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New research suggests that vitamin C may give you some of the same heart benefits as regular exercise.
A study from the University of Colorado, Boulder examined the effects of vitamin C supplements on overweight and obese adults. This group of people is often advised to exercise to improve their heart health but more than 50% ignore the advice.
In a presentation at the 14th International Conference on Endothelin: Physiology, Pathophysiology and Therapeutics, the Colorado researchers revealed that taking a 500 mg time-released vitamin C supplement every day can have similar cardiovascular benefits as regular exercise in these adults.[i]
The researchers noted that the blood vessels of overweight and obese people have elevated activity of a protein called endothelin-1 (ET-1). This protein constricts small blood vessels making them less responsive to blood flow demand. That increases the risk of developing cardiovascular disease.
Exercise has been shown to reduce ET-1 activity. But the researchers found that vitamin C reduced ET-1 vessel constriction as much as walking for exercise did.
The researchers concluded that "vitamin C supplementation represents an effective lifestyle strategy for reducing ET-1-mediated vessel constriction in overweight and obese adults."
Although many people tend to think of vitamin C as an antioxidant, immune system booster, and common cold treatment, it is also powerful support for the cardiovascular system.
Albert Szent-Gyorgyi, a Hungarian-born biochemist, won the Nobel Prize for Physiology or Medicine in 1937 for isolating Vitamin C. Later, two-time Nobel Laureate Linus Pauling became the world's foremost vitamin C proponent.
Dr. Pauling highlighted the fact that humans - unlike most other animals - are born without the ability to manufacture vitamin C. He theorized that our primate ancestors lost the ability to make vitamin C when they lived in an environment with plentiful fruits and vegetables.
He advocated large doses of vitamin C (10 to 12 grams per day) to offset the deficiency. He also believed that our modern diet low in vitamin C-rich foods explained the epidemic of heart disease.
Vitamin C Reduces Heart Attack and Stroke
Research has since supported Dr. Pauling's theory. Studies show that, compared to people getting the least vitamin C, those getting the most had a dramatic 80% lower risk of heart attack.[ii]
In a large study of 800 people who had already suffered a heart attack, patients were given high doses of vitamin C (1200 mg daily) and vitamin E. After just one month rates of death, new heart attacks, and other serious complications were reduced by about 20%.[iii]
A 2008 study from the University of Cambridge showed that higher plasma vitamin C levels are associated with a significantly reduced risk of stroke. Scientists tracked 20,649 men and women aged 40 to 79 years for 12 years. Individuals who had the highest vitamin C levels showed a 42% reduction in stroke risk.
Vitamin C works in many different ways to support cardiovascular health. For one thing, it reduces blood pressure. In one double-blind crossover study of 40 people, those taking 500 mg of vitamin C per day reduced systolic pressure by an average of 2 mm Hg, with the greatest drop in subjects who had the highest starting pressures.[iv]
In another study, 31 patients were randomly assigned to take 500, 1,000, or 2,000 mg of vitamin C every day. After eight months the vitamin C reduced systolic pressure by 4.5 mm Hg and diastolic pressure by 2.8 mm Hg.[v]
Vitamin C also protects against endothelial dysfunction[vi] and helps prevent atherosclerosis. In a Finnish study of 440 adults with high total cholesterol, subjects took 500 mg slow-release vitamin C daily along with 272 IU of vitamin E. After six years the researchers found that intima-media thickness (IMT) of the carotid artery decreased by 26%. The carotid artery supplies blood to the brain and the IMT is an indicator of stroke risk.[vii]
Vitamin C supports the production of collagen needed to heal arteries. In patients with low vitamin C levels, the body produces small, sticky cholesterol called lipoprotein A which leads to the formation of arterial plaque. Linus Pauling advocated large amounts of vitamin C combined with the amino acid lysine to reverse the damage done to the arteries. Vitamin C's antioxidant powers are also credited with reducing or even reversing some of these vascular changes.[viii]
A British study found that vitamin C could reduce the adhesion of monocytes in blood vessels. Monocytes are white blood cells that stick to the walls of the endothelium in the early stages of vascular disease. The blood vessel walls thicken and lose elasticity. That can lead to "hardening of the arteries." The study looked at 40 adults with low vitamin C levels. They had 30% greater monocyte adhesion than normal. After six weeks of taking 250 mg per day of vitamin C, their monocyte adhesion dropped by 37%.[ix]
In a study of 100 patients with aortic stenosis, patients were given either 1000 mg of vitamin C plus 400 IU of vitamin E, or just 1,000 mg of vitamin C, or a placebo every day. Both supplement groups significantly reduced several types of adhesion molecules that may contribute to heart valve disease.[x]
And vitamin C is fast-acting. In one study just a single 2,000 mg dose taken by healthy male volunteers reduced arterial stiffness by 10% and platelet aggregation by 35% in just six hours.[xi]
Vitamin C Enhances Exercise
Vitamin C isn't just a possible replacement for exercise. It can also magnify the benefits.
Exercise increases the body's production of harmful free radicals. As an antioxidant, vitamin C defends against that oxidative damage.[xii]
It also reduces recovery time. One study found that it only takes 200 mg twice a day to reduce muscle soreness, improve muscle function, and lower signs of oxidative stress after a 90 minute run.[xiii] But another study suggested that vitamin C is only effective if taken before a workout.[xiv]
Vitamin C may also support heart health by helping to control weight. In one study of 118 inactive adults who were either overweight or obese, lower vitamin C levels were significantly linked to higher body mass index (BMI), percentage of body fat, and waist circumference.[xv]
The Recommended Dietary Allowance (RDA) for vitamin C is 90 mg for men and 75 mg for women. Many practitioners recommend that some people should get even more. Smokers, women on estrogen or birth control pills, diabetics, pregnant women, and people taking aspirin or other drugs, need more vitamin C.
The best way to get vitamin C is from food. Szent-Gyorgi discovered that isolated vitamin C was not as effective against scurvy as organ meats and foods like paprika. That's because real foods contain a long list of cofactors, such as rutin, bioflavonoids, and various enzymes that increase the natural efficacy of the other nutrients. In other words, foods are more than their individual nutrients.
The best source of vitamin C may be acerola cherries. They have 1,678 mg per 100 grams. Other goods choices are oranges, dark, green leafy vegetables, bell peppers, parsley, black currants, strawberries, blueberries, guava, and papaya.
Vitamin C supplements of course are widely available. As ascorbic acid vitamin C can be used in much higher doses than the RDA without adverse side effects. In times of stress or sickness, some doctors recommend up to 20,000 mg. But taken orally, vitamin C in large doses can irritate your stomach and cause severe diarrhea. Intravenous vitamin C does not present the same problem.
The half-life of vitamin C is 30 minutes. So instead of one big dose it's better to take multiple doses during the day to keep your blood levels up. In other words, three doses of 500 mg. taken at intervals will raise your average blood levels more than a single dose of 1,500 mg.
For more about its therapeutic value visit GreenMedInfo's page on vitamin C.
[i] American Physiological Society (APS). "Vitamin C: The exercise replacement?" ScienceDaily. ScienceDaily, 4 September 2015. <www.sciencedaily.com/releases/2015/09/150904144604.htm>.
[ii] Lopes C, Von HP, Ramos E, et al. "Diet and risk of myocardial infarction. A case-control community-based study." Acta Med Port. 1998 Apr;11(4):311-7.
[iii] Jaxa-Chamiec T et al. "Antioxidant effects of combined vitamins C and E in acute myocardial infarction. The randomized, double-blind, placebo controlled, multicenter pilot Myocardial Infarction and VITamins (MIVIT) trial." Kardiol Pol. 2005;62(4):344-50.
[iv] Fotherby MD, Williams JC, Forster LA, Craner P, Ferns GA. "Effect of vitamin C on ambulatory blood pressure and plasma lipids in older persons." J Hypertens. 2000 Apr;18(4):411-5.
[v] Hajjar IM, George V, Sasse EA, Kochar MS. "A randomized, double-blind, controlled trial of vitamin C in the management of hypertension and lipids." Am J Ther. 2002 Jul;9(4):289-93.
[vi] Rossig L, Hoffmann J, Hugel B, et al. "Vitamin C inhibits endothelial cell apoptosis in congestive heart failure." Circulation. 2001 Oct 30;104(18):2182-7.
[vii] Salonen RM, Nyyssonen K, Kaikkonen J, et al. "Six-year effect of combined vitamin C and E supplementation on atherosclerotic progression: the Antioxidant Supplementation in Atherosclerosis Prevention (ASAP) Study." Circulation. 2003 Feb 25;107(7):947-53.
[viii] Wilkinson IB, Megson IL, MacCallum H, et al. "Oral vitamin C reduces arterial stiffness and platelet aggregation in humans." J Cardiovasc Pharmacol. 1999 Nov;34(5):690-3.
[ix] Woollard KJ, Loryman CJ, Meredith E, et al. "Effects of oral vitamin C on monocyte: endothelial cell adhesion in healthy subjects." Biochem Biophys Res Commun. 2002 Jun 28;294(5):1161-8.
[x] Tahir M, Foley B, Pate G, et al. "Impact of vitamin E and C supplementation on serum adhesion molecules in chronic degenerative aortic stenosis: a randomized controlled trial." Am Heart J. 2005 Aug;150(2):302-6.
[xi] Wilkinson IB, Megson IL, MacCallum H, et al. "Oral vitamin C reduces arterial stiffness and platelet aggregation in humans." J Cardiovasc Pharmacol. 1999;34(5):690-3.
[xii] Khassaf M, McArdle A, Esanu C, et al. "Effect of vitamin C supplements on antioxidant defence and stress proteins in human lymphocytes and skeletal muscle." J Physiol. 2003 Jun 1;549(Pt 2):645-52.
[xiii] Thompson D, Williams C, McGregor SJ, et al. "Prolonged vitamin C supplementation and recovery from demanding exercise." Int J Sport Nutr Exerc Metab. 2001 Dec;11(4):466-81.
[xiv] Thompson D, Williams C, Garcia-Roves P, et al. "Post-exercise vitamin C supplementation and recovery from demanding exercise." Eur J Appl Physiol. 2003 May;89(3-4):393-400.
[xv] Johnston CS, Beezhold BL, Mostow B, Swan PD. "Plasma vitamin C is inversely related to body mass index and waist circumference but not to plasma adiponectin in nonsmoking adults." J Nutr. 2007;137(7):1757-62.