Brigham and Women's Hospital, Harvard Medical School, and Harvard School of Public Health, Boston, Massachusetts 02115, USA.
Ann Intern Med. 2010 Dec 21;153(12):790-9. doi: 10.7326/0003-4819-153-12-201012210-00005.
Palmitoleic acid (cis-16:1n-7), which is produced by endogenous fat synthesis, has been linked to both beneficial and deleterious metabolic effects, potentially confounded by diverse determinants and tissue sources of endogenous production. Trans-palmitoleate (trans-16:1n-7) represents a distinctly exogenous source of 16:1n-7, unconfounded by endogenous synthesis or its determinants, that may be uniquely informative.
To investigate whether circulating trans-palmitoleate is independently related to lower metabolic risk and incident type 2 diabetes.
Prospective cohort study from 1992 to 2006.
Four U.S. communities.
3736 adults in the Cardiovascular Health Study.
Anthropometric characteristics and levels of plasma phospholipid fatty acids, blood lipids, inflammatory markers, and glucose-insulin measured at baseline in 1992 and dietary habits measured 3 years earlier. Multivariate-adjusted models were used to investigate how demographic, clinical, and lifestyle factors independently related to plasma phospholipid trans-palmitoleate; how trans-palmitoleate related to major metabolic risk factors; and how trans-palmitoleate related to new-onset diabetes (304 incident cases). Findings were validated for metabolic risk factors in an independent cohort of 327 women.
In multivariate analyses, whole-fat dairy consumption was most strongly associated with higher trans-palmitoleate levels. Higher trans-palmitoleate levels were associated with slightly lower adiposity and, independently, with higher high-density lipoprotein cholesterol levels (1.9% across quintiles; P = 0.040), lower triglyceride levels (-19.0%; P < 0.001), a lower total cholesterol-HDL cholesterol ratio (-4.7%; P < 0.001), lower C-reactive protein levels (-13.8%; P = 0.05), and lower insulin resistance (-16.7%, P < 0.001). Trans-palmitoleate was also associated with a substantially lower incidence of diabetes, with multivariate hazard ratios of 0.41 (95% CI, 0.27 to 0.64) and 0.38 (CI, 0.24 to 0.62) in quintiles 4 and 5 versus quintile 1 (P for trend < 0.001). Findings were independent of estimated dairy consumption or other fatty acid dairy biomarkers. Protective associations with metabolic risk factors were confirmed in the validation cohort.
Results could be affected by measurement error or residual confounding.
Circulating trans-palmitoleate is associated with lower insulin resistance, presence of atherogenic dyslipidemia, and incident diabetes. Our findings may explain previously observed metabolic benefits of dairy consumption and support the need for detailed further experimental and clinical investigation.
National Heart, Lung, and Blood Institute and National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health.
棕榈油酸（cis-16:1n-7）是内源性脂肪合成产生的，与有益和有害的代谢效应都有关联，其潜在影响可能受到多种决定因素和内源性产生的组织来源的影响。反式棕榈油酸（trans-16:1n-7）是 16:1n-7 的一种明显外源性来源，不受内源性合成或其决定因素的影响，可能具有独特的信息价值。
研究循环反式棕榈油酸是否与较低的代谢风险和 2 型糖尿病的发生独立相关。
1992 年至 2006 年进行的前瞻性队列研究。
美国四个社区。
心血管健康研究中的 3736 名成年人。
1992 年基线时测量的人体测量特征和血浆磷脂脂肪酸水平、血脂、炎症标志物和血糖-胰岛素，以及 3 年前测量的饮食习惯。使用多变量调整模型来研究人口统计学、临床和生活方式因素如何独立与血浆磷脂反式棕榈油酸相关；反式棕榈油酸与主要代谢危险因素的关系；以及反式棕榈油酸与新发糖尿病（304 例病例）的关系。在一个由 327 名女性组成的独立队列中验证了代谢风险因素的发现。
在多变量分析中，全脂乳制品的消费与较高的反式棕榈油酸水平最密切相关。较高的反式棕榈油酸水平与较低的肥胖程度相关，并且独立地与较高的高密度脂蛋白胆固醇水平相关（五分位数跨度为 1.9%；P=0.040）、较低的甘油三酯水平（-19.0%；P<0.001）、总胆固醇-高密度脂蛋白胆固醇比值较低（-4.7%；P<0.001）、C 反应蛋白水平较低（-13.8%；P=0.05）和胰岛素抵抗较低（-16.7%；P<0.001）。反式棕榈油酸与糖尿病的发生也有明显较低的关联，五分位 4 和 5 与五分位 1 相比，多变量危险比分别为 0.41（95%CI，0.27 至 0.64）和 0.38（CI，0.24 至 0.62）（趋势 P<0.001）。这些发现独立于估计的乳制品消费或其他脂肪酸乳制品生物标志物。在验证队列中，与代谢风险因素的保护关联得到了确认。
结果可能受到测量误差或残余混杂因素的影响。
循环反式棕榈油酸与较低的胰岛素抵抗、存在致动脉粥样硬化的血脂异常和新发糖尿病有关。我们的发现可以解释先前观察到的乳制品消费的代谢益处，并支持对详细的进一步实验和临床研究的需求。
美国国立卫生研究院下属的国家心肺血液研究所和国家糖尿病、消化和肾脏疾病研究所的国家心、肺和血液研究所。
