Postprandial Inflammation and Nuts (PIN) in Older Adults

The aging population is rapidly increasing, and it is important to identify dietary factors that can prevent disease and promote health in this group. Legumes, such as peanuts, are a plant-based food high in protein and unsaturated fat making this a healthy choice but are not consumed frequently enough in older adults. Studies have shown that regular nut consumption is associated with lower adiposity and reduced weight gain, and several dietary pattern studies indicate that nuts and legumes are associated with better bone health. Given these findings, this study will address the postprandial effects of meals with 2 levels of saturated fatty acids (SFA) on metabolic endotoxemia, inflammation and satiety, using a randomized cross-over design. The low SFA meal includes peanuts that are high in monounsaturated fatty acids (MUFA) and the serum endotoxin (lipopolysaccharide, LPS) postprandial response will be compared to a high SFA meal. Baseline measurements will include body composition and serum lipids and glucose. The objectives of the study are: 1. To determine the endotoxin and inflammatory response to a meal with two levels of saturated fat in older individuals with overweight or obesity using a randomized cross-over design; 2. To evaluate satiety and fullness in response to the two meals. It is hypothesized that postprandial circulating endotoxin and inflammation will be higher, and satiety will be similar after the SFA enriched compared to the lower SFA (peanut based) meal. A sample size analysis indicates that 16 participants are needed (α set at 0.05, and power set at 90%) to detect a significant difference in endotoxin between groups. Assuming a 10% dropout, up to 18 individuals will be enrolled. The results of this study have the potential to provide valuable insights into the role of peanuts in promoting health and preventing disease in at-risk older adults.

• monounsaturated fatty acids (MUFA) peanut meal (Behavioral), also known as Saturated fatty acid (SFA) meal: mixed meal tolerance test and postprandial measurements

Primary outcomes

• Concentration of Endotoxin [Change over 6 hour MMT]: serum

Secondary outcomes

• Concentration of Glucose and Insulin [Change over 6 hour MMT]: serum (mg/dL)
• Concentration of Triglyceride [Change over 6 hour MMT]: serum
• Appetite [Change over 6 hour MMT]: visual analogue scale from 0 (not at all) to 14 (extremely)
• Concentration of Inflammatory markers [Change over 6 hour MMT]: Interleukin-6, tumor necrosis factor-alpha, plasminogen activator inhibitor-1, lipopolysaccharide binding protein, hs-C reactive protein (grams/volume)

Other outcomes

• Concentration of zonulin [Baseline only]: serum permeability marker
• Lipid Profile [Baseline only]: serum
• Characterization of the Microbiome [Baseline only]: alpha and beta diversity of bacteria in feces
• Concentration of incretin hormones [Change over 6 hour MMT]: serum GLP-1, gherlin, peptide YY (grams/volume)
• Concentration of Bone regulating markers [Fasting and change over 6 hour MMT]: Serum carboxyterminal crosslinking telopeptide of type I collagen (CTX), Procollagen type-I aminoterminal propeptide (PINP), Osteocalcin (grams/volume)

Sex: All, ages: 55 Years to any, accepts healthy volunteers

Inclusion Criteria:

* Older adults across all racial/ethnic groups
* Older men, and postmenopausal women > 2 years since last menses.

Exclusion Criteria:

* Anemia
* Diagnosed with, active, or history of liver cirrhosis, chronic or persisting hepatitis
* Diagnosed with, active, or history of cancer
* History of gastrointestinal disease or surgical procedure for weight loss.
* Diagnosed with immune diseases, type 1 or 2 diabetes, pancreatitis, metabolic bone disease or infectious diseases
* Any surgery in the past 6 months
* Currently using or have used antibiotics continuously > 3 days in the past 3 months
* Regular use of medications for that affect the gastrointestinal tract, cholecystitis, urinary tract infection, significant renal disease, severe organic diseases including coronary heart disease, myocardial infarction, infectious diseases including pulmonary tuberculosis and AIDS
* Known allergy or intolerance to any ingredients in the meal intervention
* Recent colonoscopy (within the previous two months)
* Uncontrolled hypertension or uncontrolled severe hyperlipidemia.
* Participation in another clinical research trial that may interfere with the results of this study.

• Informed Consent Form (PDF, 2023-09-13)

• Sue Shapses, PhD, Principal investigator, Rutgers, the State University of NJ