台灣成人女性素食與非素食生活型態與各項身體因素及血液中生化因素的關係

Abstract

世界上隨著經濟的發展，肥胖已成為一個世界性的警訊，新陳代謝症候群也盛行於各國家，新陳代謝症候群與心血管中風有著密切的關係。不同的飲食型態可能影響體內代謝發炎狀況，因此素食者可能有較低的代謝疾病及心血管疾病風險、較好的胰島素敏感性、較好的血管內皮功能。 胰島素抗性是指胰島素的生理作用有缺陷，臨床表現有血脂異常、高血壓、葡萄糖不耐、或第二型糖尿病、高尿酸血症或痛風等。脂肪細胞分泌多種荷爾蒙，很多基因可在脂肪細胞內表達，如瘦素(leptin)、脂締素(adiponectin)，近來已將脂肪細胞視為一種內分泌器官。脂締素是脂肪細胞分泌的荷爾蒙，在過重的人身上可見較低的脂締素。脂締素是一個重要的新陳代謝症候群的指標。脂締素有增加胰島素敏感的作用及避免動脈粥狀變化的保護作用，可抑制單核球黏至內皮細胞及脂質的堆積，並且經由抑制腫瘤壞死因子α而有抗發炎作用，低的血中脂締素與內皮細胞功能不良、心血管疾病、糖尿病、高血壓有關。本研究嘗試著驗證著成人女性素食者與非素食者各項身體因子與血液中生化因子，尤其是胰島素抗性、脂締素、活動量的關聯性。 研究方法與進行步驟：為一橫斷式關聯性研究。 對象: 以大林慈濟醫院參與健康檢查的健康人，經解說後簽署同意書後進行，本研究經研究倫理委員會通過後進行： (1)定義: 研究定義素食者為蛋奶素或全素且維持一年以上者，非素食者定義為不合乎本研究定義素食者。 (2)問卷表格，如附件包括背景資料、身高、血壓、運動習慣等。 (3)配合受檢過程經八小時禁食後，進行高級體檢並登錄檢查結果，另配合體檢抽血留下3cc血液檢體，依研究檢驗步驟方法冷凍待收集完成，統一進行本實驗欲研究之因子檢測胰島素、脂締素。 結果與討論：共收案素食組397位，非素食組400位，整體年齡平均為55.10歲，標準差為8.81歲，比較素食組56.47 ± 8.88歲與非素食組53.71 ± 8.56歲的年紀，素食者年紀稍大，平均數差為2.76歲(p < 0.001)。在身高、體重、身體質量指數方面，素食者皆比較小。腰圍比較，素食組72.90 ± 6.88公分平均比非素食者74.61 ± 7.83公分小1.71公分(p = 0.003)。空腹血糖比較上，發現素食組89.78 ± 15.94mg/dL平均比非素食組91.48 ± 16.20mg/dL小1.70mg/dL (p = 0.007)。在總膽固醇、高密度脂蛋白膽固醇、低密度脂蛋白膽固醇，素食組平均皆比非素食組小。三酸甘油酯比較，兩組(素食組108.18 ± 68.15 mg/dL，非素食組102.16 ± 59.22 mg/dL)無差異(p = 0.121)。以腹部肥胖（腰圍大於或等於80公分）變項，取年紀、收縮壓、空腹血糖、三酸甘油酯、停經與否、每天每公斤活動仟卡數、素食與否做多因子邏輯斯迴歸，素食對非素食為顯著因子，素食者有較低的腹部肥胖機會（勝算比估計值0.412，95%信賴區間為0.274-0.62，p < 0.0001）。以糖尿病為依變項，對年紀、收縮壓、身體質量指數、三酸甘油酯、高密度脂蛋白膽固醇、停經與否、活動量、及素食與否做多因子邏輯斯迴歸分析，發現素食是一個顯著因子，素食組對非素食組有較低的糖尿病機會（勝算比估計值0.473，95%信賴區間為0.233-0.962，p = 0.0389）。對新陳代謝症候群台灣標準為依變項，取年紀、停經與否、及素食、素食年數、睡眠時間、每天活動仟卡數做邏輯斯迴歸，可得素食對非素食為顯著因子，素食者有較低的風險（勝算比估計值0.368，95%信賴區間為0.191-0.708，p = 0.0028）。以胰島素抗性（HOMA-IR）當成依變項，取年紀、收縮壓、腰圍、高密度脂蛋白膽固醇、三酸甘油酯、停經與否、素食、每天活動仟卡數作多因子線性迴歸分析，結果發現素食組顯著比非素食組低（β = -0.3548，p = 0.001）。以脂締素為依變項做多因子線性迴歸分析，發現素食（p = 0.3801）不是顯著因子。使用運動當量換算出一週的總活動量，其關於胰島素抗性的關係，在調整年紀、收縮壓、腰圍、總膽固醇、三酸甘油酯、停經、素食情形下，仍與胰島素抗性呈顯著負相關（β = -0.144，p = 0.0086），運動可以改善胰島素抗性。進一步分析素食年數對於胰島素抗性的關係，發現在11年內有顯著降低胰島素抗性的效果。 結論：素食對於健康的影響是廣泛性的，除了有較低的血糖、血脂、較低的肥胖糖尿病發生機會，並且是胰島素抗性獨立顯著因子，素食者有較低的胰島素抗性，素食者對於脂締素的關係則是可能透過影響其他身體因子如減少腰圍發生機會等，而有較好的關聯性。總活動量是胰島素抗性的獨立影響因子，兩者呈負相關，而活動量與脂締素並未有直接顯著關係。進一步的研究，要考慮性別是否有不同的效益，及長期追蹤素食對於身體的影響。

Obesity is a global warning sign after the development of world economics. High prevalence rate of metabolic syndrome has been noted in the most countries. The different lifestyle may influence the inflammatory status of the body. Vegetarians may have the lower risk of metabolic and cardiovascular diseases, better insulin sensitivity, improved endothelium cells function. Insulin resistance is a physiological defect of insulin function. The clinical manifestation is associated with dyslipidemia, type 2 diabetes, hypertension, gout etc. The fat cells can secret several hormones and several genes can be expressed in the fat cells., such as leptin, adiponectin. Adiponectin, an adipose-derived plasma protein, has been well established as an important biomarker for metabolic syndrome. Plasma concentration of adiponectin was found to be lower in overweight or obese subjects. Adiponectin is associated with inproved insulin sensitivity and has the function of atherosclerosis prevention, inhibits the adhesion of manocytes to the endothelium cells and the accumulation of lipids, and has the potential of anti-inflammation by the inhibition of α-tumor necrosis factor. Low adiponectin level is associated with the endothelium dysfunction, cardiovascular disease, diabetes and carotid artery atherosclerosis. The aim of this cross sectional study is aimed to explore the effect of vegetarian lifestyle, physical activity and clinical outcomes on concentration of plasma adiponectin, and insulin resistance among vegetarians and omnivores of the female adults in Taiwan. Methods: Those healthy adults that take part of Health Physical Exam are our possible study group. Informed consent will be given before enrollment .This study was approved by the IRB of the Buddhist Dalin Tzu Chi General Hospital. 1. Definition of vegetarians: those who practiced ovo-lacto-vegetarian diet or vegan for more than one year. 2. Questionnaires are including the demographic data, which including 7-day physical activity and exercise. 3. Blood was collected for routine physical exam and the data will be recorded for analysis. Another 10cc blood will be collected for adiponectin and insulin assay after informed consent. Results: Totally 397 female vegetarians (VEG) and 400 female non-vegetarians (non-VEG), with a mean age of 55.10 (S.D.: 8.81) years old, were enrolled in our study. The year of VEG are 10.23±7.22. The age of VEG was significantly older than the non-VEG by 2.76 years (p < 0.001). There were no significant difference between the VEG and non-VEG group among systolic blood pressure (p = 0.566), diastolic blood pressure (p = 0.747), heart rate (p = 0.6547), triglyceride (p = 0.121) and the prevalence of diabetes (p = 0.235) and hypertension (p = 0.747). The VEG has better metabolic parameters than the non-VEG among the variables of body height ( mean difference = -0.81cm, p = 0.039), body weight [ mean difference (VEG minus non-VEG) = -2.12kg, p < 0.001],BMI ( mean difference = -0.67kg/m^2, p = 0.015), waist circumference ( mean difference = -1.71cm, p = 0.003), glucose AC ( mean difference = -1.70mg/dL, p = 0.007), total cholesterol ( mean difference = -16.45 mg/dL, p <0.001), high density lipoprotein-cholesterol ( mean difference = -3.86 mg/dL, p < 0.001), low density lipoprotein-cholesterol ( mean difference = -12.83 mg/dL, p < 0.001). Using multivariate logistic regression, the VEG (vs. non-VEG) is an independent factor for central obesity (OR: 0.412, 95%CI: 0.274-0.62, p < 0.0001) for central obesity after adjusting for the variables of age , systolic blood pressure, glucose AC, triglyceride (TG), menopause statue, activity score. Using logistic regression analysis with an adjustment for age, systolice blood pressure, body mass index, triglyceride, high density lipoprotein-cholesterol (HDL-C), menopause status, activity score, the VEG (vs. non-VEG) has a lower probability of diabetes, with an odds ratio of 0.473, 95%CI: 0.233-0.962, p = 0.0389). Using logistic regression analysis with an adjustment for age, menopause status, years of vegetarian diet, sleep hours, activity score, the VEG (vs. non-VEG) has a lower probability of Taiwan modified metabolic syndrome, with an odds ratio of 0.368, 95% CI: 0.191-0.708, p = 0.0028. For the insulin resistance, multivariate linear regression analysis showed that VEG (vs. non-VEG, β = -0.3548, p = 0.001) were significant independent factors when controlling for the variables of age, systolic blood pressure, waist, HDL-C, TG, menopause status, and activity score. Using multivariate linear regression analysis for adiponectin, VEG (vs. non-VEG, p = 0.3801) was not a significant factor. Daily activity is negative associated with insulin resistance（β = -0.144，p = 0.0086）after adjusting age, systolic blood pressure, waist, total cholesterol, TG, menopause status, vegetarian status. Moreover, the effect of VEG was most contributed by the cases of years of vegetarian diet below 11 years. In conclusion, vegetarian lifestyle is good for health. The vegetarians have lower glucose, total cholesterol, HDL-C, LDL-C, waist circumference, and lower probability of obesity and diabetes. The vegetarian is an independent significant factor of insulin resistance and has lower insulin resistance. The association between smaller waist circumference, and lower probability of diabetes with vegetarian lifestyle may result into higher adiponectin level. The physical activity is an independent risk factor for insulin resistance. The higher physical activity score, the lower insulin resistance. There is no direct association between physical activity score with adiponectin. Further prospective follow up studies are still necessary for more investigation about the gender effect and the long term impact of vegetarian lifestyle on the health.