Table_4_The Omega-3 Index Response to an 8 Week Randomized Intervention Containing Three Fatty Fish Meals Per Week Is Influenced by Adiposity in Overweight to Obese Women.XLSX

BackgroundThe Dietary Guidelines for Americans (DGA) recommends consuming ~225 g/wk of a variety of seafood providing >1.75 g/wk of long-chain omega-3 fatty acids to reduce cardiovascular disease risk, however individual responses to treatment vary.
ObjectiveThis study had three main objectives. First, to determine if a DGA-conforming diet (DGAD), in comparison to a typical American diet (TAD), can increase the omega-3 index (OM3I), i.e., the red blood cell mol% of eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA). Second, to identify factors explaining variability in the OM3I response to dietary treatment. Third to identify factors associated with the baseline OM3I.
DesignThis is a secondary analysis of a randomized, double-blind 8 wk dietary intervention of overweight/obese women fed an 8d rotating TAD (n = 20) or DGAD (n = 22) registered at www.clinicaltrials.gov as NCT02298725. The DGAD-group consumed 240 g/wk of Atlantic farmed salmon and albacore tuna in three meals with an estimated EPA + DHA of 3.7 ± 0.6 g/wk. The TAD-group consumed ~160 g/wk of farmed white shrimp and a seafood salad containing imitation crab in three meal with an estimated EPA + DHA of 0.45 ± 0.05 g/wk. Habitual diet was determined at baseline, and body composition was determined at 0 and 8wks. Red blood cell fatty acids were measured at 0, 2 and 8 wk.
ResultsAt 8 wk, the TAD-group OM3I was unchanged (5.90 ± 1.35–5.80 ± 0.76%), while the DGAD-group OM3I increased (5.63 ± 1.27–7.33 ± 1.36%; p < 0.001). In the DGAD-group 9 of 22 participants achieved an OM3I >8%. Together, body composition and the baseline OM3I explained 83% of the response to treatment variability. Baseline OM3I (5.8 ± 1.3%; n = 42) was negatively correlated to the android fat mass (p = 0.0007) and positively correlated to the FFQ estimated habitual (EPA+DHA) when expressed as a ratio to total dietary fat (p = 0.006).
ConclusionsAn 8 wk TAD did not change the OM3I of ~6%, while a DGAD with 240 g/wk of salmon and albacore tuna increased the OM3I. Body fat distribution and basal omega-3 status are primary factors influencing the OM3I response to dietary intake in overweight/obese women.

背景：美国膳食指南（Dietary Guidelines for Americans, DGA）建议每周摄入约225克多种类海鲜，以获取每周超过1.75克的长链ω-3脂肪酸，从而降低心血管疾病风险，但个体对膳食干预的应答存在异质性。
研究目标：本研究包含三项核心目标。其一，对比符合DGA的膳食模式（DGA-conforming diet, DGAD）与典型美国膳食模式（typical American diet, TAD）对ω-3指数（omega-3 index, OM3I，即红细胞膜中二十碳五烯酸（eicosapentaenoic acid, EPA）与二十二碳六烯酸（docosahexaenoic acid, DHA）的摩尔百分比）的提升效果；其二，明确可解释膳食干预后OM3I应答差异的影响因素；其三，识别与基线OM3I相关的影响因素。
研究设计：本研究为一项随机双盲8周膳食干预研究的二次分析，原始研究对象为超重/肥胖女性，受试者被随机分为8天轮换式典型美国膳食组（n=20）与符合DGA的膳食组（n=22），该临床试验已于www.clinicaltrials.gov注册，注册号为NCT02298725。其中DGAD组受试者每周分三次进食240克大西洋养殖三文鱼与长鳍金枪鱼，经估算其EPA+DHA摄入量为3.7±0.6克/周；TAD组受试者每周分三次进食约160克养殖白虾及一款含仿蟹肉的海鲜沙拉，经估算其EPA+DHA摄入量为0.45±0.05克/周。研究于基线时评估受试者的习惯性膳食摄入，分别于0周与8周检测身体成分；并于0、2、8周三个时间点检测红细胞脂肪酸水平。
研究结果：干预8周后，TAD组受试者的OM3I无显著变化（5.90±1.35 → 5.80±0.76%），而DGAD组受试者的OM3I显著升高（5.63±1.27 → 7.33±1.36%；p<0.001）。DGAD组共有9/22的受试者OM3I达到8%以上。综合分析显示，身体成分与基线OM3I可解释83%的膳食干预应答差异。基线OM3I（5.8±1.3%；n=42）与躯干脂肪量（android fat mass）呈负相关（p=0.0007），与以总膳食脂肪占比计算的、通过食物频率问卷（Food Frequency Questionnaire, FFQ）估算的习惯性EPA+DHA摄入量呈正相关（p=0.006）。
结论：8周的典型美国膳食模式未改变受试者的OM3I水平（维持在约6%），而每周摄入240克三文鱼与长鳍金枪鱼的符合DGA的膳食模式可显著提升OM3I水平。在超重/肥胖女性群体中，体脂分布与基础ω-3营养状态是影响膳食摄入后OM3I应答的核心因素。