Walnuts: Blood Sugar and Diabetes

Table of Contents

1. Five Blood-Sugar Measurements
2. What a Walnut Brings to the Question
3. Trials in People With Type 2 Diabetes
4. The Prediabetes Trial
5. Metabolic Syndrome, Obesity and Single Meals
6. The Cohort Studies: Who Developed Diabetes
7. PREDIMED: A Randomised Test of Diabetes Prevention
8. The Meta-Analyses: Pooled Numbers
9. Proposed Mechanisms (Hypotheses)
10. Walnut Oil, Leaf Extract and Peptides Are Different Products
11. What Is Not Known
12. Who the Research Raises Concerns For
13. Connections
14. Key Research Papers
15. Featured Videos

Five Blood-Sugar Measurements

Walnut studies rarely measure the same thing, so it helps to know the five common markers before reading the trials. Each tells a different part of the story.

• Fasting glucose is the sugar level in the blood after a night without food. It is a snapshot of one morning.
• Fasting insulin is how much insulin the pancreas has to release to hold that fasting glucose steady. A high fasting insulin with a normal glucose can mean the body is working harder than it used to. See the fasting insulin test page.
• HOMA-IR (homeostatic model assessment of insulin resistance) is a number calculated from fasting glucose and fasting insulin together. Higher values suggest the body's cells respond less well to insulin. See HOMA-IR.
• HbA1c (glycated haemoglobin) is the share of red-blood-cell haemoglobin that has sugar stuck to it. Because red cells live about three months, it reflects average blood sugar over roughly that period. A trial of a few weeks is too short for HbA1c to move much. See Hemoglobin A1C.
• Post-meal (postprandial) glucose and insulin are measured in the hours after a test meal, often summarised as an "area under the curve". This captures the spike a meal causes rather than the long-term average.

A food can change one of these without touching the others. A trial that reports "no effect on blood sugar" may have measured only fasting glucose, and a trial that reports "improved insulin" may have measured only fasting insulin. The sections below name which markers each study measured.

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What a Walnut Brings to the Question

Walnuts are mostly fat and contain little digestible carbohydrate, so eating them causes almost no direct rise in blood sugar. Most of that fat is polyunsaturated, and walnuts are the one common nut that supplies a meaningful amount of alpha-linolenic acid (ALA), the plant omega-3 fat. They also carry fibre, protein and polyphenols, especially ellagitannins in the thin brown skin. The Walnuts: Nutrient Profile page gives the full composition table.

That profile is why researchers expected walnuts to help: replacing refined starch or saturated fat with a low-carbohydrate, polyunsaturated food could plausibly lower post-meal glucose and, over time, improve how cells respond to insulin. The trials below test that expectation directly.

Walnuts are also energy-dense. The 56 g daily amount used in several American trials was reported as providing 366 kcal. A controlled feeding study in 18 healthy adults measured how much of that energy the body actually absorbs: one 28 g serving delivered 146 kcal, 21% less than the 185 kcal predicted by standard food-label calculations, because part of the fat leaves the body unabsorbed (Baer 2016). That matters for blood sugar because body weight is one of the strongest drivers of type 2 diabetes risk.

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Trials in People With Type 2 Diabetes

Tapsell 2004: six months of dietary advice with 30 g a day

In Australia, 58 men and women with type 2 diabetes (mean age 59) were randomised to one of three dietary-advice groups, all with 30% of energy from fat: low fat, modified low fat, or modified low fat including 30 g of walnuts a day. Blood lipids and HbA1c were measured at 0, 3 and 6 months. The walnut group had a larger rise in HDL cholesterol and its ratio to total cholesterol, and a 10% fall in LDL cholesterol. There were no significant differences between groups in HbA1c, body weight or body fat. Red-blood-cell fatty acids confirmed the walnut group really did eat more omega-3 fat.

Tapsell 2009: one year, and the fasting-insulin finding

A second Australian trial randomised 50 overweight adults with type 2 diabetes not treated with insulin (mean age 54) to low-fat dietary advice with or without 30 g of walnuts a day for one year, targeting weight maintenance at around 2,000 kcal. Walnuts supplied 67% of the walnut group's polyunsaturated fat at 12 months. Both groups lost 1-2 kg and both improved on most clinical measures over time. The walnut group had a significantly greater reduction in fasting insulin (P = 0.046), and the authors reported that most of the effect appeared in the first three months. The abstract does not report a between-group difference in fasting glucose or HbA1c.

Ma 2010: eight weeks of 56 g a day

In a single-blind crossover trial in the United States, 24 people with type 2 diabetes (mean age 58; 14 women, 10 men) ate an unrestricted diet with 56 g of walnuts a day for eight weeks and an unrestricted diet without walnuts for eight weeks. The main outcome was blood-vessel function (flow-mediated dilation), which improved more on walnuts. For blood sugar the results were neutral or unfavourable: fasting glucose rose from baseline on the walnut diet by about 10 mg/dL, although this was not significant compared with the no-walnut diet, and there were no significant changes in HbA1c or insulin sensitivity.

What these three trials show together

In people who already have type 2 diabetes, adding walnuts improved blood fats and, in one trial, blood-vessel function and fasting insulin, but did not lower HbA1c or fasting glucose in any of them. The trials were small (24 to 58 people), and in two of the three the walnuts were part of broader dietary advice, so the walnut's own contribution cannot be fully separated from the rest of the diet.

A separate laboratory finding sometimes cited in this context is not a diabetes trial in people. Fifteen postmenopausal women with high cholesterol ate 40 g of walnuts a day for four weeks; their isolated LDL particles were then applied to diabetic fat cells grown in the laboratory, where they reduced the inflammatory signals IL-6 and IL-8 (Borkowski 2019). It shows walnut fats changing lipoprotein contents, not a change in anyone's blood sugar.

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The Prediabetes Trial

The largest walnut trial in people at risk of diabetes enrolled 112 adults (31 men, 81 women) in Connecticut. Participants were first randomised to receive dietary counselling to adjust calories or no counselling, and within each arm they ate a diet including 56 g (366 kcal) of walnuts a day and a diet without walnuts, each for six months, in random order.

Compared with the walnut-free diet, the walnut diet improved overall diet quality on the Healthy Eating Index, blood-vessel function, and total and LDL cholesterol. On blood sugar the finding was null: fasting glucose and HbA1c did not change significantly, nor did body mass index, body fat, visceral fat or blood pressure (Njike 2015). A follow-up analysis of the same trial found that people ate more seafood and plant-protein foods and more healthful fats while walnuts were in the diet (Njike 2016). The 2016 report states that the study was funded by a public-health agency and a walnut-industry body, and that one author had been paid by that body for public speaking.

The Prediabetes page covers the condition itself and the lifestyle trials that have changed its course.

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Metabolic Syndrome, Obesity and Single Meals

Metabolic syndrome is a cluster of findings (large waist, high triglycerides, low HDL, raised blood pressure and raised fasting glucose) that predicts both diabetes and heart disease; see Metabolic Syndrome. Walnut results in this group are split.

Positive: Hwang 2019, 16 weeks in Korea

A crossover trial in 119 Korean adults with metabolic syndrome (84 completed) compared 45 g of walnuts a day with the same calories as white bread, each for 16 weeks with a six-week washout. After walnuts, compared with the bread period, HDL cholesterol, fasting glucose (P = 0.013) and HbA1c (P = 0.021) improved and adiponectin, a fat-cell hormone linked with better insulin sensitivity, rose. About half the participants (51.2%) no longer met the criteria for metabolic syndrome after the walnut period. This is the clearest positive glucose result for whole walnuts in the trial literature, and the comparison food matters: the control was white bread, a refined starch, so the result reflects swapping bread for walnuts as well as adding walnuts.

Null: Mukuddem-Petersen 2007, eight weeks in South Africa

Sixty-four people with metabolic syndrome were randomised to a controlled feeding diet with walnuts, with unsalted cashews, or with no nuts for eight weeks. Walnuts had no significant effect on HDL, triglycerides, cholesterol, fructosamine (a two-to-three-week blood-sugar marker), C-reactive protein or blood pressure compared with the control diet. The authors concluded that neither nut improved the markers of metabolic syndrome while body weight was held steady.

Null on glucose: Mateș 2025, four weeks in Romania

Twenty middle-aged adults with at least one metabolic-syndrome feature completed a crossover trial of 45 g of walnuts a day versus no walnuts, each for 28 days. Waist circumference fell significantly; the change in fasting glucose was small and not statistically significant (P = 0.089).

The inpatient physiology studies

A Boston group ran a series of tightly controlled studies in which volunteers lived in a clinical research centre and drank breakfast smoothies containing walnuts or a matched placebo with the same calories, carbohydrate and fat.

• Brennan 2010 (20 adults with metabolic syndrome, 4 days each arm): walnuts increased feelings of fullness by days 3 and 4, but there was no change in insulin resistance or in satiety hormones. No author reported a conflict of interest.
• Aronis 2012 (15 obese adults with metabolic syndrome, 48 g a day for 4 days): apolipoprotein A rose, while a long list of inflammation and blood-vessel-injury markers did not change.
• Tuccinardi 2019 (10 obese adults, 48 g a day for 5 days): the lipoprotein insulin-resistance score fell, and the post-meal glucose and insulin areas under the curve decreased significantly. Small, dense LDL particles and several ceramides (fats linked with insulin resistance) fell, and the gut hormone peptide YY rose. One author had served as a consultant to a walnut-industry body.
• Tuccinardi 2021 (same 10 volunteers): fasting levels of two branched-chain amino acids, valine and isoleucine, fell on walnuts, and those levels tracked HOMA-IR. The authors present this as a possible contributor to longer-term effects, not a demonstrated one.
• Farr 2018 (10 volunteers, 5 days each arm): brain scans showed more activity in the insula, a region involved in appetite control, when participants viewed highly desirable food, and participants reported less hunger.

These studies are useful for mechanism but are very short, with 10 to 20 people, so they cannot show what happens to diabetes risk over years.

Single test meals in healthy adults

In 30 healthy adults, breakfasts in which butter was replaced by black walnuts or English walnuts increased fullness, but there were no treatment differences in post-meal glucose (Rodrigues 2019). In 21 healthy young men, a walnut-enriched high-fat meal raised post-meal adiponectin compared with butter and olive-oil meals and lowered free fatty acids at three hours (Lozano 2013); glucose was not reported as an outcome in that abstract.

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The Cohort Studies: Who Developed Diabetes

The Nurses' Health Studies (Pan 2013)

The largest walnut-specific analysis followed 58,063 women aged 52-77 in the Nurses' Health Study (1998-2008) and 79,893 women aged 35-52 in the Nurses' Health Study II. Diet was recorded every four years by food-frequency questionnaire, and 5,930 new cases of type 2 diabetes were documented over ten years. Compared with women who never or rarely ate walnuts, the hazard ratios (a hazard ratio of 0.76 means 24% lower risk in that group) were:

Two details matter. First, adjusting for body mass index weakened the link, and only the highest intake group stayed clearly below 1.0, which suggests part of the association runs through body weight. Second, total nuts and other tree nuts were also linked with lower risk, but those associations were "largely explained by BMI", while walnuts kept a significant link after that adjustment. The disclosure in the abstract states that one author had received funding support from a walnut-industry body.

NHANES (Arab 2018)

Using US National Health and Nutrition Examination Survey data pooled from 1999 to 2014, people who reported walnuts in a 24-hour dietary recall were less likely to have diabetes than people who reported no nuts: odds ratio 0.47 by self-report, relative risk ratio 0.32 by fasting glucose and 0.51 by HbA1c, after adjustment. The authors suggested the link might be stronger in women. This is a cross-sectional survey: it measures diet and diabetes at the same moment, so it cannot show which came first. People who already know they have diabetes may also change what they eat.

A blood-chemistry fingerprint of walnut eating (Guasch-Ferré 2021)

In 1,833 Spanish adults at high cardiovascular risk from the PREDIMED study, researchers identified 19 blood metabolites that tracked self-reported walnut intake. That metabolite profile was linked with lower risk of later type 2 diabetes (hazard ratio 0.83 per standard deviation; 95% CI 0.71-0.97). The correlation between the profile and reported walnut intake was weak (about 0.15), so the profile is an imperfect stand-in for walnut eating.

Association is not causation

People who eat walnuts regularly also tend to differ in income, exercise, smoking and overall diet. Cohorts adjust for the factors they measure, but they cannot rule out the ones they do not. The cohorts and the randomised trials ask different questions: the cohorts ask whether walnut eaters develop diabetes less often over a decade, while the trials ask whether a few months of walnuts change a blood marker. The two kinds of evidence do not yet agree, which is one reason this remains an open question.

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PREDIMED: A Randomised Test of Diabetes Prevention

The only randomised trial that counted new cases of diabetes as an outcome with a nut arm is a sub-study of PREDIMED, and it used mixed nuts, not walnuts alone. In the PREDIMED-Reus centre in Spain, 418 adults aged 55-80 without diabetes but at high cardiovascular risk were randomised to low-fat diet advice (control), a Mediterranean diet with free virgin olive oil, or a Mediterranean diet with 30 g of nuts a day. Diets were unrestricted in calories.

After a median of four years, diabetes developed in 17.9% of the control group, 11.0% of the nut group and 10.1% of the olive-oil group. The adjusted hazard ratio for the nut group was 0.48 (0.24-0.96), and the reduction occurred without significant changes in body weight (Salas-Salvadó 2011). The journal published an erratum to this paper in 2018, the year the main PREDIMED trial was re-analysed and republished after departures from the randomisation protocol were found; in the republished analysis, results were similar after omitting the 1,588 participants whose assignments were known or suspected to have departed from protocol (Estruch 2018).

Because the nut arm was part of a whole Mediterranean diet and used a nut mix, this trial cannot isolate walnuts. The Walnuts: Heart Health and PREDIMED page covers the trial in detail.

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The Meta-Analyses: Pooled Numbers

A meta-analysis pools the results of several trials to get a more stable estimate. For walnuts, the pooled trial evidence on blood sugar is mostly null.

The Neale 2020 authors concluded that the heart benefits linked with walnuts "are not mediated via improvements in glycaemic control". The Hadi 2025 HOMA-IR result is the one pooled signal in walnuts' favour, and its confidence interval sits just below zero.

Tree nuts in diabetes, and nuts as a food group

A 2014 meta-analysis of 12 trials (450 people) of mixed tree nuts in people with diabetes, at a median 56 g a day, found small but significant falls in HbA1c (-0.07%) and fasting glucose (-0.15 mmol/L), with no significant change in fasting insulin or HOMA-IR; most trials were short and of poor quality (Viguiliouk 2014). The abstract's disclosures list research funding and advisory roles with nut-industry bodies among several authors.

For diabetes risk in whole populations, a 2017 meta-analysis of prospective studies graded the evidence for nuts and type 2 diabetes as "low" (Schwingshackl 2017), and a 2025 umbrella review of 67 meta-analyses found the association between nuts and type 2 diabetes to be generally neutral and not statistically significant (Banjarnahor 2025). Neither review looked at walnuts separately.

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Proposed Mechanisms (Hypotheses)

The ideas below are proposed explanations. Some rest on small human studies, some on laboratory work, and none has been shown to lower diabetes risk on its own.

• Swapping out refined carbohydrate. Walnuts contain little starch or sugar. When they replace bread or other refined starch, as in the Korean trial, the meal's glucose load falls. This is the simplest explanation for the Hwang 2019 result, and it is a property of the swap as much as of the walnut.
• ALA and polyunsaturated fat. Replacing saturated fat with polyunsaturated fat is thought to improve how cell membranes respond to insulin. The one-year Tapsell trial raised polyunsaturated fat intake and lowered fasting insulin, but did not show a change in HbA1c. The ALA Omega-3 and Brain page covers ALA itself.
• Oxylipins. In the Borkowski 2019 study, walnuts raised ALA-derived epoxides (oxidised fats called oxylipins) in lipoproteins, and those, rather than ALA itself, tracked the reduced inflammatory response of laboratory-grown diabetic fat cells.
• Ceramides and branched-chain amino acids. In the five-day inpatient studies, walnuts lowered blood ceramides and fasting valine and isoleucine, molecules that are linked with insulin resistance in other research. The trials were too short to show whether this changes diabetes risk.
• Adiponectin. Walnut meals and diets raised adiponectin in several studies (Lozano 2013, Aronis 2012, Hwang 2019). Low adiponectin is associated with insulin resistance; whether raising it with food improves insulin sensitivity is not established.
• Fullness and appetite. Walnuts increased fullness (Brennan 2010, Rodrigues 2019), reduced reported hunger and changed brain responses to food pictures (Farr 2018), and raised peptide YY (Tuccinardi 2019). Eating less overall could, over time, help weight and therefore blood sugar, but the trials did not show weight loss: the Lockyer 2022 review found that 6 of 6 trials favoured control on body weight, although the effects were small.
• Polyphenols and gut bacteria. Walnut ellagitannins are converted by gut bacteria into urolithins, and the bacteria involved differ between people. This is covered on the Walnuts: Gut Microbiome and Urolithins page; a direct link to blood sugar in people has not been shown.

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Walnut Oil, Leaf Extract and Peptides Are Different Products

Several "walnut and diabetes" studies did not test the nut. Their results do not transfer automatically to eating whole walnuts.

• Walnut oil. In an Iranian trial of 100 people with type 2 diabetes, 15 g of walnut oil a day for three months was followed by a fall in HbA1c from 7.00% to 6.37% and in fasting blood sugar from 158 to 138 mg/dL within the oil group, while the control group, which received no intervention, did not change significantly (Zibaeenezhad 2016). The abstract reports within-group changes rather than a direct comparison between the groups, and the control received nothing. A double-blind trial by the same group in 100 people with diabetes and high blood fats gave 15 mL of walnut oil or placebo for 90 days and reported lower total cholesterol, LDL and triglycerides; its primary outcomes were lipids, not glucose (Zibaeenezhad 2017).
• Walnut leaf extract. The leaves of Juglans regia are a traditional Persian remedy for high blood sugar. A meta-analysis of four trials (195 people with type 2 diabetes) found that leaf extract lowered fasting blood glucose by about 18 mg/dL and raised fasting insulin; HbA1c fell only in trials longer than eight weeks (Mirzababaei 2022). The leaf is a herbal extract with its own chemistry, not a food.
• Walnut peptides and shell extracts. Protein fragments, shell polysaccharides and walnut-meal extracts have been tested mainly in diabetic mice and rats. These are animal studies and do not show an effect in people.

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What Is Not Known

• Whether walnuts prevent diabetes. No randomised trial has counted new diabetes cases with walnuts alone. The cohort signal (Pan 2013) and the mixed-nut PREDIMED-Reus result are the closest evidence, and neither isolates the walnut.
• Why cohorts and trials disagree. Possible explanations include confounding in the cohorts, trials too short for HbA1c to move, participants with near-normal glucose, and the choice of comparison food. A walnut that replaces white bread may perform differently from a walnut added on top of a usual diet.
• Long-term effects on HbA1c. The longest trial in type 2 diabetes ran one year with 50 people. Larger, longer trials with HbA1c as the main outcome have not been reported.
• Dose. Trials used 30 to 56 g a day. Whether smaller amounts, such as the one to two servings a week seen in the cohorts, change any blood marker has not been tested directly.
• Who responds. The NHANES analysis hinted at a stronger link in women, and gut-bacteria types vary between people, but neither has been tested in a trial designed for it.
• Quality. The 2020 meta-analysis rated every included trial as having some concerns or a high risk of bias, and the 2022 review found only one trial at low risk of bias for any outcome.

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Who the Research Raises Concerns For

• People with tree-nut allergy. Tree-nut allergies usually begin in childhood, rarely fade, and are among the main causes of fatal allergic reactions in children and adults; in the United States walnut is the most common tree-nut allergy (Kuźmiński 2021).
• People watching energy intake. The 56 g amounts used in several trials provide about 366 kcal on label values, although the body absorbs about a fifth less than labels predict (Baer 2016). The Ma 2010 trial in type 2 diabetes saw fasting glucose rise from baseline on an unrestricted walnut diet, though not significantly against the comparison diet.
• People taking glucose-lowering medicines. The walnut trials were not designed to study interactions with diabetes medicines, and walnut leaf extract, which did lower glucose in trials, is a different product from the nut. Decisions about diabetes treatment belong with a clinician.

For the conditions themselves, see Type 2 Diabetes, Prediabetes and Insulin Resistance.

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Connections

• Nuts — the section landing page
• Walnuts — the main topic page
• Walnuts — Benefits Deep Dive — the hub for every walnut article
• Walnuts: Nutrient Profile — the full composition table
• ALA Omega-3 and Brain — the walnut's omega-3 fat
• Heart Health and PREDIMED — the trial behind the diabetes sub-study
• Cognitive Aging — the WAHA trial
• Gut Microbiome and Urolithins — walnut polyphenols and gut bacteria
• Soaking and Phytates — preparation and minerals
• Pistachios: Blood Sugar and Diabetes — the parallel pistachio evidence
• Almonds: Blood Sugar and Diabetes — the parallel almond evidence
• Pecans: Insulin and Metabolic Health — another tree nut tested on insulin
• Type 2 Diabetes — the condition in full
• Prediabetes — the stage before diabetes
• Insulin Resistance — what HOMA-IR is measuring
• Metabolic Syndrome — the cluster several trials enrolled
• Hemoglobin A1C — the three-month blood-sugar test
• HOMA-IR — the insulin-resistance calculation
• Fasting Insulin — the marker the one-year trial moved
• Blood Sugar and Insulin (animation) — how insulin moves glucose
• Flaxseed: ALA Omega-3 and Heart Health — the other major ALA food

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Key Research Papers

1. Pan A, Sun Q, Manson JE, et al. Walnut consumption is associated with lower risk of type 2 diabetes in women. J Nutr. 2013;143(4):512-8. PubMed PMID: 23427333
2. Arab L, Dhaliwal SK, Martin CJ, et al. Association between walnut consumption and diabetes risk in NHANES. Diabetes/metabolism research and reviews. 2018;34(7):e3031. PubMed PMID: 29927053
3. Guasch-Ferré M, Hernández-Alonso P, Drouin-Chartier JP, et al. Walnut Consumption, Plasma Metabolomics, and Risk of Type 2 Diabetes and Cardiovascular Disease. J Nutr. 2021;151(2):303-311. PubMed PMID: 33382410
4. Tapsell LC, Gillen LJ, Patch CS, et al. Including walnuts in a low-fat/modified-fat diet improves HDL cholesterol-to-total cholesterol ratios in patients with type 2 diabetes. Diabetes care. 2004;27(12):2777-83. PubMed PMID: 15562184
5. Tapsell LC, Batterham MJ, Teuss G, et al. Long-term effects of increased dietary polyunsaturated fat from walnuts on metabolic parameters in type II diabetes. Eur J Clin Nutr. 2009;63(8):1008-15. PubMed PMID: 19352378
6. Ma Y, Njike VY, Millet J, et al. Effects of walnut consumption on endothelial function in type 2 diabetic subjects: a randomized controlled crossover trial. Diabetes Care. 2010;33(2):227-32. PubMed PMID: 19880586
7. Njike VY, Ayettey R, Petraro P, et al. Walnut ingestion in adults at risk for diabetes: effects on body composition, diet quality, and cardiac risk measures. BMJ Open Diabetes Res Care. 2015;3(1):e000115. PubMed PMID: 26688734
8. Njike VY, Yarandi N, Petraro P, et al. Inclusion of walnut in the diets of adults at risk for type 2 diabetes and their dietary pattern changes: a randomized, controlled, cross-over trial. BMJ Open Diabetes Res Care. 2016;4(1):e000293. PubMed PMID: 27843557
9. Hwang HJ, Liu Y, Kim HS, et al. Daily walnut intake improves metabolic syndrome status and increases circulating adiponectin levels: randomized controlled crossover trial. Nutr Res Pract. 2019;13(2):105-114. PubMed PMID: 30984354
10. Mukuddem-Petersen J, Stonehouse Oosthuizen W, Jerling JC, et al. Effects of a high walnut and high cashew nut diet on selected markers of the metabolic syndrome: a controlled feeding trial. Br J Nutr. 2007;97(6):1144-53. PubMed PMID: 17381974
11. Mateș L, Albert-Ani D, Fizeșan I, et al. Benefits of Short-Term (4-Week) Daily Walnut Consumption in Middle-Aged Adults at Risk for Metabolic Syndrome: Outcomes of a Randomized Controlled Trial. Nutrients. 2025;17(13):2072. PubMed PMID: 40647178
12. Brennan AM, Sweeney LL, Liu X, et al. Walnut consumption increases satiation but has no effect on insulin resistance or the metabolic profile over a 4-day period. Obesity (Silver Spring). 2010;18(6):1176-82. PubMed PMID: 19910942
13. Aronis KN, Vamvini MT, Chamberland JP, et al. Short-term walnut consumption increases circulating total adiponectin and apolipoprotein A concentrations, but does not affect markers of inflammation or vascular injury in obese humans with the metabolic syndrome: data from a double-blinded, randomized, placebo-controlled study. Metabolism. 2012;61(4):577-82. PubMed PMID: 22075273
14. Tuccinardi D, Farr OM, Upadhyay J, et al. Mechanisms underlying the cardiometabolic protective effect of walnut consumption in obese people: A cross-over, randomized, double-blind, controlled inpatient physiology study. Diabetes Obes Metab. 2019;21(9):2086-2095. PubMed PMID: 31087608
15. Tuccinardi D, Perakakis N, Farr OM, et al. Branched-Chain Amino Acids in relation to food preferences and insulin resistance in obese subjects consuming walnuts: A cross-over, randomized, double-blind, placebo-controlled inpatient physiology study. Clin Nutr. 2021;40(5):3032-3036. PubMed PMID: 33541836
16. Farr OM, Tuccinardi D, Upadhyay J, et al. Walnut consumption increases activation of the insula to highly desirable food cues: A randomized, double-blind, placebo-controlled, cross-over fMRI study. Diabetes Obes Metab. 2018;20(1):173-177. PubMed PMID: 28715141
17. Rodrigues LL, Cooper JA, Paton CM. Acute consumption of Black walnuts increases fullness and decreases lipid peroxidation in humans. Nutrition research (New York, N.Y.). 2019;71:56-64. PubMed PMID: 31757635
18. Lozano A, Perez-Martinez P, Marin C, et al. An acute intake of a walnut-enriched meal improves postprandial adiponectin response in healthy young adults. Nutr Res. 2013;33(12):1012-8. PubMed PMID: 24267040
19. Borkowski K, Yim SJ, Holt RR, et al. Walnuts change lipoprotein composition suppressing TNFα-stimulated cytokine production by diabetic adipocyte. The Journal of nutritional biochemistry. 2019;68:51-58. PubMed PMID: 31030167
20. Salas-Salvadó J, Bulló M, Babio N, et al. Reduction in the incidence of type 2 diabetes with the Mediterranean diet: results of the PREDIMED-Reus nutrition intervention randomized trial. Diabetes Care. 2011;34(1):14-9. PubMed PMID: 20929998
21. Estruch R, Ros E, Salas-Salvadó J, et al. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts. The New England journal of medicine. 2018;378(25):e34. PubMed PMID: 29897866
22. Neale EP, Guan V, Tapsell LC, et al. Effect of walnut consumption on markers of blood glucose control: a systematic review and meta-analysis. The British journal of nutrition. 2020;124(7):641-653. PubMed PMID: 32312354
23. Cahoon D, Shertukde SP, Avendano EE, et al. Walnut intake, cognitive outcomes and risk factors: a systematic review and meta-analysis. Annals of medicine. 2021;53(1):971-997. PubMed PMID: 34132152
24. Hadi A, Khosroshahi MZ, Zwamel AH, et al. Impact of walnut consumption on glycemic control and anthropometric indices: a systematic review and meta-analysis of randomized controlled trials. J Diabetes Metab Disord. 2025;24(1):62. PubMed PMID: 39911204
25. Mateș L, Popa DS, Rusu ME, et al. Walnut Intake Interventions Targeting Biomarkers of Metabolic Syndrome and Inflammation in Middle-Aged and Older Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Antioxidants (Basel). 2022;11(7):1412. PubMed PMID: 35883903
26. Lockyer S, de la Hunty AE, Steenson S, et al. Walnut consumption and health outcomes with public health relevance-a systematic review of cohort studies and randomized controlled trials published from 2017 to present. Nutr Rev. 2022;81(1):26-54. PubMed PMID: 35912883
27. Viguiliouk E, Kendall CW, Blanco Mejia S, et al. Effect of tree nuts on glycemic control in diabetes: a systematic review and meta-analysis of randomized controlled dietary trials. PLoS One. 2014;9(7):e103376. PubMed PMID: 25076495
28. Schwingshackl L, Hoffmann G, Lampousi AM, et al. Food groups and risk of type 2 diabetes mellitus: a systematic review and meta-analysis of prospective studies. European journal of epidemiology. 2017;32(5):363-375. PubMed PMID: 28397016
29. Banjarnahor RL, Javadi Arjmand E, Onni AT, et al. Umbrella Review of Systematic Reviews and Meta-Analyses on Consumption of Different Food Groups and Risk of Type 2 Diabetes Mellitus and Metabolic Syndrome. The Journal of nutrition. 2025;155(5):1285-1297. PubMed PMID: 40122387
30. Zibaeenezhad M, Aghasadeghi K, Hakimi H, et al. The Effect of Walnut Oil Consumption on Blood Sugar in Patients With Diabetes Mellitus Type 2. Int J Endocrinol Metab. 2016;14(3):e34889. PubMed PMID: 28115966
31. Zibaeenezhad MJ, Farhadi P, Attar A, et al. Effects of walnut oil on lipid profiles in hyperlipidemic type 2 diabetic patients: a randomized, double-blind, placebo-controlled trial. Nutr Diabetes. 2017;7(4):e259. PubMed PMID: 28394361
32. Mirzababaei A, Daneshvar M, Abaj F, et al. The Effect of Walnut (Juglans regia) Leaf Extract on Glycemic Control and Lipid Profile in Patients With Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Clinical Trials. Clin Nutr Res. 2022;11(2):120-132. PubMed PMID: 35558998
33. Baer DJ, Gebauer SK, Novotny JA. Walnuts Consumed by Healthy Adults Provide Less Available Energy than Predicted by the Atwater Factors. The Journal of nutrition. 2016;146(1):9-13. PubMed PMID: 26581681
34. Kuźmiński A, Przybyszewski M, Przybyszewska J, et al. Tree nut allergy. Postepy dermatologii i alergologii. 2021;38(4):544-549. PubMed PMID: 34658691

PubMed Topic Searches

1. PubMed: walnuts and type 2 diabetes in randomised trials
2. PubMed: walnuts, prediabetes and insulin resistance
3. PubMed: walnut intake and diabetes risk in cohorts
4. PubMed: walnuts and metabolic syndrome
5. PubMed: walnut peptides in diabetic animal models
6. PubMed: walnut leaf extract and type 2 diabetes

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