Diets with avocados contain a good source of viscous and prebiotic fiber, which help improve all four identified avocado health benefits. For cardiovascular health, avocados are consistent with the Third Report of the National Cholesterol Education Program Expert Panel and meta-analyses of RCTs, which showed that one gram of viscous pectin could significantly lower TC by −2.7 mg/dL and LDL-C by −2.1 mg/dL
[31][32]. Pectin also slows the progression of intima-media plaque deposits in the common carotid arteries
[33] and 4 g of fruit fiber daily lowers the risk of coronary heart disease by 8%
[34]. The major mechanism for pectin and other fiber components is to increase viscosity in the ileal region of the small intestine, leading to reduced efficiency of saturated fat and cholesterol absorption and bile acid reabsorption, thus increasing the uptake of circulatory LDL-C by the liver to reduce the circulatory LDL-C load. Fruit fiber fermentation in the microbiota of SCFAs also reduces hepatic fatty acid synthesis to help lower LDL-C formation
[35][36]. For weight control, numerous studies show that adequate fiber intake reduces body weight, waist circumference, and visceral fat, especially in women, compared to lower fiber diets
[37][38][39][40][41][42][43]. The main mechanisms for increased fruit fiber intake and weight control are increases in gastrointestinal bulking volume that promote satiety hormones and reduce macronutrient bioavailability (e.g., reduced metabolizable energy), and promoting healthier microbiota metabolites and microflora that support a more metabolically lean phenotype
[2][4][44][41][45][46]. For cognitive function, daily intake of a prebiotic type fiber of at least 5–10 g/day can help restore or maintain colonic microbiota homeostasis to reduce systemic inflammation and improve insulin sensitivity, which helps optimize the gut-brain axis for better hippocampal and frontal cortex function
[47][48][49][50][51]. In young adults, avocado intake improved cognitive functions such as increased processing speed, sustained attention, and working memory in midlife
[52]. For colonic microbiota health, adequate intake of fiber, especially prebiotics, can generate metabolically active SCFAs
[48][49]. Fruits are among the best fiber sources for improving colonic microbiota health. As they ripen, their semi-hydrated cell wall fiber components, including pectin, hemicellulose, and cellulose, become progressively disassembled, and with eating and digestion, their fiber components become highly accessible to the colonic microbiome for fermentation
[2][7]. Overall, fruit fiber acts as a prebiotic to help re-balance the colonic microbiota towards a higher anti-inflammatory profile by increasing the
Bacteroidetes/
Firmicutes ratio, increasing microflora diversity, optimizing colonic mucosal barrier, and lowering levels of primary and secondary bile acids, which are important for maintaining overall health
[2][53][54].