By Dr. John Neustadt

Vitamin C is one of the body’s most important antioxidants. You need it to create collagen and for healthy bones, joints, skin, blood sugar regulation, and immunity. Vitamin C also supports cardiovascular, kidney, and liver health. 

Since your body doesn’t manufacture its own vitamin C, the only way to get it is through diet and dietary supplements. Although there are lots of great food sources for vitamin C, including citrus fruits, berries, tomatoes, potatoes, and green leafy vegetables, about one third of Americans don’t get enough.¹ In fact, researchers have determined that vitamin C deficiency is fourth on the list of top micronutrient deficiencies in the United States.² 

For some people, the risk of low vitamin C is even higher. People more likely to not have enough vitamin C include those with pre-diabetes and diabetes, pregnant women, smokers, and people exposed to second-hand smoke and pollution. Food processing can destroy vitamin C, so people who consume processed foods are also at risk.^3,4 Additionally, the immune system burns through vitamin C faster when fighting infections and increases how much vitamin C people need.⁵ Finally, the body requires more of vitamin C and other nutrients like B vitamins, selenium, and magnesium when in the stress-induced fight or flight response.⁶ 

Collagen production

Vitamin C is required to create mature, strong collagen. When people don’t have enough vitamin C, weak collagen makes the skin, mucous membranes, blood vessels, and bones weaker. Vitamin C also helps with wound healing.  

Immune support

Vitamin C plays an important role in immunity. Among other things, vitamin C mops up free radicals to quench inflammation and enhance white blood cell activity against infections.^7-10  

Liver health

Vitamin C accelerates the detoxification of liver enzymes so toxic compounds are more effectively eliminated.¹¹

Blood sugar 

People with diabetes have lower levels of vitamin C and need more of it because of insulin resistance. Insulin helps vitamin C get into cells, and insulin resistance decreases how much vitamin C gets inside. Providing higher amounts of vitamin C increases the amount of vitamin C that gets into the cells, which is important to detoxify sorbitol. Sorbitol is toxic to cells and increased sorbitol is found in all tissues affected by major diabetic complications, including the lens of the eye, kidneys, nerves, and the lining of blood vessels.¹²  

Not only does vitamin C decrease sorbitol, but it also supports the ability of insulin to control blood sugar.^13-15 An 8-week clinical trial with sixty-four volunteers evaluated the benefits of taking vitamin C on fasting blood sugar and two markers of inflammation—C-reactive protein (CRP) and interleukin-6 (IL-6). All the participants had elevated fasting blood sugar at the beginning of the study, and were randomized to take 1000 mg/day of vitamin C or not to take any vitamin C. At the end of the study, those people taking vitamin C had a 33% decrease in fasting blood sugar. Since CRP and IL-6 are important for heart health, those results are discussed below.¹⁶

Heart health

Studies have looked at the ability of vitamin C to decrease free radical damage and support heart health. The study that showed an improvement in fasting blood sugar that was discussed above, also evaluated the effects of taking 1000 mg/day of vitamin C on CRP and IL-6. After taking 1000 mg/day of vitamin C for two months, CRP decreased by 52% and IL-6 decreased by 36%.¹⁶ 

To evaluate the effects of vitamin C on CRP, another study took 396 volunteers and gave them vitamin E (as d-alpha tocopherol), vitamin C, or a placebo for two months. Those who took 1000 mg/day of vitamin C had 25.3% lower CRP at the end of the study compared to placebo. In contrast, vitamin E did not significantly reduce CRP.¹⁷ 

Not only has vitamin C been shown to improve markers of inflammation, but higher vitamin C intake has also been associated with promoting a healthier cardiovascular system. One study followed 118 female nurses for 16 years. At the end of the study, those who took vitamin C dietary supplements had significantly better cardiovascular health compared to those who only got their vitamin C from the diet.¹⁸ 

In addition to vitamin C, supplementing with vitamin D is important for supporting healthy inflammation balance. In one clinical trial, volunteers who took 4000 IU/day of vitamin D3 reduced their CRP by 300% compared to placebo.¹⁹ 

Healthy blood pressure

Numerous studies have shown that vitamin C promotes healthy blood pressure. One study of 168 adults found that the higher the vitamin C in the blood, the better the person’s blood pressure.²⁰ Another study with 242 adults determined that over a 10-year period, people with the highest intake of vitamin C had the healthiest blood pressure.²¹ 

Vitamin C 1000

Take NBI Vitamin C 1000, which provides 1000 mg of vitamin C per capsule from natural plant sources like rose hips and acerola fruit. Plus, 50 mg of citrus bioflavonoids for added antioxidant protection.