Pecans: Cholesterol and Lipids

Table of Contents

1. What Is in a Pecan’s Fat
2. Plant Sterols and Fiber
3. How a Food Can Move Cholesterol
4. The 2001 Step I Diet Trial
5. Adding Pecans Versus Swapping Them In
6. Older Adults and LDL Particle Number
7. The Controlled Feeding Trial in Overweight Adults
8. Patients With Coronary Artery Disease
9. After a High-Fat Meal
10. Where Pecans Sit in the Pooled Evidence
11. The FDA’s 2003 Qualified Health Claim
12. What Is Not Known
13. Who the Research Raises Concerns For
14. Connections
15. Key Research Papers
16. Featured Videos

What Is in a Pecan’s Fat

The figures below are for raw pecan kernels from the United States Department of Agriculture’s FoodData Central entry 170182 (Nuts, pecans). The one-ounce column is the 100-gram value multiplied by 0.28 and rounded.

Worked out as shares of the fat, those numbers say that about 57 percent of a pecan’s fat is monounsaturated (almost all of it oleic acid), about 30 percent polyunsaturated (almost all linoleic acid) and under 9 percent saturated. Of the saturated fraction, palmitic acid makes up about 70 percent and stearic acid most of the rest. That is the profile cardiologists noticed: a whole food in which the fat that tends to raise LDL is scarce and the fats that tend to lower it when they replace saturated fat are abundant.

Two comparisons put it in context. Pecans carry far less omega-3 than walnuts — under one gram per 100 grams — so whatever pecans do to blood lipids is not an omega-3 story. And the oleic lean is shared with macadamias, avocado and olive oil, which is why those foods keep turning up in the same studies. Reviews of nut composition describe the same broad picture for pecans: unsaturated fatty acids alongside phytosterols, tocopherols and polyphenols (Maestri 2024; Sandhu 2025).

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Plant Sterols and Fiber

Plant sterols are the plant kingdom’s structural equivalent of cholesterol — molecules of almost the same shape that sit in plant cell membranes. FoodData Central lists, per 100 grams of raw pecans:

• Beta-sitosterol: 117 mg (about 33 mg per ounce)
• Campesterol: 6 mg
• Stigmasterol: 3 mg
• Other phytosterols: 32.8 mg, which the database footnote breaks into delta-5-avenasterol (14.3 mg), campestanol (2.8 mg), brassicasterol (0.5 mg) and other minor sterols (15.1 mg)

Beta-sitosterol is therefore the dominant sterol in a pecan by a wide margin. The FoodData Central entry does not give a single total-phytosterol figure for pecans; the named components add up to roughly 160 mg per 100 grams. A 2011 systematic review of tree-nut phytochemicals that covered pecans notes that measured sterol values depend heavily on the cultivar and on the solvents used to extract them, and that methods validated specifically for nuts are lacking (Bolling 2011) — so any single number is an estimate.

Sterols are only part of the non-fat package. A pecan also carries 9.6 grams of fiber per 100 grams, and the same review lists hypocholesterolaemic (cholesterol-lowering) actions among those attributed to tree-nut phytochemicals in general (Bolling 2011). How much of the lipid effect in the pecan trials comes from sterols and fiber, rather than from the fat swap, has not been separated in any pecan study.

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How a Food Can Move Cholesterol

Three ideas recur in the pecan papers to explain why the trials below found what they did. None of them has been isolated and tested inside a pecan trial; they are the explanations the researchers and reviewers offer.

1. The fat swap. When pecans enter a diet, some other food usually leaves it. If what leaves carried saturated fat or refined starch, the diet’s fat shifts toward oleic and linoleic acid. That swap toward monounsaturated fat is the premise the 2001 pecan trial was designed around.
2. Competition in the gut. Plant sterols look enough like cholesterol to compete with it for absorption in the small intestine, so some dietary and bile cholesterol leaves the body instead of being absorbed. The amount of beta-sitosterol in a handful of pecans is small, so this is a plausible contributor rather than a demonstrated one.
3. Fiber and bile. Some fiber holds onto bile acids in the gut. The liver makes bile acids from cholesterol, so losing more of them draws cholesterol out of circulation to replace them.

The trials measured outcomes, not these pathways. They report what happened to lipid numbers; they do not show which part of the nut did it.

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The 2001 Step I Diet Trial

The first well-known pecan lipid trial came from Loma Linda University in 2001 (Rajaram and colleagues, PMID 11533266). Its comparison was demanding. The control was the American Heart Association’s “Step I” diet of that era — already a cholesterol-lowering diet, with about 28 percent of energy from fat. The pecan diet was built by shrinking every food in the Step I diet by one fifth and filling that 20 percent of calories with pecans, which raised fat to about 40 percent of energy.

• Who: 23 adults (14 men, 9 women, mean age 38) with normal to moderately high cholesterol
• Design: single-blind, randomized crossover — everyone ate both diets, 4 weeks each
• Result versus the Step I diet: total cholesterol down a further 6.7 percent, LDL cholesterol down 10.4 percent, triglycerides down 11.1 percent, HDL cholesterol up slightly (2.5 mg/dL), apoB down 11.6 percent, lipoprotein(a) down 11.1 percent and apolipoprotein A1 up 2.2 percent; the abstract reports all differences as statistically significant and body weight as unchanged

The point of the design was that a higher-fat diet built around pecans beat a lower-fat diet on every lipid measure taken. The limits are equally plain: 23 people, four weeks per diet, and a dose — one fifth of all calories — far larger than a typical serving. The lipoprotein(a) result is unusual, because Lp(a) is largely set by genes and few diets move it; no later pecan trial in this page’s set reports Lp(a), so it stands as a single small finding.

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Adding Pecans Versus Swapping Them In

The largest modern pecan lipid trial asked a practical question the earlier work had not: does it matter whether people simply add pecans to what they already eat, or are told to cut other foods to make room? Researchers at the University of Georgia ran it for 8 weeks (Guarneiri 2021, The Journal of Nutrition).

• Who: 56 adults at higher cardiovascular risk — a BMI of 28 or more, or high cholesterol
• Groups: a nut-free control (18 people); an ADD group (16) who ate 68 g of pecans a day on top of their usual diet; a SUB group (18) who ate the same 68 g but swapped out foods of equal calories
• Dose: 68 g is about 2.4 ounces, close to 470 kcal by the USDA figures above — well over a typical handful

From baseline to 8 weeks, both pecan groups showed significant falls in fasting lipids, with no changes in the control group:

Post-meal triglycerides after a high-fat test meal fell in the ADD group, and post-meal glucose fell in the SUB group. The surprise was that the two pecan arms looked so alike: being told to substitute did not produce a clearly bigger lipid change than simply adding the nuts. These are within-group changes from baseline; the abstract reports the control group as unchanged rather than giving a full between-group comparison for each measure.

The same research group reported other outcomes in companion papers. In an 8-week trial of the same ADD/SUB/control design with 93 adults, body weight rose in every group, including control, with a trend (P = 0.09) toward more gain in the pecan arms (1.1 kg ADD, 0.9 kg SUB, 0.3 kg control); body-fat percentage rose in the SUB group only. Actual weight gain was far below the roughly 3.2–3.3 kg predicted if the pecan calories had not been offset at all, and the authors conclude that 8 weeks of pecans did not cause significant weight gain (Guarneiri 2022, Journal of Nutritional Science). An energy-metabolism analysis of the 56-person trial (47 completers) found higher fasting resting metabolic rate and fat oxidation within the SUB group, but no differences between groups for any outcome (Guarneiri 2022, Journal of Human Nutrition and Dietetics).

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Older Adults and LDL Particle Number

A shorter trial from the same Georgia group turned to older adults and added a measure the earlier pecan work lacked: the number of LDL particles, counted directly by lipoprotein analysis (Cogan 2023, Nutrition Research).

• Who: 44 older adults, average age 59
• Groups: 68 g of pecans a day (21 people) versus a control group who ate no nuts at all (23 people)
• Duration: 4 weeks

This time the comparison was between groups, which is the stronger test. Compared with control, the pecan group had greater reductions in:

• Fasting total cholesterol: −14 mg/dL versus −0.2 mg/dL
• LDL cholesterol: −15 mg/dL versus +1.9 mg/dL
• Non-HDL cholesterol: −15 mg/dL versus −0.5 mg/dL
• LDL particle number: −126 nmol/L versus +43 nmol/L
• Medium-sized LDL particles: −34 nmol/L versus +16 nmol/L

Post-meal triglycerides after a high-fat test meal were suppressed in the pecan group and not in control. On blood vessels, the result was mixed: post-meal microvascular reactivity (how quickly small vessels re-open after a brief blockage, measured by near-infrared light) differed in favour of pecans, but fasting macrovascular function (flow-mediated dilation of the arm artery) and fasting microvascular function were unaffected — a null finding worth keeping beside the positive ones.

This is the only trial in the pack that measured lipoprotein particles directly. Because each LDL particle carries one apoB molecule, the particle-count result points the same way as the apoB fall in the 8-week trial above: fewer particles, not just less cholesterol per particle. It is one trial of 44 people over a month.

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The Controlled Feeding Trial in Overweight Adults

A 2018 trial from Tufts University took a different approach: participants were given a pecan-rich diet and, in the other period, an isocaloric control diet designed to match it in total fat and fiber but without nuts (McKay 2018, Nutrients). Participants were healthy middle-aged and older adults who were overweight or obese with central adiposity, and each diet ran 4 weeks.

The results the abstract reports as significant are about insulin, not cholesterol: compared with control, the pecan diet produced greater changes in serum insulin, insulin resistance (HOMA-IR) and beta-cell function (HOMA-β), and a better score on a composite of cardiometabolic risk markers. The abstract does not report a separate significant LDL or total cholesterol result. That is worth noticing, because the control diet was matched for fat and fiber — exactly the features thought to drive the lipid effect — so it removed much of the contrast the 2001 and 2021 trials relied on. The insulin findings are covered on the parallel page, Pecans: Insulin and Metabolic Health.

On funding, the abstract states that the study’s sponsors had no role in its design, data collection, analysis, interpretation or the decision to publish; it does not name them.

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Patients With Coronary Artery Disease

The biggest pecan trial by enrolment was run in Porto Alegre, Brazil, in people who already had stable coronary artery disease. Over 12 weeks, 204 patients were assigned to a healthy diet alone (67), a healthy diet plus 30 g of pecans a day (68), or a healthy diet plus 30 mL of extra-virgin olive oil a day (69). Two papers from that trial are in the pack:

• Glycemic profile: the primary outcome was the triglyceride-glucose (TyG) index, a combined marker of triglycerides and fasting glucose. After adjustment, there were no differences between groups in glycemic or body-fat-distribution measures at 12 weeks. The pecan group did improve its overall diet-quality score (Alternate Healthy Eating Index) compared with both other groups (dos Santos 2022).
• Inflammation: no differences between groups in hs-CRP, fibrinogen, interleukins or interferon-γ; IL-6 fell in all three groups, including the diet-only control (Weschenfelder 2022).

These are null results, and they matter. The dose here — 30 g, close to one ounce — is the closest to a typical serving in the whole set, the analyses adjusted for statin use, and the comparison was against a healthy diet rather than a typical one. The abstracts in the pack do not report the trial’s cholesterol results separately, so this page does not state them.

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After a High-Fat Meal

Most lipid tests are taken fasting, but people spend most of the day in the hours after a meal, when triglyceride-rich particles from food are circulating. Several pecan trials gave participants a high-saturated-fat test meal before and after the diet period and drew blood over the following hours:

• In the 8-week adults-at-risk trial, post-meal triglycerides fell in the ADD group (Guarneiri 2021, The Journal of Nutrition).
• In the 4-week older-adult trial, post-meal triglycerides were suppressed in the pecan group compared with control (Cogan 2023, Nutrition Research).
• In the same two trial programmes, post-meal lipid peroxidation — damage to fats by oxidation, measured as malondialdehyde — was suppressed after the pecan period, and total antioxidant capacity rose in the 8-week trial (Guarneiri 2021, Nutrition Research; Cogan 2023, Journal of Medicinal Food). In the 4-week trial there were no differences in fasting or post-meal antioxidant capacity, glucose or insulin.

The oxidation side of this story — gamma-tocopherol, the polyphenols in the skin, and oxidized LDL — is covered in depth on the parallel page Pecans: Antioxidants and Oxidized LDL.

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Where Pecans Sit in the Pooled Evidence

Five or six pecan trials cannot settle a question on their own, so the larger context comes from meta-analyses that pool many nut trials. In every one below, pecans are a small minority of the trials, and none of the abstracts gives a pecan-specific estimate.

• Nishi 2025 (113 trials, 8,060 adults). At a median of 45.5 g of nuts a day compared with no nuts, nut intake produced moderate reductions in total cholesterol (−0.14 mmol/L, about 5 mg/dL) and LDL cholesterol (−0.12 mmol/L, about 5 mg/dL), and small reductions in triglycerides, the TC:HDL and LDL:HDL ratios and apoB (−0.04 g/L). There was no significant effect on HDL. Certainty of evidence was rated high for apolipoprotein A and generally moderate or low for the other outcomes. The authors’ disclosures, printed with the abstract, include research support and fees from nut-industry and food-industry bodies, which they state had no role in the study.
• Houston 2023 (139 studies, 129 in the meta-analysis), tree nuts and peanuts. Significant decreases in LDL cholesterol, total cholesterol, triglycerides, the TC:HDL and LDL:HDL ratios and apoB. The authors rated certainty as moderate for the ratios and apoB, low for triglycerides, and very low for LDL and total cholesterol because of inconsistency and likely publication bias.
• Liu 2020 (network meta-analysis, 34 trials, 1,677 people). Compared walnut-, pistachio-, hazelnut-, cashew- and almond-enriched diets head to head; pistachios ranked best for lowering triglycerides, LDL and total cholesterol. Pecans were not among the nuts compared, and the authors rated the evidence quality as low.
• Gunathilake 2022. Found no significant overall effect of nut consumption on the lipid profile, with nut-type differences (a total-cholesterol fall for pistachios, an HDL rise for cashews). The journal later published an expression of concern about this paper, so its result carries less weight than the others.

Read together, the pooled trials point to a modest LDL and apoB reduction from nuts in general, of a size well below what the 68 g pecan trials reported within groups, and with real disagreement between analyses about how certain it is. The pecan trials sit comfortably inside that picture: their direction matches, and their larger numbers come from small samples and doses above the pooled median. A 2025 review devoted to pecans summarizes the human trials the same way — replacing foods or snacks with pecans improved diet quality and lipid profiles, while effects on vascular function, blood sugar and inflammation were inconsistent (Sandhu 2025). The authors’ statement in the abstract notes that the funders had no role in the review.

For the broader cross-nut picture, see the site’s Nut Benefits overview and the peanut page Heart Health, Cholesterol and Long-Term Mortality.

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The FDA’s 2003 Qualified Health Claim

On July 14, 2003, the U.S. Food and Drug Administration issued a letter of enforcement discretion for a qualified health claim on nuts and coronary heart disease (FDA letter, Docket 02P-0505; listed on the FDA’s Qualified Health Claims: Letters of Enforcement Discretion page). The permitted wording is:

“Scientific evidence suggests but does not prove that eating 1.5 ounces per day of most nuts [, such as name of specific nut,] as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease.”

The petition covered peanuts and nine tree nuts. The FDA allowed the claim for nuts including pecans, and excluded Brazil nuts, macadamias, cashews and some pine nut varieties because their saturated fat exceeded the disqualifying level. Three things about the claim are worth knowing:

• A qualified claim is a lower tier than an authorized health claim: the agency permits it with the “suggests but does not prove” wording because the evidence does not meet the significant-scientific-agreement standard.
• It is about heart disease risk, not about cholesterol numbers directly, and it ties the nuts to a diet low in saturated fat and cholesterol.
• The 1.5 ounces in the claim is about 42 g — between the 30 g used in the Brazilian trial and the 68 g used in the Georgia trials.

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What Is Not Known

• Heart attacks and strokes. No pecan trial was designed or long enough to measure cardiovascular events. Every result on this page is a blood marker.
• Durability. The longest pecan lipid trial ran 12 weeks; most ran 4 to 8. Whether the changes hold over years is untested.
• Realistic doses. The clearest lipid results came at 68 g a day or at one fifth of calories. The one trial at about an ounce a day, in heart patients on a healthy diet, found no differences in the outcomes its pack abstracts report.
• Which component matters. No pecan study has separated the fat swap from the sterols, fiber or polyphenols.
• Who was studied. Samples were small — 23, 44 and 56 people in the three clearest lipid trials — and drawn from a few research centres. The Lp(a) fall in 2001 has not been repeated in the trials here.
• Pecans specifically, in pooled data. The meta-analyses either pool all nuts or, in the one network analysis, leave pecans out entirely.
• Roasted, salted or sweetened pecans. The trials used plain pecans; candied and praline products add sugar that none of these studies tested.

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Who the Research Raises Concerns For

• People with tree-nut allergy. Tree-nut allergy, pecans included, usually begins in childhood, rarely fades and is among the main causes of fatal allergic reactions in children and adults (Kuźmiński 2021). Pecans and walnuts are closely related: in a study of 76 walnut-sensitized patients, 49 of the 61 who were walnut-allergic were also pecan-allergic, none of the walnut-tolerant patients reacted to pecan, and laboratory tests suggested pecan carries a subset of walnut’s allergenic determinants (Elizur 2020).
• People watching calories or weight. The doses in the Georgia trials are near 470 kcal a day. Weight rose slightly in every group of the 8-week trial, with a non-significant trend toward more gain on pecans and a rise in body-fat percentage in the swap group, though far less than the calories predicted (Guarneiri 2022).
• People on cholesterol medicines. The Brazilian trial adjusted for statin use, but no pecan trial was designed to test pecans alongside lipid-lowering drugs. Decisions about such medicines belong with a clinician.

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Connections

• Nuts — the section landing page
• Pecans — the main topic page
• Pecans — Benefits Deep Dive — the hub for the pecan articles
• Pecans: Antioxidants and Oxidized LDL — the post-meal oxidation trials
• Pecans: Insulin and Metabolic Health — the insulin results
• Pecans: Nutrient Profile — the full composition table
• Nut Benefits — the cross-nut evidence
• Lipid Panel — the numbers these trials moved
• ApoB — the particle-count test
• Lipoprotein(a) — the 2001 trial’s unusual finding
• Cholesterol Management — the wider picture
• Atherosclerosis — what the lipid findings are ultimately about
• Cholesterol and Lipoproteins — an animation of how the particles work
• Almonds: Heart Health and LDL — the same question for almonds
• Peanuts: Heart Health and Mortality — trials and cohorts for peanuts
• Macadamias — the other oleic-rich nut
• Walnuts — pecan’s botanical relative
• Olive Oil — the comparison arm in the Brazilian trial

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Key Research Papers

1. Guarneiri LL, Paton CM, Cooper JA. Pecan-Enriched Diets Alter Cholesterol Profiles and Triglycerides in Adults at Risk for Cardiovascular Disease in a Randomized, Controlled Trial. The Journal of nutrition. 2021;151(10):3091-3101. PubMed PMID: 34383903
2. Cogan B, Pearson RC, Paton CM, et al. Pecan-enriched diet improves cholesterol profiles and enhances postprandial microvascular reactivity in older adults. Nutrition research (New York, N.Y.). 2023;111:44-58. PubMed PMID: 36822079
3. McKay DL, Eliasziw M, Chen CYO, et al. A Pecan-Rich Diet Improves Cardiometabolic Risk Factors in Overweight and Obese Adults: A Randomized Controlled Trial. Nutrients. 2018;10(3). PubMed PMID: 29534487
4. Guarneiri LL, Paton CM, Cooper JA. Pecan-enriched diets decrease postprandial lipid peroxidation and increase total antioxidant capacity in adults at-risk for cardiovascular disease. Nutrition research (New York, N.Y.). 2021;93:69-78. PubMed PMID: 34428717
5. Cogan B, Pearson RC, Jenkins NT, et al. A 4-Week Pecan-Enriched Diet Improves Postprandial Lipid Peroxidation in Aging Adults. Journal of medicinal food. 2023;26(9):654-662. PubMed PMID: 37638838
6. Guarneiri LL, Paton CM, Cooper JA. Changes in body weight in response to pecan-enriched diets with and without substitution instructions: a randomised, controlled trial. Journal of nutritional science. 2022;11:e16. PubMed PMID: 35320927
7. Guarneiri LL, Paton CM, Cooper JA. Pecan-enriched diets increase energy expenditure and fat oxidation in adults at-risk for cardiovascular disease in a randomised, controlled trial. Journal of human nutrition and dietetics : the official journal of the British Dietetic Association. 2022;35(5):774-785. PubMed PMID: 34841598
8. Dos Santos JL, Portal VL, Markoski MM, et al. Effect of pecan nuts and extra-virgin olive oil on glycemic profile and nontraditional anthropometric indexes in patients with coronary artery disease: a randomized clinical trial. European journal of clinical nutrition. 2022;76(6):827-834. PubMed PMID: 34811509
9. Weschenfelder C, Gottschall CBA, Markoski MM, et al. Effects of supplementing a healthy diet with pecan nuts or extra-virgin olive oil on inflammatory profile of patients with stable coronary artery disease: a randomised clinical trial. The British journal of nutrition. 2022;127(6):862-871. PubMed PMID: 33971993
10. Nishi SK, Paz-Graniel I, Ni J, et al. Effect of nut consumption on blood lipids: An updated systematic review and meta-analysis of randomized controlled trials. Nutrition, metabolism, and cardiovascular diseases : NMCD. 2025;35(5):103771. PubMed PMID: 39638677
11. Houston L, Probst YC, Chandra Singh M, et al. Tree Nut and Peanut Consumption and Risk of Cardiovascular Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Advances in nutrition (Bethesda, Md.). 2023;14(5):1029-1049. PubMed PMID: 37149262
12. Liu K, Hui S, Wang B, et al. Comparative effects of different types of tree nut consumption on blood lipids: a network meta-analysis of clinical trials. The American journal of clinical nutrition. 2020;111(1):219-227. PubMed PMID: 31773150
13. Gunathilake M, Van NTH, Kim J. Effects of nut consumption on blood lipid profile: A meta-analysis of randomized controlled trials. Nutrition, metabolism, and cardiovascular diseases : NMCD. 2022;32(3):537-549. PubMed PMID: 35144856 (Editorial note: the journal published an expression of concern about this article in 2023.)
14. Sandhu AK, Edirisinghe I, Burton-Freeman B. Pecans and Human Health: Distinctive Benefits of an American Nut. Nutrients. 2025;17(23). PubMed PMID: 41373975
15. Bolling BW, Chen CY, McKay DL, et al. Tree nut phytochemicals: composition, antioxidant capacity, bioactivity, impact factors. A systematic review of almonds, Brazils, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts. Nutrition research reviews. 2011;24(2):244-75. PubMed PMID: 22153059
16. Maestri D. Groundnut and tree nuts: a comprehensive review on their lipid components, phytochemicals, and nutraceutical properties. Critical reviews in food science and nutrition. 2024;64(21):7426-7450. PubMed PMID: 39093582
17. Elizur A, Appel MY, Nachshon L, et al. Clinical and Molecular Characterization of Walnut and Pecan Allergy (NUT CRACKER Study). The journal of allergy and clinical immunology. In practice. 2020;8(1):157-165.e2. PubMed PMID: 31513892
18. Kuźmiński A, Przybyszewski M, Przybyszewska J, et al. Tree nut allergy. Postepy dermatologii i alergologii. 2021;38(4):544-549. PubMed PMID: 34658691
19. Rajaram S, Burke K, Connell B, et al. A monounsaturated fatty acid-rich pecan-enriched diet favorably alters the serum lipid profile of healthy men and women. J Nutr. 2001;131(9):2275-9. PubMed PMID: 11533266

PubMed Topic Searches

1. Pecans and cholesterol, lipoproteins or triglycerides
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