Understanding Dose Related Effects of Strawberry

Phase

N/A

Condition

Diabetes And Hypertension

Allergy

Allergies & Asthma

Treatment

freeze-dried whole strawberry powder 12 g

freeze-dried control powder 0 g strawberry

freeze-dried whole strawberry powder 36 g powder

Clinical Study ID

NCT06173765

IRB-2021-98

Ages 20-60
All Genders
Accepts Healthy Volunteers

Study Summary

The proposed research is designed to extend previous research findings building on the knowledge of strawberries as fruits that support a healthy immune and vascular system. The proposed research leverages a recently funded proposal by the USDA to study in greater depth inflammation, glucoregulation and oxidative stress defense and their relation to improving endothelial function and insulin sensitivity.

Before and after strawberry intake, blood samples will be collected for monocyte (immune cells and source of inflammatory cytokines) isolation and activation via changes in cellular NF-κB and Nrf-2 (key transcription factors of inflammation/oxidative stress defense) status along with products of their activation (ie., plasma cytokines). Because inflammation and oxidative stress impairs endothelial function and insulin sensitivity, acutely and chronically, investigators will also study changes in vascular and insulin sensitivity status, assessing changes in vascular adhesion molecules, endothelial responsiveness through flow mediated vasodilation (ie., FMD) and insulin sensitivity using the Liquid Meal Tolerance (LMTT) if intravenous glucose tolerance test (IVGTT) method cannot be used due to supply chain issues of sterile Dextrose. Glucoregulation will be assessed by placing a Continuous Glucose monitoring (CGM) machine (Dexcom-6) to participants for 10 days at the beginning and at the end of the study period of intervention. The study will be a randomized, double-blinded, 3-arm parallel, 4-week, dose-response study. Individuals with chronic low grade inflammation will be sought to test the anti-inflammation - vaso-relaxing - insulin sensitivity effects of strawberry.

Eligibility Criteria

Inclusion

Inclusion Criteria

Men or women 20-60 years of age
High sensitivity C-Reactive Protein (hs-CRP), a global marker of inflammation, >1.0and ≤10 ng/L
BMI ≥ 25 kg/m2
Nonsmokers (Past smokers can be allowed if they have abstinence for minimum of 1years). Occasional smoker may be allowed at investigator discretion
Judged to be in good health on the basis of the medical history ie., no clinicalevidence of cardiovascular, metabolic, respiratory, renal, gastrointestinal orhepatic disease
Not taking any medications that would interfere with outcomes of the study, i.e.lipid lowering medications, anti-inflammatory drugs, dietary supplements, etc.
Able to provide informed consent
Able to comply and perform the procedures requested by the protocol (includingdietary restrictions, consumption of study treatments, records of food diary andstudy visit schedule)
Able to maintain usual physical activity pattern
Able to abstain from alcohol consumption and avoid vigorous physical activity for 24hours prior to and during study visit

Exclusion

Exclusion Criteria:

Men and women who smoke regularly
Men and women with known or suspected intolerance, allergies or hypersensitivity tostudy foods or treatments
Men and women who have blood pressure >160 mmHg (systolic)/100 mmHg (diastolic) atscreening visit
Men and women who have fasting blood glucose concentration >125 mg/dL at screeningvisit
Men and women with documented vascular disease, e.g., heart failure, myocardialinfarction, stroke, angina, related surgeries, etc. that, in the opinion of theinvestigator, could interfere with the interpretation of the study results
Men and women with cancer other than non-melanoma skin cancer in previous 5 years
Men and women diagnosed with chronic constipation, diarrhea or other chronicgastrointestinal complaint (e.g. irritable bowel syndrome)
Women who are known to be pregnant or who are intending to become pregnant over thecourse of the study
Women who are lactating
Taking medication or dietary supplements that may interfere with the outcomes of thestudy; e.g., antioxidant supplement, anti-inflammation, lipid lowering medication,blood pressure lowering medication, etc... Subjects may choose to go off dietarysupplements (requires 30-day washout); e.g., fish oil, probiotics, etc...
Men and women who has participated in prebiotics or laxative trial within 3 monthsprior to enrollment or any other clinical trial within 1 month
Major trauma or a surgical event within 2 months or longer depending on trauma orevent and after consultation with PI.
Vegan or other extreme dietary regimens (e.g., Atkins diet, etc.) as judged by theinvestigator.
Has a known intolerance or sensitivity to any ingredients in the study products
Has used antibiotics within the previous 2 months
History of an eating disorder (e.g., anorexia nervosa, bulimia nervosa, or bingeeating) diagnosed by a health professional
Substance (alcohol or drug) abuse within the last 2 years
Excessive coffee and tea consumers (> 4 cups/d)
Donated blood within last 3 months
Men and women who do excessive exercise regularly or are an athlete
Unstable weight: gained or lost weight +/- 5 kg (11 lbs) in previous 2 months
Women who are taking unstable dose and brand of hormonal contraceptives and/orstable dose and brand less than 6 months
Unusual working hours i.e., working overnight (e.g. 3rd shift)

Study Design

freeze-dried whole strawberry powder 12 g

August 31, 2022

January 28, 2025

Study Description

Investigators are proposing to leverage ongoing research funded by USDA to study in greater depth the effect of strawberry intake on chronic low grade inflammation and its relation to endothelial function and insulin sensitivity (InsS). Investigators' rationale is based on facts that inflammation is a key feature in the development of atherosclerotic cardiovascular disease and diabetes, and strawberry intake has been shown to modulate biomarkers of inflammation, but with inconsistencies deserving follow up and better understanding. Of note, meal-induced inflammatory responses seem to be counteracted better with lower amounts of strawberry intake [1 cup fresh weight equivalent (FWeq) vs 3 cups FWeq]. In contrast, markers of inflammation in the fasting state in humans have been relatively unremarkable showing no or limited change with daily strawberry intake. However, many of these investigations used higher intake levels (2-3 cup FWeq) to test hypotheses on alternative endpoints (ie., lipids) and in groups with varied health risks. To better understand the effects of strawberry intake on systemic inflammation, investigators propose to study mechanisms (ie., NF-kB/Nrf-2 mediated signaling) within a sub population of immune cells (ie., monocytes) that result in plasma markers of inflammation. Investigators propose to do this by harvesting monocytes from subjects and study the activation of these signaling pathways after 4-week strawberry intake compared to a control condition. To address dose-response dynamics, investigators propose to study two strawberry intake levels (1 cup FWeq and 3 cup FWeq vs Control). Investigators are also interested in expanding recently completed vascular work in our lab showing improved vasodilation (by flow mediated vasodilation) 1 h after strawberry intake and after 4-week strawberry intake (3 cup FWeq) daily in individuals with modestly elevated cholesterol levels. Because chronic inflammation and oxidative stress impair endothelial function, investigators hypothesize that intake levels of strawberry that have the greatest benefit in reducing inflammation and oxidative stress will align with lower markers of endothelial inflammation and enhanced endothelial function (ie., vasodilation). Dietary patterns and components of the diet that preserve or improve endothelial function have an important risk lowering impact on cardiovascular disease development.

And finally, investigators aim to explore more deeply the relationship of strawberry intake, inflammation and InsS using the Liquid Meal Tolerance (LMTT) if intravenous glucose tolerance test (IVGTT) method cannot be used due to supply chain issues of sterile Dextrose. Investigators' previous work with strawberries is suggestive of improved peripheral InsS in a meal-challenge paradigm in overweight individuals with 1 cup FWeq and in abdominally obese individuals and impaired InsS with 3 cup FWeq. Changes in fasting insulin concentrations after intake of strawberries with 1-3 cup FWeq have been neutral.

However, fasting insulin concentrations give insight about liver InsS and less about peripheral InsS, which is relevant in post-meal glucose tolerance. In normal physiology, a major function of insulin in post meal state is to suppress hepatic gluconeogenesis while stimulating glucose uptake into muscle and fat. As impaired InsS is a major risk for developing pre-diabetes and type 2 diabetes, intervening early and strategically with diet, and with specific foods as science supports to restore InsS, is prudent. The proposed research can help characterize the role of strawberries in improving InsS and its relation to inflammation status.

Glucoregulation will be assessed by placing a Continuous Glucose monitoring (CGM) machine (Dexcom-6) which monitors interstitial glucose levels every 5 minutes for 10 days. This will be placed to participants at the beginning of the study for 7-10 days and similarly at the end of the study for 7-10 days of period. The study is focused on three areas important to public health and consumers: inflammation, vascular, and metabolic health. The project will provide new, deeper knowledge in these areas elucidating pathways by which strawberries reduce inflammation and risk for atherosclerotic vascular disease and diabetes. The data can contribute to health claim petitions. The new knowledge can be used to inform/educate a number of stakeholders, including the strawberry industry, consumers, health professionals, the scientific, medical and regulatory communities/agencies, and contribute to the evidence-base for establishing intake recommendations of polyphenolic rich fruits, like strawberries, in the USA, to promote health and reduce chronic disease risk.

Connect with a study center

Clinical Nutrition Research Center
Chicago, Illinois 60616
United States
Site Not Available

Not the study for you?

Let us help you find the best match. Sign up as a volunteer and receive email notifications when clinical trials are posted in the medical category of interest to you.