CLINICAL
STUDIES
The therapeutic use of high and mega-dose Vitamin C to reduce atherosclerosis
is validated in many well-conducted clinical trials.
1.
Vitamin C Intake Neutralizes A High Fat Meal.
In a study conducted by Dr. Plotnick, University of Maryland School of Medicine,
20 healthy men and women were fed on one of the three breakfasts: -
(1) A high-fat meal consisting of an Egg McMuffin, Sausage McMuffin, and two
hash brown patties.
(2) A high-fat breakfast after the subjects were given 1,000 mg of Vitamin C
and 800 IU of vitamin E.
(3) A low-fat breakfast of cereal, skim milk, and orange juice.
In this study, Dr Plotnick discovered that a
single high-fat meal increased blood triglyceride levels by more than 60 percent
and decreased endothelial function by two to four hours. The decrease
in endothelial function also correlated with an increase in triglyceride levels,
but not with fasting triglyceride levels. The researchers were also pleased
to note that taking Vitamins C and E just
before the high-fat meal helped to maintain normal endothelial functions.
Surprisingly, the effects of the vitamin
were the same as eating the low-fat meal, which produced no increase in triglycerides
or decrease in endothelial function.
2.
Vitamin C Helps to Normalize Blood Flow
rabbits were given
supplemental Vitamin C, their blood flow returned to normal.
3.
Vitamin C Protects Vascular Wall
Vitamin
C is very effective for patients with congestive heart failure (CHF). It prevents
endothelial cell apoptosis.
In a series of experiments, Dr. Stefanie Dimmeler, University of Frankfurt
first showed that tumor necrosis factor-alpha (TNF-alpha) increased apoptosis
in cultured endothelial cells by 3 times. However, when Vitamin C was added
to the cultures, this apoptosis was remarkably decreased. Similar results
were also seen in cells treated with angiotensin II.
Researchers explained then Vitamin C interfered with apoptosis signaling by
inhibiting the ability of TNF-alpha to induce cytochrome C released from the
mitochondria. This suppressed the activation of caspase-9.
In an investigation, 34 patients were given Vitamin C or placebo. At first,
they were given 2.5 g of Vitamin C or sodium chloride 0.9% intravenously for
10 minutes. This was followed by 2 g of Vitamin C or placebo given orally
twice a day for a period of 3 days.
The results reported that after taking Vitamin C, plasma levels of circulating
apoptotic microparticles were reduced to 32% of baseline levels. Patients
treated with placebo were reduced by an insignificant amount to 87% of baseline
levels.
When cultured endothelial cells were exposed to the patient's serum, apoptosis
was significantly reduced from the patients treated with Vitamin C compared
with the subjects treated with placebo.
The researchers also noted that Vitamin C did not affect serum concentrations
of TNF-alpha or other circulating cytokines. As such, the altered serum levels
of circulating cytokines do not contribute to the protective effects of Vitamin
C on endothelial cell apoptosis in CHF patients.
4.
Vitamin C Helps to Neutralize Cigarette Smoke
Cigarette smoking causes endothelial dysfunction.
A study using 20 smokers and non-smokers was conducted to examine the effects
of Vitamin C and cigarette smoking on endothelium-dependent vasodilation.
The lumen diameter and the velocity flow of the brachial arteries at rest
were measured during:
1. The reactive hyperemia following transient arterial occlusion
2. After 0.3 mg of sublingal nitroglycerin with high-resolution ultrasound.
3. After infusion of saline or saline plus Vitamin C (10 mg/min for 20 min).
The same study was also performed in 15 smokers before and 10 minutes after
cigarette smoking. Their serum levels of Vitamin C and plasma levels of thiobarbituric
acid reactive substances (TBARS) as an index of lipid peroxidation were also
measured. The results showed that the smokers had lower Vitamin C levels and
higher TBARS levels. Their results also showed the impairment of flow-dependent
vasodilatation when compared with non-smokers. When Vitamin C was given,
it improved the impairment of flow -dependent vasodilatation and decreased
TBARS in smokers. However, Vitamin C administration did not have any effects
in the non-smokers. The researchers also concluded that cigarette smoking
acutely worsened the impairment of flow-dependent vasodilatation and increased
TBARS. As such, researchers conclude that:
(1) Endothelium-dependent vasodilatation in the brachial arteries was impaired
in smokers. When Vitamin C was given, there was a decrease in TBARS.
(2) Cigarette smoking produced acute impairment of endothelium-dependent vasodilatation
in smokers in association with an increase in TBARS.
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