Vitamin C against atherosclerosis (hardened arteries)

Claus Hancke

March 23, 2006

So far a British research study is showing that C vitamin fights inflammation. Therefore it is very possible that it also fights hardened arteries and blodclots.

If one compares peoples’ eating habits with their risk of blood clots in the heart, one gets the impression that vitamin C prevents blood clots. So far it has been hard to prove through randomised trails that vitamin C supplements protect high risk patients from blood clots. This is how it has been up to now, even though one can claim that many of the studies have been lacking.

Whatever the objections, it is widely believed that the debate over.

It is currently said that vitamin C does not protect against atherosclerosis, but is it true? A recent summary could indicate that the debate is long from over. It shows that vitamin C counteracts inflammation, which is to say infection-like reactions. There is also widespread agreement that atherosclerosis is due to inflammation. Does vitamin C therefore protect against atherosclerosis?

In order to understand the problem it is necessary to take a little detour in this discussion:
Until 20-30 years ago, atherosclerosis was believed to be a process which was roughly due to the depositing of cholesterol in the walls of the blood vessels followed by the build up of calcium. Today it is understood the vessel walls are composed of living cells, and that both the build up of cholesterol and the thickening of the vessel walls are related to inflammation. The same is true for the bursting of the surface against the blood stream, with the emptying of cholesterol and cell products, which causes the platelets (etc.) to clump together, causing a blood clot.

Inflammation appears, curiously enough, to be a part of the sales success of the cholesterol lowering medications, the so called statins. It cannot be denied that they save lives, but is it because they lower the blood’s cholesterol level?

Vitamin C lowers CRP
Here there is doubt. Statins do not only lower cholesterol, but also reduce inflammation. This can be directly measured by a simple blood test (CRP) which hundreds of thousands of Danes get taken when their doctors what to know if they have infection in their bodies. The two effects of statins, the lowering of CRP and the reduction of cholesterol, are not necessarily related, but the risk of blood clots in the heart is more related to CRP than to cholesterol levels. In a study where statins were shown to reduce the risk of heart disease by ca. 30%, their favourable effect was statistically shown to be related to CRP levels, regardless of the cholesterol level! It looks like CRP is more important than cholesterol!

With this we can return to vitamin C. Does vitamin C reduce CRP, just like statins?

In a couple of small randomised studies it was examined whether or not this is the case. In both studies the daily dose of vitamin C was about 500 mg. In the first (with smokers as the participants) CRP was markedly reduced, in the second nothing happened. The contradictory results have now been explained by a study with 3258 reasonably cardio-vascular healthy men between the ages of 60-79.

The primary result was that the more vitamin C that the men had in their blood (serum), the lower their CRP. The quarter of the participants who had the highest level of vitamin C in their blood (with or without consideration of supplements), had the lowest CRP values. The difference was overwhelmingly statistically certain. Concurrently, other measurements indicated that the likelihood for “irritability” of the vessel walls (endothelial dysfunction) was also the lowest in the highest vitamin C group. There is common agreement that this “irritability” mirrors a tendency for atherosclerosis.

Vitamin C is therefore believed to lower CRP, which is an important indicator for inflammation, and therefore the risk of dying of a blood clot. The debate rages on!

By: Vitality Council

References:
1. Ridker et al. C-reactive protein levels and outcomes after statin therapy. N Engl J Med 2005;352:20-8
2. Ridker PM, C-reactive protein levels and outcomes after statin therapy. N Engl J Med. 2005 Jan 6;352(1):20-8
3. Libby P. Inflammation and cardiovascular disease mechanisms. Am J Clin Nutr 2006;83(Suppl):456S-60S
4. Goya S et al. Associations of vitamin C status, fruit and vegetable intakes, and markers of inflammation and hemostasis. Am J Clin Nutr 2006;83:567-74
5. Ishwarlal J et al. Is vitamin C an anti-inflammatory agent? Am J Clin Nutr 2006;83:525-6
6. Mora S Justification for the Use of Statins in Primary Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER)–can C-reactive protein be used to target statin therapy in primary prevention?Am J Cardiol. 2006 Jan 16;97(2A):33A-41A. Epub 2005 Dec 1.
7. Bruunsgaard H, Long-term combined supplementations with alpha-tocopherol and vitamin C have no detectable anti-inflammatory effects in healthy men. J Nutr. 2003 Apr;133(4):1170-3.
8. Block G Plasma C-reactive protein concentrations in active and passive smokers: influence of antioxidant supplementation. J Am Coll Nutr. 2004 Apr;23(2):141-7.

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