Vitamin C and arteries

[Guest guest]

http://www.lef.org/featured-articles/may2000_vitamin_c_01.html

 

An article from May of 2000

 

 

Why conventional doctors doubt the value of vitamin C

 

The medical profession has traditionally been biased against dietary

supplements for a variety of economic and political reasons.

As mentioned earlier in this article, there are published studies

that show that vitamin C fails to confer a protective effect in

reducing cardiovascular disease risk. While the majority of studies

(31 favorable studies compared to 7 showing no response) indicate

that vitamin C supplements reduce cardiovascular disease risk

factors, it appears that the few studies showing no benefit carry

great weight in the medical profession. Conventional physicians also

tend to be unenlightened about 76 additional human studies published

since 1990 showing that vitamin C confers other health benefits such

as lowered risks of cancer and other diseases. 99-174

 

Mainstream organizations have a propensity to look at studies showing

no health benefit when vitamin C is consumed in low doses, and then

make a public announcement that insufficient evidence exists to

recommend widespread vitamin supplementation. The news media is quick

to report on studies that show that vitamin C may not protect against

cardiovascular disease, without presenting the counter view that not

enough vitamin C was consumed in the particular study to provide the

expected benefit.

 

So, despite a rather intensive amount of research that has occurred

over the past 10 years, we are still without a scientific consensus

as to whether vitamin C is protective against cardiovascular or other

diseases, ergo the continued debate over the value of vitamin C

supplementation.

 

 

 

 

Dr. Paul Wand, M.D., Neurologist

photo by: Matthew Pace

The latest controversy

 

At a meeting of the American Heart Association held on March 2, 2000,

a presentation was made of an unpublished trial indicating that those

who consumed high amounts of vitamin C supplements had increased

carotid intima-media wall thickening over an 18-month time period. 41

The doctors who made this presentation described high amounts of

vitamin C as up to 500 mg a day. This presentation contradicts

previous published studies showing that vitamin C protects against

carotid atherosclerosis and intima-media wall thickening. 42

 

In response to this unpublished American Heart Association

presentation, The Life Extension Foundation asked me to oversee a

pilot study of 30 people who had been taking very high doses of

vitamin C (and other nutrients) for at least four years.

 

The objective of this study was to ascertain whether those who have

consumed more than 2000 mg a day of vitamin C have a greater or

lesser degree of carotid artery wall thickening and atherosclerotic

plaque in relationship to their age and other risk factors.

 

The subjects in our test group ranged from age 45 to 81 years, with a

median age of 61. Our test subjects were significantly older than the

group tested by the American Heart Association.

 

The procedure used to evaluate the carotid arteries of these 30

subjects was a high resolution ultrasound of the carotids with

doppler evaluation. Multiple sonographic scans were obtained through

the area of the right and left carotid systems. This test enabled me

to ascertain if there was atherosclerotic plaque present, the degree

of intimamedia thickening if any, blood flow velocity and the

percentage of stenosis (narrowing or blockage), if any. I routinely

use this test to help determine if neurologic deficit is caused by

carotid artery disease. It is not uncommon for me to detect 60% to

90% blockage in the carotid arteries of patients, along with

significant increase of carotid blood flow velocity and severe

intimamedia thickening. Lay readers should know that increased blood

flow velocity is indicative of greater carotid artery stenosis

(narrowing).

 

I was surprised that the doctors who made the presentation at the

American Heart Association conference only tested for carotid

intimamedia thickening. This is only one of four parameters that can

be evaluated via carotid ultrasound testing. I believe the American

Heart Association doctors should have also checked for carotid

atherosclerotic plaque, stenosis and blood flow velocity, in addition

to intima-media thickening. Of all parameters that can be evaluated,

intima-media wall thickening is the least important factor.

Atherosclerotic plaque, stenosis and blood flow velocity are far more

important indicators of underlying carotid disease.

 

The results of The Life Extension Foundation™s four-pronged carotid

ultrasound test showed that in 23 out of 30 of these very high

vitamin C supplement takers, there was no evidence of carotid plaque

formation, obstruction (stenosis) or intima-media thickening. Blood

flow velocity through the carotids was completely normal in these 23

subjects.

 

In seven cases, there was some evidence of carotid pathology, but the

extent of disease was insignificant with the exception of two persons

who showed carotid stenosis of 30% and 40%. Based on the advanced age

of these two subjects, the 30 and 40% stenosis observed was not

considered abnormal and was not indicative of a clinically

significant disease state.

 

In the seven cases showing some evidence of carotid pathology,

preliminary follow up has at the time of this publication revealed

elevated levels of homocysteine, LDL cholesterol and/or glucose as

potential causative factors. Additional blood testing of these seven

subjects will be conducted to evaluate serum iron, Creactive protein,

LDL particle size, fibrinogen and other potential risk factors for

carotid stenosis. When adjusting for age and other confounding

factors such as high cholesterolhomocysteine, the slight to moderate

carotid pathology detected in these 7 out of 30 subjects is below

what would be normally expected.

 

Overall, this group of very high vitamin C supplement takers showed

remarkably healthy carotid arteries, with 23 out of 30 having

absolutely no sign of intima-media thickening, blood flow

restriction, atherosclerosis or stenosis.

 

Our pilot study of 30 subjects differed from the American Heart

Association study in the following ways

 

The American Heart Association tested people aged 40 to 60. We

thought age 40 was too young to observe significant carotid artery

disease in asymptomatic people, so we tested people beginning at age

45. We had no upper age cutoff limit, and tested many people in their

60s, 70s and one 81-year-old.

 

The American Heart Association only tested for carotid intimamedia

thickening, while we tested for carotid atherosclerosis, stenosis and

blood flow velocity, in addition to intima-media thickening.

Atherosclerotic plaque, stenosis and blood flow velocity are far more

important indicators of underlying disease than intima- media

thickening.

 

The upper limit for vitamin C intake was apparently 500 mg in the

American Heart Association study. Our subjects, on the other hand,

consumed well over 2,000 mg a day of vitamin C along with potent

doses of other nutrients purported to reduce risk of atherosclerosis

and cardiovascular disease.

 

If we had set a cutoff of 60 years of age like the American Heart

Association did, we would have found that none of our test subjects

would have shown clinically significant carotid artery pathology. In

other words, had we used the same narrow parameters (under age 60)

that were presented at the American Heart Association meeting, we

would have had no carotid artery pathology to report in this group of

people who take very high doses of supplements.

 

Since aging is a risk factor in the development of carotid artery

disease, we choose to evaluate a much older group (45 to 81 years) of

people consuming greater levels of vitamin C and other nutrients. By

testing an older age group, we obtained a more clinically significant

picture of the carotid artery status of people who have consumed very

high doses of vitamin C and other nutrients for long periods of time.

 

Additional considerations

 

It is well established that excess iron accelerates atherosclerosis,

and one study specifically showed that high levels of iron cause

carotid atherosclerosis 43 . It is therefore possible that the people

in the American Heart Association study who were taking low potency

vitamin C supplements were consuming a multi-vitamin that contained a

relatively high level of iron. There is also a possibility that these

relatively low-potency vitamin C supplements where causing excess

iron absorption from food, but not enough vitamin C to protect

against iron-induced LDL cholesterol oxidation that could have

contributed to the intima-media thickening observed in the American

Heart Association presentation.

 

Previously published research shows vitamin C as either having a

protective effect, or no effect in the development of carotid artery

disease. The most significant positive study was published in the

American Heart Association™s own journal 42 and measured the

relationship between the intake of dietary and supplemental vitamin

C, vitamin E and provitamin A carotenoids and average carotid artery

wall thickness. In 6,318 female and 4,989 male participants 45 to 64

years old, carotid artery intima-media wall thickness was measured as

an indicator of atherosclerosis at multiple sites with ultrasound

testing. Among men and women over age 55 who had not recently begun a

special diet, those in the high vitamin C intake group showed

significantly less average carotid artery wall thickness adjusted for

age, body mass index, fasting serum glucose, systolic and diastolic

blood pressures, HDL and LDL cholesterol, total caloric intake,

cigarette use, race and education. Vitamin C showed an 81% protective

effect in women and a 65% protective effect in men. The doctors

concluded by stating:

 

 

" These data provide limited support for the hypothesis that dietary

vitamin C and alpha- tocopherol may protect against atherosclerotic

disease, especially in individuals over 55 years old. "

 

Carotid endarterectomy is a surgical procedure used to remove

atherosclerotic plaque in the carotid artery. In a study of 45 people

undergoing this procedure, the lower the plasma content in vitamin C

over a 12-month period, the higher the percentage of vessel re-

narrowing after endarterectomy. This study implies that even in

advanced cases of carotid stenosis, supplemental vitamin C may be of

benefit in preventing further occlusion. 44

 

Another study involved the feeding of oxidized lab chow along with

vitamin C and iron to rabbits for four weeks to induce experimental

atherosclerosis. These rabbits had been fed a trans-fatty acid rich

diet for 36 weeks prior. Administration of coenzyme Q10 after the

feeding of a trans-fatty acid-rich diet showed a decrease in coronary

atherosclerosis, artery plaque size and atherosclerosis scores when

compared to the placebo group. 45 This study indicates that

supplemental coenzyme Q10 may be required when people take vitamin C

and iron supplements.

 

While Linus Pauling, Matthias Rath and others make a good case that

vitamin C protects against atherosclerosis, there are studies

suggesting that garlic, 46 homocsyteine-lowering nutrients folate, 30-

38 B6, 28 B12, 26,27 TMG (trimetheylglycine), 47-50 and calcium

regulating nutrients such as vitamin K 51 provide even greater

benefits. One study on people with elevated homocysteine showed that

supplementation with folic acid, vitamins B12 and B6 resulted in a

regression in carotid artery stenosis within one year as measured by

ultrasound testing. 52

 

 

Conclusions

 

Our direct observation, based on carotid ultrasound testing, show

that very high vitamin C supplement users have remarkably healthy

carotid arteries. When adjusted for other factors such as age,

elevated homocysteine, LDL cholesterol and glucose, these very high

vitamin C takers as a group appear to have less carotid pathology

than the general population. A review of previously published

findings indicates that consuming a wide variety of very high potency

dietary supplements, combined with blood screening to monitor

cholesterol, homocysteine, glucose, iron and other atherogenic risk

factors, confers a significant protective effect against the

development of carotid artery disease.

 

Continuation of: The Vitamin C Controversy (References)

 

Abstracts: Rebuttals to the AHA's attack on vitamin C