The goal of this study is to examine the impact of a diet high in fresh lean pork, compared to a plant-based diet, on cardiovascular function and vasomotor symptoms in perimenopausal women with overweight and obesity. The main questions it aims to answer are:
1. How does a diet high in pork, compared to a plant-based diet, affects blood lipids, endothelial function, and blood pressure? 2. How does a diet high in pork, compared to a plant-based diet, affects blood nitrate, cardiometabolic biomarkers, inflammatory biomarkers, and vasomotor symptoms?
Researchers will compare the diet high in pork to a plant-based diet to see if pork helps improve cardiovascular and mesopause symptoms.
Participants will:
* Consume both of the diets, each for 4 weeks, with a washout period between 2 and 6 weeks in between the diets trials * Visit the clinic 5 times with weekly meal pick ups during the diet trials * Undergo testing procedures including: weight and body composition, blood pressure and pulse, endothelial function using ultrasound of upper arm, microvascular blood flow, blood draws, physical activity measurements, and questionnaires.
Are female
Are between 40 and 55 years of age
Have a BMI (a number calculated from participant height and weight) between 28 and45 kg/m2
Are experiencing irregular menstrual cycles but have not gone longer than 12 consecutive months without a period
Hysterectomy (partial or full) or oophorectomy
Using hormone replacement therapy use and/or hormonal contraception use 6 months prior to study start
Has systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥ 90 mmHg)
Triglycerides ≥350 mg/dL, low-density lipoprotein cholesterol (LDL-C) ≥190 mg/dL, and/or taking a lipid-lowering medication -Diagnosed cardiovascular disease, diabetes (type 1 or 2), or endocrine- related disease (e.g. thyroid, PCOS), unstable gastrointestinal disease, kidney, liver, and/or pancreatic disease
Crossover
Pork Diet
BehavioralThe diet will follow the Dietary Guidelines for Americans with 80% of the meat consumption per week being pork. Other animal protein (e.g., turkey, chicken, beef) will be minimized in the dietary plans (≤ 20%) so lean and processed pork are the primary protein source consumed. Within each day, \~80% of the daily pork intake will be fresh, unprocessed lean cuts (e.g., tenderloin, loin chops, sirloin roast, flank, and rump roast) and \~20% will be cured sources (e.g., Canadian bacon, pork sausage).
Plant Diet
BehavioralThe diet will be a Lacto-Ovo Vegetarian Diet following the Dietary Guidelines for Americans with no more than 21 oz per week of animal protein (e.g., eggs, cheese).
Change in Macrovascular Function
Macrovascular function will be measured by endothelial function. Investigators will use brachial artery flow mediated dilation (FMD) using ultrasound. Ultrasound images will be captured (Cardiovascular Suit 4, QUIPU, Pisa, Italy) at three time points 1) end-diastole for each cardiac cycle at baseline (\~30 s), 2) during occlusion (\~5 min), and 3) after occlusion (\~5 min). The shear rate will be calculated for each cardiac cycle as 8 × mean blood velocity/ diameter, and the shear rate area under the curve from cuff release to peak diameter will be quantified as an index of the stimulus for FMD. The FMD values will be expressed as relative (%) changes from baseline to peak diameter and FMD/SRAUC will be corrected for shear rate (FMD/shear rate \[SR\] area under the curve \[AUC\]) in order to account for shear stress inter-individual variability.
Change in Microvascular Function
Microvascular blood flow will be assessed by near-infrared spectroscopy for oxygenated hemoglobin/myoglobin (O2Hb/O2Mb), deoxygenated hemoglobin/myoglobin (HHb/HMb), total hemoglobin/myoglobin (tHb/tMb), and tissue oxygen saturation (StO2, %)
Change in Blood Lipids
A blood lipid panel (total cholesterol, triglycerides, LDL, and HDL) will be performed at each outcome visit.
Change in Total Score for Hot Flash Related Daily Interference Scale
The Hot Flash Related Daily Interference Scale (HFRDIS) is scored by summing responses to 10 items that assess how hot flashes interfere with daily activities such as work, social interactions, sleep, mood, and concentration. Each item is rated on a scale from 0 (do not interfere) to 10 (completely interfere), resulting in a total score ranging from 0 to 100. Higher scores indicate greater interference from hot flashes, with the scale providing a reliable measure of symptom impact on quality of life.
Change in Total Score for Menopause Rating Scale
The Menopause Rating Scale (MRS) consists of 11 items grouped into three subscales: somatic, psychological, and urogenital symptoms. Each symptom is rated from 0 (no symptoms) to 4 (very severe), with a total score ranging from 0 to 44. Subscale scores are calculated by summing the items within each domain, and higher scores reflect greater severity of menopausal symptoms.
Change in Total Score for Greene Climacteric Scale
The Greene Climacteric Scale includes 21 items measuring psychological, somatic, and vasomotor symptoms, plus one item assessing sexual interest. Each item is rated on a 4-point scale from 0 (not at all) to 3 (extremely), with higher total and subscale scores indicating greater symptom severity. Scores are calculated by summing item responses within each domain and across the entire scale.
Change in Blood Nitrates/Nitrites
Levels of nitrates/nitrites will be assessed from a blood draw.
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