Vitamin C are you getting enough? Part 2

Vitamin C are you getting enough? 
  Part 2

Does Vitamin C effect your lipid profile........

Lipid Profiles, Blood Pressure, and Body Mass Index

Most people have learned to pay attention to the amount and kinds of fats and cholesterol in their blood (lipid profiles), their blood pressure, and their body mass indexVitamin C are you getting enough? (BMI), the most meaningful measure of how weight and health are related. This group of parameters not only influences endothelial function but is instrumental in laying down atherosclerotic plaque, helping set the stage for atherosclerosis.

Data from just the past few years reveal that vitamin C plays an important role in helping to prevent such a scenario.

In 2000, British researchers reported a six-month, double-blind study of vitamin C 500 mg/day versus placebo in 40 men and women, aged 60-80 years. The study was a “crossover” design in which subjects took the assigned pills for three months, stopped them for one week, and then reversed their assignments for another three months; this is a particularly strong study design because it helps to eliminate individual differences. The results were impressive—daytime systolic blood pressure dropped by an average of 2 mm Hg, with the greatest drop seen in subjects who had the highest initial pressures. Women in the study also had a modest increase in their beneficial high-density lipoprotein (HDL) levels. The authors concluded that these effects might “contribute to the reported association between higher vitamin C intake and lower risk of cardiovascular disease and stroke.”

Researchers in South Carolina conducted a 2002 study of 31 patients with a mean age of 62 years, who were randomly assigned to take 500, 1,000, or 2,000 mg of vitamin C daily for eight months. This research group actually found a drop in both systolic (4.5 mm Hg) and diastolic (2.8 mm Hg) blood pressure over the course of supplementation, although there was no change in blood lipid levels. Interestingly, this study found no differences between the groups taking the various doses, though the number of subjects was small and a larger study might have demonstrated important dose-related differences.

Body mass index (BMI) and waist circumference correlate well with risk for cardiovascular diseases and diabetes. A landmark 2007 study from nutritionists at the University of Arizona explored the relationships between vitamin C levels, body mass index, and waist circumference. In 118 sedentary, non-smoking adults, 54% of whom were classified as obese and 24% overweight by BMI standards, lower vitamin C levels were significantly correlated with higher BMI, percentage of body fat, and waist circumference. Women with higher vitamin C levels also had higher levels of the fat-suppressing hormone, adiponectin. This remarkable study demonstrated a vital relationship between vitamin C levels and obesity-related risk factors for cardiovascular disease.

Vascular Stiffness and Coagulation

The development of atherosclerosis involves dysfunction of the vascular endothelium. As plaque accumulates and as vessel walls thicken, blood vessels become increasingly stiff, making them less able to participate in blood pressure control and to deliver appropriate amounts of blood flow. Endothelial dysfunction increases the tendency for arterial blockage due to a blood clot, or thrombosis. Like several other “atherogenic” changes, these effects are related to the impact of free-radical damage. Vitamin C’s antioxidant characteristics are showing great power in reducing or even reversing some of these ominous vascular changes.

Medical researchers explored the impact of vitamin C supplements on both arterial stiffness and platelet aggregation (an important early step in clot formation). They provided vitamin C in a single 2,000 mg oral dose, or placebo, to healthy male volunteers. Just six hours after supplementation, measures of arterial stiffness decreased by 10% in the supplemented group, and platelet aggregation (as stimulated chemically) by 35%, with no changes at all seen in the placebo group. As the authors point out, this impressive impact of vitamin C even in healthy subjects may imply an even greater effect in patients with atherosclerosis or cardiovascular risk factors, and that “vitamin C supplementation might prove an effective therapy in cardiovascular disease.”

Many other studies have further advanced our understanding of how vitamin C might reduce atherosclerosis risk factors. Finnish researchers studied 440 adults aged 45-69 years with elevated total serum cholesterol. Subjects took daily doses of just 500 mg slow-release vitamin C and 272 IU vitamin E and were followed for six years for evidence of progression of atherosclerotic changes in blood vessels. The chief study outcome was the intima-media thickness, or IMT (an indicator of stroke risk) of the carotid arteries, which supply blood to the brain. Supplementation with vitamins C and E significantly decreased the rate of IMT increase over the six-year period by 26%. Importantly, this effect was even larger in people with low baseline vitamin C levels and those with pre-existing plaques in their coronary arteries. In other words, supplementation seemed to provide the greatest benefit to those with the greatest need. This study shows that supplementation with vitamin C slows down the progression of stroke-inducing atherosclerosis.
Part 3 tomorrow.