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Valentin-Escalera J, Leclerc M, Calon F. High-Fat Diets in Animal Models of Alzheimer's Disease: How Can Eating Too Much Fat Increase Alzheimer's Disease Risk? J Alzheimers Dis 2024; 97:977-1005. [PMID: 38217592 PMCID: PMC10836579 DOI: 10.3233/jad-230118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/15/2023] [Indexed: 01/15/2024]
Abstract
High dietary intake of saturated fatty acids is a suspected risk factor for neurodegenerative diseases, including Alzheimer's disease (AD). To decipher the causal link behind these associations, high-fat diets (HFD) have been repeatedly investigated in animal models. Preclinical studies allow full control over dietary composition, avoiding ethical concerns in clinical trials. The goal of the present article is to provide a narrative review of reports on HFD in animal models of AD. Eligibility criteria included mouse models of AD fed a HFD defined as > 35% of fat/weight and western diets containing > 1% cholesterol or > 15% sugar. MEDLINE and Embase databases were searched from 1946 to August 2022, and 32 preclinical studies were included in the review. HFD-induced obesity and metabolic disturbances such as insulin resistance and glucose intolerance have been replicated in most studies, but with methodological variability. Most studies have found an aggravating effect of HFD on brain Aβ pathology, whereas tau pathology has been much less studied, and results are more equivocal. While most reports show HFD-induced impairment on cognitive behavior, confounding factors may blur their interpretation. In summary, despite conflicting results, exposing rodents to diets highly enriched in saturated fat induces not only metabolic defects, but also cognitive impairment often accompanied by aggravated neuropathological markers, most notably Aβ burden. Although there are important variations between methods, particularly the lack of diet characterization, these studies collectively suggest that excessive intake of saturated fat should be avoided in order to lower the incidence of AD.
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Affiliation(s)
- Josue Valentin-Escalera
- Faculté de Pharmacie, Université Laval, Québec, Canada
- Axe Neurosciences, Centre de recherche du centre Hospitalier de l'Université Laval (CHUL), Québec, Canada
- Institut sur la Nutrition et les Aliments Fonctionnels, Québec, Canada
- OptiNutriBrain - Laboratoire International Associé (NutriNeuro France-INAF Canada)
| | - Manon Leclerc
- Faculté de Pharmacie, Université Laval, Québec, Canada
- Axe Neurosciences, Centre de recherche du centre Hospitalier de l'Université Laval (CHUL), Québec, Canada
- Institut sur la Nutrition et les Aliments Fonctionnels, Québec, Canada
- OptiNutriBrain - Laboratoire International Associé (NutriNeuro France-INAF Canada)
| | - Frédéric Calon
- Faculté de Pharmacie, Université Laval, Québec, Canada
- Axe Neurosciences, Centre de recherche du centre Hospitalier de l'Université Laval (CHUL), Québec, Canada
- Institut sur la Nutrition et les Aliments Fonctionnels, Québec, Canada
- OptiNutriBrain - Laboratoire International Associé (NutriNeuro France-INAF Canada)
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Juul F, Vaidean G, Parekh N. Ultra-processed Foods and Cardiovascular Diseases: Potential Mechanisms of Action. Adv Nutr 2021; 12:1673-1680. [PMID: 33942057 PMCID: PMC8483964 DOI: 10.1093/advances/nmab049] [Citation(s) in RCA: 131] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 02/02/2021] [Accepted: 03/31/2021] [Indexed: 12/31/2022] Open
Abstract
Ultra-processed foods are industrially manufactured ready-to-eat or ready-to-heat formulations containing food additives and little or no whole foods, in contrast to processed foods, which are whole foods preserved by traditional techniques such as canning or pickling. Recent epidemiological studies suggest that higher consumption of ultra-processed food is associated with increased risk of cardiovascular disease (CVD). However, epidemiological evidence needs to be corroborated with criteria of biological plausibility. This review summarizes the current evidence on the putative biological mechanisms underlying the associations between ultra-processed foods and CVD. Research ranging from laboratory-based to prospective epidemiological studies and experimental evidence suggest that ultra-processed foods may affect cardiometabolic health through a myriad of mechanisms, beyond the traditionally recognized individual nutrients. Processing induces significant changes to the food matrix, for which ultra-processed foods may affect health outcomes differently than unrefined whole foods with similar nutritional composition. Notably, the highly degraded physical structure of ultra-processed foods may affect cardiometabolic health by influencing absorption kinetics, satiety, glycemic response, and the gut microbiota composition and function. Food additives and neo-formed contaminants produced during processing may also play a role in CVD risk. Key biological pathways include altered serum lipid concentrations, modified gut microbiota and host-microbiota interactions, obesity, inflammation, oxidative stress, dysglycemia, insulin resistance, and hypertension. Further research is warranted to clarify the proportional harm associated with the nutritional composition, food additives, physical structure, and other attributes of ultra-processed foods. Understanding how ultra-processing changes whole foods and through which pathways these foods affect health is a prerequisite for eliminating harmful processing techniques and ingredients.
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Affiliation(s)
- Filippa Juul
- Department of Epidemiology, School of Global Public Health, New York University, New York, NY, USA
| | - Georgeta Vaidean
- School of Pharmacy and Health Sciences, Fairleigh Dickinson University, Florham Park, NJ, USA,Division of Cardiology, Lenox Hill Hospital, Northwell Health, New York, NY, USA
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Hong SH, Ku JM, Lim YS, Kim HI, Shin YC, Ko SG. Cervus nippon var. mantchuricus water extract treated with digestive enzymes (CE) modulates M1 macrophage polarization through TLR4/MAPK/NF-κB signaling pathways on murine macrophages. EUR J INFLAMM 2021. [DOI: 10.1177/20587392211000898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The objective of this study was to investigate the effects of Cervus nippon var. mantchuricus water extract treated with digestive enzymes (CE) on the promotion of M1 macrophage polarization in murine macrophages. Macrophages polarize either to one phenotype after stimulation with LPS or IFN-γ or to an alternatively activated phenotype that is induced by IL-4 or IL-13. Cell viability of RAW264.7 cells was determined by WST-1 assay. NO production was measured by Griess assay. IL-6, IL-12, TNF-α, and iNOS mRNA levels were measured by RT-PCR. IL-6, IL-12, and IL-10 cytokine levels were determined by ELISA. TLR4/MAPK/NF-κB signaling in RAW264.7 cells was evaluated by western blotting. The level of NF-κB was determined by immunoblotting. CE induced the differentiation of M1 macrophages. CE promoted M1 macrophages to elevate NO production and cytokine levels. CE-stimulated M1 macrophages had enhanced IL-6, IL-12, and TNF-α. CE promoted M1 macrophages to activate TLR4/MAPK/NF-κB phosphorylation. M2 markers were downregulated, while M1 markers were upregulated in murine macrophages by CE. Consequently, CE has immunomodulatory activity and can be used to promote M1 macrophage polarization through the TLR4/MAPK/NF-κB signaling pathways.
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Affiliation(s)
- Se Hyang Hong
- Department of Preventive Medicine, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
- Clinical Medicine Division, Korea Institute of Oriental Medicine, Daejeon, Republic of Korea
| | - Jin Mo Ku
- Department of Preventive Medicine, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Ye Seul Lim
- Department of Preventive Medicine, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Hyo In Kim
- Department of Preventive Medicine, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Yong Cheol Shin
- Department of Preventive Medicine, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Seong-Gyu Ko
- Department of Preventive Medicine, College of Korean Medicine, Kyung Hee University, Seoul, Republic of Korea
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Saturated Fats and Health: A Reassessment and Proposal for Food-Based Recommendations: JACC State-of-the-Art Review. J Am Coll Cardiol 2020; 76:844-857. [PMID: 32562735 DOI: 10.1016/j.jacc.2020.05.077] [Citation(s) in RCA: 267] [Impact Index Per Article: 66.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/07/2020] [Accepted: 05/12/2020] [Indexed: 12/29/2022]
Abstract
The recommendation to limit dietary saturated fatty acid (SFA) intake has persisted despite mounting evidence to the contrary. Most recent meta-analyses of randomized trials and observational studies found no beneficial effects of reducing SFA intake on cardiovascular disease (CVD) and total mortality, and instead found protective effects against stroke. Although SFAs increase low-density lipoprotein (LDL) cholesterol, in most individuals, this is not due to increasing levels of small, dense LDL particles, but rather larger LDL particles, which are much less strongly related to CVD risk. It is also apparent that the health effects of foods cannot be predicted by their content in any nutrient group without considering the overall macronutrient distribution. Whole-fat dairy, unprocessed meat, and dark chocolate are SFA-rich foods with a complex matrix that are not associated with increased risk of CVD. The totality of available evidence does not support further limiting the intake of such foods.
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Liu R, Cheng M, Kothapalli KSD, Wang Z, Mendralla E, Park HG, Block RC, Wang X, Brenna JT. Glycerol derived process contaminants in refined coconut oil induce cholesterol synthesis in HepG2 cells. Food Chem Toxicol 2019; 127:135-142. [PMID: 30878531 PMCID: PMC6467815 DOI: 10.1016/j.fct.2019.03.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 03/05/2019] [Accepted: 03/07/2019] [Indexed: 10/27/2022]
Abstract
Despite its 50-year history, the conventional diet-heart hypothesis holding that dietary saturated fats raise serum cholesterol, and with it, cardiovascular risk, remains controversial. Harsh chemical and physical treatment generates process contaminants, and refined oils raise serum and tissue cholesterol in vivo independent of saturated fat content. We developed an in vitro bioassay for rapidly assessing the influence of oils on cholesterol metabolism in the human liver HepG2 cell line, and tested it using coconut oil (CO) of various stages of refinement. CO was dissolved with dipalmitoyl phosphatidylcholine (DPPC) surfactant, solvent evaporated, and emulsified into fat-free cell culture media. After 24 h treatment cellular cholesterol and triacylglycerol increased; HMG-CoA Reductase (HMGCR) increased and CYP7A1 (cholesterol 7α-hydroxylase) decreased with sequential processing steps, deacidification, bleaching, deodorization, while fatty acid profiles were not affected. Glycerol-derived process contaminants glycidyl esters and monochloropropandiol (MCPD) increased with processing. Addition of glycidyl or MCPD to virgin CO (VCO) had similar effects to processing, while addition of phenolic antioxidants to fully refined CO reduced HMGCR and increased CYP7A1. We conclude that harsh processing creates contaminants that raise cholesterol levels in vitro, consistent with a role as a contributing atherosclerotic factor.
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Affiliation(s)
- Ruijie Liu
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, 14853, USA; Synergetic Innovation Center of Food Safety and Nutrition of Jiangsu Province, School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu Province, PR China; Dell Pediatric Research Institute and the Depts. of Chemistry, of Pediatrics, and of Nutrition, University of Texas at Austin, 1400 Barbara Jordan Blvd, Austin, TX, 78723, USA
| | - Min Cheng
- Synergetic Innovation Center of Food Safety and Nutrition of Jiangsu Province, School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu Province, PR China
| | - Kumar S D Kothapalli
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, 14853, USA; Dell Pediatric Research Institute and the Depts. of Chemistry, of Pediatrics, and of Nutrition, University of Texas at Austin, 1400 Barbara Jordan Blvd, Austin, TX, 78723, USA
| | - Zhen Wang
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, 14853, USA; Dell Pediatric Research Institute and the Depts. of Chemistry, of Pediatrics, and of Nutrition, University of Texas at Austin, 1400 Barbara Jordan Blvd, Austin, TX, 78723, USA
| | - Elizabeth Mendralla
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, 14853, USA
| | - Hui Gyu Park
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, 14853, USA; Dell Pediatric Research Institute and the Depts. of Chemistry, of Pediatrics, and of Nutrition, University of Texas at Austin, 1400 Barbara Jordan Blvd, Austin, TX, 78723, USA
| | - Robert C Block
- Department of Community and Preventive Medicine and Cardiology Division, Department of Medicine, The University of Rochester School of Medicine and Dentistry, Saunders Research Building, Rochester, NY, 14642, USA
| | - Xingguo Wang
- Synergetic Innovation Center of Food Safety and Nutrition of Jiangsu Province, School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu Province, PR China
| | - J Thomas Brenna
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, 14853, USA; Dell Pediatric Research Institute and the Depts. of Chemistry, of Pediatrics, and of Nutrition, University of Texas at Austin, 1400 Barbara Jordan Blvd, Austin, TX, 78723, USA.
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