin D-3 absorption.

    BACKGROUND: The plasma 25-hydroxyvitamin D response to supplementation with vitamin D varies widely, but vitamin D absorption differences based on diet composition is poorly understood.

    OBJECTIVES: We tested the hypotheses that absorption of vitamin D-3 is greater when the supplement is taken with a meal containing fat than with a fat-free meal and that absorption is greater when the fat in the meal has a higher monounsaturated-to-polyunsaturated fatty acid ratio (MUFA:PUFA).

    DESIGN: Open, three-group, single-dose vitamin D-3 comparative absorption experiment.

    PARTICIPANTS/SETTING: Our 1-day study was conducted in 50 healthy older men and women who were randomly assigned to one of three meal groups: fat-free meal, and a meal with 30% of calories as fat with a low (1:4) and one with a high (4:1) MUFA:PUFA. After a 12-hour fast, all subjects took a single 50,000 IU vitamin D-3 supplement with their test breakfast meal.

    MAIN OUTCOME MEASURES: Plasma vitamin D-3 was measured by liquid chromatography-mass spectrometry before and 10, 12 (the expected peak), and 14 hours after the dose.

    STATISTICAL ANALYSES PERFORMED: Means were compared with two-tailed t tests for independent samples. Group differences in vitamin D-3 absorption across the measurement time points were examined by analysis of variance with the repeated measures subcommand of the general linear models procedure.

    RESULTS: The mean peak (12-hour) plasma vitamin D-3 level after the dose was 32% (95% CI 11% to 52%) greater in subjects consuming fat-containing compared with fat-free meals (P=0.003). Absorption did not differ significantly at any time point in the high and low MUFA and PUFA groups.

    CONCLUSIONS: The presence of fat in a meal with which a vitamin D-3 supplement is taken significantly enhances absorption of the supplement, but the MUFA:PUFA of the fat in that meal does not influence its absorption.

    Be well!


  4. Ben Says:

    Interestingly, at least for peanuts, the antioxidant (reseveratrol) INCREASES with roasting, and increases even more after boiling! Too bad macadamia nuts don’t work that way.


    I like ghee, coconut oil, lard/butter, macadamia nut oil, and in a pinch, high oleic sunflower seed oil for high-temp cooking.. but how does oxidation , antioxidants, and refined oils play into this? Perhaps, it’s best to stick with only saturated fats for cooking?


    There’s a nice paper on on how diets high in linoleic acid (omega-6) reduce the risk of CVD, and that the concept of omega-6 to omega-3 ratio is not useful.

    http://www.ncbi.nlm.nih.gov/pubmed/18990555 http://i.imgur.com/6ZKKtR2.jpg

  5. JP Says:

    Hi Ben,

    Thank you for your thoughtful comments.

    Roasting tends increase both negative and positive attributes. Coffee is a prime example of this:


    J Agric Food Chem. 2015 Feb 25;63(7):1996-2005.

    Role of degradation products of chlorogenic acid in the antioxidant activity of roasted coffee.

    Antioxidant activities of brewed coffees prepared from six commercial brands ranged from 63.13 ± 1.01 to 96.80 ± 1.68% at the highest levels tested. Generally, the degree of antioxidant activity of the brewed coffee was inversely proportional to the total chlorogenic acid concentration. A sample obtained from the major chlorogenic acid, 5-caffeoylquinic acid (5-CQA), heated at 250 °C exhibited potent antioxidant activity (79.12 ± 2.49%) at the level of 10 μg/mL, whereas unheated 5-CQA showed only moderate antioxidant activity (44.41 ± 0.27%) at the level of 100 μg/mL. Heat produced relatively high levels of pyrocatechol (2,809.3 μg/g) and 2-methoxy-4-vinylphenol (46.4 μg/g) from 5-CQA, and their antioxidant activity levels were 76.57 ± 3.00 and 98.63 ± 0.01%, respectively. The results of the present study suggest that roasting degrades chlorogenic acids to form potent antioxidants and thus plays an important role in the preparation of high-antioxidant low-acid coffee.

    I try to avoid baking or cooking at very high heat. I typically use extra virgin olive oil, grass fed butter or unrefined coconut oil when baking/cooking. The antioxidant content of fat/oil influences the health effects of the end product:


    Mol Nutr Food Res. 2012 Mar;56(3):510-4.

    The postprandial inflammatory response after ingestion of heated oils in obese persons is reduced by the presence of phenol compounds.

    SCOPE: Heating during the process of cooking alters the chemical properties of foods and may affect subsequent postprandial inflammation. We tested the effects of four meals rich in different oils subjected to heating on the postprandial inflammatory metabolism of peripheral blood mononuclear cells (PBMCs).

    METHODS AND RESULTS: Twenty obese participants received four breakfasts following a randomized crossover design, consisting of milk and muffins made with different oils (virgin olive oil (VOO), sunflower oil (SFO), and a mixture of seeds oil (SFO/canola oil) with added either dimethylpolysiloxane (SOD), or natural antioxidants from olive mill wastewater alperujo (phenols; SOP)), previously subjected to 20 heating cycles. Postprandial inflammatory status in PBMCs was assessed by the activation of nuclear NF-κB, the concentration in cytoplasm of the NF-κB inhibitor (IκB-α), the mRNA levels of NF-κB subunits and activators (p65, IKKβ, and IKKα) and other inflammatory molecules (TNF-α, IL-1β, IL-6, MIF, and JNK), and lipopolysaccharide (LPS) levels. VOO and SOP breakfasts reduced NF-κB activation, increased IκB-α, and decreased LPS plasma concentration. SFO increased IKKα, IKKβ, p65, IL-1b, IL-6, MIF, and JNK mRNA levels, and plasma LPS.

    CONCLUSION: Oils rich in phenols, whether natural (VOO) or artificially added (SOP), reduce postprandial inflammation, compared with seed oil (sunflower).

    re: omega-3/6 ratio

    The findings are mixed to be sure. But, there’s a considerable amount of data indicating that the modern shift towards much higher omega-6 intake may be contributing to a variety of diseases. A few recent examples:


    BMC Med. 2014 Mar 27;12:54. doi: 10.1186/1741-7015-12-54.

    Helping women to good health: breast cancer, omega-3/omega-6 lipids, and related lifestyle factors.

    In addition to genetic predisposition and sex hormone exposure, physical activity and a healthy diet play important roles in breast cancer (BC). Increased intake of omega-3 fatty acids (n-3) associated with decreased omega-6 (n-6), resulting in a higher n-3/n-6 ratio compared with the western diet, are inversely associated with BC risk, as shown by Yang et al. in their meta-analysis in BMC Cancer. High consumption of polyphenols and organic foods increase the n-3/n-6 ratio, and in turn may decrease BC risk. Intake of high fiber foods and foods with low glycemic index decreases insulin resistance and diabetes risk, and in turn may decrease BC risk. The modernized Mediterranean diet is an effective strategy for combining these recommendations, and this dietary pattern reduces overall cancer risk and specifically BC risk. High-risk women should also eliminate environmental endocrine disruptors, including those from foods. Drugs that decrease the n-3/n-6 ratio or that are suspected of increasing BC or diabetes risk should be used with great caution by high-risk women and women wishing to decrease their BC risk.


    Biomed Res Int. 2015;2015:524948.

    Novel insights on nutrient management of sarcopenia in elderly.

    Sarcopenia is defined as a syndrome characterized by progressive and generalized loss of muscle mass and strength. The more rationale approach to delay the progression of sarcopenia is based on the combination of proper nutrition, possibly associated with the use of dietary supplements and a regular exercise program. We performed a narrative literature review to evaluate the till-now evidence regarding (1) the metabolic and nutritional correlates of sarcopenia; (2) the optimum diet therapy for the treatment of these abnormalities. This review included 67 eligible studies. In addition to the well recognized link between adequate intake of proteins/amino acids and sarcopenia, the recent literature underlines that in sarcopenic elderly subjects there is an unbalance in vitamin D synthesis and in omega-6/omega-3 PUFA ratio. Given the detrimental effect of these metabolic abnormalities, a change in the lifestyle must be the cornerstone in the treatment of sarcopenia. The optimum diet therapy for the sarcopenia treatment must aim at achieving specific metabolic goals, which must be reached through accession of the elderly to specific personalized dietary program aimed at achieving and/or maintaining muscle mass; increasing their intake of fish (4 times/week) or taking omega-3 PUFA supplements; taking vitamin D supplementation, if there are low serum levels.

    Be well!


  6. JP Says:

    Updated 1/31/16:


    Maturitas. 2016 Feb;84:11-6.

    Current knowledge on the effects of nut consumption on human health has rapidly increased in recent years and it now appears that nuts may play a role in the prevention of chronic age-related diseases. Frequent nut consumption has been associated with better metabolic status, decreased body weight as well as lower body weight gain over time and thus reduce the risk of obesity. The effect of nuts on glucose metabolism, blood lipids, and blood pressure is still controversial. However, significant decreased cardiovascular risk has been reported in a number of observational and clinical intervention studies. Thus, findings from cohort studies show that increased nut consumption is associated with a reduced risk of cardiovascular disease and mortality (especially that due to cardiovascular-related causes). Similarly, nut consumption has been also associated with reduced risk of certain cancers, such as colorectal, endometrial, and pancreatic neoplasms. Evidence regarding nut consumption and neurological or psychiatric disorders is scarce, but a number of studies suggest significant protective effects against depression, mild cognitive disorders and Alzheimer’s disease. The underlying mechanisms appear to include antioxidant and anti-inflammatory actions, particularly related to their mono- and polyunsaturated fatty acids (MUFA and PUFA, as well as vitamin and polyphenol content). MUFA have been demonstrated to improve pancreatic beta-cell function and regulation of postprandial glycemia and insulin sensitivity. PUFA may act on the central nervous system protecting neuronal and cell-signaling function and maintenance. The fiber and mineral content of nuts may also confer health benefits. Nuts therefore show promise as useful adjuvants to prevent, delay or ameliorate a number of chronic conditions in older people. Their association with decreased mortality suggests a potential in reducing disease burden, including cardiovascular disease, cancer, and cognitive impairments.

    Be well!


  7. JP Says:

    Updated 09/12/16:


    Am J Clin Nutr. 2016 Sep;104(3):722-8.

    Associations between nut consumption and inflammatory biomarkers.

    BACKGROUND: Increased nut consumption has been associated with reduced risk of cardiovascular disease and type 2 diabetes, as well as a healthy lipid profile. However, the associations between nut consumption and inflammatory biomarkers are unclear.

    OBJECTIVE: We investigated habitual nut consumption in relation to inflammatory biomarkers in 2 large cohorts of US men and women.

    DESIGN: We analyzed cross-sectional data from 5013 participants in the Nurses’ Health Study (NHS) and Health Professionals Follow-Up Study (HPFS) who were free of diabetes. Nut intake, defined as intake of peanuts and other nuts, was estimated from food-frequency questionnaires, and cumulative averages from 1986 and 1990 in the NHS and from 1990 and 1994 in the HPFS were used. Plasma biomarkers were collected in 1989-1990 in the NHS and 1993-1995 in the HPFS. Multivariate linear regression was used to assess the associations of nut consumption with fasting plasma C-reactive protein (CRP, n = 4941), interleukin 6 (IL-6, n = 2859), and tumor necrosis factor receptor 2 (TNFR2, n = 2905).

    RESULTS: A greater intake of nuts was associated with lower amounts of a subset of inflammatory biomarkers, after adjusting for demographic, medical, dietary, and lifestyle variables. The relative concentrations (ratios) and 95% CIs comparing subjects with nut intake of ≥5 times/wk and those in the categories of never or almost never were as follows: CRP: 0.80 (0.69, 0.90), P-trend = 0.0003; and IL-6: 0.86 (0.77, 0.97), P-trend = 0.006. These associations remained significant after further adjustment for body mass index. No significant association was observed with TNFR2. Substituting 3 servings of nuts/wk for 3 servings of red meat, processed meat, eggs, or refined grains/wk was associated with significantly lower CRP (all P < 0.0001) and IL-6 (P ranges from 0.001 to 0.017). CONCLUSION: Frequent nut consumption was associated with a healthy profile of inflammatory biomarkers. Be well! JP

  8. ophi Says:

    hi JP
    just wanted to ask, what’s the ideal number of macademia’s to eat per day? in my case to reduce dry eyes (among the rest of the health benefits!) (and is there a difference between number needed for the dry eyes problem versus what’s ideally healthy. who knows maybe for one you need to take more than for another symptom).
    thanks, Ophi

  9. JP Says:

    Hi Ophi,

    I can’t say for certain. If you enjoy macadamia nuts, you might try eating an ounce or two daily – or, if not daily, often. If your primary concern is dry eyes, there are other natural alternatives available with good research to support their use: fish oil, sea buckthorn oil and others.



    I’ve worked with a number of clients who have found positive results by eating more fish (wild sardines and salmon, etc.) and supplementing with 2 grams of organic sea buckthorn oil daily. The dosage of sea buckthorn oil can be reduced once the symptoms improve (1 gram/day) – and increased if the symptoms return.

    I hope this is helpful.

    Be well!


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