This article was downloaded by: [INASP - Pakistan (PERI)]On: 19 November 2014, At: 01:06Publisher: RoutledgeInforma Ltd Registered in England and Wales Registered Number: 1072954 Registered office: MortimerHouse, 37-41 Mortimer Street, London W1T 3JH, UK

Journal of the American College of NutritionPublication details, including instructions for authors and subscription information:http://www.tandfonline.com/loi/uacn20

Cookies Enriched with Psyllium or Oat BranLower Plasma LDL Cholesterol in Normal andHypercholesterolemic Men from Northern MexicoAna Lourdes Romero MSa, Jesus Enrique Romero MDa, Samuel Galaviz PhDa & Maria LuzFernandez PhDb

a Centro de Investigacion y Postgrado (A.L.R., J.E.R., S.G.), Universidad de Sonora,Hermosillo, Sonora, Mexicob Department of Nutritional Sciences (M.L.F.), University of Connecticut, StorrsPublished online: 08 Jun 2013.

To cite this article: Ana Lourdes Romero MS, Jesus Enrique Romero MD, Samuel Galaviz PhD & Maria LuzFernandez PhD (1998) Cookies Enriched with Psyllium or Oat Bran Lower Plasma LDL Cholesterol in Normal andHypercholesterolemic Men from Northern Mexico, Journal of the American College of Nutrition, 17:6, 601-608, DOI:10.1080/07315724.1998.10718809

To link to this article: http://dx.doi.org/10.1080/07315724.1998.10718809

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) containedin the publications on our platform. However, Taylor & Francis, our agents, and our licensors make norepresentations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose ofthe Content. Any opinions and views expressed in this publication are the opinions and views of the authors,and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be reliedupon and should be independently verified with primary sources of information. Taylor and Francis shallnot be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and otherliabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to orarising out of the use of the Content.

This article may be used for research, teaching, and private study purposes. Any substantial or systematicreproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in anyform to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions

Original Paper

Cookies Enriched with Psyllium or Oat Bran LowerPlasma LDL Cholesterol in Normal andHypercholesterolemic Men from Northern Mexico

Ana Lourdes Romero, MS, Jesus Enrique Romero, MD, Samuel Galaviz, PhD, and Maria Luz Fernandez, PhD

Centro de Investigacion y Postgrado (A.L.R., J.E.R., S.G.), Universidad de Sonora, Hermosillo, Sonora, Mexico; and Departmentof Nutritional Sciences (M.L.F.), University of Connecticut, Storrs

Key words: psyllium, oat bran, LDL cholesterol, hypercholesterolemia, Northern Mexico

Background: Psyllium and oat bran have been shown to lower plasma LDL cholesterol levels in differentpopulations. Hypercholesterolemia is prevalent in the Northern part of Mexico and might be associated to dietaryhabits and sedentary lifestyle.

Methods: Sedentary normal (cholesterol,200 mg/dL) (n536) and hypercholesterolemic (cholesterol.220mg/dL) (n530) men from the Northern part of Mexico aged 20 to 45 years of age participated in an 8-week studyto determine the effects of dietary soluble fiber, either psyllium or oat bran, in lowering plasma LDL cholesterolin this population. Fiber was administered by feeding the subjects an amount of cookies (100 g) equivalent to1.3 or 2.6 g/day of soluble fiber from psyllium or oat bran, respectively. Subjects were randomly allocated tothree groups: a control group consuming cookies with wheat bran, a known source of fiber with no cholesterollowering effects, psyllium, or oat bran.

Results:Food frequency questionnaires indicated that subjects from the three groups had similar intakes offoods classified as hypercholesterolemic (p.0.05). Plasma LDL cholesterol concentrations were reduced by anaverage of 22.6 and 26% in the psyllium and oat bran groups (p,0.001) while a non-significant reduction of8.4% was observed in the hypercholesterolemic individuals from the control group. No effects on plasma HDLor triglycerides levels were observed among the three dietary treatments except for hypercholesterolemicindividuals supplemented with oat bran where a 28% reduction in plasma triglycerides was observed after 8weeks (p,0.01).

Conclusion: These results indicate that psyllium and oat bran are efficacious in lowering plasma LDLcholesterol in both normal and hypercholesterolemic individuals from this population.

INTRODUCTION

High intake of dietary fiber has been associated with favor-able effects on human health [1,2]. Several sources of dietarysoluble fiber including psyllium and oat bran have been shownto decrease plasma LDL cholesterol concentrations in normaland hyperlipidemic subjects [3–6]. Since there is a positiveassociation with plasma LDL cholesterol levels and coronaryheart disease risk [7], intake of nutrients known to lower theconcentration of LDL in plasma is considered to be highlybeneficial.

Based on the potential use as hypercholesterolemic agents,

numerous clinical studies have been conducted to test differentsources of soluble fiber in different populations varying in age[8] dietary intakes [9] or plasma lipid levels [10]. From thesestudies, psyllium intake has consistently shown significant re-ductions in plasma LDL cholesterol levels ranging from 10 to24% [3,4,8,10]. Other sources of fiber such as oat bran havebeen more controversial [11–14] apparently due to the lack ofconsistency between studies, the diet consumed by subjects[12] or variations in the preparation or the source of the oatbran [14].

The secondary mechanisms by which psyllium lowersplasma LDL cholesterol concentrations have been tested in

Address reprint requests to: Maria Luz Fernandez, PhD, University of Connecticut, Department of Nutritional Sciences, 3624 Horsebarn Road Extension, U-17, Storrs,CT 06269.

Journal of the American College of Nutrition, Vol. 17, No. 6, 601–608 (1998)Published by the American College of Nutrition

601

Dow

nloa

ded

by [

INA

SP -

Pak

ista

n (P

ER

I)]

at 0

1:06

19

Nov

embe

r 20

14

several animal models [15–23]. Studies in male and femaleguinea pigs have demonstrated that psyllium lowers plasmaLDL cholesterol and hepatic cholesterol concentrations result-ing in an up-regulation of cholesterol 7a-hydroxylase activitywhich suggests an interruption of the enterohepatic circulationof bile acids [15–18]. Increases in LDL fractional catabolic rateand hepatic apo B/E receptor number have also been observedby psyllium intake [15–18]. Up-regulation of cholesterol 7ahy-droxylase activity and mRNA abundance [19] and decreases inLDL production rate and accelerated LDL catabolism havebeen shown in hamsters consuming psyllium diets [20,21]. InAfrican green monkeys, decreases in LDL apo B flux waspostulated as the major mechanism of plasma LDL loweringinduced by psyllium intake [22]. Oat bran has been shown toreduce plasma cholesterol and hepatic cholesterol concentra-tions in the cholesterol-fed rat [23,24].

Based on these numerous reports for clinical [3–6,8–14]and animal studies [15–24], we decided to test the effects ofpsyllium and oat bran on individuals characterized by highconsumption of dietary fat and total calories [25]. For ourstudies we recruited sedentary males aged 20 to 45 years froma population living in the Northern part of Mexico which hasbeen identified as having higher plasma cholesterol concentra-tions compared to the rest of the country [26].

MATERIALS AND METHODS

Materials

Enzymatic cholesterol assay kits, cholesterol standard andtriglyceride kits were purchased from Boehringer Mannheim(Indianapolis, IN). Plastic bags were obtained from Reynoldscompany, (Richmond, VA). Psyllium (PSY) husks (Plantagoovata) with 87.3% total fiber and 11.2% soluble fiber wereobtained from Laboratories Hormona (Mexico City, Mexico).

Oat bran (OB) containing 14.3% total dietary fiber and 4.3%soluble fiber was purchased from a local natural store. Wheatflour and other baking ingredients were purchased in the localmarket.

Subjects

Male subjects were recruited to participate in the study.They were randomly assigned to one of three fiber groups:control, PSY or OB. A frequency questionnaire was developedto assess consumption of food items associated with hypercho-lesterolemia or hypertriglyceridemia. Individuals were advisedto reduce the consumption of those food items during the timeof the experiment. Two blood draws were performed to assessbaseline values for plasma lipids at the beginning of the exper-iment within the first week and at end of the experiment after8 weeks. An amount of cookies equivalent to 100 g/day con-taining the different fibers were given to subjects every Tues-day (for the next 3 days) and every Friday (for the following 4days including the week end). Subjects were asked to returnevery week the portion of the cookies that was not consumed.

Subjects ranged in age from 20 to 45 years (mean 35–38 y),mean body weight ranged from 74 to 83 kg, body mass indexvalues from 26.4 to 27.3 kg/m2 and mean systolic and diastolicpressure values ranged from 77 to 80 and from 116 to 123,respectively. Summarized details of subjects’ characteristicsare given in Table 1.

Patients treated with lipid-lowering drugs, diabetic individ-uals, cardiovascular or active gastrointestinal diseases wereexcluded from the study. All subjects selected were interviewedto inform them of the nature of the experiment and they wererequested to provide a written informed consent. Subjects werefollowed on an ambulatory basis for 8 weeks. All subjects fromthe normal and hypercholesterolemic groups consumed 100 gof cookies daily which is equivalent to 0.6 g, 1.7 g or 2.8 g ofsoluble fiber derived from wheat bran, psyllium or oat bran,

Table 1. Characteristics of subjects (normal and hypercholesterolemic) fed control, psyllium or oat bran cookies at baseline andafter 8 weeks of dietary treatment1

Characteristic

Control (n514) Psyllium (n510) Oat bran (n512)

Normal subjects (cholesterol,220 mg/dL)

Baseline 8 weeks Baseline 8 weeks Baseline 8 weeks

Age (years) 296 9 — 356 5 — 406 9 —Weight (kg) 77.06 8.5 74.86 8.7 84.06 11.5 83.26 10.2 83.76 6.9 83.46 6.5Body mass index (kg/m2) 26.36 3.1 25.86 3.2 27.66 3.0 27.46 3.3 27.56 2.8 27.46 2.6

Hypercholesterolemic subjects (cholesterol.220 mg/dL)

Control (n510) Psyllium (n510) Oat bran (n510)

Age (years) 366 8 — 386 6 — 386 3 —Weight (kg) 83.16 13.9 82.16 14.2 83.46 10.4 83.56 10.6 82.16 10.4 82.16 10.7Body mass index (kg/m2) 26.66 3.1 26.06 3.7 26.56 2.2 26.36 2.3 27.16 2.8 27.16 2.9

1 Values represent the mean6 SD for the number of subjects indicated in parentheses. No significant differences were found between baseline and 8 weeks for any of

these characteristics as determined by paired t-test.

Psyllium, Oat Bran and Hypercholesterolemia in Mexico

602 VOL. 17, NO. 6

Dow

nloa

ded

by [

INA

SP -

Pak

ista

n (P

ER

I)]

at 0

1:06

19

Nov

embe

r 20

14

respectively. All human experiments were carried out accord-ing to the guidelines of the University of Sonora and protocolswere approved by the Human Subject Committee.

Preparation of Cookies

Cookies were prepared according to the micro-method III[27]. Mixing was performed in a Hobart mixer (Model AS200T, Hobart Company, Troy, OH) in a 1:1.25 proportion ofsolid: water for one min at low speed. After 10 minutes, mixwas extended for a final 7 mm thick, 5 cm diameter cookie.Baking was conducted in a convection oven (model Z-X-4,Hornos Carcamo S.A., Mexico, D.F.) After 60 minutes cooling,the daily cookie portion (10 cookies corresponding to 100 g)was packed in individual plastic bags. Chemical composition ofcookies is shown in Table 2.

Additional Measurements

Informed consent, a medical history, a physical examina-tion, the food frequency questionnaire and the discomfort ques-tionnaire were provided to subjects during the grouping time/baseline period. Subjects were advised to restrict consumptionof certain dietary items listed in the food frequency question-naire which are part of their normal diet. Frequency of con-sumption (0 to 7 times a week) of each or these food items wasrecorded by each subject every week. The discomfort question-naire addressed the following symptoms that could be presentdue to fiber intake: nausea, stomach acidity, vomit, abdominaldistention, diarrhea, increased evacuation number and flatu-lence. Personnel from the study visited with each patient twicea week to distribute the corresponding packages of cookies andthe weekly discomfort questionnaire. To reduce possible gas-trointestinal effects of increased fiber intake, subjects wereadvised to consume one-third of the cookies with every mealfor a total of three meals per day. Body weight was recordedweekly.

Plasma Lipids

Plasma lipids were measured during baseline and after 8weeks. Standardization and quality control for plasma choles-terol and triglyceride assays have been maintained in our lab-oratory by participation in the Centers for Disease Control-National Lung and Blood Institute (CDC-NHLBI) LipidStandardization Program since 1989. Two blood draws at base-line and two blood draws after 8 weeks were obtained for allsubjects to measure total plasma cholesterol, triglycerides andHDL-cholesterol. Total cholesterol was determined by enzy-matic methods [28] using Boehringer-Mannheim cholesterolstandards. HDL cholesterol was measured in the supernatantafter precipitation of apo B containing lipoproteins [29], andLDL-cholesterol was calculated as described by Friedewald etal [30]. Triglycerides were determined adjusting for free glyc-erol according to Carr et al [31].

Statistics

Differences in the frequency of consumption of the differentfood items provided in the list was evaluated by the Kruskal-Wallis non-parametric test with a statistics software program(SAS, 1988). One-way ANOVA and the Newman-Keuls post-hoc test were used to evaluate significant differences inchanges between baseline and 8 weeks among dietary treat-ments. Paired t-test was used to evaluate differences in plasmatotal, LDL and HDL cholesterol, triglycerides and LDL/HDLratios at the beginning of the experiment and after 8 weeks oftreatment using the same statistics software program. Within-group analyses were averages of measurements obtained duringthe establishment of baseline, compared with average measure-ments obtained during the final week of the treatment period.p,0.05 was considered significant.

RESULTS

At the beginning of the experiment 70 subjects were re-cruited and randomly distributed to the three dietary treatmentsand four of them did not complete the study for several reasons.The final distribution of the 66 individuals who completed thestudy was 24 for the control, 22 for the oat bran and 20 for thepsyllium group. There were no significant differences in bodyweight, body mass index between baseline and after 8 weeks oftreatment for all groups of subjects. Normal and hypercholes-terolemic subjects in control, PSY or OB groups did not havea significant change in any of those characteristics (Table 1)indicating that fluctuations in body weight were not related tothe observed changes in plasma lipids discussed below. How-ever, normal individuals from the control group had lowerplasma cholesterol levels at baseline than subjects from theother two groups and higher HDL cholesterol concentrationsthan the OB group (Table 3). In addition, individuals from

Table 2. Chemical composition of cookies1

Parameter Control Psyllium Oat bran

Composition (%)Moisture 3.96 1.0 5.66 0.8 14.26 0.9Protein 9.36 0.5 11.66 0.8 6.86 0.4Fat 21.26 2.0 14.46 1.2 17.56 1.4Ashes 2.66 0.2 2.66 0.2 2.66 0.2Total fiber 1.96 0.2 13.16 0.5 9.66 1.2Soluble fiber 0.66 0.1 1.76 0.3 2.86 0.5Insoluble fiber 1.36 0.4 11.46 0.3 6.86 0.3Carbohydrates 61.16 1.5 52.66 4.5 49.36 2.9

1 Values represent mean6SD of n53 determinations.

Psyllium, Oat Bran and Hypercholesterolemia in Mexico

JOURNAL OF THE AMERICAN COLLEGE OF NUTRITION 603

Dow

nloa

ded

by [

INA

SP -

Pak

ista

n (P

ER

I)]

at 0

1:06

19

Nov

embe

r 20

14

the control group had higher plasma HDL cholesterol con-centrations than the psyllium and oat bran groups for thehypercholesterolemic individuals (p,0.05). No differenceswere observed in plasma cholesterol at baseline among hyper-cholesterolemic subjects from the three groups or in plasmatriglycerides for all subjects (Table 3).

As described above, subjects from this population normallyconsume diets high in dietary fat and calories [25]. The averageconsumption of saturated fat is 18% of total calories (Fernan-dez, unpublished observations). Individuals from the three di-etary groups were advised to reduce the intake of certain fooditems associated with increases in plasma cholesterol. Subjectsparticipating in the study were highly motivated and made aconscientious effort to change their dietary habits and they all(n566) reduced their usual intake of animal products duringthe 8 weeks of the study. The questionnaire to determinefrequency of consumption was distributed weekly and themode for each item in each dietary group was used for thesummary of the 8 weeks as presented in Table 4. There were nodifferences in the food frequency intake mode for the fooditems under study for the three dietary groups as analyzed bythe Kruskall-Wallis non-parametric test (Table 4). These dataindicate that differences in the frequency of consumption ofthose food items was not a factor affecting plasma lipid levels

in the subjects participating in this study. In addition, none ofthe subjects for any of the dietary groups complained of symp-toms indicated in the discomfort questionnaire (data not shown)thus all subjects consumed the allotted amount of cookies andcompleted the 8 weeks of the study.

Plasma Lipids

Changes of plasma total, LDL and HDL cholesterol, plasmatriglycerides and LDL/HDL ratio between baseline and after 8weeks of dietary treatment were calculated for all subjectsparticipating in the study (Table 5). Reductions in total choles-terol were 33.5 to 45.5 mg/dL for subjects in the psyllium andoat bran groups while reductions in total cholesterol for thecontrol group were an average of only 2.1 mg/dL. The reduc-tions in plasma total cholesterol were significantly greater inthe psyllium and oat bran groups compared to the control group(p,0.001). Similar results were obtained for LDL cholesterol(Table 5). The psyllium and oat bran groups had 44 and 43mg/dL reduction in LDL cholesterol which was significantlyhigher than the 6.0 mg/dL reduction observed in control sub-jects. Similarly, reductions in the LDL/HDL ratio in the PSYand OB groups were significantly more pronounced than thoseobserved for the control group (p,0.01) as indicated in Table

Table 3. Plasma lipids at baseline for normal and hypercholesterolemic individuals fed control, psyllium or oat bran cookies

Groups

Normal Hypercholesterolemic

Plasma lipids (mg/dL)

Cholesterol HDL Triglycerides Cholesterol HDL Triglycerides

Control 1806 33b 476 19a 1276 83a 2606 26a 436 17a 2546 111a

Psyllium 2146 19a 376 8ab 1546 67a 2706 18a 326 7b 2136 137a

Oat bran 2141 13a 276 7b 2346 187a 2796 28a 366 7b 2626 194a

1 Values are expressed as mean6 SD for 14 normal and 10 hypercholesterolemic individuals for control, 10 normal and 10 hypercholesterolemic for psyllium, and 12

normal and 10 hypercholesterolemic for the oat bran group.2 Different superscripts indicate significantly different as determined by one-way ANOVA and the Newman-Keules post hoc test.

Table 4. Frequency of food consumption in individuals from the control, psyllium and oat bran groups1,2

Food item

Dietary treatments

ControlNumber of days

PsylliumNumber of days

Oat branNumber of days

0–2 3–5 6–7 0–2 3–5 6–7 0–2 3–5 6–7

Meat 6 16 1 8 15 1 4 14 1Fowl 22 3 0 16 2 0 14 3 0Sausages 17 5 0 13 6 0 13 7 0Bacon, chorizo 21 0 0 9 3 0 16 0 0Organs 22 0 0 2 0 0 15 0 0Fish 24 0 0 11 1 0 16 1 0Shrimp 23 0 0 7 0 0 16 0 0Eggs 14 10 0 12 7 0 14 3 0Alcohol 22 2 0 18 2 0 16 1 0

1 Each number represents the mode for each time within each dietary group.2 There were no statistical differences in the frequency of consumption for any of these dietary items in the three groups (control, psyllium and oat bran) as determined

by the Kruskall-Wallis non-parametric test.

Psyllium, Oat Bran and Hypercholesterolemia in Mexico

604 VOL. 17, NO. 6

Dow

nloa

ded

by [

INA

SP -

Pak

ista

n (P

ER

I)]

at 0

1:06

19

Nov

embe

r 20

14

5. Psyllium and oat bran intake had similar reductions ofplasma total and LDL cholesterol. Changes in HDL cholesteroland triglycerides were not different among the three dietarygroups.

After analyzing changes in plasma lipids among groups, theefficiency of each dietary treatment compared to baseline wasevaluated. Plasma total cholesterol concentrations were signif-icantly reduced after 8 weeks of PSY or OB consumption forthe normal and the hypercholesterolemic population (Table 6).The plasma cholesterol reduction ranged from 10 to 19% forthe PSY group and 10 to 14% for the OB. No significantdifferences in plasma cholesterol were observed for subjectsconsuming the wheat bran cookies (control diet).

The observed reductions in plasma cholesterol concentrationswere mostly associated with decreases in plasma LDL cholesterolas indicated in Table 7. Subjects consuming PSY or OB cookieshad a 20 to 27% reduction in plasma LDL cholesterol after 8weeks of consumption of these sources of dietary soluble fiberwhich was highly significant (p,0.0001). Although subjects con-suming the wheat bran cookies had a small reduction in plasmaLDL cholesterol in the order of 0.5 to 8%, it was not significantlydifferent from baseline values (p.0.05).

No significant changes were observed in plasma HDL cho-lesterol for any of the dietary treatments for the normal or

hypercholesterolemic subjects (p.0.05) (Table 8). Plasma trig-lycerides did not change for the majority of the tested groupsexcept for the oat bran group in the hypercholesterolemicindividuals where a 27% reduction in plasma triglycerides wasobserved after 8 weeks of treatment (Table 8). From the ob-served values in these variables, it is clear that the control grouphad normal HDL levels while the two groups assigned to thesoluble fiber treatments were characterized by low plasmaHDL cholesterol concentrations. In addition, all hypercholes-terolemic individuals were characterized by having high base-line plasma triglycerides in addition to the high cholesterolvalues which probably classify these individuals as havingmixed hyperlipidemia (Table 8). Further, individuals from theOB and characterized as normal (plasma cholesterol,220 mg/dL) also had elevated plasma triglyceride values at baseline.

The overall LDL/HDL ratio, a reliable predictor for coro-nary heart disease risk was significantly improved after 8weeks of PSY or OB intake (p,0.001) (Table 9). Although thecontrol group presented a reduction in the LDL/HDL ratio after8 weeks, this value was not significantly different from thebaseline in the normal or the hypercholesterolemic individuals.

DISCUSSION

In this study, we demonstrated that enriching the diet witha fiber supplement derived from psyllium or oat bran reducedplasma LDL cholesterol concentrations and improved the LDL/HDL ratio in a population characterized by having significantlipid disorders including high plasma cholesterol and triglyc-erides and low levels of HDL cholesterol.

In these studies, recommendations were made to subjects todecrease the consumption of dietary items high in fat anddietary cholesterol characteristic in this part of Mexico. Sub-jects obviously complied since intake of meat, organs, bacon,chorizo and other high fat foods typical of the daily intake ofthis population were reduced as assessed by the food frequencyquestionnaire. Moderate intakes of alcohol have been associ-ated with higher plasma HDL levels [32,33]. However, alcoholintake was monitored in this study due to the association

Table 5. Difference between baseline and 8 weeks oftreatment in plasma total cholesterol, LDL cholesterol, HDLcholesterol, triglycerides and LDL/HDL ratio for all subjectsin the wheat bran (control), psyllium or oat bran groups

Measurement Control Psyllium Oat bran

Difference from baselineTotal cholesterol (mg/dL)22.16 3.1a 233.56 6.7b 245.56 9.5b

LDL cholesterol (mg/dL)26.06 3.2a 244.46 6.1b 243.46 10.7b

HDL cholesterol (mg/dL)23.66 1.0a 6.56 0.9a 3.66 0.9a

Triglycerides (mg/dL) 1.96 2.9a 20.56 2.8a 228.66 26.9a

LDL/HDL ratio 20.66 0.2a 22.36 0.3b 21.86 0.4b

1 Values are expressed as mean6 SD for 24 individuals for control, 20 for

psyllium, and 22 for the oat bran group.2 Different superscripts in the same row indicate significantly different as deter-

mined by one way ANOVA and the Newman Keuls post hoc test. (p,0.001) for

plasma total and LDL cholesterol and p,0.01 for LDL/HDL ratio.

Table 6. Changes between baseline and 8 weeks in total cholesterol of normal (cholesterol,220 mg/dL) or hypercholesterolemic(cholesterol.220 mg/dL) subjects fed control, psyllium or oat bran cookies1

Totalcholesterol

Normal (mg/dL) Hypercholesterolemic (mg/dL)

Baseline2 8 weeks Difference Baseline 8 weeks Difference

Control 1806 33a 1856 30a 15 (11.0%) 2606 26a 2486 21a 212 (25.0%)Psyllium 2146 19a 1936 26b 221 (210.0%) 2706 18a 2206 31b 250 (218.5%)Oat bran 2146 13a 1846 22b 230 (214.0%) 2796 28a 2156 36b 263 (222.8%)

1 Values are expressed as mean6 SD for 14 normal and 10 hypercholesterolemic individuals for control, 10 normal and 10 hypercholesterolemic for psyllium, and 12

normal and 10 hypercholesterolemic for the oat bran group.2 Different superscripts indicate significantly different as determined by paired t-test for control, psyllium and oat bran groups within the normalor hypercholesterolemic

individuals.

Psyllium, Oat Bran and Hypercholesterolemia in Mexico

JOURNAL OF THE AMERICAN COLLEGE OF NUTRITION 605

Dow

nloa

ded

by [

INA

SP -

Pak

ista

n (P

ER

I)]

at 0

1:06

19

Nov

embe

r 20

14

between hypertriglyceridemia and high alcohol consumption[34,35] since most of the subjects participating in this study hadelevated plasma triglyceride levels.

Although eggs, a known source of dietary cholesterol wereincluded in the dietary frequency questionnaire, a recentlypublished meta-analysis including 224 studies with 8,143 indi-viduals, either free-living subjects or metabolic ward patients,reported that decreasing dietary cholesterol from the average385 mg/day to 300 mg/day would reduce plasma total choles-terol only by 1.9 mg/dL [36]. According to that same study,reducing fat content from 37 to 30% and saturated fat from 13

to 10% would decrease plasma cholesterol by 5.8 mg/dL, amore significant response [36]. However, studies by Schaeferet al [37] have demonstrated that there is a genetic componentto the response to dietary cholesterol possibly associated withdifferent apo E phenotypes [37]. Since the subjects participat-ing in this study, especially the hypercholesterolemic groupappear to have substantial lipid disorders, it is possible that theycan be classified in one of those phenotypes where subjects aremore responsive to dietary cholesterol [37]. Thus, typical foodshigh in dietary fat and cholesterol were included in this ques-tionnaire.

Table 7. Changes between baseline and 8 weeks in LDL cholesterol of normal (cholesterol,220 mg/dL) or hypercholesterolemic(cholesterol.220 mg/dL) subjects fed control, psyllium or oat bran cookies1

LDLcholesterol

Normal (mg/dL) Hypercholesterolemic (mg/dL)

Baseline2 8 weeks Difference Baseline 8 weeks Difference

Control 1096 29a 1096 22a 20.1 (0.1%) 1666 22a 1526 12a 214 (8.4%)Psyllium 1466 16a 1216 20b 225 (217.1%) 1966 29a 1416 30b 255 (228.0%)Oat bran 1406 43a 1036 33b 237 (226.4%) 1976 52a 1466 53b 251 (225.8%)

1 Values are expressed as mean6SD for 14 normal and 10 hypercholesterolemic individuals for control, 10 normal and 10 hypercholesterolemic for psyllium, and 12 normal

and 10 hypercholesterolemic for the oat bran group.2 Different superscripts in the same row indicate significantly different as determined by paired t-test for control, psyllium and oat bran groups within the normal or

hypercholesterolemic individuals.

Table 8. Changes between baseline and 8 weeks in plasma HDL cholesterol and triglyceride of normal (cholesterol,220 mg/dL)or hypercholesterolemic (cholesterol.220 mg/dL) subjects fed control, psyllium or oat bran cookies1

HDL cholesterol(mg/dL)

Normal Hypercholesterolemic

Control Psyllium Oat bran Control Psyllium Oat branBaseline 476 19a 376 8a 276 7a 436 17a 326 7a 306 4a

8 Weeks 506 17a 416 9a 326 8a 466 16a 366 7b 326 7b

Difference (%) (6) (9) (15.6) (6.5) (11.1) (11.8)

Triglyceride(mg/dL)

Normal Hypercholesterolemic

Baseline 1276 83a 1546 67a 2346 187a 2546 111a 2136 137a 2626 194a

8 Weeks 1306 91a 1546 73a 2466 97a 2556 107a 2126 134a 1886 140b

Difference (%) (2.3) (0.0) (4.9) (0.4) (20.5) (228.2)1 Values are expressed as mean6SD for 14 normal and 10 hypercholesterolemic individuals for control, 10 normal and 10 hypercholesterolemic for psyllium, and 12 normal

and 10 hypercholesterolemic for the oat bran group.2 Different superscripts in the same column indicate significantly different as determined by paired t-test for control, psyllium and oat bran groupswithin the normal or

hypercholesterolemic individuals.

Table 9. Changes between baseline and 8 weeks in LDL/HDL ratio of normal (cholesterol,220 mg/dL) or hypercholesterolemic(cholesterol.220 mg/dL) subjects fed control, psyllium or oat bran cookies1

LDL/HDLNormal Hypercholesterolemic

Baseline2 8 weeks Difference Baseline 8 weeks Difference

Control 3.06 1.6a 2.46 0.8a 20.6 (220%) 4.36 1.5a 3.66 1.0a 20.83 (216.2%)Psyllium 4.26 1.0a 3.06 1.0b 21.2 (228.5%) 6.56 1.5a 4.06 1.2b 22.5 (238.5%)Oat bran 5.26 1.6a 3.46 1.5b 21.8 (234.6%) 6.66 1.9a 4.66 2.0b 22.0 (230.3%)

1 Values are expressed as mean65.0 SEM for 14 normal and 10 hypercholesterolemic individuals for control, 10 normal and 10 hypercholesterolemic for psyllium, and

12 normal and 10 hypercholesterolemic for the oat bran group.2 Different superscripts indicate significantly different as determined by paired t-test for control, psyllium and oat bran groups within the normal(p,0.01) or

hypercholesterolemic (p,0.001) individuals.

Psyllium, Oat Bran and Hypercholesterolemia in Mexico

606 VOL. 17, NO. 6

Dow

nloa

ded

by [

INA

SP -

Pak

ista

n (P

ER

I)]

at 0

1:06

19

Nov

embe

r 20

14

The results from this study are in agreement with severalreports on the hypocholesterolemic effects of psyllium [8–10]and with some of the reports on the plasma cholesterol lower-ing effects of oat bran [4,13,14]. Psyllium apparently lowersplasma cholesterol even in the cases where individuals con-sume high fat diets [38]. In contrast, oat bran apparently is notas effective in the cases of individuals consuming high amountsof fat [11]. In the present study, individuals decreased theirnormal fat consumption which agrees with oat bran beingeffective with lower intakes of dietary fat. In this study, weobserved a substantial decrease in plasma triglycerides for thehypercholesterolemic individuals. Similar to our results,Anderson et al [4] reported a 19% significant reduction inplasma triglycerides in hypertriglyceridemic individuals con-suming oat bran while no significant changes in this parameterwere observed for the normotriglyceridemic subjects.

The direct action of psyllium in the intestinal lumen appearsto be related to interruption of the enterohepatic circulation ofbile acids which will alter hepatic cholesterol homeostasis andreduce plasma LDL cholesterol concentrations [39]. Studies byEverson et al [9] have demonstrated that psyllium does notreduce cholesterol absorption but rather binds to the bile acidsemphasizing that this action could be the major primary mech-anism by which psyllium reduces plasma cholesterol.

Studies conducted in animal models are in agreement with thehuman studies. In guinea pigs, psyllium intake is not related todecreases in cholesterol absorption but rather to interruption ofentero-hepatic circulation of bile acids associated with the ob-served up-regulation of cholesterol 7a-hydroxylase activity [17].Similarly in hamsters, psyllium increases both the activity andmRNA abundance of this enzyme [19]. In addition, and similar tothe human studies, reductions in plasma LDL cholesterol concen-trations have been observed in guinea pigs and hamsters with bothnormal and hypercholesterolemic diets [15–19] indicating thatpsyllium is effective independent of the amount of dietary lipids.There are several metabolic responses associated with this primaryaction of psyllium in the small intestine which have been studiedin detail in hamsters and guinea pigs.

The increases in cholesterol catabolism via bile acid syn-thesis results in a substantial reduction in hepatic cholesterolconcentrations [15]. This reduction in hepatic cholesterol poolshas been shown to alter hepatic cholesterol homeostasis inguinea pigs by up-regulating HMG-CoA reductase and down-regulating ACAT activities, the regulatory enzymes of choles-terol synthesis and esterification, respectively [15,16]. As aresult of these alterations, secretion rates of apo B VLDL arereduced [18]. LDL apo B flux is decreased [18,21,22] and thereare increases in LDL catabolism due to the up-regulation ofhepatic apo B/E receptors [15,17,21]. It is possible that similarmechanisms are taking place in humans as a response to theincreases in bile acid excretion [9,39] and that mobilization ofhepatic cholesterol for the synthesis of bile acids also occursresulting in the up-regulation of LDL receptors and increasedLDL removal from plasma.

The active ingredient in oat bran isb-glucan and carefullycontrolled studies in ileostomic patients have shown that bileacid excretion is increased during oat bran consumption com-pared to wheat bran or oat bran containing hydrolyzedb-glucan[13]. These results suggest that both oat bran and psyllium havesimilar primary mechanisms in the intestinal lumen whichresult in plasma LDL cholesterol lowering. The observed de-creases in plasma triglycerides due to oat bran intake in ourpresent report and in the findings of other investigators [4,40]suggest that oat bran might decrease VLDL synthesis rates oraccelerate VLDL removal in hyperlipidemic individuals as hasbeen observed by other dietary interventions that lower plasmatriglycerides [41,42]. Although other studies have shown a lackof effect of oat bran in decreasing plasma cholesterol [11,12],several reports [4,13,14], including our present study haveshown that this source of soluble fiber is effective in loweringplasma cholesterol.

In summary we can conclude from this study that psyllium andoat bran were equally potent in reducing plasma LDL cholesterolconcentrations and improving LDL/HDL ratio in normal subjectsand in those with lipid disorders when an effort was made toreduce the amount of dietary fat. Further, oat bran had an addi-tional beneficial effect in hypercholesterolemic individuals byreducing plasma triglycerides. This study is relevant to the indi-viduals living in the Northern region in Mexico characterized byhaving the highest plasma cholesterol levels compared to the restof the country [26] in addition to elevated plasma triglycerides andlow HDL levels. Inclusion of a source of dietary soluble fibersupplement in addition to controlling fat intake appears to be quiteeffective for this population.

REFERENCES

1. Jenkins DJA, Spadofora PJ, Jenkins SL: Effect of dietary fiber onplasma lipoproteins. In Spiller GA: “Handbook of Lipids in HumanNutrition.” De. Boca Raton: CRC Press Inc., pp 173–198, 1996.

2. Anderson JW: Dietary fiber, lipids and atherosclerosis. Am JCardiol 60:17G–22G, 1987.

3. Anderson JW, Riddell-Mason S, Gustafson NJ, Smith SF, MackeyM: Cholesterol-lowering effects of psyllium-enriched cereal as anadjunct to a prudent diet in the treatment of mild to moderatehypercholesterolemia. Am J Clin Nutr 56:93–98, 1992.

4. Anderson JW, Spencer DB, Hamilton CC, Smith SF, Tietyen J,Bryant CA, Oeltgen P: Oat-bran cereal lowers serum total andLDL cholesterol in hypercholesterolemic men. Am J Clin Nutr52:495–499, 1992.

5. Sprecher DL, Harris BV, Goldberg AC, Anderson EC, Bayuk LM,Russell BS, Crone DS, Quinn C, Bateman J, Kuzmak BR, AllfoodLD: Efficacy of psyllium in reducing serum cholesterol levels inhypercholesterolemic patients on high- or low-fat diets. Ann InterMed 7:545–554, 1993.

6. Hunninghake DB, Miller VT, LaRosa JC, Kinosian B, Brown V,Howard WJ, SiDerio FJ, O’Connor RR: Hypocholesterolemic effectsof a dietary fiber supplement. Am J Clin Nutr 59:1050–1054, 1994.

7. National Cholesterol Education Program Expert Panel on Detec-tion, Evaluation, and Treatment of High Blood Cholesterol in

Psyllium, Oat Bran and Hypercholesterolemia in Mexico

JOURNAL OF THE AMERICAN COLLEGE OF NUTRITION 607

Dow

nloa

ded

by [

INA

SP -

Pak

ista

n (P

ER

I)]

at 0

1:06

19

Nov

embe

r 20

14

Adults: Report of the National Cholesterol Education ProgramExpert Panel on detection, evaluation and treatment of high bloodcholesterol in adults. Arch Intern Med 148:36–69, 1993.

8. Davidson MH, Dugan LD, Burns JH, Sugimoto D, Story K,Drennan K: A psyllium-enriched cereal for the treatment of hy-percholesterolemia in children: a controlled double-blind, cross-over study. Am J Clin Nutr 63:96–102, 1996.

9. Everson GT, Daggy BP, McKinley C, Story J: Effects of psylliumhydrophilic mucilloid on LDL-cholesterol and bile acid synthesisin hypercholesterolemic men. J Lipid Res 23:1183–92, 1992.

10. Bell LP, Hectome K, Reynolds H, Balm TK, Hunninghake DB:Cholesterol-lowering effects of psyllium hydrophilic mucilloid.Adjunct therapy to a prudent diet for patients with mild to mod-erate hypercholesterolemia. J Am Med Soc 261:3419–3423, 1989.

11. Leadbetter J, Bull MJ, Mann JI: Effects of increasing quantities ofoat bran in hypercholesterolemic people. Am J Clin Nutr 54:841–845, 1991.

12. Uusitupa MIJ, Ruuskanen E, Makinen E, Laitinen J, Toskala E,Kervinen K, Kesainiemi YA: A controlled study of the effect ofbeta-glucan-rich oat bran on serum lipids in hypercholesterolemicsubjects: Relation to apolipoprotein E phenotype. J Am Coll Nutr11:651–659, 1992.

13. Lia A, Hallmans G, Sandberg AS, Sundberg B, Aman P, Anders-son H: Oatb-glutan increases bile acid excretion and a fiber-richbarley fraction increases cholesterol excretion in ileostomy sub-jects. Am J Clin Nutr 62:1245–1251, 1995.

14. Ripsin CM, Keenan JM, Jacobs DR: Oat products and lipid low-ering: a meta analysis. JAMA 267:3317–3325, 1992.

15. Fernandez ML, Ruiz LR, Conde KA, Sun D-M, Erickson SK, Mc-Namara DJ: Psyllium reduces plasma LDL in guinea pigs by alteringhepatic cholesterol homeostasis. J Lipid Res 36:1128–1138, 1995.

16. Fernandez ML, Vergara-Jimenez M, Romero AL, Erickson SK,McNamara DJ: Gender differences in response to dietary solublefiber in guinea pigs: effects of pectin, guar gum and psyllium.J Lipid Res 36:2191–2202, 1995.

17. Fernandez ML: Distinct mechanisms of plasma LDL lowering bydietary fiber in the guinea pig: specific effects of pectin, guar gum,and psyllium. J Lipid Res 36:2394–2404, 1995.

18. Fernandez ML, Vergara-Jimenez M, Conde K, Behr T, Abdel-FattahG: Regulation of apolipoprotein B-containing lipoproteins by dietarysoluble fiber in guinea pigs. Am J Clin Nutr 65:814–822, 1997.

19. Horton JD, Cuthbert JA, Spady DK: Regulation of hepatic 7a-hydroxylase expression by dietary psyllium in the hamster. J ClinInvest 93:2084–2092, 1994.

20. Turley SC, Daggy B, Dietschy JM: Psyllium augments the cholesterollowering action of cholestyramine in hamsters by enhancing sterolloss from the liver. Gastroenterology 1107:444–452, 1994.

21. Turley SD, Dietschy JM: Mechanisms of LDL-cholesterol lower-ing action of psyllium hydrophillic mucilloid in the hamster. Bio-chim Biophys Acta 1255:177–184, 1995.

22. McCall MR, Mehta T, Leathers CW, Foster DM: Psyllium husk II:effect on the metabolism of apolipoprotein B in African greenmonkeys. Am J Clin Nutr 56:385–393, 1992.

23. Shinnick FL, Ink SL, Marlett JA: Dose response to a dietary oatbran fraction in cholesterol-fed rats. J Nutr 12:561–568, 1990.

24. Chen Lin WJ, Anderson JW, Jennings D: Propionate may mediatethe hypocholesterolemic effects of certain soluble plant fibers incholesterol-fed rats. Proc Soc Exp Biol Med 175:215–218, 1984.

25. Wyatt CJ, Mendez RO, Triana MA, Melendez JM: Protein, energy,

fat, and mineral composition of diets for low-income adults in

Sonora, Mexico. Am Chem Soc 43; 1995.

26. Posadas-Romero C, Tapia-Conyer R, Lerman-Garber I: Choles-

terol levels and prevalence of hypercholesterolemia in a Mexican

adult population. Atherosclerosis 118:275–284, 1995.

27. Finney KF, Morris VH, Yamazaki WT: Micro versus macro cook-

ies baking procedures for evaluating the cookie quality of wheat

varieties. Cereal Chem 27:42–44, 1950.

28. Allain CC, Poon LS, Richmond W, Fu PC: Enzymatic determina-

tion of total serum cholesterol. Clin Chem 20:470–475, 1974.

29. Warnick RS, Teng LE: Analytical Procedures for measurement of

the lipid and lipoproteins in cardiovascular risk assessment. In

Spiller GA: “Handbook of Lipids in Human Nutrition.” De. Boca

Raton: CRC Press, Inc, pp 21–35, 1996.

30. Friedewald WT, Levy RI, Fredrickson DS: Estimation of the concen-

tration of low-density lipoprotein cholesterol in plasma, without use of

the preparative ultracentrifuge. Clin Chem 18:499–502, 1978.

31. Carr T, Andressen CJ, Rudel LL: Enzymatic determination of

triglyceride, free cholesterol and total cholesterol in tissue lipid

extracts. Clin Biochem 26:39–42, 1993.

32. Mayer EJ, Newman B, Quesenberry CP, Friedman GD, Selby JV:

Alcohol consumption and insulin concentrations. Role of insulin in

associations of alcohol intake with high-density lipoprotein cho-

lesterol and triglycerides. Circulation 88:2190–2197, 1993.

33. Sillanaukee P, Koivula T, Jokela H, Myllyharju H, Seppa K:

Relationship of alcohol consumption to changes in HDL-

subfractions. Eur J Clin Invest 23:486–491, 1993.

34. Sabesin MY: Lipid and lipoprotein abnormalities in alcoholic liver

disease. Circulation 64 (suppl III):72–84, 1981.

35. Rossouw JE, Lai-Tung M-T, Jooste PL, Weight MJ, Benade AJS:

Alcohol intake in relation to lipids, lipoproteins and blood pres-

sure. S Afr Med J 82:246–250, 1992.

36. Howell WH, McNamara DJ, Tosca MA, Smith BT, Gaines JA:

Plasma lipid and lipoprotein responses to dietary fat and choles-

terol: a meta-analysis. Am J Clin Nutr 65:1747–1764, 1997.

37. Schaefer DJ, Lmon-Fava S, Ausma LM, Ordovas JM, Clevidence

BA, Judd JT, Goldin BR, Woods M, Gorbach S, Lichtenstein AH:

Individual variability in lipoprotein cholesterol in response to

dietary cholesterol. National Education Program Step 2 Diets.

Am J Clin Nutr 65:823–830, 1997.

38. Sprecher DL, Hariis BV, Goldberg AC et al: Efficacy of psyllium

in reducing serum cholesterol levels in hypercholesterolemic pa-

tients on high- or low-fat diets. Ann Intern Med 7:545–554, 1993.

39. Miettinen TA, Tarpila S: Serum lipids and cholesterol metabolism

during guar gum, plantago ovata en high fibre treatments. Clin

Chim Acta 183:253–262, 1989.

40. Anderson JW, Gustafson NJ: Hypocholesterolemic effects of oat

and bean products. Am J Clin Nutr 48:749–753, 1988.

41. Ginsberg HN, Le N-A, Melish J: Effect of a high carbohydrate diet on

apoprotein B catabolism in man. Metabolism 30:347–354, 1980.

42. McNamara DJ: Dietary fatty acids, lipoproteins and cardiovascular

disease. Adv Food Nutr Res 36:253–351, 1992.

Received January 1998; revision accepted May 1998.

Psyllium, Oat Bran and Hypercholesterolemia in Mexico

608 VOL. 17, NO. 6

Dow

nloa

ded

by [

INA

SP -

Pak

ista

n (P

ER

I)]

at 0

1:06

19

Nov

embe

r 20

14