本帖最後由 goodcat1111 於 2009-4-20 10:15 編輯
作者：Caroline Cassels
出處：WebMD醫學新聞
April 7, 2009 — 新研究認為，茹素的青少年與年輕成人發生異常飲食行為的風險較大。
針對Project EAT這項青少年飲食和體重狀態與社會環境、個人與行為研究之資料的大型橫斷面研究分析顯示，茹素的青少年與年輕成人比非茹素者更可能發生失控的暴食。
再者，相較於未曾茹素者，曾經茹素的青少年與年輕成人更可能發生偏激的體重控制行為。
主要研究者、聖約翰大學與聖Benedict學院的Ramona Robinson-O'Brien博士向Medscape Psychiatry表示，已發表的研究結果認為，茹素的青少年與年輕成人可藉由增加蔬果攝取而對健康有好處，年輕成人也能有降低過重與肥胖相關風險的好處。
她指出，不過，現正茹素者的暴食風險可能增加，曾經茹素者可能發生偏激、不健康的體重控制行為。
這項研究發表於4月號的美國飲食協會期刊。
【可接受的減重策略】
根據作者表示，之前的研究指出，有飲食異常症狀的青少年可將茹素作為可行的減重策略，因為這是社會上可接受作為避免食用某些類型食物的方法。再者，他們指出，青少女比青少年更可能採用茹素作為減重方法。
為了檢視現正茹素與曾經茹素之青少年與年輕成人的特徵，並探究茹素、體重、飲食攝取、體重控制行為等的關聯，研究者分析了2,516名年紀15至23歲研究對象的資料。
這些研究對象屬於Project EAT-I這個對31所明尼蘇達學校之中高年級學生的課堂調查，在1998至1999學年進行有關食物頻率問卷，與人體測量資料的調查。
研究對象分類為現正茹素者(4.3%)、曾經茹素者(10.8%)、未曾茹素者(84.9%)。根據年齡分為兩個世代：青少年(15至18歲)與年輕成人(19至23歲)。
研究者郵寄調查給Project EAT-I所有的研究對象，包括評估茹素與體重狀態的問題、飲食品質、體能、暴食、體重控制行為、物質濫用與人口統計學資料等調查。總共獲得2,516人完成調查，據以進行最後的分析。
【比較不會過重】
在青少年中，相較於未曾茹素者，曾經茹素者有較高比率進行比較偏激的不健康的體重控制行為，例如吃減肥藥與催吐，以及使用瀉藥和利尿劑(P < .005)。曾經茹素的年輕成人也是如此(P < .001)。
此外，相較於未曾茹素者，現正茹素和曾經茹素的青少年，有較高比率發生過失控的暴食(P < .001)。
在年輕成人中，相較於曾經茹素和未曾茹素者，現正茹素者有較高比率發生過失控的暴食。
研究者也發現，在青少年中，體重狀態並無相關的統計顯著差異。年輕成人中，相較於未曾茹素者，現正茹素者有較低的身體質量指數，且比較不會過重或肥胖。
在青少年中，相較於曾經茹素和未曾茹素者，現正茹素者每日攝取最多的蔬果份數(P < .001)與最低的總脂肪與飽和脂肪熱量(P < .001)。
在青少年和年輕成人中，現正茹素、曾經茹素和未曾茹素者，有關從事中度與強度體能活動或參與可維持某一體重的運動或活動的時間，並無統計上的顯著差異 。
【評估動機可能是重要的】
Robinson-O'Brien博士表示，研究發現認為，醫師評估個人選擇素食的動機可能會有所幫助，評估異常飲食行為時，需詢問有關目前和以前的素食狀態。
再者，她表示，當指導青少年和年輕成人茹素者的適當營養與餐食計畫時，重點在於確認潛在的健康利益與素食飲食的風險。
Robinson-O'Brien博士表示，對此族群的後續研究對於確認茹素的長期利益與風險將有所幫助。她指出，青少年的深度質性研究可對異常飲食行為的特定動機和風險關聯有更深入的瞭解。
母嬰健康局以及疾病管制預防中心青少年健康保護計畫支持本研究。作者宣告沒有相關財務關係。
Young Vegetarians May Be at Increased Risk for Eating Disorders
By Caroline Cassels
Medscape Medical News
April 7, 2009 — Adolescent and young adult vegetarians appear to be at greater risk for disordered eating behaviors, new research suggests.
A large cross-sectional analysis of data from Project EAT (Eating Among Teens) — a study of socioenvironmental, personal, and behavioral determinants of dietary intake and weight status in adolescents — shows that adolescent and young adult vegetarians are more likely to report binge eating with loss of control compared with nonvegetarians.
Further, adolescents and young adult former vegetarians were more likely than never vegetarians to engage in extreme weight-control behaviors.
"Findings from the present study indicate that adolescent and young adult vegetarians may experience the health benefits associated with increased fruit and vegetable intake, and young adults may have the added advantage of decreased risk for overweight and obesity," principal investigator Ramona Robinson-O'Brien, PhD, RD, from the College of Saint Benedict and Saint John's University, in St. Joseph, Minnesota, told Medscape Psychiatry.
"However, current vegetarians may be at increased risk for binge eating, while former vegetarians may be at increased risk for extreme unhealthful weight-control behaviors," she added.
The study is published in the April issue of the Journal of the American Dietetic Association.
"Acceptable" Weight-Loss Strategy
According to the authors, previous research indicates that adolescents with symptoms of eating disorders may adopt a vegetarian diet as a weight-loss strategy because it is a "socially acceptable way to avoid eating certain food groups." Further, they note, female adolescents are more likely than boys to adopt vegetarianism as a method of weight loss.
To examine characteristics of current and former adolescent and young adult vegetarians and investigate the potential link between vegetarianism, weight, dietary intake, and weight-control behaviors, the investigators analyzed data from 2516 study participants aged 15 to 23 years.
These subjects had been part of Project EAT-I, an earlier survey of middle- and high-school students from 31 Minnesota schools using in-class surveys, food frequency questionnaires, and anthropometric measures taken during the 1998–1999 academic year.
Participants were identified as current (4.3%), former (10.8%), and never (84.9%) vegetarians. Subjects were divided into 2 cohorts categorized by age — adolescents (15 to 18 years) and young adults (19 to 23 years).
Mailed surveys, which included questions assessing vegetarian and weight status, dietary quality, physical activity, binge eating, weight-control behaviors, substance use, and demographics were sent to all participants of Project EAT-I.
The final analysis was based on completed surveys from 2516 subjects.
Less Likely to Be Overweight
Among adolescent subjects, a higher percentage of former vegetarians reported engaging in more extreme unhealthful weight-control behaviors such as taking diet pills and vomiting as well as laxative and diuretic use compared with never vegetarians (P < .005). This was also the case among young adult former vegetarians (P < .001).
In addition, a higher percentage of young current and former vegetarians reported engaging in binge eating with loss of control compared with never vegetarians (P < .001).
In the older cohort, a higher percentage of current vegetarians also reported engaging in binge eating with loss of control compared with former and never vegetarians.
The investigators also found that, among the younger cohort, no statistically significant differences were found with regard to weight status. Among the older cohort, current vegetarians had a lower body-mass index and were less likely to be overweight or obese when compared with never vegetarians.
Among the younger cohort, current vegetarians consumed the highest daily servings of fruits and vegetables (P < .001) and the lowest proportion of calories as total and saturated fat (P < .001) when compared with former and never vegetarians.
In both the younger and older cohort, no statistically significant differences were found between current, former, and never vegetarians with regard to time spent engaged in moderate and vigorous physical activity or participation in a sport or activity where it is important to stay a certain weight.
Assessing Motives May Be Important
The study findings, said Dr. Robinson-O'Brien, suggest it may be beneficial for clinicians to investigate an individual's motives for choosing a vegetarian diet and ask about current and former vegetarian status when assessing risk for disordered eating behaviors.
Further, she said, "when guiding adolescent and young adult vegetarians in proper nutrition and meal planning, it is important to recognize the potential health benefits and risks associated with a vegetarian diet."
Future research in this population may be useful in identifying longer-term benefits and risks associated with vegetarian diets, said Dr. Robinson-O'Brien.
She added that in-depth qualitative research with teens might provide additional insight into the associations between specific motivations and risk for disordered eating behaviors.
The study is supported by Maternal and Child Health Bureau and the Centers for Disease Control and Prevention Adolescent Health Protection Program. The authors report no relevant financial disclosures.
J Am Diet Assoc. 2009;109:648-655. |
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