Nwaru Bright I, Dierkes Jutta, Ramel Alfons, Arnesen Erik Kristoffer, Thorisdottir Birna, Lamberg-Allardt Christel, Söderlund Fredrik, Bärebring Linnea, Åkesson Agneta
Krefting Research Centre, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden.
Centre for Nutrition, Department of Clinical Medicine, University of Bergen, Bergen, Norway.
Food Nutr Res. 2022 Jul 28;66. doi: 10.29219/fnr.v66.8629. eCollection 2022.
To identify, critically appraise, and synthesize evidence on the effect of quality of dietary fat intake and different classes of fatty acids on the risk of Alzheimer's disease (AD) and dementia in adults aged ≥50 years.
We searched MEDLINE, EMBASE, Cochrane Central of Controlled Trials, and Scopus for clinical trials and prospective cohort studies published until May 2021. Two reviewers independently screened retrieved literature, extracted relevant data, and performed risk of bias assessment. Classes of fatty acids included were saturated fatty acids (SFAs), trans fatty acids (TFAs), monounsaturated fatty acids (MUFAs), poly-unsaturated fatty acids (PUFAs), and their subtypes and sources. Given between-study heterogeneity, we did not perform meta-analyses but narratively described findings from the studies.
From 4,491 identified records, five articles (based on four prospective cohort studies) met the inclusion criteria. Three studies had an overall serious risk of bias, while one study had a moderate risk. Overall, we found no robust association between intake of any fatty acids type and the development of AD and dementia. For example, for SFA and TFA, there was contradictory associations reported on AD: one study found that each unit increase in energy-adjusted intake of SFA (risk ratio [RR] 0.83, 95%CI 0.70-0.98) and TFA (RR 0.80, 95%CI 0.65-0.97) was associated with a decreased risk of AD, but not dementia. For PUFA, one study found that higher quintile intake of marine-based n-3 PUFA was associated with a decreased risk of AD. The intake of other fatty acids was not associated with the outcomes. The certainty of the overall evidence was inconclusive.
We found no clear association between the intake of various classes of fatty acids and the risk of AD and dementia in adults. More well-designed prospective studies are required to clarify these findings.
识别、严格评估并综合关于膳食脂肪摄入质量及不同种类脂肪酸对≥50岁成年人患阿尔茨海默病（AD）和痴呆症风险影响的证据。
我们检索了MEDLINE、EMBASE、Cochrane对照试验中心数据库和Scopus，查找截至2021年5月发表的临床试验和前瞻性队列研究。两名评审员独立筛选检索到的文献，提取相关数据，并进行偏倚风险评估。纳入的脂肪酸种类包括饱和脂肪酸（SFA）、反式脂肪酸（TFA）、单不饱和脂肪酸（MUFA）、多不饱和脂肪酸（PUFA）及其亚型和来源。鉴于研究间存在异质性，我们未进行荟萃分析，而是对研究结果进行了叙述性描述。
从4491条识别记录中，5篇文章（基于4项前瞻性队列研究）符合纳入标准。3项研究总体存在严重偏倚风险，1项研究存在中度风险。总体而言，我们发现任何类型脂肪酸的摄入量与AD和痴呆症的发生之间均无有力关联。例如，对于SFA和TFA，关于AD的报道存在相互矛盾的关联：一项研究发现，能量调整后的SFA摄入量每增加一个单位（风险比[RR]0.83，95%CI 0.70 - 0.98）和TFA摄入量每增加一个单位（RR 0.80，95%CI 0.65 - 0.97）与AD风险降低相关，但与痴呆症无关。对于PUFA，一项研究发现，海洋来源的n - 3 PUFA摄入量处于较高五分位数与AD风险降低相关。其他脂肪酸的摄入量与研究结果无关。总体证据的确定性尚无定论。
我们发现各类脂肪酸的摄入量与成年人患AD和痴呆症的风险之间无明确关联。需要更多设计良好的前瞻性研究来阐明这些发现。
