婴儿饮食早期加入花生或鸡蛋可能降低过敏风险
如今，越来越多的孩子对食物过敏。一些家长认为，为避免出现过敏反应，应该推迟给孩子尝试花生、鸡蛋等易过敏食物的时间。
2016年9月20日，《美国医学会杂志》正式发表英国伦敦帝国学院、阿伯丁大学、卡迪夫大学、牛津大学、诺丁汉大学的系统回顾与荟萃分析，发现结果恰恰相反。
该研究荟萃分析了146项研究后发现，婴儿初次尝试易过敏食物的年龄与食物过敏间存在相关性，4～6个月时吃鸡蛋可使鸡蛋过敏风险降低44%（风险比：0.56，95%置信区间：0.36～0.87，I2=36%，P=0.009），4～11个月吃花生可使花生过敏风险降低71%（风险比：0.29，95%置信区间：0.11～0.74，I2=66%，P=0.009）。不过，第一次接触麸质的时间与过敏风险无关。
食物过敏是身体免疫系统错把某种食品中的无害蛋白质当成有害物质而发动“攻击”造成的，症状包括麻疹、湿疹、瘙痒、恶心呕吐甚至昏厥。鸡蛋、牛奶、大豆、小麦、鱼、花生、坚果等是较为常见的易过敏食物。早早接触花生、鸡蛋或许能降低肠道的免疫特性，从而减少过敏风险。
不过，该研究提醒，给婴儿喂食花生时一定要碾碎，否则会有窒息风险。
JAMA. 2016 Sep 20;316(11):1181-92.
Timing of Allergenic Food Introduction to the Infant Diet and Risk of Allergic or Autoimmune Disease: A Systematic Review and Meta-analysis.
Despo Ierodiakonou, Vanessa Garcia-Larsen, Andrew Logan, Annabel Groome, Sergio Cunha, Jennifer Chivinge, Zoe Robinson, Natalie Geoghegan, Katharine Jarrold, Tim Reeves, Nara Tagiyeva-Milne, Ulugbek Nurmatov, Marialena Trivella, DPhil, Jo Leonardi-Bee, Robert J. Boyle.
Imperial College London, London, England; University of Aberdeen, Aberdeen, Scotland; Cardiff University, Cardiff, Wales; University of Oxford, Oxford, England; University of Nottingham, Nottingham, England.
IMPORTANCE: Timing of introduction of allergenic foods to the infant diet may influence the risk of allergic or autoimmune disease, but the evidence for this has not been comprehensively synthesized.
OBJECTIVE: To systematically review and meta-analyze evidence that timing of allergenic food introduction during infancy influences risk of allergic or autoimmune disease.
DATA SOURCES: MEDLINE, EMBASE, Web of Science, CENTRAL, and LILACS databases were searched between January 1946 and March 2016.
STUDY SELECTION: Intervention trials and observational studies that evaluated timing of allergenic food introduction during the first year of life and reported allergic or autoimmune disease or allergic sensitization were included.
DATA EXTRACTION AND SYNTHESIS: Data were extracted in duplicate and synthesized for meta-analysis using generic inverse variance or Mantel-Haenszel methods with a random-effects model. GRADE was used to assess the certainty of evidence.
MAIN OUTCOMES AND MEASURES: Wheeze, eczema, allergic rhinitis, food allergy, allergic sensitization, type 1 diabetes mellitus, celiac disease, inflammatory bowel disease, autoimmune thyroid disease, and juvenile rheumatoid arthritis.
RESULTS: Of 16,289 original titles screened, data were extracted from 204 titles reporting 146 studies. There was moderate-certainty evidence from 5 trials (1915 participants) that early egg introduction at 4 to 6 months was associated with reduced egg allergy (risk ratio [RR], 0.56; 95% CI, 0.36-0.87; I2 = 36%; P = .009). Absolute risk reduction for a population with 5.4% incidence of egg allergy was 24 cases (95% CI, 7-35 cases) per 1000 population. There was moderate-certainty evidence from 2 trials (1550 participants) that early peanut introduction at 4 to 11 months was associated with reduced peanut allergy (RR, 0.29; 95% CI, 0.11-0.74; I2 = 66%; P = .009). Absolute risk reduction for a population with 2.5% incidence of peanut allergy was 18 cases (95% CI, 6-22 cases) per 1000 population. Certainty of evidence was downgraded because of imprecision of effect estimates and indirectness of the populations and interventions studied. Timing of egg or peanut introduction was not associated with risk of allergy to other foods. There was low- to very low-certainty evidence that early fish introduction was associated with reduced allergic sensitization and rhinitis. There was high-certainty evidence that timing of gluten introduction was not associated with celiac disease risk, and timing of allergenic food introduction was not associated with other outcomes.
CONCLUSIONS AND RELEVANCE: In this systematic review, early egg or peanut introduction to the infant diet was associated with lower risk of developing egg or peanut allergy. These findings must be considered in the context of limitations in the primary studies.
DOI: 10.1001/jama.2016.12623
