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Effect of Strawberry Consumption on the Microbiome

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT04217122
Recruitment Status : Completed
First Posted : January 3, 2020
Last Update Posted : January 7, 2020
Information provided by (Responsible Party):
Zhaoping Li, University of California, Los Angeles

Brief Summary:
This pilot study will assess the ability of daily consumption of two servings of California strawberries to alter gut microbiome composition, leading to increased bile secretion and decreased plasma cholesterol in a free-living population.

Condition or disease Intervention/treatment Phase
Microbiome Other: strawberry powder Other: placebo powder Not Applicable

Detailed Description:

This will be a randomized, double-blinded, placebo controlled, parallel design. Thirty subjects will be randomized to consume two servings of standardized freeze-dried strawberry powder (2 x 13g) daily or placebo for 4 weeks, followed by 2 weeks of follow up with beige diet only to observe whether the effect can be sustained for 2 weeks. Blood will be collected at baseline (week 0), weeks 4 and week 6 after strawberry consumption. On the day prior to the study visits participants will collect a stool and a 24-hr urine sample and bring to the lab. In addition, body weight and composition will be determined and questionnaires and 3-day food record will be completed. Twenty-four hour urine content of pelargonidin glucuronide will be measured for compliance. Plasma and fecal cholesterol and bile acids will be determined at baseline (week 0) and weeks 4 and 6.

Subjects will be assigned an enrollment number after signing the informed consent form approved by the UCLA Medical Internal Review Board. Subjects will undergo a physical exam, complete medical history, and blood draw. A standard chem. panel will be performed at the UCLA clinical laboratory. Eligible subjects will be enrolled into the study upon completion of screening evaluations and will be randomized to the strawberry or placebo arm at their baseline visit.

The study will be conducted in healthy free-living subjects (18-55 years). Subjects consume 13 grams standard strawberry powder in the morning and afternoon/evening or placebo powder for 4 weeks. Subjects will be instructed to eat a beige diet (low fiber<10g and low polyphenols <3 servings of polyphenol rich fruit/vegetables per day) during the entire study period. 24 hr urine pelargonidin glucuronide will be measured at weeks 2 (baseline), 6 and 8 for compliance. In addition, pelargondin, ellagic acid, dimethylellagic acid glucuronide and urolithin glucuronide will be measured in plasma and urine to determine strawberry phytochemical bioavailability and intestinal/microbiome metabolic capacity. Participants will meet with the dietitian for assessment of habitual dietary pattern and instructions on maintain on a beige diet. A list of foods with high fiber and phenolic compounds will be provided and subjects are instructed to follow the diet during the entirety of the study.

A standardized freeze-dried strawberry powder and a strawberry placebo powder provided by the California Strawberry Commission will be used. Ten grams of freeze dried powder is equivalent to about 110 g fresh fruit. One serving of fresh strawberry (one cup) is estimated to weigh 144 g and therefore is equivalent to 13 g of freeze dried powder. Subjects will consume two packages of 13 g of strawberry powder per day. The powder can be mixed into beverages and consumed with breakfast and dinner.

Strawberry powder ingredients include Individually Quick Frozen (IQF) strawberries. Placebo powder ingredients include fructose, sucrose, dextrose, tapioca maltodextrin, modified food starch, erythritol, cellulose gum, citric acid (anhydrous), N-C Strawberry Flavor Natual WONF, xanthan gum, malic acid, sugar beet fiber, silicon dioxide, nat. strawberry-type flavor, FD&C Red #40, FD&C Yellow 6, FD&C Blue 2.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 30 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single (Investigator)
Primary Purpose: Other
Official Title: Effect of Strawberry Consumption on the Microbiome in Healthy Subjects: A Pilot Study
Actual Study Start Date : September 11, 2018
Actual Primary Completion Date : February 21, 2019
Actual Study Completion Date : December 19, 2019

Arm Intervention/treatment
Experimental: Strawberry intervention group
Participants consume two packages of 13 g of standard strawberry powder in the morning and afternoon/evening per day for 4 weeks
Other: strawberry powder
Participants consume 2 packages of standard strawberry powder (13 g x 2) daily for 4 weeks

Placebo Comparator: Placebo group
Participants consume two packages of 13 grams placebo powder in the morning and afternoon/evening for 4 weeks.
Other: placebo powder
Participants consume 2 packages of placebo powder (13 g x 2) daily for 4 weeks

Primary Outcome Measures :
  1. Change in microbiome composition [ Time Frame: 4 weeks ]
    Change in phyla, genes and species of gut bacteria

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   18 Years to 55 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Healthy human adults age 18-55 years old (females have to be premenopausal)
  • Typically consume low fiber/polyphenol diet (beige diet)

Exclusion Criteria:

  • Eating a high fiber/polyphenol diet or taking any medication or dietary supplement which interfere with the absorption of polyphenols.
  • History of gastrointestinal surgery, diabetes mellitus on medications, or other serious medical condition, such as chronic hepatic or renal disease, bleeding disorder, congestive heart disease, chronic diarrhea disorders, myocardial infarction, coronary artery bypass graft, angioplasty within 6 months prior to screening, current diagnosis of uncontrolled hypertension (defined as systolic BP >160mmHg, diastolic BP > 95mmHg), active or chronic gastrointestinal disorders, bulimia, anorexia, laxative abuse, or endocrine diseases (except thyroid disease requiring medication) as indicated by medical history or routine physical examination.
  • Screening laboratory value outside of the laboratory normal range that is considered clinically significant for study participation by the investigator.
  • Is known HIV positive (subjects who are HIV positive are known to have high evels of LDL cholesterol and generalized heart inflammation).
  • Is unable or unwilling to comply with the study protocol.
  • Using prebiotics, probiotics, yogurt, and/or any fiber supplements regularly
  • Allergy or sensitivity to strawberries. Subjects will be excluded if there is a prior history of such sensitivity. Since these foods are commonly eaten and allergies are rare, subjects should be aware of this sensitivity prior to entering the study. To determine this, a positive affirmation by the subject of strawberry ingestion without incident will be requested. In addition, any subject with a history of allergy or anaphylaxis of any kind will be excluded.
  • Taking antibiotics or laxatives within the past 3 months
  • Any subject who demonstrate a risk of non-compliance with study procedure, or one who cannot read, understand or complete study - related materials in the opinion of the study investigator.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT04217122

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United States, California
UCLA Center for Human Nutrition, 1000 Veteran Ave.
Los Angeles, California, United States, 90095
Sponsors and Collaborators
University of California, Los Angeles
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Responsible Party: Zhaoping Li, Principal Investigator, University of California, Los Angeles Identifier: NCT04217122    
Other Study ID Numbers: IRB#18-000312
First Posted: January 3, 2020    Key Record Dates
Last Update Posted: January 7, 2020
Last Verified: January 2020
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by Zhaoping Li, University of California, Los Angeles: