"Plant-derived alpha-LA for 4 weeks"
Anyone care to venture a guess as to WHY these two studies are
sooooo .. different .. in their results?
"Polyunsaturated fatty acid diet improves antioxidant status"
"Polyunsaturated fatty acids resulting in a higher peroxidation"
J Nutr. 2001 Jan;131(1):39-45. Links
A polyunsaturated fatty acid diet lowers blood pressure and improves
antioxidant status in spontaneously hypertensive rats.
Frenoux JM, Prost ED, Belleville JL, Prost JL.
UPRES, Lipids and Nutrition 2422, Nutrition Cellulaire et Métabolique,
Université de Bourgogne, 21078 Dijon Cedex, France.
Gamma-Linolenic acid [GLA, 18:3(n-6)], eicosapentaenoic acid [EPA,
20:5(n-3)] and docosahexaenoic acid [DHA, 22:6(n-3)] have been
reported to prevent cardiovascular diseases.
However, they are highly unsaturated and therefore more sensitive to
oxidation damage.
We investigated the effects of a diet rich in these polyunsaturated
fatty acids (PUFA) on blood pressure, plasma and lipoprotein lipid
concentrations, total antioxidant status, lipid peroxidation and
platelet function in spontaneously hypertensive rats (SHR) and
normotensive Wistar Kyoto rats (WKY).
Five-week-old SHR and WKY rats were fed for 10 wk either a diet
containing Isio 4 oil or a diet rich in GLA, EPA and DHA (5.65, 6.39
and 4.94 g/kg dry diet, respectively).
The total antioxidant status was assayed by monitoring the rate of
free radical-induced hemolysis.
VLDL-LDL sensitivity to copper-induced lipid peroxidation was
determined as the production of thiobarbituric acid reactive
substances.
After dietary PUFA supplementation, a significant decrease in blood
pressure of SHR rats (-20 mm Hg) was observed and the total
antioxidant status was enhanced.
VLDL-LDL resistance to copper-induced peroxidation was increased in
both strains.
The PUFA supplementation did not change platelet maximum aggregation
in SHR rats, but it decreased the aggregation speed. In hypertensive
rats, GLA + EPA + DHA supplementation lowers blood pressure, enhances
total anti-oxidant status and resistance to lipid peroxidation,
diminishes platelet aggregation speed and lowers plasma lipid
concentrations.
Thus, it enhances protection against cardiovascular diseases.
Therefore, nutritional recommendations for cardiovascular disease
prevention should take into account the pharmacologic properties of
GLA, EPA and DHA.
PMID: 11208936 [PubMed - indexed for MEDLINE]
--------------------------
Prostaglandins Leukot Essent Fatty Acids. 1997 Dec;57(6):545-50.Links
Influence of long-term supplementation with alpha-linolenic acid on
myocardial lipid peroxidation and antioxidative capacity in
spontaneously hypertensive rats.
Schimke I, Haberland A, Wirth M, Papies B, Moritz V, Baumann G.
Medizinische Klinik und Poliklinik 1, Universitätsklinikum Charité,
Humboldt-Universität zu Berlin, Germany.
The ischaemic vulnerability of the heart of spontaneously hypertensive
rats (SHR) is enhanced after feeding an alpha-linolenic acid (LNA)
enriched diet.
Because oxygen radical-induced reactions (e.g. lipid peroxidation) are
involved in the ischaemic damage, an increased susceptibility of the
SHR heart to such damaging reactions might be the reason. As a sign of
the enhanced susceptibility to lipid peroxidation of LNA-fed SHR, we
found (measured as TBARS) higher plasma and heart lipid peroxide
levels (3.84 +/- 0.50 micromol/l vs 2.98 +/- 0.78 micromol/l and 507
+/- 127 nmol/g prot. vs 215 +/- 80 nmol/g prot., respectively) after
feeding LNA.
Using Fe2+/Vit. C to induce lipid peroxidation in myocardial tissue
homogenates, we demonstrated the enhanced susceptibility to lipid
peroxidation of the LNA-fed SHR heart (68 +/- 12 nmol/min x g prot. vs
40 +/- 8 nmol/min x g prot.) also in vitro.
The myocardial enrichment of n-3 polyunsaturated fatty acids (PUFA)
resulting in a higher peroxidation index (PI 227 vs. 170) and the loss
in myocardial activities of the antioxidative enzymes (SOD: 76 +/- 24
U x 10(3)/g prot. vs 235 +/- 150 U x 10(3)/g prot.; GSH-Px: 32 +/- 5 U/
g prot. vs 110 +/- 30 U/g prot.) by feeding LNA could be the cause of
the increase in myocardial susceptibility to lipid peroxidation of
PUFA supplemented SHR.
PMID: 9431820 [PubMed - indexed for MEDLINE]
-------------------------------
"Plant-derived alpha-LA for 4 weeks have cardioprotective effects"
Fiziol Zh. 2006;52(5):12-20.Links
[The effects of alpha-linolenic acid on the functioning of the
isolated heart during acute myocardial ischemia/reperfusion][Article
in Ukrainian]
Kukoba TV, Shysh AM, Moĭbenko OO, Kotsiuruba AV, Kharchenko OV.
Many studies indicate that dietary omega-3 polyunsaturated fatty acids
(PUFAs) have the cardioprotective properties.
But majority of experiments were carried out with using omega-3 PUFAs
from marine fish oil.
The purpose of this study was to determine effects of the plant-
derived omega-3 PUFA (alpha-linolenic acid (a-LA) on postischemic
myocardial dysfunction, lipid peroxidation and antioxidant enzymes
activity.
Male Wistar rats (250-300 g) were divided into 4 groups (n = 10-12
each). In control group (1) were intact rats.
The hearts from 2-nd group of animal were exposed to 20 min of global
ischemia followed by 40 min reperfusion according to the Langendorff
technique.
The 3-rd and 4-th groups of animal received of the plant-derived oil
(a-LA), which is a precursor of eicosapentaenoic acid and was used as
a dietary supplement in dose 0.1 mg/kg per day for 4 weeks.
The hearts from 4-th group of animal were also exposed to ischemia/
reperfusion.
Analysis of myocardial phospholipid fatty acid content showed that
consumption of the plant-derived 6-LA for 4 weeks changes fatty acid
profile through incorporation of b-LA in cell membranes.
It also reduced content of omega-6 PUFAs in membrane phospholipids.
In 3-rd group content of a-LA and EPA were increased by 1.5- and 3.5-
times, respectively, whereas content of AA was reduced by 1.7-times.
The development of ischemia/ reperfusion in 2-nd group caused increase
of free AA content in heart tissue by 3.5-times, whereas in 4-th group
this increase was only by 1.4-time. Ischemia/reperfusion of the
isolated rat heart in 4-th group was accompanied by reduced
leukotriene C4 and thromboxane B2 production in 3-times and 1.9-times,
respectively in comparison to 2-nd group.
The time of myocardial function recovery after ischemia (heart rate,
left ventricular development pressure), was shorter compare to 2-nd
group.
Also in 4th group end-diastolic pressure and coronary perfusion
pressure during reperfusion period were significantly lower.
Dietary omega-3 PUFAs resulted in remarkable decrease of reperfusion
arrhythmias in 4-th group (in 3.8-times) and limited the oxidative
stress through decrease free radical and lipid peroxidation
production.
In this group of animals the activity of antioxidant enzymes
(superoxide dismutase and catalase) after ischemia/reperfusion were
higher than in 2-nd group.
We suggest that dietary supplement of the plant-derived alpha-LA for 4
weeks have cardioprotective effects similar to the effects of fish
oil.
PMID: 17176834 [PubMed - indexed for MEDLINE]
Who loves ya.
Tom
Jesus Was A Vegetarian!
http://tinyurl.com/2r2nkh
Man Is A Herbivore!
http://tinyurl.com/4rq595
DEAD PEOPLE WALKING
http://tinyurl.com/zk9fk
