Healthy
Conditions
Keywords
Healthy volunteers
Brief summary
The study (n = 36) will be a parallel design and will be 6 weeks in duration. Participants will start with a 2-week free-living wash-in period where they will be asked to avoid certain carotenoid-rich foods, followed by 4 weeks of a completely controlled diet. In addition to the controlled diet, participants will consume one of three beverages (300 mL/day; n = 12/group): placebo beverage (control), high beta-carotene tomato juice, and high-lycopene tomato juice. Blood, urine and feces will be collected throughout the study.
Interventions
OTHERBase diet + high beta-carotene tomato juice
Participants will receive high beta-carotene tomato juice daily in addition to the base diet. Meals will be prepared using traditional American foods with a macronutrient composition representative of a typical American diet. The base diet will be low in betacarotene and lycopene (no carrots, sweet potato, tomatoes, and dark greens). During the controlled diet period, participants will be instructed to eat all foods and only foods provided to them, with the exception of water, coffee, tea, and diet soda.
OTHERBase diet + high lycopene tomato juice
Participants will receive high lycopene tomato juice daily in addition to the base diet. Meals will be prepared using traditional American foods with a macronutrient composition representative of a typical American diet. The base diet will be low in betacarotene and lycopene (no carrots, sweet potato, tomatoes, and dark greens). During the controlled diet period, participants will be instructed to eat all foods and only foods provided to them, with the exception of water, coffee, tea, and diet soda.
OTHERBase diet + placebo beverage
Participants will receive a placebo beverage daily in addition to the base diet. Meals will be prepared using traditional American foods with a macronutrient composition representative of a typical American diet. The base diet will be low in betacarotene and lycopene (no carrots, sweet potato, tomatoes, and dark greens). During the controlled diet period, participants will be instructed to eat all foods and only foods provided to them, with the exception of water, coffee, tea, and diet soda.
Sponsors
USDA Beltsville Human Nutrition Research Center
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
21 Years to 75 Years
Healthy volunteers
Yes
Exclusion criteria
* Age less than 21 or greater than 75 years * Glucose \> 126 mg/dl * Triglycerides \> 300 mg/dl * Known allergy or intolerance to tomatoes or tomato products * Pregnant, lactating, or intend to become pregnant during the study period * History of bariatric surgery or nutrient malabsorption disease (such as celiac disease) or other metabolic disorders requiring special diet recommendations * Smoker or use of tobacco products * Presently have cancer * Use of certain medications (prescription or over-the-counter) that may interfere with the study objectives * Type 2 diabetes * Use of blood-thinning medications such as Coumadin (warfarin), Dicumarol, or Miradon (anisindione) * 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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in apocarotenoid concentrations will be measured in blood | Baseline, 2 weeks, 4 weeks | Apocarotenoid concentrations will be measured in blood (baseline, after washout; 2 wks; 4 wks). |
| Change in carotenoid concentrations will be measured in blood | Baseline, 2 weeks, 4 weeks | Carotenoid concentrations will be measured in blood (baseline, after washout; 2 wks, 4 wks). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in global gene expression | Baseline, 4 weeks | Amounts of messenger RNA will be measured in blood samples to determine if the consumption of carotenoid-rich foods will affect gene expression of pathways related to cancer risk. |
| Change in proportion of phyla of colonic microbiota | Baseline, 4 weeks | Ribosomal RNA will be measured to determine relative amounts of different bacterial phyla present in the colon after consumption of the juice products differing in carotenoid concentration. |
| Identification of unknown urinary carotenoid metabolites | Baseline, 2 weeks, 4 weeks | Identify previously unknown carotenoid metabolites in urine. |
Countries
United States
Outcome results
None listed