Clinical trial NCT06818032: Avocado and Postprandial Responses
Official title: Acute Avocado Consumption on Postprandial Glycemic and Appetite/Satiety Responses
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Healthy
Healthy Volunteer
Healthy Volunteers
Healthy Adult
Healthy Male and Female Subjects
Healthy Subjects
Healthy Volunteers Only
Healthy Non-smokers
Keywords: Persea Americana
blood glucose
blood insulin
adiponectin
leptin
GLP-1
appetite
satiety
glucose tolerance
GIP
ghrelin
Peptide YY (PYY)
glucose metabolism
dietary fats
meal challenge
meal tolerance test
dietary fiber
glycemia
Lead sponsor: University of Vermont Medical Center
Sponsor class: OTHER
Collaborators: name: Avocado Nutrition Center
First posted: 2025-02-10
Enrollment: 30
Sex: ALL
Minimum age (years): 21
Maximum age (years): 65
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: BASIC_SCIENCE

Brief summary: The purpose of this study is to see how adding avocado to a breakfast meal affects blood sugar control and signals of hunger and fullness after eating.

The investigators will test the effects of 3 breakfast meals on blood sugar control and signals of hunger and fullness after eating:

1. Whole-wheat bread and strawberry jam
2. Whole-wheat bread, strawberry jam, and avocado
3. Whole-wheat bread and strawberry jam (meal enriched with fat and fiber to mimic that of an avocado)

Participants will undergo 3 test periods, each separated by a week. Each test period consists of one day with set meals that the investigators will provide (breakfast, lunch, and dinner), and then the next morning, participants will eat a breakfast meal and have blood drawn several times over 4 hours.


Eligibility criteria: Inclusion Criteria:

* Biological sex males or females
* Age 21 to 65 years
* BMI between 18.5 and 34.9 kg/m2

Exclusion Criteria:

* Actively pregnant or lactating women
* Diagnosis of prediabetes or diabetes (fasting glucose \>100 mg/dL)
* Current diagnosis of uncontrolled hypertension (systolic BP: \>160 mmHg, diastolic BP: \>95 mmHg), may receive treatment for hypertension as long as on a stable regimen for the previous one month
* Current diagnosis of uncontrolled hyperlipidemia (fasting total blood cholesterol \>200 mg/dL, fasting triglycerides \>200 mg/dL), may receive treatment for hyperlipidemia as long as on a stable regimen for the previous one month
* Presence of kidney disease, liver disease, hyperthyroidism, untreated or unstable hypothyroidism, certain cancers, gastrointestinal disease, pancreatic disease, other chronic metabolic diseases or malabsorption syndromes, HIV, or inflammatory conditions (such as arthritis, asthma, Crohn's disease, inflammatory bowel disease, gout, Lupus)
* History of bariatric or certain other surgeries related to weight control
* Any medication used to lower blood glucose/antidiabetic medications \[including, but not limited to metformin, sulfonylureas, glucagon-like peptide-1 (GLP-1) analogues, sodium-glucose cotransporter-2 (SGL2) inhibitors, thiazolidinediones, dipeptidyl peptidase (DPP)-IV inhibitors\] as well as medications affecting weight, appetite/hunger or gut motility.
* Smoking or use of other tobacco products (during 6 months prior to the start of the study)
* Antibiotic use during the intervention or for 3 weeks prior to any treatment period
* History of eating disorders or other significant food preferences that would interfere with the diet intervention (e.g., vegan lifestyle, very low-fat diets, high-protein diets)
* Allergies or adverse reactions to study foods (e.g., gluten intolerance), or food aversions that would interfere with diet adherence
* Body weight loss of \>10% within the last 6 months prior to study start
* Unable or unwilling to give informed consent or communicate with study staff
* Self-report of alcohol or substance abuse within the past 12 months and/or current acute treatment or rehabilitation program for these problems (long-term participation in Alcoholics Anonymous is not an exclusion)
* Other medical, psychiatric, or behavioral factors that in the judgment of the Principal Investigator may interfere with study participation or the ability to follow the intervention protocol
* Undergoing hormonal therapy of any kind, with the exception of a stable regime for the prior 6 months to study start.

Primary outcomes:
measure: Diet-induced changes in postprandial glucose tolerance
timeFrame: 60-minute time point, 120-minute time point, incremental area under the curve from fasting to 180-minute time point
Secondary outcomes:
measure: Diet-induced changes in postprandial satiety hormones
timeFrame: 60-minute time point, 120-minute time point, incremental area under the curve from fasting to 180-minute time point
Other outcomes:
Locations:
city: Burlington
country: United States
facility: Clinical Research Center, University of Vermont Medical Center
state: Vermont
Study officials:
affiliation: University of Vermont
name: Jana Kraft, Ph.D.
role: PRINCIPAL_INVESTIGATOR
References:
citation: https://hassavocadoboard.com/happenings/2023-year-in-review/.
citation: Zhu L, Huang Y, Edirisinghe I, Park E, Burton-Freeman B. Using the Avocado to Test the Satiety Effects of a Fat-Fiber Combination in Place of Carbohydrate Energy in a Breakfast Meal in Overweight and Obese Men and Women: A Randomized Clinical Trial. Nutrients. 2019 Apr 26;11(5):952. doi: 10.3390/nu11050952.
citation: Wright J. Effect of high-carbohydrate versus high-monounsaturated fatty acid diet on metabolic control in diabetes and hyperglycemic patients. Clin Nutr. 1998 Sep;17 Suppl 2:35-45. doi: 10.1016/s0261-5614(98)80016-2. No abstract available.
citation: U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2020-2025. 9th Edition.
citation: Sanchez D, Miguel M, Aleixandre A. Dietary fiber, gut peptides, and adipocytokines. J Med Food. 2012 Mar;15(3):223-30. doi: 10.1089/jmf.2011.0072. Epub 2011 Dec 19.
citation: Rocca AS, LaGreca J, Kalitsky J, Brubaker PL. Monounsaturated fatty acid diets improve glycemic tolerance through increased secretion of glucagon-like peptide-1. Endocrinology. 2001 Mar;142(3):1148-55. doi: 10.1210/endo.142.3.8034.
citation: Qian F, Korat AA, Malik V, Hu FB. Metabolic Effects of Monounsaturated Fatty Acid-Enriched Diets Compared With Carbohydrate or Polyunsaturated Fatty Acid-Enriched Diets in Patients With Type 2 Diabetes: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Diabetes Care. 2016 Aug;39(8):1448-57. doi: 10.2337/dc16-0513.
citation: Pedreschi R, Uarrota V, Fuentealba C, Alvaro JE, Olmedo P, Defilippi BG, Meneses C, Campos-Vargas R. Primary Metabolism in Avocado Fruit. Front Plant Sci. 2019 Jun 26;10:795. doi: 10.3389/fpls.2019.00795. eCollection 2019.
citation: Park E, Edirisinghe I, Burton-Freeman B. Avocado Fruit on Postprandial Markers of Cardio-Metabolic Risk: A Randomized Controlled Dose Response Trial in Overweight and Obese Men and Women. Nutrients. 2018 Sep 12;10(9):1287. doi: 10.3390/nu10091287.
citation: Nansel TR, Lipsky LM, Liu A. Greater diet quality is associated with more optimal glycemic control in a longitudinal study of youth with type 1 diabetes. Am J Clin Nutr. 2016 Jul;104(1):81-7. doi: 10.3945/ajcn.115.126136. Epub 2016 May 18.
citation: Muller M, Canfora EE, Blaak EE. Gastrointestinal Transit Time, Glucose Homeostasis and Metabolic Health: Modulation by Dietary Fibers. Nutrients. 2018 Feb 28;10(3):275. doi: 10.3390/nu10030275.
citation: Levitan EB, Song Y, Ford ES, Liu S. Is nondiabetic hyperglycemia a risk factor for cardiovascular disease? A meta-analysis of prospective studies. Arch Intern Med. 2004 Oct 25;164(19):2147-55. doi: 10.1001/archinte.164.19.2147.
citation: Livesey G, Taylor R, Livesey HF, Buyken AE, Jenkins DJA, Augustin LSA, Sievenpiper JL, Barclay AW, Liu S, Wolever TMS, Willett WC, Brighenti F, Salas-Salvado J, Bjorck I, Rizkalla SW, Riccardi G, Vecchia C, Ceriello A, Trichopoulou A, Poli A, Astrup A, Kendall CWC, Ha MA, Baer-Sinnott S, Brand-Miller JC. Dietary Glycemic Index and Load and the Risk of Type 2 Diabetes: Assessment of Causal Relations. Nutrients. 2019 Jun 25;11(6):1436. doi: 10.3390/nu11061436.
citation: Ingram DK, Roth GS. Glycolytic inhibition: an effective strategy for developing calorie restriction mimetics. Geroscience. 2021 Jun;43(3):1159-1169. doi: 10.1007/s11357-020-00298-7. Epub 2020 Nov 12.
citation: Giuntini EB, Sarda FAH, de Menezes EW. The Effects of Soluble Dietary Fibers on Glycemic Response: An Overview and Futures Perspectives. Foods. 2022 Dec 6;11(23):3934. doi: 10.3390/foods11233934.
citation: Gillingham LG, Harris-Janz S, Jones PJ. Dietary monounsaturated fatty acids are protective against metabolic syndrome and cardiovascular disease risk factors. Lipids. 2011 Mar;46(3):209-28. doi: 10.1007/s11745-010-3524-y. Epub 2011 Feb 10.
citation: Ford NA, Spagnuolo P, Kraft J, Bauer E. Nutritional Composition of Hass Avocado Pulp. Foods. 2023 Jun 28;12(13):2516. doi: 10.3390/foods12132516.
citation: FoodData Central. Avocados, raw, California. Available online: https://fdc.nal.usda.gov/fdc-app.html#/food-details/171706/nutrients
citation: FruiTrop. Close-up avocado. In FruiTrop Magazine; Loeillet, D., Imbert, E., Eds.; Cirad: Montpellier, France, 2015; pp. 1-96.
citation: Akhlaghi M. The role of dietary fibers in regulating appetite, an overview of mechanisms and weight consequences. Crit Rev Food Sci Nutr. 2024;64(10):3139-3150. doi: 10.1080/10408398.2022.2130160. Epub 2022 Oct 4.
citation: Abdul-Ghani MA, Williams K, DeFronzo R, Stern M. Risk of progression to type 2 diabetes based on relationship between postload plasma glucose and fasting plasma glucose. Diabetes Care. 2006 Jul;29(7):1613-8. doi: 10.2337/dc05-1711.