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LETTERS TO THE EDITOR

1

ietary option with a variety of poten-ial health benefits (2). Many youngeople today could benefit from im-rovements in dietary intake andeight status (3,4). For some youngeople, vegetarianism may play aealth-enhancing role. Findings fromhe present study indicate that vege-arians may consume more healthfulntakes of fruits, vegetables, and di-tary fat, and may be at decreasedisk for overweight and obesity (1).

We agree that vegetarianism doesot cause eating disorders in adoles-ents and young adults; however, forome who self-identify as vegetari-ns, it may be a signal that warrantsurther exploration into the reasonsrompting this dietary choice. Cur-ent findings are consistent with pre-ious research suggesting an associa-ion between vegetarianism andisordered eating behaviors (5). Inhe present study, approximately0% of “current” and “former” adoles-ent vegetarians and 27% of “former”oung adult vegetarians reportedaving engaged in one or more of theollowing more extreme unhealthfuleight-control behaviors in the previ-us year: taking diet pills, vomiting,sing laxatives, and using diuretics1). Similar proportions of “current”egetarians reported binge eatingith loss of control (1).People may choose to adopt a vege-

arian diet for a variety of reasons. Inhe present study, the most commoneasons for choosing vegetarianismere a desire for a more healthfuliet, concern for the environment, notanting to kill animals, and not lik-

ng the taste of meat (1). Among theeasons given for choosing vegetari-nism, the highest proportion (57%)f adolescents reported concern forhe environment and the highest pro-ortion (66%) of young adults re-orted a desire for a more healthfuliet. A smaller, yet notable, propor-ion (slightly less than 20%) of partic-pants reported adopting a vegetarianiet as a way to lose weight or keeprom gaining weight (1).

Young people who are strongly mo-ivated to experiment with a varietyf weight-loss methods might also ex-eriment with vegetarianism as ancceptable form of restricting certainoods and possibly a method of con-ealing disordered eating behaviors2). Previous research suggests that

trict vegetarians may be less likely

524 September 2009 Volume 109 Number 9

han semi-vegetarians to experimentith vegetarianism as a weight-con-

rol practice (5); however, differencesn vegetarian type were not investi-ated in the present study.While it is important to recognize

he potential health benefits associ-ted with vegetarianism, it is also im-ortant to investigate a teen’s mo-ives for adopting a vegetarian dietnd identify whether the diet qualitys adequate for growth and develop-

ent. Results from the present studyuggest that as teens mature intooung adults, associations betweenegetarianism and more extreme un-ealthful weight-control behaviorsppear to be diminished, while asso-iations with the health benefits ap-ear to be enhanced.

Ramona Robinson-O’Brien, PhD, RDAssistant Professor

Nutrition DepartmentCollege of Saint Benedict and Saint

John’s UniversitySt Joseph, MN

Cheryl L. Perry, PhDProfessor and Regional Dean

Rockwell Chair in Society andHealth

Austin Regional CampusUniversity of Texas School of Public

HealthMichael & Susan Dell Center for

Advancement of Healthy LivingAustin, TX

Melanie Wall, PhDAssociate Professor

Division of BiostatisticsUniversity of Minnesota

Minneapolis, MN

Mary Story, PhD, RDProfessor

Division of Epidemiology andCommunity Health

School of Public HealthUniversity of Minnesota

Minneapolis, MN

Dianne Neumark-Sztainer, PhD,MPH, RDProfessor

Division of Epidemiology andCommunity Health

School of Public HealthUniversity of Minnesota

Minneapolis, MN t

eferences. Robinson-O’Brien R, Perry CL, Wall MM,

Story M, Neumark-Sztainer D. Adolescentand young adult vegetarianism: Better di-etary intake and weight outcomes but in-creased risk of disordered eating behaviors.J Am Diet Assoc. 2009;109:648-655.

. Position of the American Dietetic Associationand Dietitians of Canada: Vegetarian diets.J Am Diet Assoc. 2003;103:748-765.

. Ogden CL, Flegal KM, Carroll MD, JohnsonCL. Prevalence and trends in overweightamong US children and adolescents, 1999-2000. JAMA. 2002;288:1728-1732.

. Flegal KM, Carroll MD, Ogden CL, JohnsonCL. Prevalence and trends in obesity amongUS adults, 1999-2000. JAMA. 2002;288:1723-1727.

. Perry CL, McGuire MT, Neumark-SztainerD, Story M. Characteristics of vegetarian ad-olescents in a multiethnic urban population.J Adolesc Health. 2001;29:406-416.

doi: 10.1016/j.jada.2009.07.035

aturated Fat and Vascularompliance

o the Editor:The recent paper by Miller and col-

eagues (1) reported “an inverse cor-elation between flow-mediated vaso-ilatation and intake of saturated fatr�0.33; P�0.016). These data sug-est that during weight maintenance,ess favorable biological effects are ob-erved during a simulated, high-fattkins diet when compared to theouth Beach and Ornish diet.” Annalysis of their data, however, showshe opposite: consistent with the poororrelation coefficient, saturated fatntake had little effect on flow-medi-ted dilatation. In addition, the inter-ention did not conform to definitionsf the Atkins diet.The slope of the regression line is

ot shown, but appears, by inspec-ion, to be close to zero; that is, theres little correlation. More important,hose individuals who had lower lev-ls of saturated fat were almost asikely to show a reduction in vascularompliance as those at higher satu-ated fat. Three out of four at theighest levels of saturated fat showed

ittle change while in the range of the% recommended by health agencies;here is a significant chance that vas-ular compliance will get worse (seeedrawn Figure). Also, it is not clear

hat all of the high saturated fat

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LETTERS TO THE EDITOR

oints are attributable to the Atkinsroup.Weight maintenance on the Atkins

iet is determined by individual re-ponses to the previous phases; thats, it is maintenance of weight loss. In

iller’s experiment there was noeight loss phase. In addition, the At-ins diet does not recommend satu-ated fat. While the popular book al-ows saturated fat, there is noecommendation (2). Experimentaltudies have shown beneficial effectsf a low-carbohydrate diet with lowaturated fat (3), and my own study ofhe low carbers’ forum showed thateople who identified themselves aseing on the Atkins diet at least hadhe perception of not increasing satu-ated fat (4) and identified substitu-ion of non-root vegetables and greensor carbohydrates as the major change.

I would also fault the paper for noteporting the actual macronutrientonsumption; in particular, the levelf carbohydrate. The Atkins diet is,fter all, a low-carbohydrate diet andhe rationale is that the effect of anyat in the presence of high carbohy-rate is very different from the effectn the presence of low carbohydrate,n idea borne out in experimentaltudies (5-7).Krauss’s group has shown strong

orrelation between dietary carbohy-rate and small, dense (atherogenic)

igure. Relation between saturated fat intake aedrawn from reference (1). Green area shows a paturated fat below approximately 13 g (7% ene

ow-density lipoprotein particles,5

hich, if less telling than vascularompliance, cannot be excluded as aisk factor (8). This group also showedhat carbohydrate restriction wasore important than weight loss for

mprovement of cardiovascular mark-rs (6,7).In summary, the figure purporting

o show the correlation of saturatedat on vascular compliance seems tohow the opposite, and the diet la-eled as Atkins does not conform toefinitions used by those who studyow-carbohydrate diets.

Richard Feinman, PhDProfessor of Biochemistry

SUNY Downstate Medical CenterBrooklyn, NY

eferences. Miller M, Beach V, Sorkin JD, Mangano C,

Dobmeier C, Novacic D, Rhyne J, Vogel RA.Comparative effects of three popular diets onlipids, endothelial function, and C-reactiveprotein during weight maintenance. J AmDiet Assoc. 2009;109:713-717.

. Atkins RC. Dr. Atkins’ New Diet Revolution.New York, NY: Avon Books; 2002.

. Volek JS, Gomez AL, Kraemer WJ. Fastinglipoprotein and postprandial triacylglycerolresponses to a low-carbohydrate diet supple-mented with n-3 fatty acids. J Am Coll Nutr.2000;19:383-391.

. Feinman RD, Vernon MC, Westman EC. Lowcarbohydrate diets in family practice: Whatcan we learn from an internet-based supportgroup. Nutr J. 2006;5:26.

on-treatment flow-mediated vasodilation (FMD).umed beneficial increase in FMD associated with. Pink indicates no change or decrease in FMD.

. Feinman RD, Volek JS. Low carbohydrate di-ets improve atherogenic dyslipidemia even in c

September 2009 ● Journal

the absence of weight loss. Nutr Metab(Lond). 2006;3:24.

. Krauss RM, Blanche PJ, Rawlings RS, Fern-strom HS, Williams PT. Separate effects ofreduced carbohydrate intake and weight losson atherogenic dyslipidemia. Am J Clin Nutr.2006;83:1025-1031.

. Volek JS, Phinney SD, Forsythe CE, QuannEE, Wood RJ, Puglisi MJ, Kraemer WJ, Bi-bus DM, Fernandez ML, Feinman RD. Car-bohydrate restriction has a more favorableimpact on the metabolic syndrome than a lowfat diet. Lipids. 2009;44:297-309.

. Krauss RM. Atherogenic lipoprotein pheno-type and diet-gene interactions. J Nutr. 2001;131(suppl):340S-343S.

doi: 10.1016/j.jada.2009.07.034

uthors’ Response:Feinman raises the suggestion that

aturated fat intake had little effect onow-mediated dilation because individ-als who consumed lower amounts ofaturated fat were “most as likely” tohow a reduction in flow mediated va-odilation (FMD) compared to whenigher saturated fat was consumed.hese conclusions are based upon sub-ividing the groups by FMD (positiver negative response) and stratifyingaturated fat intake by using an artifi-ial cut-point. However, this interpre-ation is misguided for the followingeasons. First, there was a significantnverse correlation between saturatedat and FMD as shown in the manu-cript (r��0.33) and the slope was sig-ificant (�0.09; P�0.016). Secondly, ofhe 54 data points (18 subjects complet-ng each of the three phases), 26 dem-nstrated reduced FMD with 42% ofhese responses occurring during thetkins Phase (1). In fact, 90% of theigh-saturated fat points were attrib-table to the Atkins group. Finally, anderhaps most compelling, was that3% of the most favorable FMD re-ponses occurred during the Southeach or Ornish phase, with the very-

ow-saturated-fat Ornish diet demon-trating significantly higher FMD com-ared to Atkins (P�0.02) (Figure).The intervention also conformed to

he Atkins diet (2) by mirroring theow-carbohydrate intake and higherercentage of fat used in previoustudies (3,4). That the Atkins dietdoes not recommend saturated fat” isrguable in view of the generous rec-mmendations for fried foods, cream,nd saturated fat-enriched meatroducts (5). Moreover, the level of

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of the AMERICAN DIETETIC ASSOCIATION 1525