Dr. Cade's Case Studies

EFFECT OF TWO DIETARY SOLUBLE FIBERS ON CHOLESTEROL AND TRIGLYCERIDE CONCENTRATIONS IN HUMAN PLASMA J. Robert Cade, R. Malcolm Privette, Virginia B. Zele and Melvin J. Fregly

ABSTRACT: As elevation of concentrations of serum cholesterol, particularly the LDL fraction, and of serum triglyceride has been shown to correlate with development of coronary artery atherosclerosis while reduction of these lipid moieties retards or reverses atherogenesis. It is important to find approaches which favorably alter serum lipids without undesirable side effects. We have studied two soluble fibers, which

Departments of Medicine and Physiology, College of Medicine,

can be administered in a palatable drink, to ascertain their effect on cholesterol and triglycerides in 14 men and 10 women, who were found during a four week period to have consistently elevated cholesterol and

University of Florida, Gainesville,

triglyceride concentrations. After the control period, the subjects were

FL 32610-0204

divided into three groups. One group was given a placebo (P) which contained citric acid and orange flavor and was sweetened with 1/4 g

Running Title: Dietary Fibers on

Aspertame and 5 g sucrose per 8 oz.; the second group received the

Cholesterol and Triglyceride

same drink to which 6 g Gum Arabic {GA) /8 oz was added; the third the same drink to which 4 g carboxymethylcellulose (CMC) was added.

Each subject ingested 8 oz of drink TIO ac and at bedtime for eight weeks, during which total cholesterol, HDLC, LDLC and triglycerides were measured at weekly intervals. All patients were then changed from their original test drink to one of the other drinks for eight weeks and then crossed over again to the third drink so that during the course

Send Correspondence to:

of the study all subjects received GA 24 g/day, CMC l6 g/day, and

J. Robert Cade, M.D.

placebo for eight weeks. Eight subjects then ingested the drink with

Departments of Medicine and

GA 4 g/8 oz for an additional eight weeks. There were no changes in

Physiology Box 100204, JHMHC University of Florida

TC, HDLC, LDLC, the ratio HDLC/LDLC, or triglycerides during placebo administration. During GA 6 g/8 oz TC fell 17.9% (p<0.01), LDLC 21.4% (p<0.001), HDLC increased 12.9% (p<0.06), the ratio HDLC/LDLC increased 44% (p<O. 001} while triglycerides decreased 50%. When

Gainesville, FL 32610-0204

GA 4 g/8 oz was tested TC decreased 5.6% {p<0.05), LDLC and HDLC

Tel: (904) 392-8952

did not change, nor did the ratio HDLC/LDLC. Triglycerides, however,

Fax: (904) 392-8481

decreased 42.7% (p<0.05). When CMC was given TC decreased Continued on next page

8.8% (p<0.05) and LDLC 9.7% (p<0.05), HDLC/ LDLC increased 10.4% (p<0.05) while triglycerides did not change. Our data show GA is a potentially useful agent for preventing and for treating coronary atherosclerosis.

: s d r o w y e K

Soluble Fibers, Gum Arabic, Carboxymethylcellulose, Cholesterol

Elevations in the concentrations of cholesterol (Frick, 1987; Lipid Research Clinics Program,

in hyperlipidemic patients. One of these fibers,

1984) and triglycerides (Aberg, 1985; Carlson and

Gum Arabic (GA), is a highly soluble complex acidic

Battiger, 1985) in plasma have been implicated in

heteropolysaccharide of high molecular weight

the development of atherosclerosis in humans. Both

composed of a branched array of galactose, arabinose,

experimental observations in laboratory animals

rhamnose, and gluevronic acid (Anderson, 1966). It

(Baekey, 1988) and epidemiologic studies in humans

has been used for many years in the manufacture

(Carlson, 1985) indicate that elevation of low density

of confections and soft drinks. The second fiber,

lipoprotein (LDL) cholesterol hastens, while high

carboxymethylcellulose (CMC), is synthetically

density lipoprotein (HDL) cholesterol either retards

derived. It has been used as a suspending aid for some

or reverses atherogenesis.

insoluble pharmaceutical compounds.

Ingestion of several soluble fibers in the diet has

The objective of the present studies was to determine

been shown to lower LDL cholesterol (Anderson,

the effect of chronic ingestion of GA and CMC on

1984; Cerda, 1988). We, therefore, elected to study

the various cholesterol fractions and on triglyceride

the effect of two previously untested soluble fibers

concentrations in a group of patients with hypercho-

on serum cholesterol and triglyceride concentrations

lesterolemia and elevated triglyceride concentration.

SUBJECTS AND METHODS: Twenty-four subjects, 14 men and 10 women,

on an identical fluid to which 6 g GA/8 oz was added,

between the ages of 38 and 65 years who had type

and 8 were started on the same fluid to which 4 g

IIb hyperlipoproteinemia were enrolled in the study

CMC/8 oz was added. The concentration of CMC was

following, four weeks of blood testing to assure that

limited as higher concentrations caused the drink to

they, indeed, had elevated serum cholesterol and

become so viscid it was not palatable. All subjects

triglyceride concentrations. The purpose of the study

were instructed to consume 8 oz of their test drink

and the methods to be used were explained to each

four times each day. After 8 weeks, those subjects on

subject and informed consent was obtained.

the placebo drink were randomly assigned to either GA or CMC while those who had been ingesting one

After base-line information was obtained over a

of the fiber drinks were followed for 4 additional

4 to 6 week period, 8 subjects were started on an

weeks before being reassigned to either placebo or

orange flavored placebo drink sweetened with 1/4 g

the other fiber drink. The same procedure was again

Aspartame and 5 g sucrose per 8 oz; 8 were started

followed after the l6th week so that over the course Continued on next page

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of the study each subject had 3 four week control

count, measurement of total cholesterol, HDL and

periods and was exposed to each drink for 8 weeks.

triglycerides (using Sigma Diagnostic Kits No. 351

After the 24th week of treatment 8 subjects agreed to

& 356), VLDLC was calculated by VLDLC = TG x .2

extend the study 8 weeks by taking the drink to which

and LDLC = TG - {VLDLC•HDLC); Glucose, alkaline

4 g GA/8 oz had been added.

phosphatase, SGOT, SGPT, total and direct bilirubin, and creatinekinase and lactic dehydrogenase which

Subjects were instructed not to alter their diet in

were measured by previously reported methods

any way throughout the study and body weight was

(Cade, 1992). A physical exam was done at each visit

measured weekly to monitor, as well as possible,

and an EKG was obtained at the first visit and at the

adherence to this request.

end of each 8 week experimental period.

Blood was obtained, in the fasting state, at

Results were evaluated statistically by analysis of

weekly intervals during the study. The following

covariance for multiple observations (Winer, 1971).

determinations were made: a complete blood

RESULTS: Figure 1 shows the total cholesterol,

Fig. 1

HDL cholesterol, LDL cholesterol and

Mean weekly total cholesterol, LDL cholesterol, HDL cholesterol and ratio HDL:LDL cholesterol during a 4 week control period and during an 8 week period of placebo ingestion.

lhe ratio HDL/LDL cholesterol during

PLACEBO

the control period preceding and during the 8 weeks of placebo ingestion.

HDL

Total Cholesterol

Mean total cholesterol during the control

8.0

1.6

HDL concentration was 1.51 mmol • l-1 during the control period and did not

m mol • l -1

change with placebo ingestion. The

m mol • l -1

period was 7. 2 mmol • l-1 and did not

change with treatment; likewise, the

1.0

6.5

LDL cholesterol which was 4.4 mmol

-4 -2 0 2 4 6 8

-4 -2 0 2 4 6 8

• l and the HDL/LDL ratio which was

Weeks

.317 during the control period did not

LDL

-1

change significantly during placebo

Weeks

HDL/LDL

5.2

1.0 m mol • l -1

m mol • l -1

consumption.

4.7

4.2

-4 -2 0 2 4 6 8

Continued on next page

1.3

Weeks

0.8 0.6 0.4 0.2 0.0

-4 -2 0 2 4 6 8 Weeks 3

Fig. 2

Total Cholesterol

HDL

7.0

1.6 m mol • l -1

Figure 2 shows the same information

GUM ARABIC (16g / day)

m mol • l -1

Mean weekly values for total cholesterol, its LDL and HDL fractions and the HDL:LDL ratio during a 4 week control period and an 8 week experimental period during which 16g Gum Arabic was ingested each day.

6.5

5.2

during the trial in which 24 g GA/day was

1.0

-4 -2 0 2 4 6 8

ingested. Mean total cholesterol during

1.3

-4 -2 0 2 4 6 8

Weeks

Weeks

the control period was 7. 97 mmol • l

-1

LDL

and fell progressively during the trial to

HDL cholesterol increased from 1. 4 to 1.

58 mmol • l-1 (p<O. 06) , LDL cholesterol

m mol • l -1

During ingestion of 24 g GA each day,

1.0

m mol • l -1

6. 55 mmol • l-1. This decrease of 17. 6% was statistically significant with a p<0.01.

HDL/LDL

4.2

3.6

decreased from 5. 3 5 to 4. 21 mmol • l (p<O. 04), and the ratio HDL/LDL

0.6 0.4 0.2 0.0

-4 -2 0 2 4 6 8

-1

0.8

-4 -2 0 2 4 6 8

Weeks

Weeks

increased from .262 to .379 (p<0.001).

Fig. 3

GUM ARABIC (24g / day) Total Cholesterol

HDL

1.7 m mol • l -1

8.0 m mol • l -1

Mean weekly, values for total cholesterol, its LDL and HDL fractions and the HDL:LDL ratio during a 4 week control period and an 8 week experimental period during which 24g Gum Arabic was ingested each day.

7.5 7.0 6.5 6.0

-4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9

Weeks

1.6 1.5 1.4 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9

Weeks

Figure 3 shows the data obtained during ingestion of 16 g GA/day. Total

6.5

LDL

0.6

HDL/LDL

mmol • l-1 (p<0.05); HDL cholesterol increased from 1. 27 to 1. 4 mmol • l-1 (p<O.08); LDL cholesterol did not change significantly while the ratio HDL/LDL increased from .337 to .360 (p<0.06).

m mol • l -1

cholesterol fell from 6.86 to 6.49 0.4 5.2 0.2 4.0

-4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9

Weeks

0.0

-4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9

Weeks

Continued on next page

4

Fig. 4

Mean body weight decreased slightly more than 0.5 kg during the 8 weeks of treatment with 24 g GA/day and did not change in the other 3 treatment regimens. There were no changes in EKG throughout the study; likewise, liver function studies, muscle enzymes, glomerular filtration rate, urinalysis, and hematologic parameters did not change.

HDL

m mol • l -1

m mol • l -1

1.6

7.8

6.5

1.3

1.0

-4 -2 0 2 4 6 8

-4 -2 0 2 4 6 8

Weeks

Weeks

LDL

HDL/LDL

6.5

1.0 m mol • l -1

Figure 5 shows the changes in serum triglyceride concentration which occurred during both control and treatment periods with the four test fluids. There were no significant differences in triglyceride concentration comparing control to treatment periods in either the CMC or placebo ingestion trials. When GA was the test substance, however, a significant decrease occurred when both the 16 and 24 g/day doses were administered.

The decline during treatment with 24 g/day (from 2.67 to 1.28 mmol • l-1) was statistically significant (p<O. 001).

During treatment with 16 g/day, the decline from 3.91 to 2.74 mmol • l-1 was also statistically significant (p<0.05).

Total Cholesterol 9.0

m mol • l -1

Figure 4 shows the values obtained during CMC trials. Total cholesterol declined from 7. 64 to 6. 96 mmol • l-1; this 8Wmol • l-1 (p<0.05): while the HDL increased from 1.34 to 1.48 mmol • l-1 (p<0.07). The ratio HDL to LDL increased from .269 to .297 (p<O. 05).

CARBOXMETHYLCELLULOSE (16g / day)

5.2

4.0

-4 -2 0 2 4 6 8

0.8 0.6 0.4 0.2 0.0

-4 -2 0 2 4 6 8 Weeks

Weeks

Fig. 5

Mean weekly values for serum triglycerides during a 4 week control period and an 8 week experimental period during which either a placebo, Gum Arabic 16g (o) or 24g/day, or CMC 16g/day was ingested.

SERUM TRIGLYCERIDE CHANGES DURING SOLUBLE FIBER ADMINISTRATION Placebo Gum Arabic (16g / day) Gum Arabic (24g / day) Carboxymethyicellulose (16g / day)

4.6

m mol • l -1

Mean weekly values for total cholesterol, its LDL and HDL fractions and the HDL:LDL ratio during a control and an experimental period during which 16g carboxymethylcellulose was ingested each day.

3.6 2.6 1.6 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9

Weeks

Continued on next page

5

Almost all subjects noted increased flatulance and increase in bulk and frequency of stools during both GA and CMC ingestion. One subject had frequent abdominal cramping during ingestion of 24 g GA/ day but did not have to discontinue therapy.

DISCUSSION: Elevation of the concentrations of cholesterol and

is surprising as a metabolic effect in the internal

triglyceride in serum has been shown to be of

milieu would be required for such a result and it

importance in the genesis of atherosclerotic vascular

has not been shown that GA is absorbed from the

disease (Aberg, 1985; Baekey, 1988; Carlson, 1985;

intestine.

Frick, 1987; LRCP, 1984). Hence, the search for agents which will lower the concentration of these

The marked effect of both doses ot GA on

substances in plasma is of therapeutic importance.

triglyceride concentration is consistent with binding

Useful agents must be, first, easy to ingest, and

of triglyceride in the intestinal lumen. There was a

secondly, they must be free of untoward side effects.

mean weight loss of approximately 0.5 mg during the 8 weeks the subjects ingested 24 g GA/day.

The present studies show that both GA and CMC

While this was not statistically significant, it suggests

lowered total and LDL cholesterol significantly. In

that a longer trial may be necessary to determine

addition, HDL cholesterol increased significantly

whether the absorption of triglyceride in the small

during the ingestion of GA. The mechanism by

intestine, and its removal to the large intestine

which GA and CMC lower cholesterol is unknown.

where it undergoes bacterial degradation, is of great

Some investigators (Anderson, 1979) have assumed

enough magnitude to play a role in weight loss.

that absorption of bile acids in the intestine with excretion in the stool is the biologic mechanism

It should be noted that the 18% decrease in total

by which soluble fibers lower cholesterol. Ross,

cholesterol during high dose GA trials, the 5.3%

(1983), however, found that neutral sterols and bile

during low dose, and the 5.9% decrease with CMC

acids in the stool of humans did not increase when

occurred with no dietary change in ingestion of

GA was given. Thus, although pectin (Ross, 1983)

either fat or calories. If a low fat diet were combined

and bean and oat diets (Anderson, 1984) which

with fiber ingestion, it is possible that a greater

increase bile acids and neutral sterol excretion may

reduction in both the concentrations of cholesterol

lower cholesterol through this mechanism, it seems

and triglyceride would have occurred and that much

apparent that the hypocholesterolemic effect of GA

greater weight loss with its salubrious effect on

must be accomplished through some other pathway.

plasma concentration of cholesterol and triglyceride

The rise in HDL cholesterol during GA consumption

may also result.

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REFERENCES: Aberg, H., Lithell, I., and Hedstrand, H. 1985. Serum triglycerides are a risk factor for myocardial infarction but not for anginapectoris: results from a 10 year follow-up of Uppsala Primary Prevention Study.

Atherosclerosis 54:89-97.

Anderson, D.M.W., Hirst, E., and Stocidard, J.F. 1966. Some structural features of acacia senegal (gum arabic).

J. Chem. Soc. (Sect. C), 1959-1966.

Anderson, J.W., and Chen, W.J.L. 1979. Plant fiber: carbohydrate and lipid metabolism. Am. J. Clin. Nutr. 32: 346-363.

Anderson, J.W., Story, L., Sieling, B., Chen, W.J.L., Petro, M.S., and Story, J. 1984. Hypocholesterolemic effects of oat-bran or bean intake for hypercholesterolemic men. Am. J. Clin. Nutr. 40: 1146-1155.

Baekey, P.A., Cerda J.J., Burgin, C.W., Robbins, F.L., Rice, R.W., and Baumgartner, T.G. 1988. Grapefruit pectin inhibits hypercholesterolemia and atherosclerosis in miniature swine. Clin. Card. 11:595-600.

Cade, R., Packer, D., Zauner, c., Kaufmann, O., Peterson, J., Mars, D., Privette, M., Hommen, N., Fregly, M.J., and Rogers, J. 1992. Marathon Running: Physiologic and chemical changes accompanying late-race functional deterioration. Eur. J. Appl. Physiol. 65:485-491.

Carlson, L.A., and Battiger, L.E. 1985. Risk factors for ischemic heart disease in men and women; results of the 19th year follow-up of the Stockholm Prospective study. Acta Med. Scand. 218:207-211.

Cerda, J.J., Robbins, F.L., Burgin, c.w., Baumgartner, T.G., and Rice, R.W. 1988. The effects of grapefruit pectin on patients at risk for coronary heart disease without altering diet on life style.. Clin. Card. 11: 589-594.

Eurard, E., and Janssen, G. 1968. Gas-liquid chromatographic determination of human fecal bile acids. J. Lipid Res. 9: 226-236.

Frick, M.H., Elo, O., Haapa, K., Heinonen, O.P., Heinsalmi, P., Helo, P., Hultunen, J.K., Kaitaniemi, P., Koskinen, P., Manvinen, v. , Maenpaa, H., Malkonen, M., Manttari, M., Norola, s., Pasternack, A., Pikkarainen, J., Ramo, M., Sjoblom, T., and Nikkila, E.A. 1987. Helsinki Heart Study: Primary-Prevention Trial with Gemfibrozil in Middle-Aged Men with Dyslipemia. NEJM 317: 1237-1245.

Lipid Research Clinics Program: 1984. The lipid research clinics coronary primary prevention trial results.

JAMA 251: 351-364. Ross, A.H.M., Eastwood,¡ M.A., Brydon, W.G., Anderson, J .R., and Anderson, D.M.W. 1983. A study on the effects of dietary gum arabic humans. Am. J. Clin. Nutr. 37: 368-375.

Winer, B. J. 1971. Statistical principles in experimental design. McGraw-Hill, New York, pp. 514-608.

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