Dose Response Effects of Pecan Consumption
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 108
- 试验地点
- 2
- 主要终点
- Change in fasting serum lipoprotein and cholesterol concentrations
研究概览
简要总结
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.
详细描述
Cardiovascular disease risk factors, including higher BMIs and poor cholesterol profiles, are on the rise and contribute to the United States' growing disease burden. Research investigating the relationship between pecan nut consumption and cardiometabolic outcomes has shown that pecan nut consumption can significantly benefit fasting and postprandial blood lipids, reduce CVD risk factors, promote weight maintenance, improve subjective and psychological markers of physiological appetite, increase total antioxidant capacity, and increase energy expenditure and fat oxidation. However, the current literature on pecan consumption and health outcomes only encompasses physiological benefits coming from a dosage of ~45g/day and above, which is above the current dietary guidelines. This study will be the first dose-response study examining the minimalist effective dose and determining the most effective dosage of pecan consumption on metabolic and cardiovascular outcomes. If lower doses of pecans in the diet are found to improve fasting and postprandial lipid metabolism and markers of chronic disease risk, these study findings could lead to improvements in health.
This prospective clinical study is a single-blinded, randomized control trial in adults at increased risk for cardiovascular disease (poor cholesterol profiles or overweight/obesity). There are four diet interventions: pecan LOW (6% energy from pecans), pecan MID (13% energy from pecans), pecan HIGH (20% energy from pecans), and CON (instructed to maintain their current habitual diet and abstain from any tree nut/peanut consumption for the duration of the intervention). This study protocol consists of a 28-day diet intervention that will involve substituting pecans for commonly consumed snack or meal items every day for the entire 28-day intervention or maintaining a current/usual diet.
There are a total of six testing visits: a screening visit (V0), a pre-intervention visit (V1), short weekly visits (end of weeks 1, 2, and 3; V2-V4), and a post-intervention visit (V5).
At screening (V0), qualification is confirmed based on anthropometrics and fasting blood draw, which is analyzed for a cholesterol panel and blood glucose. Additionally, energy requirements are estimated at this visit for use in the diet intervention.
At V1, participants will have anthropometrics measured, including body composition, by DEXA. Next, a certified phlebotomist places an IV catheter and takes the fasting blood sample. Then the participant consumes a high-saturated-fat meal challenge, delivering 17% of their estimated energy needs (from V0). Then the participant has blood drawn 7 times using the IV catheter over the next 4 hours.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Prevention
- 盲法
- Single (Participant)
盲法说明
Participants are blinded to which group they are in and what oil they are receiving.
入排标准
- 年龄范围
- 30 Years 至 75 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •30 to 75-year-old men and women at increased risk of cardiovascular disease. Increased risk of cardiovascular disease will be defined by either elevated cholesterol profiles or overweight/obesity.
- •Elevated cholesterol profiles will be defined as: "Borderline High" and/or "at risk" in two or more of the following variables (total cholesterol: 180-239 mg/dL, LDL cholesterol 110- 159 mg/dL, triglycerides 130-199 mg/dL) --or---"High" in total cholesterol (240 mg/dL and higher), LDL (160 mg/dL or higher), or triglycerides (between 200-350 mg/dl).
- •Overweight/obesity will be defined by body mass index (overweight > 28 kg/m2 or obesity 30 kg/m2 or greater).
排除标准
- •Probable familial hypercholesterolemia, defined by: total cholesterol greater than 290 mg/dL or LDL levels greater than 190 mg/dL plus a family history of myocardial infarction (MI) before 50 years of age in a 2nd-degree relative or below age 60 in a 1st-degree relative
- •Alcohol intake >3 drinks/d for males or >2 drinks/d for females
- •Individuals with food allergies/sensitivities to foods provided in the study, including tree nuts, gluten, and or lactose/dairy
- •Individuals who regularly consume nuts and/or nut butter (defined as consumption of >2 servings (~56g) of tree nuts, nuts, or nut butter (e.g., peanut butter, almond butter) per week
- •Individuals adhering to special diets, including, but not limited to, the ketogenic diet, intermittent fasting, vegetarian diet, or carbohydrate-restricted diets
- •Plans to begin a weight loss/exercise regime during the trial
- •Weight gain or loss of more than 5% of their body weight in the past 3 months
- •History of previous or current renal or bowel disease
- •Females who are currently pregnant or lactating
- •Individuals participating in >3 hours/week of exercise
- •Women on hormone replacement therapy for <2 years
- •Fasting glucose >126 mg/dL
- •Blood pressure >180/120 mmHg
- •History of medical or surgical events that could affect digestion or swallowing
- •Gastrointestinal surgery, atherosclerosis, or bleeding disorders
- •Tobacco or nicotine use
- •Previous heart attack (MI) or stroke, previous or current diagnosis of cancer
- •Chronic or metabolic diseases
- •Medication use affecting digestion and absorption, medications affecting metabolism (e.g., thyroid meds), lipid-lowering medications, medications for diabetes, blood thinning medications
- •Steroid/hormone therapies or current antibiotic cycles
研究组 & 干预措施
Pecan LOW
Participants are given pecans and instructed on how to substitute study foods into their diet to maintain caloric balance.
干预措施: Pecan LOW (Other)
Pecan MID
Participants are given pecans and instructed on how to substitute study foods into their diet to maintain caloric balance.
干预措施: Pecan MID (Other)
Pecan HIGH
Participants are given pecans and instructed on how to substitute study foods into their diet to maintain caloric balance.
干预措施: Pecan HIGH (Other)
CONTROL
Participants are asked to maintain their current habitual diet and avoid any tree nut/peanut consumption for the entire 28-day intervention period.
干预措施: CONTROL (Other)
结局指标
主要结局
Change in fasting serum lipoprotein and cholesterol concentrations
时间窗: Baseline, 4 weeks
The concentration of fasting serum total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and apolipoprotein B (mg/dl).
Change in fasting and postprandial plasma glucose concentrations
时间窗: Baseline, 4 weeks
The concentration of plasma glucose before and after the high saturated fat meal challenge at both pre-and post-intervention visits (mg/dL).
Change in fasting and postprandial plasma triglyceride concentrations
时间窗: Baseline, 4 weeks
The concentration of plasma triglycerides before and after the high saturated fat meal challenge at both pre-and post-intervention visits (mg/dL).
Change in fasting and postprandial subjective feelings related to appetite
时间窗: Baseline, 4 weeks
Visual analog scale ratings of feelings related to appetite before and after the high saturated fat meal challenge at both pre-and post-intervention visits. Subjective feelings of hunger, fullness, desire to eat, prospective consumption, and a composite appetite score are measured by visual analog scales (mm).
Change in fasting and postprandial plasma inflammatory cytokine concentrations
时间窗: Baseline, 4 weeks
The concentration of interleukin-1 beta, C reactive protein, tumor necrosis factor-alpha, and interleukin-6 before and after the high saturated fat meal challenge at both pre-and post-intervention visits (pg/mL).
Change in fasting serum lipoprotein particle numbers
时间窗: Baseline, 4 weeks
The number of particles of low-density lipoproteins (LDL), LDL small, HDL large, LDL medium, lipoprotein (a) (nmol/L).
Change in fasting and postprandial plasma appetite control hormones concentrations
时间窗: Baseline, 4 weeks
The concentration of plasma appetite control hormones before and after the high saturated fat meal challenge at both pre-and post-intervention visits. Appetite control hormones include Cholecystokinin (CCK), Peptide YY (PYY), and Ghrelin (pg/mL).
Change in fasting and postprandial plasma total antioxidant capacity
时间窗: Baseline, 4 weeks
Total antioxidant capacity before and after the high saturated fat meal challenge at both pre-and post-intervention visits (U/mL).
Change in fasting and postprandial plasma antioxidant parameters
时间窗: Baseline, 4 weeks
Glutathione peroxidase activity, superoxide dismutase activity, and glutathione-s-transferase activity before and after the high saturated fat meal challenge at both pre-and post-intervention visits (U/mL).
Change in fasting and postprandial plasma non-esterified fatty acid (NEFA) concentrations
时间窗: Baseline, 4 weeks
The concentration of plasma NEFAs before and after the high saturated fat meal challenge at both pre-and post-intervention visits (mEq/L).
Change in fasting and postprandial plasma insulin concentrations
时间窗: Baseline, 4 weeks
The concentration of plasma insulin before and after the high saturated fat meal challenge at both pre-and post-intervention visits (uU/mL).
Change in fasting and postprandial plasma Malondialdehyde (MDA)
时间窗: Baseline, 4 weeks
The concentration of MDA before and after the high saturated fat meal challenge at both pre-and post-intervention visits (nmol/mL).
Change in fasting and postprandial plasma markers of coagulation potential
时间窗: Baseline, 4 weeks
The concentration of plasminogen activator inhibitor-1 and tissue factor before and after the high saturated fat meal challenge at both pre-and post-intervention visits (pg/mL).
Change in fasting and postprandial plasma angiopoietin-like (ANGPTL) proteins
时间窗: Baseline, 4 weeks
The concentration of ANGPTL 3, ANGPTL 4, and ANGPTL 8 before and after the high saturated fat meal challenge at both pre-and post-intervention visits (ng/mL).
Change in fasting insulin resistance metrics
时间窗: Baseline, 4 weeks
Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) and Homeostatic Model Assessment for β-cell function (HOMA-B) will be calculated from fasting insulin and glucose measures before and after the 28-day intervention.
次要结局
- Change in fasting serum bilirubin(Baseline, 4 weeks)
- Change in overall liking and desire to consume subjective ratings of the intervention food provided(Baseline, Week 1, Week 2, Week 3, Week 4)
- Change in additional fasting and postprandial plasma inflammatory cytokine concentrations(Baseline, 4 weeks)
- Change in additional fasting and postprandial plasma markers of coagulation potential(Baseline, 4 weeks)
- Change in acute dietary intake(Baseline, 4 weeks)
- Change in fasting serum hepatic enzymes(Baseline, 4 weeks)
- Change in fasting serum hepatic proteins(Baseline, 4 weeks)
研究者
Jamie Cooper, PhD
Professor, Director of UGA Obesity Initiative
University of Georgia