Biological Mechanisms of Fresh Hass Avocado: Comparison
View Latest Version
Please note this is a comparison between Version 2 by Jason Zhu and Version 1 by Nikki Ford.

Researchers identified four primary avocado health effects: (1) reducing cardiovascular disease risk in healthy overweight or obese adults with dyslipidemia by lowering non-HDL-C profiles, triglycerides, LDL oxidation, small atherogenic LDL particles and promoting postprandial vascular endothelial health for better peripheral blood flow; (2) lowering the risk of being overweight or obese, supporting weight loss, and reducing visceral fat tissue in overweight or obese women; (3) improving cognitive function in older normal-weight adults and in young to middle age overweight or obese adults especially in frontal cortex executive function; and (4) stimulating improved colonic microbiota health in overweight or obese adults by promoting healthier microflora and fecal metabolites.

  • Hass avocado
  • blood lipids
  • endothelial health
  • weight management
  • microbiota

1. Introduction

Global dietary guidelines, such as the 2020–2025 Dietary Guidelines for Americans, call for making half of each meal fresh fruits and vegetables consumed in a healthy dietary plan such as the Mediterranean diet to promote healthy body weight, reduce chronic disease risk, and promote better health in all age groups [1]. Fresh fruit and non-starchy vegetables tend to have a very low to low energy density (ED), low sugar, sodium, and saturated fat content. They are often good sources of fiber, vitamins A, C, and K, magnesium and potassium, and phytochemicals such as polyphenols and carotenoids that collectively support health and wellness [1,2][1][2]. However, only 10–20% of the US population meets the dietary recommendations for fruit and vegetable intake, leading to an average healthy eating index score of about 60% of the optimum dietary quality score needed to protect against overweight, obesity, and chronic diseases that compromise the wellness of Americans and other global populations in all age groups [1,2][1][2].
Hass avocado (Persea americana) fruit makes up at least 90% of the avocados consumed in the US and most of the avocados consumed worldwide [3,4][3][4]. The Hass avocado has a creamy, smooth, edible fruit texture when ripe that is rich in oleic acid, fiber, micronutrients, and phytochemicals. The tree thrives in Mediterranean-type climates and is compatible with the Mediterranean diet [5,6][5][6]. A serving of fresh Hass avocado (50 g or 1/3 of a medium-sized fruit) contains 80 kcals, 3.4 g fiber (11% DV), 44.5 μg folate (10% DV), 0.73 mg pantothenic acid (15% DV), 85 μg copper (10% DV), 10.5 μg vitamin K (10% DV), 254 mg potassium (7.5% DV), and 4 mg of sodium (0.2% DV) [6,7][6][7]. Hass avocados have a relatively low energy density of 1.6 kcals/g (79% of weight consists of water and fiber), and a glycemic index and load of near zero due to a very low level of available carbohydrates comprised of 0.15 g sugar and 0.055 g of starch. One serving of Hass avocado contains no cholesterol, 1 g of saturated fatty acids (SFA, 5% DV), 4.9 g cis-monounsaturated fatty acid (MUFA), and 1 g polyunsaturated fatty acid (PUFA), with oleic acid as the predominant fatty acid at 4.5 g/serving. Also, each serving has 136 μg of lutein and zeaxanthin, 35 mg beta-sitosterol, and 95 mg total phenolics (gallic acid equivalents) [6,7][6][7]. Non-Hass varieties differ from Hass avocados in nutritional composition, especially in fatty acid levels [7,8][7][8]. National Health and Nutrition Examination Surveys (NHANES) from 2001–2012 showed that US Hass avocado adult consumers had a better nutrient intake, higher diet quality, and lower adiposity than non-consumers [4]. The average Hass avocado consumer eats 76 g/day or about 60% of one avocado, which leads to a significantly higher intake of fiber, cis-MUFA, vitamins E and C, folate, magnesium, potassium, total fruits and vegetables, and a lower intake of sodium compared to non-consumers.

2. Discussion

Researchers found that the Hass avocado has four major health benefits: (1) cardiovascular health [12,13,14,15,16,17,18,19,20,21,22]; (2), weight control [23,24,25,26,27,28,29,30]; (3) cognitive health [18,31,33]; and (4) colonic microbiota health [26,34]. Researchers also found that four nutritional features were primarily responsible for all the major avocado health benefits: (1) high unsaturated to saturated fat ratio [7]; (2) viscous and prebiotic fiber [2,7]; (3) a relatively low energy density of 1.6 kcal/g [7]; and (4) high carotenoid bioavailability [35,36]. Avocados are also a unique nutrient/phytochemical dense fruit with minerals, vitamins, β-sitosterol, and polyphenols that provide additional secondary health benefits in promoting overall health and wellness to varying degrees. Still, more research is needed to understand their specific health effects better.

2.1. Biological Mechanisms

2.1.1. High Unsaturated to Saturated Fatty Acid Ratio

Diets including avocados have a higher unsaturated to saturated fat ratio, which helps improve cardiovascular health, weight control, and cognitive function. For cardiovascular health, avocados are consistent with the American Heart Association’s Presidential Advisory Report recommending a shift from saturated to unsaturated fatty acids such as cis-MUFAs to promote healthier blood lipid profiles, including lowering LDL-C, a major cause of atherosclerosis [37][9]. Also, the avocados’ fat ratio helps improve vascular endothelial function by maintaining healthy postprandial FMD blood flow. The fat profile maintains low circulatory non-esterified fatty acids to optimize insulin sensitivity. This is critical as vascular endothelial cells depend on insulin activity for proper function. Also, the fatty acid profile likely reduces the risk of LDL oxidation, thus protecting against atherosclerosis [13,38,39,40,41,42,43][10][11][12][13][14][15][16]. For weight control, higher oleic acid intake leads to lower fat storage compared to long-chain saturated fats, especially when consumed in a moderate refined carbohydrate diet [44,45][17][18]. The mechanisms include converting oleic acid to oleoylethanolamide in the intestine and liver, which helps induce satiety and increase energy expenditure by stimulating a cascade of biochemical activities [46,47,48][19][20][21]. Oleic acid-rich diets improve cognitive function compared to low fat and high SFA diets [49,50,51,52,53,54,55][22][23][24][25][26][27][28]. Avocados’ healthy fatty acid ratio helps improve cerebral cortex blood flow, compared to long-chain saturated fats, to help assure the critical delivery of oxygen to the brain to match the increased needs of activated neurons [56,57][29][30].

2.1.2. Viscous and Prebiotic

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 [58,59][31][32]. Pectin also slows the progression of intima-media plaque deposits in the common carotid arteries [60][33] and 4 g of fruit fiber daily lowers the risk of coronary heart disease by 8% [61][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 [62,63][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 [64,65,66,67,68,69,70][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 [2,4,25,68,71,72][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 [73,74,75,76,77][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 [78][52]. For colonic microbiota health, adequate intake of fiber, especially prebiotics, can generate metabolically active SCFAs [74,75][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][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 [2,26,34][2][53][54].

2.1.3. Low Energy Density (ED)

For weight control, avocados with an ED of 1.6 kcal/g (79% by weight of water and fiber) support better weight management and improve body composition [23,24,25,26,27,28,29,30,31,32][55][56][44][53][57][58][59][60][61][62]. Most fresh fruits have a high bulk volume and low energy density (ED), ranging from 0.3 to 1.6 kcal/g [2,5,6,7][2][5][6][7]. Humans tend to have relatively low energy regulatory sensitivity to food or meals with an ED greater than 1.75 kcal/g, leading to a positive energy balance and thus to an increased risk of weight gain [79][63]. According to NHANES analyses, the estimated US mean daily ED is 1.9 kcal/g, consistent with Western diets low in fruit and vegetable intake resulting in a higher risk of being overweight or obese over time [80][64]. A longitudinal study in young overweight women consuming higher ED diets ≥ 1.85 kcals/g showed an average weight gain of 6.4 kg over six years [81][65].

2.1.4. Highly Bioavailable Carotenoids

Avocados are a unique, oleic acid-rich fruit that provides a highly bioavailable source of lutein, and the lipid boosts carotenoid absorption from co-consumed fruit and vegetables [35,36][66][67]. This nutritional feature supports cardiovascular health and cognitive function. For cardiovascular health, highly bioavailable lutein from avocados helps protect LDL from oxidation, decreasing the uptake of macrophages, and helps protect against atherosclerosis pathogenesis [82,83][68][69]. Observational studies show that higher lutein intake and blood levels are moderately associated with lowered coronary heart disease and stroke risk [84][70]. Combinations of lutein and lycopene are twice as effective at reducing carotid artery intima-media thickness than lutein alone [85][71], which may be achieved by consuming avocados with salsa or other tomato-based foods [35,36][66][67]. This can significantly lower mean LDL-C, increase FMD, and decrease systolic blood pressure [86][72]. For cognitive function, a higher intake of carotenoid-rich fruit and vegetables is generally associated with enhanced cognitive function in younger and older adults [87,88][73][74]. Several RCTs of lutein and zeaxanthin supplements after 12 months show improved visual episodic memory performance in young and middle-aged adults, and improved inhibition and attention performance in middle-aged and older adults compared to controls [89][75]. Importantly, avocado lutein is more highly bioavailable than that of supplements or low-fat fruits. Lutein and zeaxanthin can cross the blood-brain barrier and direct their antioxidant and anti-inflammatory functions to act directly on the brain structure and function with selective distribution to the prefrontal cortex, visual cortex, hippocampus, and central retina, as measured by macular pigment optical density [87,88,89,90,91,92][73][74][75][76][77][78]. The concentration of lutein in the brain is higher in the prefrontal cortex than other regions and positively correlated with the gray matter volume in the parahippocampal gyrus, suggesting that lutein plays a role in memory and inhibition functions [18,31,33,90,91,92][79][61][80][76][77][78].

2.2. Strengths and Limitations

The strengths are that it: (1) identifies four primary Hass avocado health effects and their linkage to a unique combination of four primary nutritional features responsible for these benefits; (2) summarizes all the research in a short overview, with numerous figures and tables to help readers get a clear and complete assessment of Hass avocado research to date; (3) connects the existing Hass avocado research and primary nutritional features to previous research from major reports on dietary recommendations for reducing CVD risk, systematic reviews and meta-analyses, and clinical trials; and (4) calls for and identifies additional areas for future research and other study design gaps. The limitations are that: (1) many of the clinical trials were relatively short in duration using a small number of subjects; and (2) the clinical trials or observational studies were not scored for quality or assessed by statistical analysis of mean effects or heterogeneity supporting each health effect.

3. Conclusions

Clinical trials and observational studies have identified four primary Hass avocado health effects which promote: (1) cardiovascular health by improving blood lipid profiles and acute endothelial blood flow; (2) healthier weight and body composition; (3) better cognitive function, especially in areas of executive function; and (4) colonic microbiota health and related cardiometabolic and brain benefits. These health effects are primarily due to the Hass avocado’s unique combination of four nutritional features: (1) high oleic acid to SFA ratio; (2) multifunctional prebiotic and viscous fiber; (3) relatively low energy density; and (4) uniquely high bioavailable lutein along with other carotenoids, especially when avocados are consumed with other fruits and vegetables, i.e., in salads or salsa. Hass avocados are also micronutrient dense (e.g., 10% or more of the daily value for folate, vitamin K, pantothenic acid, and copper), very low in sodium and sugar, and contain polyphenols to further support secondary health and wellness benefits. Hass avocados are compatible with healthy dietary regimens such as the Mediterranean diet. Larger and longer clinical trials are needed to better understand the effects of Hass avocados on health, especially in glycemic and insulinemic control in normal and T2D subjects.

References

  1. US Department of Agriculture and Health and Human Services. Dietary Guidelines for Americans 2020–2025, 9th ed.; US Department of Agriculture and Health and Human Services: Washington, DC, USA, 2020.
  2. Dreher, L.M. Whole fruits and fruit fiber emerging health effects. Nutrients 2018, 10, 1833.
  3. McCormack, L.A.; Laska, M.N.; Larson, N.; Story, M. Review of the nutritional implications of farmers markets and community gardens: A call for evaluation and research efforts. Am. J. Diet. Assoc. 2010, 110, 399–408.
  4. O’Neil, C.E.O.; Nicklas, T.A.; Fulgoni, V.L. Avocado consumption by adults is associated with better nutrient intake, diet quality, and some measures of adiposity: National Health and Nutrition Examination Survey, 2001–2012. Intern. Med. Rev. 2017, 3, 1–23.
  5. Dreher, M.L.; Davenport, A.J. Hass avocado composition and potential health effects. Crit. Rev. Food Sci. Nutr. 2013, 53, 738–750.
  6. Ford, N.A.; Liu, A.G. The forgotten fruit: A case for the consuming avocado within the traditional Mediterranean diet. Front. Nutr. 2020, 7, 78.
  7. Avocados, Raw, California and Florida, US Department of Agriculture Food Data Central, Legacy 1717069038. 2019. Available online: fdc.nal.usda.gov (accessed on 11 June 2021).
  8. Yanty, N.A.M.; Marikkar, J.M.N.; Long, K. Effect of variety differences on composition and thermal characteristic of avocado oil. J. Am. Oil Chem. Soc. 2011, 881, 997–2008.
  9. Sacks, F.M.; Lichtenstein, A.H.; Wu, J.H.Y.; Appel, L.J.; Creager, M.A.; Kris-Etherton, P.M.; Miller, M.; Rimm, E.B.; Rudel, L.L.; Robinson, J.L.; et al. Dietary fats and cardiovascular disease a presidential advisory from the American Heart Association. Circulation 2017, 136, e1–e23.
  10. Wang, L.; Tao, L.; Stanley, T.H.; Huang, K.-H.; Lambert, J.D.; Kris-Etherton, P.M. A moderate-fat diet with one avocado per day increases plasma antioxidants and decreases the oxidation of small, dense LDL in adults with overweight and obesity: A randomized controlled trial. J. Nutr. 2020, 150, 276–284.
  11. Lacroix, S.; Des Rosiers, C.; Gayda, M.; Nozza, A.; Thorin, E.; Tardif, J.-C.; Nigam, A. A single Mediterranean meal does not impair postprandial flow-mediated dilation in healthy mean with subclinical metabolic dysregulations. Appl. Physiol. Nutr. Metab. 2016, 41, 888–894.
  12. Tentolouris, N.; Arapostathi, C.; Perrea, D.; Kyriaki, D.; Revenas, C.; Katsilambros, N. Differential effects of two isoenergetic meals rich in saturated or monounsaturated fat on endothelial function in subjects with type 2 diabetes. Diabetes Care 2008, 31, 2276–2278.
  13. Newens, K.J.; Thompson, A.K.; Jackson, K.G.; Wright, J.; Williams, C.M. Acute effects of elevated NEFA on vascular function: A comparison of SFA and MUFA. Br. J Nutr. 2011, 105, 1343–1351.
  14. Moreno, J.A.; Lopez-Miranda, J.; Perez-Martinez, P.; Marin, C.; Moreno, R.; Gomez, P.; Paniagua, J.A.; Perez-Jimenez, F. A monounsaturated fatty acid-rich diet reduces macrophage uptake of plasma oxidized low-density lipoprotein in healthy young men. Br. J. Nutr. 2008, 100, 569–575.
  15. Gradinaru, D.; Borsa, C.; Ionescu, C.; Prada, G.; Oxidized, I. LDL and NO synthesis—Biomarkers of endothelial dysfunction and aging. Mech. Aging Develop. 2015, 151, 101–113.
  16. Joris, P.J.; Mensink, R.P. Role of cis-monounsaturated fatty acids in the prevention of coronary heart disease. Curr. Atheroscler. Rep. 2016, 18, 281–287.
  17. DiNicolontonio, J.J.; O’Keefe, J.H. Good fats versus bad fats: A comparison of fatty acids in the promotion of insulin resistance, inflammation, and obesity. Mo. Med. 2017, 114, 303–307.
  18. Tutunchi, H.; Ostadrahimi, A.; Saghafi-Asl, M. The effects of diets enriched in monounsaturated oleic acid on the management and prevention of obesity: A systematic review of human intervention studies. Adv. Nutr. 2020, 11, 864–877.
  19. Sihag, J.; Jones, P.J.H. Oleoylethanolamide: The role of a bioactive lipid amide in modulating eating behaviour. Obes. Rev. 2018, 19, 178–197.
  20. Piers, L.S.; Walker, K.Z.; Stoney, R.M.; Soares, M.J.; O’Dea, K. Substitution of saturated with monounsaturated fat in a 4-week diet affects body weight and composition of overweight and obese men. Br. J. Nutr. 2003, 90, 717–727.
  21. Liu, X.; Kris-Etherton, P.M.; West, S.G.; Lamarche, B.; Jenkins, D.J.A.; Fleming, J.A.; McCrea, C.E.; Pu, S.; Couture, P.; Connelly, P.W.; et al. Effects of canola and high-oleic acid canola oils on abdominal fat mass in individuals with central obesity. Obesity 2016, 24, 2261–2268.
  22. Lehert, P.; Villaseca, P.; Hogervorst, E.; Maki, P.M.; Henderson, V.W. Individually modifiable risk factors to ameliorate cognitive aging: A systematic review and meta-analysis. Climacteric 2015, 18, 678–689.
  23. Van den Brink, A.C.; Brouwer-Brolsma, E.M.; Berendsen, A.A.; van de Rest, M. The Mediterranean, dietary approaches to stop hypertension (DASH), and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diets are associated with less cognitive decline and a lower risk of Alzheimer’s disease-a review. Adv. Nutr. 2019, 10, 1040–1065.
  24. Martinez-Lapiscina, E.H.; Clavero, P.; Toledo, E.; San Julian, B.; Sanchez-Tainta, A.; Corella, D.; Lamuela-Raventos, R.M.; Martinez, J.A.; Martinez-Gonzalez, M.A. Virgin olive oil supplementation and long-term cognition: The Predimed-Navarra randomized, trial. J. Nutr. Health Aging 2013, 17, 544–552.
  25. Sakura, K.; Shen, C.; Shiraishi, I.; Hisatsune, T. Consumption of oleic acid on the preservation of cognitive functions in Japanese elderly individuals. Nutrients 2021, 13, 284.
  26. Cao, G.-Y.; Li, M.; Han, L.; Tayic, F.; Yao, S.-S.; Huang, Z.; Ai, P.; Liu, Y.-Z.; HU, Y.-H.; Xu, B. Dietary fat intake and cognitive function among older populations: A systematic review and meta-analysis. J. Prev. Alz. Dis. 2019, 3, 204–211.
  27. Keogh, J.B.; Grieger, J.A.; Noakes, M.; Clifton, P.M. Flow-mediated dilatation is impaired by a high-saturated fat diet but not by high-carbohydrate diet. Arterioscler. Thromb. Vasc. Biol. 2005, 25, 1278–1279.
  28. Nooyens, A.C.J.; Yildiz, B.; Hendriks, L.G.; Bas, S.; van Boxtel, M.P.J.; Picavet, H.S.J.; Boer, J.M.A.; Verschuren, W.M.M. Adherence to dietary guidelines and cognitive decline from middle age: The Doetinchem Cohort Study. Am. J. Clin. Nutr. 2021, 114, 871–881.
  29. Naiberg, M.R.; Newton, D.F.; Goldstein, B.I. Flow-mediated dilation and neurocognition: Systematic review and future directions. Psychosom Med. 2016, 78, 192–207.
  30. Csipo, T.; Lipecz, A.; Fulop, G.A.; Hand, R.A.; Ngo, B.-T.N.; Dzialendzik, M.; Tarantini, S.; Balasubramanian, P.; Kiss, T.; Yabluchanska, V.; et al. Age-related decline in peripheral vascular health predicts cognitive impairment. GeroScience 2019, 41, 125–136.
  31. National Cholesterol Education Program; National Heart, Lung and Blood Institute; National Institutes of Health. Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on the Detection, Evaluation and Treatment of High Blood Cholesterol in Adults; NIH Publication No.02-5215; National Institutes of Health: Bethesda, MD, USA, 2002; p. 116.
  32. Brown, L.; Rosner, B.R.; Willet, W.W.; Sacks, F.M. Cholesterol-lowering effects of dietary fiber: A meta-analysis. Am. J. Clin. Nutr. 1999, 69, 30–42.
  33. Wu, H.; Dwyer, K.M.; Fan, Z.; Shircore, A.; Fan, J.; Dwyer, J.H. Dietary fiber and progression of atherosclerosis: The Los Angeles Atherosclerosis Study. Am. J. Clin. Nutr. 2003, 78, 1085–1089.
  34. Threapleton, D.E.; Greenwood, D.C.; Evans, C.E.L.; Cleghorn, C.L.; Nykjaer, C.; Woodhead, C.; Cade, J.E.; Gale, C.P.; Burley, V.J. Dietary fibre intake and risk of cardiovascular disease: Systematic review and meta-analysis. BMJ 2013, 347, 6879.
  35. Schoeler, M.; Caesar, R. Dietary lipids, gut microbiota and lipid metabolism. Rev. Endocr. Metab. Disord. 2019, 20, 461–472.
  36. Jonsson, A.L.; Backhed, F. Role of gut microbiota in atherosclerosis. Nat. Rev. Cardiol. 2017, 14, 79–87.
  37. Liu, S.; Willett, W.C.; Manson, J.E.; Hu, F.B.; Rosner, B.; Coldit, G. Relation between changes in intakes of dietary fiber and grain products and changes in weight and development of obesity among middle-aged women. Am. J. Clin. Nutr. 2003, 78, 920–927.
  38. Romaguera, D.; Angquist, L.; Du, H.; Jakobsen, M.U.; Forouhi, N.G.; Halkjaer, J.; Feskens, E.J.; Masala, G.; Steffen, A. Dietary determinants of changes in waist circumference adjusted for body mass index—A proxy measure of visceral adiposity. PLoS ONE 2010, 5, e11588.
  39. Ferdowsian, H.R.; Barnard, N.D.; Hoover, V.I.; Katcher, H.I.; Levin, S.M.; Green, A.A.; Cohen, J.L. A multi-component intervention reduced body weight and cardiovascular risk at a GEICO corporate site. Am. J. Health Promt. 2010, 24, 384–387.
  40. Bajerska, J.; Chmurzynska, A.; Muzsik, A.; Krzyzanowska, P.; Madry, E.; Malinowska, A.M.; Walkowiak, J. Weight loss and metabolic health effects from energy-restricted Mediterranean and Central-European diets in postmenopausal women: A randomized controlled trial. Sci. Rep. 2018, 8, 11170.
  41. Miketinas, D.; Bray, G.A.; Beyl, R.A.; Ryan, D.H.; Sacks, F.M.; Champagne, C.M. Fiber intake predicts weight loss and dietary adherence in adults consuming calorie-restricted diets: The POUNDS lost (preventing overweight using novel dietary strategies) study. J. Nutr. 2019, 149, 1742–1748.
  42. Jovanovski, E.; Mazhar, N.; Komishon, A.; Khayyat, R.; Li, D.; Mejia, A.B.; Khan, T.; Jenkins, A.L.; Smirvic-Duvnjak, L.; Vuksan, V. Can dietary viscous fiber affect body weight independently of an energy-restricted diet? A systematic review and meta- analysis of randomized controlled trials. Am. J. Clin. Nutr. 2020, 111, 471–485.
  43. Jovanovski, E.; Mazhar, N.; Komishon, A.; Khayyat, R.; Li, D.; Mejia, A.B.; Khan, T.; Jenkins, A.L.; Smirvic-Duvnjak, L.; Vuksan, V. Effect of viscous fiber supplementation on obesity indicators in individuals consuming calorie-restricted diets: A systematic review and meta-analysis of randomized controlled trials. Eur. J. Nutr. 2021, 60, 101–112.
  44. Heskey, C.; Oda, K.; Sabate, J. Avocado intake and longitudinal weight and body mass index changes in an adult cohort. Nutrients 2019, 11, 691.
  45. Dreher, M.L.; Ford, N.A. A comprehensive critical assessment of increased fruit and vegetable intake on weight loss in women. Nutrients 2020, 12, 1919.
  46. Seganfredo, F.B.; Blume, C.A.; Moehlecke, M.; Giongo, M.; Casagrande, D.S.; Spolidoro, J.V.N.; Padoin, A.V.; Schaan, B.D.; Mottin, C.C. Weight-loss interventions and gut microbiota change in overweight and obese patients: A systematic review. Obes. Rev. 2017, 18, 832–851.
  47. Holscher, H.D. Dietary fiber and prebiotics and the gastrointestinal microbiota. Gut Microb. 2017, 8, 172–184.
  48. Cui, J.; Lan, Y.; Zhao, C.; Du, H.; Han, Y.; Gao, W.; Xiao, H.; Zheng, J. Dietary fibers from fruits and vegetables and their health benefits via modulation of gut microbiota. Compr. Rev. Food Sci. Food Saf. 2019, 18, 1514–1532.
  49. Noble, E.E.; Hsu, T.M.; Kanoski, S.E. Gut to brain dysbiosis: Mechanisms linking Western diet consumption, the microbiome, and cognitive impairment. Front. Behav. Neurosci. 2017, 11, 1–10.
  50. Bourassa, M.W.; Alim, I.; Bultman, S.J.; Ratan, R.R. Butyrate, neuroepigenetics and the gut microbiome: Can a high fiber diet improve brain health? Neurosci. Lett. 2016, 625, 56–63.
  51. Serra, M.C.; Nocera, J.R.; Kelleher, J.L.; Addison, O. Prebiotic intake in older adults: Effects on brain function and behavior. Curr. Nutr. Rep. 2019, 8, 66–73.
  52. Mao, X.; Chen, C.; Xun, P.; Daviglus, M.L.; Steffen, L.M.; Jacobs, D.R.; Van Horn, L.; Sidney, S.; Zhu, N.; Qin, B.; et al. Intake of vegetables and fruits through young adulthood is associated with better cognitive function in middle in the US general population. J. Nutr. 2019, 149, 1424–1433.
  53. Henning, S.M.; Yang, J.; Woo, S.L.; Lee, R.-P.; Huang, J.; Rasmusen, A.; Carpenter, C.L.; Thames, G.; Gilbuena, I.; Tseng, C.-H.; et al. Hass avocado inclusion in a weight-loss diet supported weight loss and altered gut microbiota: A 12-week randomized, parallel-controlled trial. Curr. Dev. Nutr. 2019, 3, nzz068.
  54. Thompson, S.V.; Bailey, M.A.; Taylor, A.M.; Kaczmarek, J.L.; Mysonhimer, A.R.; Edwards, C.G.; Reeser, G.E.; Burd, N.A.; Khan, N.A.; Holscher, H.D. Avocado consumption alters gastrointestinal bacteria abundance and microbial metabolite concentrations among adults with overweight or obesity: A randomized controlled trial. J. Nutr. 2021, 151, 753–762.
  55. Fulgoni, V.L.; Dreher, M.; Davenport, J. Avocado consumption is associated with better diet quality and nutrient intake, and lower metabolic syndrome risk in US adults: Results from the National Health and Nutrition Examination Survey (NHANES) 2001–2008. Nutr. J. 2013, 12, 1–6.
  56. Bertoia, M.L.; Mukamal, K.J.; Cahill, L.E.; Hou, T.; Ludwig, D.S.; Mozaffarian, D.; Willett, W.C.; Hu, F.B. Changes in intake of fruits and vegetables and weight change in United States men and women followed for up to 24 years: Analysis from three prospective cohort studies. PLoS Med. 2015, 12, e1001878.
  57. Khan, N.A.; Edwards, C.G.; Thompson, S.V.; Hannon, B.A.; Burke, S.K.; Walk, A.D.M.; Mackenzie, R.W.A.; Reeser, G.E.; Fiese, B.H.; Burd, N.A.; et al. Avocado consumption, abdominal adiposity, and oral glucose tolerance among persons with overweight and obesity. J. Nutr. 2021, 151, 2513–2521.
  58. Zhu, L.; Huang, Y.; Edirisinghe, I.; Park, E.; Burton-Freeman, B. Using the avocado to test the satiety effects of a fat-fiber combination in place of carbohydrate energy in a breakfast meal in overweight and obese men and women: A randomized clinical trial. Nutrients 2019, 11, 952.
  59. Wien, M.; Haddad, E.; Oda, K.; Sabate, J. A randomized 3 × 3 crossover study to evaluate the effects of Hass avocado intake on post-ingestive satiety, glucose and insulin levels, and subsequent energy intake in overweight adults. Nutr. J. 2013, 12, 155.
  60. Haddad, E.; Wien, M.; Oda, K.; Sabate, J. Postprandial gut hormone responses to Hass avocado meals and their association with visual analog scores in overweight adults: A randomized 3 × 3 crossover trial. Eating Behav. 2018, 31, 35–40.
  61. Edwards, C.G.; Walk, A.M.; Thompson, S.V.; Reeser, G.E.; Erdman, J.W.; Burd, N.A.; Holscher, H.D.; Khan, N.A. Effects of 12-week avocado consumption on cognitive function among adults with overweight and obesity. Int. J. Psychophysiol. 2020, 148, 13–24.
  62. Guan, V.; Neale, E.; Probst, Y. Consumption of avocado and associations with nutrient, food, and anthropometric measures in a representative survey of Australians: A secondary analysis of the 2011–2012 National Nutrition and Physical Activity Survey. Br. J. Nutr. 2021, 1–19.
  63. Brunstrom, J.M.; Drake, A.C.L.; Forde, C.G.; Rogers, P.J. Undervalued and ignored: Are humans poorly adapted to energy dense foods? Appetite 2018, 120, 589–595.
  64. Kant, A.K.; Graubard, B.I. Energy density of diets reported by American adults: Association with food group intake and body weight. Int. J. Obes. (Lond.) 2005, 29, 950–956.
  65. Savage, J.S.; Marini, M.; Birch, L.L. Dietary energy density predicts women’s weight change over 6 y. Am. J. Clin. Nutr. 2008, 88, 677–684.
  66. Unlu, N.Z.; Bohn, T.; Clinton, S.K.; Schwartz, S.J. Carotenoid absorption from salad and salsa by humans is enhanced by the addition of avocado or avocado oil. J. Nutr. 2005, 135, 431–436.
  67. Kopec, R.E.; Cooperstone, J.L.; Schweiggert, R.M.; Young, G.S.; Harrison, E.H.; Francis, D.M.; Clinton, S.K.; Schwartz, S.J. Avocado consumption enhances human postprandial provitamin A absorption and conversion from a novel high-β-carotene tomato sauce and from carrots. J. Nutr. 2014, 144, 1158–1166.
  68. Leermakers, E.T.M.; Darweesh, S.K.L.; Baena, C.P.; Moreira, E.M.; van Lent, D.M.; Tielemans, M.J.; Muka, T.; Vitezova, A.; Chowdhury, R.; Bramer, W.M.; et al. The effects of lutein on cardiometabolic health across the life course: A systematic review and meta-analysis. Am. J. Clin. Nutr. 2016, 103, 481–494.
  69. Steinberg, D.; Witztum, J.L. Oxidized low-density lipoprotein and atherosclerosis. Arterioscler. Thromb. Vac. Biol. 2010, 30, 2311–2316.
  70. Xu, X.-R.; Zou, Z.-Y.; Huang, Y.-M.; Xiao, L.; Lin, X.-M. Serum carotenoids in relation to risk factors for development of atherosclerosis. Clin. Biochem. 2012, 45, 1357–1361.
  71. Zou, Z.-Y.; Xu, X.-R.; Lin, X.-M.; Zhang, H.-B.; Xiao, X.; Ouyang, L.; Huang, Y.-M.; Wang, X.; Liu, Y.-Q. Effects of lutein and lycopene on carotid-media thickness in Chinese subjects with subclinical atherosclerosis: A randomised, double blind, placebo-controlled trial. Br. J. Clin. Nutr. 2014, 111, 474–480.
  72. Cheng, H.M.; Koutsidis, G.; Lodge, J.K.; Ashor, A.; Siervo, M.; Lara, J. Tomato and lycopene supplementation and cardiovascular risk factors; a systematic review and meta-analysis. Atherosclerosis 2017, 257, 100–108.
  73. Yagi, A.; Nouchi, R.; Butler, L.; Kawashima, R. Lutein has a positive impact on brain health in healthy older adults: A systematic review of randomized controlled trials and cohort studies. Nutrients 2021, 13, 1746.
  74. Nouchi, R.; Suiko, T.; Kimura, E.; Takenaka, H.; Murakoshi, M.; Uchiyama, A.; Aono, M.; Kawashima, R. Effects of lutein and astaxanthin intake on the improvement of cognitive functions among healthy adults: A systematic review of randomized controlled trials. Nutrients 2020, 12, 617.
  75. Li, L.H.; Lee, J.C.-Y.; Leung, H.H.; Lam, W.C.; Fu, Z.; Lo, A.C.Y. Lutein supplementation for eye diseases. Nutrients 2020, 12, 1721.
  76. Vishwanathan, R.; Iannaccone, A.; Scott, T.M.; Kritchevsky, S.B.; Jennings, B.J.; Carboni, G.; Forma, G.; Satterfield, S.; Harris, T.; Johnson, K.C.; et al. Macular pigment optical density is related to cognitive function in older people. Age Aging 2014, 43, 271–275.
  77. Moran, N.E.; Mohn, E.S.; Hason, N.; Erdman, J.W.; Johnson, E.J. intrinsic and extrinsic factors impacting absorption, metabolism, and health effects of dietary carotenoids. Adv. Nutr. 2018, 9, 465–492.
  78. Johnson, E.J.; McDonald, K.; Caldarella, S.M.; Chung, H.-Y.; Troen, A.M.; Snodderly, D.M. Cognitive findings of an exploratory trial of docosahexaenoic acid and lutein supplementation in older women. Nutr. Neurosci. 2008, 11, 75–83.
  79. Scott, T.M.; Rasmussen, H.M.; Chen, O.; Johnson, E.J. Avocado consumption increases macular pigment density in older adults: A randomized, controlled trial. Nutrients 2016, 9, 919.
  80. Cheng, F.W.; Ford, N.A.; Taylor, M. US older adults that consume avocado or guacamole have better cognition than non-consumers: National Health and Nutrition Examination Survey 2011–2014. Front. Nutr. 2021.
More
© Text is available under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)
Video Production Service
Feedback