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Rong L, Peng Y, Shen Q, Chen K, Fang B, Li W. Effects of ketogenic diet on cognitive function of patients with Alzheimer's disease: a systematic review and meta-analysis. J Nutr Health Aging 2024; 28:100306. [PMID: 38943982 DOI: 10.1016/j.jnha.2024.100306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 06/09/2024] [Accepted: 06/24/2024] [Indexed: 07/01/2024]
Abstract
BACKGROUND Ketogenic diets (KD) have shown remarkable effects in many disease areas. It has been demonstrated in numerous animal experiments that KD is effective in the treatment of Alzheimer's disease (AD). But the clinical effect of treating AD is uncertain. OBJECTIVE To systematically review the impact of KD on cognitive function in AD. METHODS We conducted a search of three international databases-PubMed, Cochrane Library, and Embase-to retrieve RCTs on the KD intervention for AD from the inception of the databases through October 2023. Two reviewers searched and screened the literature, extracted and checked relevant data independently, and assessed the risk of bias of the included studies. The meta-analysis was carried out utilizing RevMan 5.3 software. RESULTS A total of 10 RCTS involving 691 patients with AD were included. There were 357 participants in the intervention group and 334 participants in the control group. The duration of the KD intervention ranged from a minimum of 3 months to a maximum of 15 months. Meta-analysis results showed that KD could effectively improve the mental state of the elderly (NM scale) [MD = 7.56, 95%CI (3.02, 12.10), P = 0.001], MMSE [MD = 1.25, 95%CI (0.46, 2.04), P = 0.002], and ADAS-Cog [MD = -3.43, 95%CI (-5.98, -0.88), P = 0.008]. The elevation of ketone body (β-hydroxybutyric) [MD = 118.84, 95%CI (15.20, 222.48), P = 0.02] may also lead to the elevation of triglyceride [MD = 0.19, 95%CI (0.03, 0.35), P = 0.02] and low density lipoprotein [MD = 0.31, 95%CI (0.04, 0.58), P = 0.02]. CONCLUSION Research conducted has indicated that the KD can enhance the mental state and cognitive function of those with AD, albeit potentially leading to an elevation in blood lipid levels. In summary, the good intervention effect and safety of KD are worthy of promotion and application in clinical treatment of AD.
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Affiliation(s)
- Liyang Rong
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, China; Sanya Hospital of Traditional Chinese Medicine, Sanya, China
| | - Yating Peng
- School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Qi Shen
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Keying Chen
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Bangjiang Fang
- Department of Emergency, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Weirong Li
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou, China.
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Tavener SK, Jackson MI, Panickar KS. Immune-Modulating Effects of Low-Carbohydrate Ketogenic Foods in Healthy Canines. Curr Dev Nutr 2024; 8:102128. [PMID: 38590952 PMCID: PMC10999821 DOI: 10.1016/j.cdnut.2024.102128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 02/19/2024] [Accepted: 02/23/2024] [Indexed: 04/10/2024] Open
Abstract
Background Ketogenic foods limit digestible carbohydrates but contain high fat, and have antioxidant and anti-inflammatory effects as well as improving mitochondrial function. β-Hydroxybutyrate (BHB), 1 of the ketone bodies, reduces the proinflammatory NLR family pyrin domain containing 3 inflammasomes, as well as chemokines in cultures. Objectives We assessed the immune-modulating effects of 2 low-carbohydrate (LoCHO) foods varying in protein and fat and compared their effects with a food replete with high-carbohydrate (HiCHO) in healthy canines. Methods Dogs were fed control food [HiCHO; ketogenic ratio (KR: 0.46) followed by LoCHO_PROT (KR: 0.97), then LoCHO_FAT (KR: 1.63) or LoCHO_FAT followed by LoCHO_PROT. Each food was fed for 5 wk, with collections in the 5th wk; 15 wk feeding total. Gene expression for circulating inflammatory cytokines from 10 dogs was assessed using the Canine RT2 Profiler polymerase chain reaction array, and fold changes were calculated using the ΔΔCt method. Results LoCHO_FAT significantly increased circulating β-hydroxybutyrate compared with both HiCHO and LoCHO_PROT. When compared with HiCHO, there was a significant decrease in several proinflammatory cytokines/chemokines in LoCHO_PROT and LoCHO_FAT groups, including chemokine (C-C motif) ligand (CCL)1, CCL8, CCL13, CCL17, CCL24, chemokine (C-X3-C motif) ligand 1, chemokine (C-X-C motif) receptor 1, Interleukin-10 receptor alpha ((IL)-10RA), IL-1 receptor antagonist, IL-5, and secreted phosphoprotein 1 (all P < 0.05). Interestingly, a subset of inflammatory proteins that decreased in LoCHO_PROT but not in LoCHO_FAT included IL-33, IL-6 receptor, IL-7, IL-8, Nicotinamide phosphoribosyltransferase, and tumor necrosis factor (TNF) receptor superfamily member 11B. In contrast, the decrease in inflammatory markers in LoCHO_FAT, but not in LoCHO_PROT, included complement component 5, granulocyte colony-stimulating factor or G-CSF, interferon-γ, IL-3, IL-10RB, IL-17C, Tumor necrosis factor superfamily (TNFSF)13, TNFSF13B, and TNFSF14. Decreased concentrations of selected cytokines indicate that both low-carbohydrate foods exert an anti-inflammatory effect and provide a strong rationale for testing their efficacy in dogs with inflammatory conditions. Conclusions Both LoCHO_PROT and LoCHO_FAT foods might be important as part of immune-modulating therapeutic nutritional strategies to reduce inflammation to maintain health in canines. Our study identifies several inflammatory genes that are reduced when fed ketogenic food that were not previously reported.
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Affiliation(s)
- Selena K. Tavener
- Science and Technology Center, Hill’s Pet Nutrition, Inc., Topeka, KS, United States
| | - Matthew I. Jackson
- Science and Technology Center, Hill’s Pet Nutrition, Inc., Topeka, KS, United States
| | - Kiran S. Panickar
- Science and Technology Center, Hill’s Pet Nutrition, Inc., Topeka, KS, United States
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Ruppert PMM, Kersten S. Mechanisms of hepatic fatty acid oxidation and ketogenesis during fasting. Trends Endocrinol Metab 2024; 35:107-124. [PMID: 37940485 DOI: 10.1016/j.tem.2023.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/02/2023] [Accepted: 10/04/2023] [Indexed: 11/10/2023]
Abstract
Fasting is part of many weight management and health-boosting regimens. Fasting causes substantial metabolic adaptations in the liver that include the stimulation of fatty acid oxidation and ketogenesis. The induction of fatty acid oxidation and ketogenesis during fasting is mainly driven by interrelated changes in plasma levels of various hormones and an increase in plasma nonesterified fatty acid (NEFA) levels and is mediated transcriptionally by the peroxisome proliferator-activated receptor (PPAR)α, supported by CREB3L3 (cyclic AMP-responsive element-binding protein 3 like 3). Compared with men, women exhibit higher ketone levels during fasting, likely due to higher NEFA availability, suggesting that the metabolic response to fasting shows sexual dimorphism. Here, we synthesize the current molecular knowledge on the impact of fasting on hepatic fatty acid oxidation and ketogenesis.
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Affiliation(s)
- Philip M M Ruppert
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5000 C Odense, Denmark
| | - Sander Kersten
- Nutrition, Metabolism, and Genomics Group, Division of Human Nutrition and Health, Wageningen University, 6708 WE Wageningen, The Netherlands; Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA.
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Ji J, Fotros D, Sohouli MH, Velu P, Fatahi S, Liu Y. The effect of a ketogenic diet on inflammation-related markers: a systematic review and meta-analysis of randomized controlled trials. Nutr Rev 2024:nuad175. [PMID: 38219223 DOI: 10.1093/nutrit/nuad175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2024] Open
Abstract
CONTEXT Despite the important role of inflammation-related factors on the occurrence of chronic diseases, there is still conflicting evidence about the effects of the ketogenic diet (KD) on these factors. OBJECTIVE In order to obtain a better viewpoint, this study aimed to comprehensively investigate the effects of a KD on inflammation-related markers. DATA SOURCES To find pertinent randomized controlled trials up to August 2023, databases including PubMed/Medline, Web of Science, Scopus, Cochrane Library, and Embase were searched. DATA EXTRACTION This study included all randomized controlled trials investigating the effects of a KD on C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, IL-8, and IL-10 levels. Pooled weighted mean difference (WMD) and 95% confidence intervals (CIs) were achieved by random-effects model analysis for the best estimation of outcomes. DATA ANALYSIS Forty-four studies were included in this article. The pooled findings showed that a KD has an effect on lowering TNF-α (WMD: -0.32 pg/mL; 95% CI: -0.55, -0.09; P = 0.007) and IL-6 (WMD: -0.27 pg/mL; 95% CI: -0.52, -0.02; P = 0.036) compared with control groups. However, no significant effect was reported for others inflammation marker-related levels. The results of the subgroup analysis showed that, in trials following the KD for ≤8 weeks and in people aged ≤50 years, the reduction in TNF-α levels was significantly higher than in other groups. In addition, in people with a body mass index greater than 30 kg/m2 compared to a body mass index ≤30 kg/m2, IL-6 levels decreased to a greater extent after receiving the KD. CONCLUSIONS Consequently, adherence to a KD appears to improve some markers associated with inflammation, including TNF-α and IL-6.
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Affiliation(s)
- Jiawei Ji
- Department of General Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Danial Fotros
- Department of Clinical Nutrition and Dietetics, Faculty of Nutrition and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Hassan Sohouli
- Student Research Committee, Department of Clinical Nutrition and Dietetics, Faculty of Nutrition and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Periyannan Velu
- Galileovasan Offshore and Research and Development Pvt Ltd, Nagapattinam, Tamil Nadu, India
| | - Somaye Fatahi
- Department of Clinical Nutrition and Dietetics, Faculty of Nutrition and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Yinghao Liu
- Institute of Grassland Research, Chinese Academy of Agricultural Sciences, Hohhot, China
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Ramezani M, Fernando M, Eslick S, Asih PR, Shadfar S, Bandara EMS, Hillebrandt H, Meghwar S, Shahriari M, Chatterjee P, Thota R, Dias CB, Garg ML, Martins RN. Ketone bodies mediate alterations in brain energy metabolism and biomarkers of Alzheimer's disease. Front Neurosci 2023; 17:1297984. [PMID: 38033541 PMCID: PMC10687427 DOI: 10.3389/fnins.2023.1297984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 10/30/2023] [Indexed: 12/02/2023] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia. AD is a progressive neurodegenerative disorder characterized by cognitive dysfunction, including learning and memory deficits, and behavioral changes. Neuropathology hallmarks of AD such as amyloid beta (Aβ) plaques and neurofibrillary tangles containing the neuron-specific protein tau is associated with changes in fluid biomarkers including Aβ, phosphorylated tau (p-tau)-181, p-tau 231, p-tau 217, glial fibrillary acidic protein (GFAP), and neurofilament light (NFL). Another pathological feature of AD is neural damage and hyperactivation of astrocytes, that can cause increased pro-inflammatory mediators and oxidative stress. In addition, reduced brain glucose metabolism and mitochondrial dysfunction appears up to 15 years before the onset of clinical AD symptoms. As glucose utilization is compromised in the brain of patients with AD, ketone bodies (KBs) may serve as an alternative source of energy. KBs are generated from the β-oxidation of fatty acids, which are enhanced following consumption of ketogenic diets with high fat, moderate protein, and low carbohydrate. KBs have been shown to cross the blood brain barrier to improve brain energy metabolism. This review comprehensively summarizes the current literature on how increasing KBs support brain energy metabolism. In addition, for the first time, this review discusses the effects of ketogenic diet on the putative AD biomarkers such as Aβ, tau (mainly p-tau 181), GFAP, and NFL, and discusses the role of KBs on neuroinflammation, oxidative stress, and mitochondrial metabolism.
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Affiliation(s)
- Matin Ramezani
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Macquarie, NSW, Australia
| | - Malika Fernando
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Macquarie, NSW, Australia
| | - Shaun Eslick
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Macquarie, NSW, Australia
| | - Prita R. Asih
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Macquarie, NSW, Australia
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Sina Shadfar
- Motor Neuron Disease Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | | | - Heidi Hillebrandt
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Macquarie, NSW, Australia
| | - Silochna Meghwar
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Macquarie, NSW, Australia
| | - Maryam Shahriari
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Macquarie, NSW, Australia
| | - Pratishtha Chatterjee
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Macquarie, NSW, Australia
| | - Rohith Thota
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Macquarie, NSW, Australia
| | - Cintia B. Dias
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Macquarie, NSW, Australia
| | - Manohar L. Garg
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Macquarie, NSW, Australia
| | - Ralph N. Martins
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Macquarie, NSW, Australia
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
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Juby AG, Cunnane SC, Mager DR. Refueling the post COVID-19 brain: potential role of ketogenic medium chain triglyceride supplementation: an hypothesis. Front Nutr 2023; 10:1126534. [PMID: 37415915 PMCID: PMC10320593 DOI: 10.3389/fnut.2023.1126534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Accepted: 04/25/2023] [Indexed: 07/08/2023] Open
Abstract
COVID-19 infection causes cognitive changes in the acute phase, but also after apparent recovery. Over fifty post (long)-COVID symptoms are described, including cognitive dysfunction ("brain fog") precluding return to pre-COVID level of function, with rates twice as high in females. Additionally, the predominant demographic affected by these symptoms is younger and still in the workforce. Lack of ability to work, even for six months, has significant socio-economic consequences. This cognitive dysfunction is associated with impaired cerebral glucose metabolism, assessed using 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET), showing brain regions that are abnormal compared to age and sex matched controls. In other cognitive conditions such as Alzheimer's disease (AD), typical patterns of cerebral glucose hypometabolism, frontal hypometabolism and cerebellar hypermetabolism are common. Similar FDG-PET changes have also been observed in post-COVID-19, raising the possibility of a similar etiology. Ketone bodies (B-hydroxybutyrate, acetoacetate and acetone) are produced endogenously with very low carbohydrate intake or fasting. They improve brain energy metabolism in the face of cerebral glucose hypometabolism in other conditions [mild cognitive impairment (MCI) and AD]. Long-term low carbohydrate intake or prolonged fasting is not usually feasible. Medium chain triglyceride (MCT) is an exogenous route to nutritional ketosis. Research has supported their efficacy in managing intractable seizures, and cognitive impairment in MCI and AD. We hypothesize that cerebral glucose hypometabolism associated with post COVID-19 infection can be mitigated with MCT supplementation, with the prediction that cognitive function would also improve. Although there is some suggestion that post COVID-19 cognitive symptoms may diminish over time, in many individuals this may take more than six months. If MCT supplementation is able to speed the cognitive recovery, this will impact importantly on quality of life. MCT is readily available and, compared to pharmaceutical interventions, is cost-effective. Research shows general tolerability with dose titration. MCT is a component of enteral and parenteral nutrition supplements, including in pediatrics, so has a long record of safety in vulnerable populations. It is not associated with weight gain or adverse changes in lipid profiles. This hypothesis serves to encourage the development of clinical trials evaluating the impact of MCT supplementation on the duration and severity of post COVID-19 cognitive symptoms.
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Affiliation(s)
- Angela G. Juby
- Division of Geriatrics, Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Stephen C. Cunnane
- Research Center on Aging, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Diana R. Mager
- Agriculture Food and Nutrition Science, University of Alberta, Edmonton, AB, Canada
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Qin Y, Bai D, Tang M, Zhang M, Zhao L, Li J, Yang R, Jiang G. Ketogenic Diet Alleviates Brain Iron Deposition and Cognitive Dysfunction via Nrf2-mediated Ferroptosis pathway in APP/PS1 Mouse. Brain Res 2023; 1812:148404. [PMID: 37164173 DOI: 10.1016/j.brainres.2023.148404] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 04/26/2023] [Accepted: 05/06/2023] [Indexed: 05/12/2023]
Abstract
Progressive cognitive decline and increased brain iron deposition with age are important features of Alzheimer's disease. Previous studies have found that the short-term ketogenic diet has neuroprotective effects in a variety of neurodegenerative diseases, but the effects of an early and long-term ketogenic diet on brain iron content and cognition of Alzheimer's disease have not been reported. In our study, 8-week-old APP/PS1 mice were given a 12-month ketogenic or standard diet, while C57BL/6 mice matched with the age and genetic background of APP/PS1 mice were used as normal controls to be given a standard diet for the same length of time. We found that 12 months of an early ketogenic diet improved the impaired learning and memory ability of APP/PS1 mice. The improvement of cognitive function may be related to the reduction of amyloid-beta deposition and neuronal ferroptosis. The mechanism was achieved by the regulation of ferroptosis-related pathways after activation of nuclear factor erythroid 2-related factor 2 by ketogenic diet-induced elevated β-hydroxybutyrate. In addition, blood biochemical results showed that compared with the standard diet group of the disease, although the early and long-term ketogenic diet increased blood lipids to some extent, it seemed to reduce liver, renal, and myocardial damage caused by genetic differences. This will provide a piece of positive evidence for the early and long-term use of ketogenic diets in people at risk of Alzheimer's disease.
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Affiliation(s)
- Yaya Qin
- Department of Neurology, Affiliated Hospital of North Sichuan Medical College, 1 South Maoyuan Road, Nanchong 637000, Sichuan, China; Institute of Neurological Diseases, North Sichuan Medical College, 234 Fujiang Road, Nanchong, Sichuan, China
| | - Dazhang Bai
- Department of Neurology, Affiliated Hospital of North Sichuan Medical College, 1 South Maoyuan Road, Nanchong 637000, Sichuan, China; Institute of Neurological Diseases, North Sichuan Medical College, 234 Fujiang Road, Nanchong, Sichuan, China
| | - Ming Tang
- Department of Neurology, Affiliated Hospital of North Sichuan Medical College, 1 South Maoyuan Road, Nanchong 637000, Sichuan, China; Institute of Neurological Diseases, North Sichuan Medical College, 234 Fujiang Road, Nanchong, Sichuan, China
| | - Ming Zhang
- Department of Neurology, Affiliated Hospital of North Sichuan Medical College, 1 South Maoyuan Road, Nanchong 637000, Sichuan, China; Institute of Neurological Diseases, North Sichuan Medical College, 234 Fujiang Road, Nanchong, Sichuan, China
| | - Li Zhao
- Department of Neurology, Affiliated Hospital of North Sichuan Medical College, 1 South Maoyuan Road, Nanchong 637000, Sichuan, China; Institute of Neurological Diseases, North Sichuan Medical College, 234 Fujiang Road, Nanchong, Sichuan, China
| | - Jia Li
- Department of Neurology, Affiliated Hospital of North Sichuan Medical College, 1 South Maoyuan Road, Nanchong 637000, Sichuan, China; Institute of Neurological Diseases, North Sichuan Medical College, 234 Fujiang Road, Nanchong, Sichuan, China
| | - Rui Yang
- Department of Neurology, Affiliated Hospital of North Sichuan Medical College, 1 South Maoyuan Road, Nanchong 637000, Sichuan, China; Institute of Neurological Diseases, North Sichuan Medical College, 234 Fujiang Road, Nanchong, Sichuan, China
| | - Guohui Jiang
- Department of Neurology, Affiliated Hospital of North Sichuan Medical College, 1 South Maoyuan Road, Nanchong 637000, Sichuan, China; Institute of Neurological Diseases, North Sichuan Medical College, 234 Fujiang Road, Nanchong, Sichuan, China.
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Xu Y, Zheng F, Zhong Q, Zhu Y. Ketogenic Diet as a Promising Non-Drug Intervention for Alzheimer’s Disease: Mechanisms and Clinical Implications. J Alzheimers Dis 2023; 92:1173-1198. [PMID: 37038820 DOI: 10.3233/jad-230002] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder that is mainly characterized by cognitive deficits. Although many studies have been devoted to developing disease-modifying therapies, there has been no effective therapy until now. However, dietary interventions may be a potential strategy to treat AD. The ketogenic diet (KD) is a high-fat and low-carbohydrate diet with adequate protein. KD increases the levels of ketone bodies, providing an alternative energy source when there is not sufficient energy supply because of impaired glucose metabolism. Accumulating preclinical and clinical studies have shown that a KD is beneficial to AD. The potential underlying mechanisms include improved mitochondrial function, optimization of gut microbiota composition, and reduced neuroinflammation and oxidative stress. The review provides an update on clinical and preclinical research on the effects of KD or medium-chain triglyceride supplementation on symptoms and pathophysiology in AD. We also detail the potential mechanisms of KD, involving amyloid and tau proteins, neuroinflammation, gut microbiota, oxidative stress, and brain metabolism. We aimed to determine the function of the KD in AD and outline important aspects of the mechanism, providing a reference for the implementation of the KD as a potential therapeutic strategy for AD.
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Affiliation(s)
- Yunlong Xu
- Shenzhen Key Laboratory of Drug Addiction, Shenzhen Neher Neural Plasticity Laboratory, the Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences (CAS), Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
- University of Chinese Academy of Sciences, Beijing, China
- Department of Neonatology, Shenzhen Maternity & Child Healthcare Hospital, The First School of Clinical Medicine, Southern Medical University, Shenzhen, China
| | - Fuxiang Zheng
- Department of Clinical Laboratory, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, Guangdong, China
| | - Qi Zhong
- Department of Neurology, Shenzhen Luohu People’s Hospital; The Third Affiliated Hospital of Shenzhen University, Shenzhen, China
| | - Yingjie Zhu
- Shenzhen Key Laboratory of Drug Addiction, Shenzhen Neher Neural Plasticity Laboratory, the Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences (CAS), Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
- University of Chinese Academy of Sciences, Beijing, China
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9
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Bohnen JLB, Albin RL, Bohnen NI. Ketogenic interventions in mild cognitive impairment, Alzheimer's disease, and Parkinson's disease: A systematic review and critical appraisal. Front Neurol 2023; 14:1123290. [PMID: 36846143 PMCID: PMC9947355 DOI: 10.3389/fneur.2023.1123290] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 01/17/2023] [Indexed: 02/11/2023] Open
Abstract
Background There is increasing interest in therapeutic ketosis as a potential therapy for neurodegenerative disorders-in particular, mild cognitive impairment (MCI), Alzheimer's disease (AD), and Parkinson's disease (PD)-following a proof-of-concept study in Parkinson's disease published in 2005. Methods To provide an objective assessment of emerging clinical evidence and targeted recommendations for future research, we reviewed clinical trials involving ketogenic interventions in mild cognitive impairment, Alzheimer's disease, and Parkinson's disease reported since 2005. Levels of clinical evidence were systematically reviewed using the American Academy of Neurology criteria for rating therapeutic trials. Results 10 AD, 3 MCI, and 5 PD therapeutic ketogenic trials were identified. Respective grades of clinical evidence were objectively assessed using the American Academy of Neurology criteria for rating therapeutic trials. We found class "B" evidence (probably effective) for cognitive improvement in subjects with mild cognitive impairment and subjects with mild-to-moderate Alzheimer's disease negative for the apolipoprotein ε4 allele (APOε4-). We found class "U" evidence (unproven) for cognitive stabilization in individuals with mild-to-moderate Alzheimer's disease positive for the apolipoprotein ε4 allele (APOε4+). We found class "C" evidence (possibly effective) for improvement of non-motor features and class "U" evidence (unproven) for motor features in individuals with Parkinson's disease. The number of trials in Parkinson's disease is very small with best evidence that acute supplementation holds promise for improving exercise endurance. Conclusions Limitations of the literature to date include the range of ketogenic interventions currently assessed in the literature (i.e., primarily diet or medium-chain triglyceride interventions), with fewer studies using more potent formulations (e.g., exogenous ketone esters). Collectively, the strongest evidence to date exists for cognitive improvement in individuals with mild cognitive impairment and in individuals with mild-to-moderate Alzheimer's disease negative for the apolipoprotein ε4 allele. Larger-scale, pivotal trials are justified in these populations. Further research is required to optimize the utilization of ketogenic interventions in differing clinical contexts and to better characterize the response to therapeutic ketosis in patients who are positive for the apolipoprotein ε4 allele, as modified interventions may be necessary.
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Affiliation(s)
| | - Roger L. Albin
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
- Neurology Service and GRECC, VA Ann Arbor Healthcare System, Ann Arbor, MI, United States
- Morris K. Udall Center of Excellence for Parkinson's Disease Research, University of Michigan, Ann Arbor, MI, United States
- Parkinson's Foundation Research Center of Excellence, University of Michigan, Ann Arbor, MI, United States
| | - Nicolaas I. Bohnen
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
- Neurology Service and GRECC, VA Ann Arbor Healthcare System, Ann Arbor, MI, United States
- Morris K. Udall Center of Excellence for Parkinson's Disease Research, University of Michigan, Ann Arbor, MI, United States
- Parkinson's Foundation Research Center of Excellence, University of Michigan, Ann Arbor, MI, United States
- Department of Radiology, University of Michigan, Ann Arbor, MI, United States
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10
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Teng F, Samuelsson LM, Milan AM, Subbaraj A, Agnew M, Shrestha A, Cameron-Smith D, Day L. Postprandial lipemic response in dairy-avoiding females following an equal volume of sheep milk relative to cow milk: A randomized controlled trial. Front Nutr 2023; 9:1029813. [PMID: 36687710 PMCID: PMC9846784 DOI: 10.3389/fnut.2022.1029813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Accepted: 11/14/2022] [Indexed: 01/06/2023] Open
Abstract
Background Sheep milk (SM) is an alternate dairy source, which despite many similarities, has both compositional and structural differences in lipids compared to cow milk (CM). Studies are yet to examine the apparent digestibility of SM lipids, relative to CM, and the potential impact on the plasma lipidome. Objective To determine the response of the circulatory lipidome to equal volume servings of SM and CM, in females who avoid dairy products. Method In a double-blinded, randomized, cross-over trial, self-described dairy avoiding females (n = 30; 24.4 ± 1.1 years) drank SM or CM (650 mL; 33.4 vs. 21.3 g total lipid content; reconstituted from spray dried milk powders) following an overnight fast. Blood samples were collected at fasting and at regular intervals over 4 h after milk consumption. The plasma lipidome was analyzed by LC-MS and fatty acids were quantified by GC-FID. Results The overall postprandial triglyceride (TG) response was similar between SM and CM. TG concentrations were comparable at fasting for both groups, however they were higher after CM consumption at 30 min (interaction milk × time p = 0.003), well before any postprandial lipemic response. This was despite greater quantities provided by SM. However, there were notable differences in the postprandial fatty acid response, with SM leading to an increase in short- and medium-chain fatty acids (MCFAs) (C6:0, C8:0, and C10:0) and several long-chain fatty acids (LCFAs) (C18:1 t11, c9, t11-CLA, and C20:0; interaction time × milk p < 0.05). This corresponded to a greater postprandial response for medium chain triglycerides (MCTs) C10:0, including TG(10:0/14:0/18:1), TG(16:0/10:0/12:0), and TG(16:0/10:0/14:0) (interaction time × milk p < 0.05). Conclusions Despite a higher fat content, SM ingestion resulted in a greater circulating abundance of MCTs, without increasing total postprandial triglyceride response, when compared to CM. The greater abundance and postprandial appearance of MCTs may provide advantageous metabolic responses in children and adults. Unique identifier and registry U1111-1209-7768; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=375324.
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Affiliation(s)
- Fei Teng
- AgResearch Ltd., Grasslands Research Centre, Palmerston North, New Zealand
| | | | - Amber Marie Milan
- AgResearch Ltd., Grasslands Research Centre, Palmerston North, New Zealand,The Liggins Institute, The University of Auckland, Auckland, New Zealand
| | - Arvind Subbaraj
- AgResearch Ltd., Lincoln Research Center, Lincoln, New Zealand
| | - Michael Agnew
- AgResearch Ltd., Grasslands Research Centre, Palmerston North, New Zealand
| | - Aahana Shrestha
- The Liggins Institute, The University of Auckland, Auckland, New Zealand,Riddet Institute, Palmerston North, New Zealand
| | - David Cameron-Smith
- The Liggins Institute, The University of Auckland, Auckland, New Zealand,AgResearch Ltd., Lincoln Research Center, Lincoln, New Zealand,College of Health, Medicine and Wellbeing, University of Newcastle, Callaghan, NSW, Australia
| | - Li Day
- AgResearch Ltd., Grasslands Research Centre, Palmerston North, New Zealand,*Correspondence: Li Day
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11
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Marcos Pasero H, García Tejedor A, Giménez-Bastida JA, Laparra Llopis JM. Modifiable Innate Biology within the Gut–Brain Axis for Alzheimer’s Disease. Biomedicines 2022; 10:biomedicines10092098. [PMID: 36140198 PMCID: PMC9495985 DOI: 10.3390/biomedicines10092098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/17/2022] [Accepted: 08/22/2022] [Indexed: 11/16/2022] Open
Abstract
Alzheimer’s disease (AD) is a prototypical inflammation-associated loss of cognitive function, with approximately 90% of the AD burden associated with invading myeloid cells controlling the function of the resident microglia. This indicates that the immune microenvironment has a pivotal role in the pathogenesis of the disease. Multiple peripheral stimuli, conditioned by complex and varied interactions between signals that stem at the intestinal level and neuroimmune processes, are involved in the progression and severity of AD. Conceivably, the targeting of critical innate immune signals and cells is achievable, influencing immune and metabolic health within the gut–brain axis. Considerable progress has been made, modulating many different metabolic and immune alterations that can drive AD development. However, non-pharmacological strategies targeting immunometabolic processes affecting neuroinflammation in AD treatment remain general and, at this point, are applied to all patients regardless of disease features. Despite these possibilities, improved knowledge of the relative contribution of the different innate immune cells and molecules comprising the chronically inflamed brain network to AD pathogenesis, and elucidation of the network hierarchy, are needed for planning potent preventive and/or therapeutic interventions. Moreover, an integrative perspective addressing transdisciplinary fields can significantly contribute to molecular pathological epidemiology, improving the health and quality of life of AD patients. This review is intended to gather modifiable immunometabolic processes based on their importance in the prevention and management of AD.
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Affiliation(s)
- Helena Marcos Pasero
- Bioactivity and Nutritional Immunology Group (BIOINUT), Faculty of Health Sciences, Universidad Internacional de Valencia—VIU, Pintor Sorolla 21, 46002 Valencia, Spain
| | - Aurora García Tejedor
- Bioactivity and Nutritional Immunology Group (BIOINUT), Faculty of Health Sciences, Universidad Internacional de Valencia—VIU, Pintor Sorolla 21, 46002 Valencia, Spain
| | - Juan Antonio Giménez-Bastida
- Laboratory of Food and Health, Research Group on Quality, Safety and Bioactivity of Plant Foods, Department Food Science and Technology, CEBAS-CSIC, Campus de Espinardo, 30100 Murcia, Spain
| | - José Moisés Laparra Llopis
- Molecular Immunonutrition Group, Madrid Institute for Advanced Studies in Food (IMDEA Food), Ctra Cantoblanco 8, 28049 Madrid, Spain
- Correspondence: ; Tel.: +34-(0)-9-1787-8100
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12
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Abstract
Alzheimer’s disease (AD) is the most common major neurocognitive disorder of ageing. Although largely ignored until about a decade ago, accumulating evidence suggests that deteriorating brain energy metabolism plays a key role in the development and/or progression of AD-associated cognitive decline. Brain glucose hypometabolism is a well-established biomarker in AD but was mostly assumed to be a consequence of neuronal dysfunction and death. However, its presence in cognitively asymptomatic populations at higher risk of AD strongly suggests that it is actually a pre-symptomatic component in the development of AD. The question then arises as to whether progressive AD-related cognitive decline could be prevented or slowed down by correcting or bypassing this progressive ‘brain energy gap’. In this review, we provide an overview of research on brain glucose and ketone metabolism in AD and its prodromal condition – mild cognitive impairment (MCI) – to provide a clearer basis for proposing keto-therapeutics as a strategy for brain energy rescue in AD. We also discuss studies using ketogenic interventions and their impact on plasma ketone levels, brain energetics and cognitive performance in MCI and AD. Given that exercise has several overlapping metabolic effects with ketones, we propose that in combination these two approaches might be synergistic for brain health during ageing. As cause-and-effect relationships between the different hallmarks of AD are emerging, further research efforts should focus on optimising the efficacy, acceptability and accessibility of keto-therapeutics in AD and populations at risk of AD.
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13
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Shcherbakova K, Schwarz A, Apryatin S, Karpenko M, Trofimov A. Supplementation of Regular Diet With Medium-Chain Triglycerides for Procognitive Effects: A Narrative Review. Front Nutr 2022; 9:934497. [PMID: 35911092 PMCID: PMC9334743 DOI: 10.3389/fnut.2022.934497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 06/15/2022] [Indexed: 01/09/2023] Open
Abstract
It is now widely accepted that ketosis (a physiological state characterized by elevated plasma ketone body levels) possesses a wide range of neuroprotective effects. There is a growing interest in the use of ketogenic supplements, including medium-chain triglycerides (MCT), to achieve intermittent ketosis without adhering to a strict ketogenic diet. MCT supplementation is an inexpensive and simple ketogenic intervention, proven to benefit both individuals with normal cognition and those suffering from mild cognitive impairment, Alzheimer's disease, and other cognitive disorders. The commonly accepted paradigm underlying MCT supplementation trials is that the benefits stem from ketogenesis and that MCT supplementation is safe. However, medium-chain fatty acids (MCFAs) may also exert effects in the brain directly. Moreover, MCFAs, long-chain fatty acids, and glucose participate in mutually intertwined metabolic pathways. Therefore, the metabolic effects must be considered if the desired procognitive effects require administering MCT in doses larger than 1 g/kg. This review summarizes currently available research on the procognitive effects of using MCTs as a supplement to regular feed/diet without concomitant reduction of carbohydrate intake and focuses on the revealed mechanisms linked to particular MCT metabolites (ketone bodies, MCFAs), highlighting open questions and potential considerations.
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Affiliation(s)
- Ksenia Shcherbakova
- I.P. Pavlov Department of Physiology, Institute of Experimental Medicine, Saint Petersburg, Russia,*Correspondence: Ksenia Shcherbakova
| | - Alexander Schwarz
- Laboratory of the Molecular Mechanisms of Neuronal Interactions, Institute of Evolutionary Physiology and Biochemistry (RAS), Saint Petersburg, Russia
| | - Sergey Apryatin
- I.P. Pavlov Department of Physiology, Institute of Experimental Medicine, Saint Petersburg, Russia
| | - Marina Karpenko
- I.P. Pavlov Department of Physiology, Institute of Experimental Medicine, Saint Petersburg, Russia
| | - Alexander Trofimov
- I.P. Pavlov Department of Physiology, Institute of Experimental Medicine, Saint Petersburg, Russia
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14
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The Therapeutic Role of Ketogenic Diet in Neurological Disorders. Nutrients 2022; 14:nu14091952. [PMID: 35565918 PMCID: PMC9102882 DOI: 10.3390/nu14091952] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 04/30/2022] [Accepted: 05/04/2022] [Indexed: 02/01/2023] Open
Abstract
The ketogenic diet (KD) is a high-fat, low-carbohydrate and adequate-protein diet that has gained popularity in recent years in the context of neurological diseases (NDs). The complexity of the pathogenesis of these diseases means that effective forms of treatment are still lacking. Conventional therapy is often associated with increasing tolerance and/or drug resistance. Consequently, more effective therapeutic strategies are being sought to increase the effectiveness of available forms of therapy and improve the quality of life of patients. For the moment, it seems that KD can provide therapeutic benefits in patients with neurological problems by effectively controlling the balance between pro- and antioxidant processes and pro-excitatory and inhibitory neurotransmitters, and modulating inflammation or changing the composition of the gut microbiome. In this review we evaluated the potential therapeutic efficacy of KD in epilepsy, depression, migraine, Alzheimer’s disease and Parkinson’s disease. In our opinion, KD should be considered as an adjuvant therapeutic option for some neurological diseases.
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Wu XJ, Shu QQ, Wang B, Dong L, Hao B. Acetoacetate Improves Memory in Alzheimer's Mice via Promoting Brain-Derived Neurotrophic Factor and Inhibiting Inflammation. Am J Alzheimers Dis Other Demen 2022; 37:15333175221124949. [PMID: 36113018 PMCID: PMC10581103 DOI: 10.1177/15333175221124949] [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] [Indexed: 11/16/2022]
Abstract
The ketone bodies, especially the β-hydroxybutyrate, had been shown to modulate the function of the central nervous system and prevent the pathological progression of Alzheimer's disease (AD). However, little is known about the role of acetoacetate in the AD brain. Thus, we intraventricularly injected acetoacetate into familial AD mice (APPSWE) for 14 days and monitored their memory and biochemical changes. During the behavior test, acetoacetate at 100 mg/kg led to significant improvement in both Y-maze and novel object recognition tests (NORTs) (both P < .05), indicating ameliorating spatial and recognition memory, respectively. Biomedical tests revealed two mechanisms were involved. Firstly, acetoacetate inhibited the GPR43-pERK pathway, which led to apparent inhibition in tumor necrosis factor-α and Interleukin-6 expression in the hippocampus in a concentration-dependent manner. Secondarily, acetoacetate stimulated the expression of hippocampal brain-derived neurotrophic factor (BDNF). We concluded that acetoacetate could ameliorate AD symptoms and exhibited promising features as a therapeutic for AD.
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Affiliation(s)
- Xiao-Jun Wu
- Department of Neurosurgery, Shanghai Cancer Center, Shanghai Fu-Dan University School of Medicine, Shanghai, PR China
| | - Qin-Qin Shu
- Department of Emergency Medicine, Shanghai No. 4 People’s Hospital Affiliated to Shanghai Tongji University School of Medicine, Shanghai, PR China
| | - Bin Wang
- Department of Neurosurgery, Putuo Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, PR China
| | - Lan Dong
- Department of Emergency Medicine, Shanghai Chang Zheng Hospital, Shanghai, PR China
| | - Bin Hao
- Department of Neurosurgery, Shanghai Cancer Center, Shanghai Fu-Dan University School of Medicine, Shanghai, PR China
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