Oat Products and Lipid Lowering - A Meta-Analysis.

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Oat Products and Lipid Lowering - A Meta-Analysis.

JoAnn Guest

May 17, 2006 18:13 PDT

 

 

 

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Oats, via their high fiber content, are already known to help remove

cholesterol from the digestive system that would otherwise end up in

the bloodstream.

Now, the latest research suggests they may have another

cardio-protective mechanism.

 

Antioxidant compounds unique to oats, called avenanthramides,

help prevent free radicals from damaging LDL cholesterol,

thus reducing the risk of cardiovascular disease,

suggests a study conducted at Tufts University and published in the

June 2004 issue of " The Journal of Nutrition " .

 

In this study, hamsters were fed saline containing 0.25 grams of

phenol-rich oat bran, after which blood samples were taken at

intervals from 20 to 120 minutes.

 

After 40 minutes, blood concentrations of avenanthramides had

peaked,

showing these compounds were bioavailable (able to be absorbed).

 

Next, the researchers tested the antioxidant ability of

avenanthramides

to protect LDL cholesterol against oxidation (free radical damage)

induced by copper.

 

Not only did the avenanthramides increase the amount of time before

LDL

became oxidized, but when vitamin C was added, the oat phenols

interacted synergistically with the vitamin, extending the time

during

which LDL was protected from 137 to 216 minutes.

 

In another study also conducted at Tufts and published in the July

2004

issue of Atherosclerosis,

researchers exposed human arterial wall cells to " purified

avenenthramides " from oats for 24 hours,

and found that these oat " phenols " significantly suppressed the

production of several types of molecules involved in the attachment

of

monocytes (immune cells in the bloodstream) to the arterial wall—

 

the *first step* in the " development " of atherosclerosis.

 

Oat avenanthamides suppressed production of ICAM-1

(intracellular adhesion molecule-1)

and VCAM-1 (vascular adhesion molecule-1),

E-selectin,

and the secretion of pro-inflammatory cytokines KL-6,

chemokines IL-8 and

protein MCP-1 (monocyte chemoattractant protein).

 

If you prefer some other whole grain for your breakfast cereal, top

it with a heaping spoonful of organic oat bran.(August 1, 2004)

 

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Historical and traditional use:

 

Oats are used to treat high cholesterol as well as high

triglycerides. It also is believed beneficial for patients with

insomnia and for anxiety.

 

It is beneficial as a mild diuretic.

 

Active constituents: Oats contain a number of alkaloids that have a

relaxing action. Included are a number of saponins which are

beneficial as anti -irritants.

Oats are rich in iron, manganese, and zinc.

 

www.alt-med.org

 

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Oat Bran Stimulates Bile Acid Synthesis Within 8 h as Measured by 7á-

hydroxy-4-cholesten-3-one.

 

 

Author:

 

Andersson M, Ellegard L, Andersson H.

 

Source:

 

Am J Clin Nutr. 2002;76(5):1111-1116.

 

Abstract:

http://www.enzy.com/abstracts/display.asp?id=4064

 

BACKGROUND: Oat bran contains soluble fibers, such as beta-glucan,

that increase bile acid excretion and thus decrease serum

cholesterol. Bile acid synthesis correlates with serum

concentrations of the metabolite 7á-hydroxy-4-cholesten-3-one (á-HC).

OBJECTIVE: The objective was to investigate whether consumption of â-

glucan from oat bran increases bile acid synthesis, as measured by

the serum á-HC concentration, within hours after consumption in

response to the loss of bile acids from the liver.

 

DESIGN: In a randomized, single-blind, wheat bran-controlled study

with crossover design, 8 subjects were served a controlled diet

during 2 periods of 3 d each, with an 11-d washout between the

periods. Breakfast included either 75 g extruded oat bran, of which

11 g was â-glucan, or 75 g wheat bran, of which 1 g was â-glucan. á-

HC was measured by HPLC on each day at 0, 12, and 24 h after

breakfast and also at 8 h after breakfast on the first day.

 

RESULTS: After 8 and 12 h of the oat bran diet period, the serum á-

HC concentration was 84% (P = 0.012) and 92% (P = 0.017) higher,

respectively, than that before breakfast. Serum concentrations

returned to the baseline value after 24 h. Wheat bran did not

influence serum á-HC concentrations.

 

CONCLUSIONS: Consumption of â-glucan from oat bran nearly doubled

the serum alpha-HC concentration within 8 h, indicating increased

bile acid synthesis. á-HC in serum could be used as a marker of

increased bile acid excretion induced by the diet.

 

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Oat â-Glucan Increases Bile Acid Excretion and a Fiber-Rich Barley

Fraction Increases Cholesterol Excretion in Ileostomy Subjects.

 

Author:

 

Lia A, Hallmans G, Sandberg AS, Sundberg B, Aman P, Andersson H.

 

Source:

 

Am J Clin Nutr. 1995;62(6):1245-51.

 

Abstract:

http://www.enzy.com/abstracts/display.asp?id=4066

 

The purpose of this study was to investigate whether oat beta-glucan

is responsible for the increased bile acid excretion previously

observed with oat-fiber diets. The excretion patterns in ileostomy

subjects given diets containing oat-bran bread with and without

added beta-glucanase, a â-glucan-degrading enzyme, were compared.

The effect of a â-glucan-rich barley fraction on sterol excretion

was also investigated. Nine ileostomy subjects were served four

diets in random order, each diet for 2 consecutive days. Four

different kinds of bread, mainly made from oat bran (OB diet, 12.5 g

â-glucan/d), oat bran with â-glucanase (OBE diet, 3.8 g â-glucan/d),

barley (B diet, 13.0 g â-glucan/d), or wheat flour (W diet, 1.2 g â-

glucan/d) were added to a basal diet. The 24-h excretion of bile

acids was 53% higher in the OB diet period than in the OBE diet

period (P < 0.05) and also was significantly higher than in the B

and W diet periods (P < 0.05). Median (range) bile acid excretion

was 851 (232-1550), 463 (123-1414), 755 (133-1187), and 606 (101-

980) mg/d in the OB, OBE, B, and W diet periods, respectively. The

excretion of cholesterol was significantly higher in the B diet

period than in the OBE and W diet periods (P < 0.05), but the

mechanism behind this effect of barley fiber is unknown. In oat

bran, however, â-glucan mediates an increase in bile acid excretion,

which most probably explains the effect of oat fiber in lowering

serum lipids.

 

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Oat Products and Lipid Lowering - A Meta-Analysis.

 

Author:

 

Ripsin CM, Keenan JM, Jacobs DR Jr, Elmer PJ, Welch RR, Van Horn L,

Liu K, Turnbull WH, Thye FW, Kestin M, et al.

 

Source:

 

JAMA. 1992;267(24):3317-3325.

http://www.enzy.com/abstracts/display.asp?id=3720

Abstract:

 

OBJECTIVES--To test the a priori hypothesis that consumption of oats

will lower the blood total cholesterol level and to assess modifiers

and confounders of this association.

DATA SOURCES--A computerized literature (MEDLINE) search and the

Quaker Oats Co identified published and unpublished trials as of

March 1991. Raw data were requested for all trials.

 

STUDY SELECTION--Trials were included in summary effect size

estimates if they were randomized and controlled, if a formal

assessment of diet and body weight changes occurred, and, if raw

data were not received, if there was enough information in the

published report to perform calculations.

 

DATA SYNTHESIS--Twenty trials were identified. Using the methods of

DerSimonian and Laird, a summary effect size for change in blood

total cholesterol level of -0.13 mmol/L (-5.9 mg/dL) (95% confidence

interval [CI], -0.19 to -0.017 mmol/L [-8.4 to -3.3 mg/dL]) was

calculated for the 10 trials meeting the inclusion criteria. The

summary effect size for trials using wheat control groups was -0.11

mmol/L (-4.4 mg/dL) (95% CI, -0.21 to -0.01 mmol/L [-8.3 to -0.38

mg/dL]). Calculation of Keys scores demonstrated that substituting

carbohydrates for dietary fats and cholesterol did not account for

the majority of blood cholesterol reduction. Larger reductions were

seen in trials in which subjects had initially higher blood

cholesterol levels (greater than or equal to 5.9 mmol/L [greater

than or equal to 229 mg/dL]), particularly when a dose of 3 g or

more of soluble fiber was employed.

 

CONCLUSION--This analysis supports the hypothesis that incorporating

oat products into the diet causes a reduction in blood

cholesterol levels.

 

 

 

JoAnn Guest

mrsjo-

www.geocities.com/mrsjoguest/Diets