Pecan Consumption for Cardiometabolic Health

Overseen By Jamie A Cooper, Ph.D.

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of Georgia

Must not be taking: Thyroid meds, Lipid-lowering, Diabetes, Blood thinners

Disqualifiers: Familial hypercholesterolemia, Alcohol, Food allergies, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 6

80 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

The bioactive compounds contained in tree nuts have been shown to beneficially affect cardiometabolic health outcomes. Pecans contain more total phenols, sterols, and flavonoids than any other tree nut. They also are a rich source of polyunsaturated fatty acids (PUFAs), fiber, vitamin A, vitamin E, folic acid, calcium, magnesium, phosphorus, potassium, and zinc. These bioactive components in pecans are likely the reason for the previously documented improvements in cardiometabolic health. The specific aims of this study are to: * Examine the effect of pecan consumption at doses of 6%, 13%, and 20% of total energy needs on fasting and postprandial blood lipids. * Examine the effect of pecan consumption at doses of 6%, 13%, and 20% of total energy needs on plasma markers associated with overall health. * Examine the effect of pecan consumption at doses of 6%, 13%, and 20% of total energy needs on subjective and physiologic postprandial measures of hunger and satiety. Participants will be asked to: * Consume pecans daily for 28 days or maintain their current habitual diet. * Attend three short weekly visits for fasting blood craws, body measurements, and collect their next week's supply of study materials. * Attend two longer (5 h) testing visits which include consuming a standard breakfast meal and having their blood drawn periodically before and after breakfast. Researchers will compare pecan LOW, pecan MID, pecan HIGH, and the Control group to examine the physiologic effects of incorporating various dosages of pecans into one's diet.

Will I have to stop taking my current medications?

Yes, you may need to stop taking certain medications. The trial excludes participants using medications that affect digestion, absorption, metabolism, lipid levels, diabetes, blood thinning, and steroid/hormone therapies.

Is pecan consumption safe for humans?

Research suggests that consuming pecans is generally safe for humans and may even improve heart health by lowering cholesterol and other risk factors for heart disease. ^{1 2 3 4 5}

How does pecan consumption as a treatment for cardiometabolic health differ from other treatments?

Pecan consumption is unique because it involves eating a natural food rich in healthy fats, which can improve heart health by lowering bad cholesterol and improving insulin function, unlike many standard treatments that may rely on medications. ^{1 4 6 7 8}

What data supports the effectiveness of this treatment for cardiometabolic health?

Research shows that a diet rich in pecans can improve markers related to heart and metabolic health, such as lowering bad cholesterol and improving insulin function, in people who are overweight or at risk for heart disease. ^{1 4 5 9 10}

Who Is on the Research Team?

Jamie A Cooper, Ph.D.

Principal Investigator

University of Georgia

Are You a Good Fit for This Trial?

This trial is for men and women aged 30-75 with overweight or obesity (BMI >28 kg/m2) and elevated cholesterol levels. It's not for those planning to change their diet/exercise, with food allergies to nuts/gluten/dairy, on special diets like keto or vegetarian, using certain medications, smokers, pregnant/lactating women, or with a history of serious health conditions.

Inclusion Criteria

You are significantly above a healthy weight based on your body mass index (BMI).

My cholesterol levels are borderline high or at risk in two or more categories, or high in any.

I am between 30 and 75 years old with high cholesterol or I am overweight.

Exclusion Criteria

Your blood pressure is higher than 180/120 mmHg.

You smoke or use nicotine products.

I have a history of issues that could affect my digestion or swallowing.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

1 week

1 visit (in-person)

Pre-intervention

Participants undergo baseline measurements and a high-saturated-fat meal challenge

1 day

1 visit (in-person)

Dietary Intervention

Participants consume pecans daily for 28 days or maintain their current habitual diet

4 weeks

3 short weekly visits (in-person), 2 longer testing visits (in-person)

Post-intervention

Participants undergo post-intervention measurements and repeat the high-saturated-fat meal challenge

1 day

1 visit (in-person)

Follow-up

Participants are monitored for safety and effectiveness after the intervention

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• CONTROL
• Pecan HIGH
• Pecan LOW
• Pecan MID

Trial Overview The study tests the effects of daily pecan consumption at different doses (low, mid, high) compared to no pecans (control) over 28 days. Researchers will monitor changes in blood lipids and markers of hunger/satiety after a standard breakfast meal.

How Is the Trial Designed?

Group I: Pecan MID Experimental Treatment 1 Intervention

Participants are given pecans and instructed on how to substitute study foods into their diet to maintain caloric balance.

Group II: Pecan LOW Experimental Treatment 1 Intervention

Participants are given pecans and instructed on how to substitute study foods into their diet to maintain caloric balance.

Group III: Pecan HIGH Experimental Treatment 1 Intervention

Participants are given pecans and instructed on how to substitute study foods into their diet to maintain caloric balance.

Group IV: CONTROL Experimental Treatment 1 Intervention

Participants are asked to maintain their current habitual diet and avoid any tree nut/peanut consumption for the entire 28-day intervention period.

Who Is Running the Clinical Trial?

University of Georgia

Lead Sponsor

Trials

109

Recruited

43,500+

Published Research Related to This Trial

A 4-week randomized controlled trial showed that a pecan-rich diet significantly improved serum insulin levels and insulin resistance compared to a control diet in healthy middle-aged and older adults who are overweight or obese.

Pecan consumption also led to a clinically significant reduction in cardiometabolic disease risk, as indicated by improvements in various biomarkers related to cardiovascular disease and type 2 diabetes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A Pecan-Rich Diet Improves Cardiometabolic Risk Factors in Overweight and Obese Adults: A Randomized Controlled Trial. McKay, DL., Eliasziw, M., Chen, CYO., et al.[2018]

In a study involving 23 participants, a pecan-enriched diet significantly improved serum lipid profiles by reducing total and LDL cholesterol and triglycerides compared to a standard Step I diet, while also increasing HDL cholesterol.

Replacing 20% of a Step I diet with pecans did not lead to weight gain, suggesting that incorporating pecans into a cholesterol-lowering diet can be both effective and safe.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A monounsaturated fatty acid-rich pecan-enriched diet favorably alters the serum lipid profile of healthy men and women. Rajaram, S., Burke, K., Connell, B., et al.[2018]

In a 12-week randomized clinical trial involving 204 patients with stable coronary artery disease, adding 30 g of pecan nuts to a healthy diet significantly reduced non-HDL cholesterol and improved the total cholesterol/HDL cholesterol ratio compared to a control group and a group receiving extra-virgin olive oil.

While the pecan nut supplementation did not affect LDL cholesterol levels, it suggests potential benefits for other lipid profile markers, indicating that pecans may be a valuable addition to dietary strategies for managing cholesterol in CAD patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effects of a healthy diet enriched or not with pecan nuts or extra-virgin olive oil on the lipid profile of patients with stable coronary artery disease: a randomised clinical trial. Campos, VP., Portal, VL., Markoski, MM., et al.[2021]

In a study involving 56 sedentary adults at risk for cardiovascular disease, daily consumption of pecans for 8 weeks led to significant increases in resting metabolic rate and fat oxidation in those who substituted pecans for other foods in their diet.

Participants who added pecans to their diet experienced increased postprandial diet-induced thermogenesis, suggesting that incorporating pecans may enhance energy expenditure and fat metabolism.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Pecan-enriched diets increase energy expenditure and fat oxidation in adults at-risk for cardiovascular disease in a randomised, controlled trial. Guarneiri, LL., Paton, CM., Cooper, JA.[2022]

In a 12-week clinical trial involving 204 patients with stable coronary artery disease, adding pecan nuts or extra-virgin olive oil to a healthy diet did not significantly change glycemic or anthropometric profiles compared to a control group.

However, the group that consumed pecan nuts showed a significant improvement in diet quality, suggesting that while these foods may not directly impact glycemic control, they can enhance overall dietary habits.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

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. Dos Santos, JL., Portal, VL., Markoski, MM., et al.[2022]

A systematic review and meta-analysis of 139 studies found that consuming tree nuts and peanuts significantly reduces several cardiovascular disease (CVD) risk factors, including LDL cholesterol, total cholesterol, and triglycerides.

Despite the positive findings, the overall quality of evidence was low for many outcomes, indicating that while nuts can contribute to CVD risk reduction, further high-quality research is needed to confirm these benefits.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Tree Nut and Peanut Consumption and Risk of Cardiovascular Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Houston, L., Probst, YC., Chandra Singh, M., et al.[2023]

Whole pecans (HF+WP diet) were the most effective in preventing high levels of leptin and reducing total cholesterol in male Wistar rats, suggesting that both the oil and polyphenols contribute to their health benefits.

The whole pecan diet also enhanced liver enzyme activities that protect against oxidative stress and reduced lipid peroxidation, indicating a strong bioactive effect compared to diets supplemented with just pecan oil or polyphenols.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The pecan nut (Carya illinoinensis) and its oil and polyphenolic fractions differentially modulate lipid metabolism and the antioxidant enzyme activities in rats fed high-fat diets. Domínguez-Avila, JA., Alvarez-Parrilla, E., López-Díaz, JA., et al.[2018]

Daily consumption of pecans for 8 weeks improved markers of appetite, such as increased levels of cholecystokinin (CCK) and peptide YY (PYY), and decreased levels of ghrelin in adults at risk for cardiovascular disease.

Participants who added pecans to their diet reported a greater reduction in appetite and desire to eat compared to those who substituted pecans for other foods or had no nuts, suggesting that pecans can enhance feelings of fullness.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Appetite responses to pecan-enriched diets. Guarneiri, LL., Paton, CM., Cooper, JA.[2022]

In an 8-week study with 19 participants, those consuming 68 g of pecans daily showed a significant reduction in LDL cholesterol levels, indicating that pecans can help improve lipid profiles.

At the end of the study, the pecan group had lower total cholesterol and HDL cholesterol levels compared to the control group, suggesting that incorporating pecans into a diet may be beneficial for heart health without affecting body weight.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Pecans lower low-density lipoprotein cholesterol in people with normal lipid levels. Morgan, WA., Clayshulte, BJ.[2022]

In a randomized controlled trial involving 56 adults at risk for cardiovascular disease, daily consumption of pecans significantly reduced fasting total cholesterol, LDL cholesterol, and triglycerides over 8 weeks.

Both groups consuming pecans (either added to their diet or substituted for other foods) showed improvements in blood lipids, with the ADD group also experiencing reduced postprandial triglycerides and the SUB group showing lower postprandial glucose levels.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Pecan-Enriched Diets Alter Cholesterol Profiles and Triglycerides in Adults at Risk for Cardiovascular Disease in a Randomized, Controlled Trial. Guarneiri, LL., Paton, CM., Cooper, JA.[2023]

Citations

1. Switzerland pubmed.ncbi.nlm.nih.gov

A Pecan-Rich Diet Improves Cardiometabolic Risk Factors in Overweight and Obese Adults: A Randomized Controlled Trial. [2018]

2. United States pubmed.ncbi.nlm.nih.gov

A monounsaturated fatty acid-rich pecan-enriched diet favorably alters the serum lipid profile of healthy men and women. [2018]

3. England pubmed.ncbi.nlm.nih.gov

Effects of a healthy diet enriched or not with pecan nuts or extra-virgin olive oil on the lipid profile of patients with stable coronary artery disease: a randomised clinical trial. [2021]

4. England pubmed.ncbi.nlm.nih.gov

Pecan-enriched diets increase energy expenditure and fat oxidation in adults at-risk for cardiovascular disease in a randomised, controlled trial. [2022]

5. England pubmed.ncbi.nlm.nih.gov

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. [2022]

6. United States pubmed.ncbi.nlm.nih.gov

Tree Nut and Peanut Consumption and Risk of Cardiovascular Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. [2023]

7. England pubmed.ncbi.nlm.nih.gov

The pecan nut (Carya illinoinensis) and its oil and polyphenolic fractions differentially modulate lipid metabolism and the antioxidant enzyme activities in rats fed high-fat diets. [2018]

8. England pubmed.ncbi.nlm.nih.gov

Appetite responses to pecan-enriched diets. [2022]

9. United States pubmed.ncbi.nlm.nih.gov

Pecans lower low-density lipoprotein cholesterol in people with normal lipid levels. [2022]

10. United States pubmed.ncbi.nlm.nih.gov

Pecan-Enriched Diets Alter Cholesterol Profiles and Triglycerides in Adults at Risk for Cardiovascular Disease in a Randomized, Controlled Trial. [2023]