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Vitamin C reduces human mortality

Humans do not internally produce vitamin C. Diets provide enough vitamin C to avoid scurvy, but nowhere near what may be optimal doses.

Researchers have found that vitamin C promotes a longer lifespan and can help prevent many of the disorders related to aging, including cancer.

In a major new study, people with higher blood levels of vitamin C were at significantly lower risk for heart disease and cancer death—and were up to 25% less likely to die from any cause.1

Vitamin C shows potential to significantly improve the quality of life.

Effect of vitamin C on mortality

In a new study, researchers examined vitamin C blood levels and their relationship with patients’ health.1 The study involved 948 randomly selected, healthy men and women aged 53 to 84, whose blood was collected in 1999-2000.1 Subjects were closely followed for the next 16 years, and their health was tracked.

What the study showed was that people whose 16-year-old blood samples contained the highest levels of vitamin C back then had significantly lower risks of dying now.1

The differences were dramatic. Those in the highest quartile of baseline blood vitamin C levels were 25% less likely to die than those in the lowest quartile.1

Finally, when the researchers analyzed data by disease type, they found that those in the top quartile of blood vitamin C levels in 1999-2000 were at a lower risk for both heart disease and cancer deaths 16 years later.1

Many other studies also show a clear link between vitamin C and leading a long, healthy life.

While higher vitamin C levels are associated with people who practice healthier behavior patterns, this study nonetheless shows striking reductions in mortality rates in those with the highest blood levels of vitamin C.

Boosting longevity

Animal studies show that vitamin C can reverse several age-related abnormalities in tissues. This includes reducing inflammatory responses, protecting DNA integrity, and reducing biomarkers of cellular stress. When left unaddressed, all of these are associated with rapid aging.2-5

Research demonstrates that vitamin C supplementation can extend lifespan in a primitive worm often used in longevity testing.5

Studies in mice show even more dramatic results. Humans are among the very few mammals not capable of making their own vitamin C and so they must obtain it from their diet. Scientists did a series of studies using mice that were genetically engineered to age prematurely and require dietary vitamin C.2-4

These studies found that in the absence of significant dietary vitamin C, the mice have a severe reduction in lifespan, and have numerous metabolic abnormalities that resemble those of older humans.2-4

But when vitamin C is added to their diet, the animals’ lifespans were significantly increased, and all metabolic abnormalities were resolved.2-4

The evidence is clear: Vitamin C is an important component to healthy longevity. The results are even more remarkable when scientists examine the role of vitamin C in specific diseases that cause premature death in humans.

WHAT YOU NEED TO KNOW

 

Vitamin C and health

Vitamin C was one of the first vitamins to be discovered. First noted for its ability to fight the connective tissue degeneration of scurvy, vitamin C has now been shown to have a vital relationship with biochemical reactions crucial to cellular health throughout the body.

A new study shows that individuals with higher blood levels of vitamin C are less likely to die from any cause.

Daily supplementation with vitamin C may help prevent cancer, boost the immune system, and protect the cardiovascular system.

Vitamin C and cancer

Vitamin C is powerful in reducing the oxidative stress that can trigger DNA damage, leading to cancer initiation, and it can inhibit the inflammatory response that promotes tumor growth.6,7   

Taking vitamin C supplements reduces markers of oxidative stress in non-smokers exposed to second-hand smoke. Vitamin C supplements have also been shown to reduce damage to human cells that was caused by exposure to radiation.6,8

In fact, some recent studies recommend vitamin C and other antioxidants as ideal protection for patients before undergoing imaging studies that use radiation (like X-rays and CT scans).8

The vitamin may act directly on developing malignancies as well. Vitamin C can generate hydrogen peroxide, which destroys rapidly-replicating cancer cells.7,9

Gastrointestinal cancers are among the most common and most preventable malignancies.

A large clinical study found that higher vitamin C levels were strongly linked to a lower risk of stomach cancer (gastric adenocarcinoma). For each 0.35 mg/dL increase in blood levels of vitamin C, there was a 14%reduction in risk of this tumor. Compared to people with the lowest vitamin C levels, those with normal concentrations had an overall 27% reduction in stomach cancer risk.10

Breast cancer studies show a similar result: Women with the highest intake of vitamin C prior to a cancer diagnosis were 25% less likely to die from the disease compared to those with the lowest levels.11

In experiments with normal mice and those genetically engineered to express human genes (including lack of vitamin C synthesis), all normal animals developed mammary cancers after implantation with human breast cancer cells. In mice bearing human genes there was a reduced growth when given modest vitamin C supplementation. Moreover, in the engineered mice on higher-dose vitamin C, none developed tumors.12

Vitamin C adds cardio protection

Research into vitamin C and cardiovascular disease has shown that the vitamin can act at multiple pathways involved in the development of atherosclerosis, arterial blockage, and the resulting heart attacks and strokes.

Lipid peroxidation, free radical damage to fats, is a crucial step in the development of atherosclerosis and heart disease. Studies show that vitamin C at doses of 1,000 mg per day lowers levels of oxidative stress markers in blood, even during the high oxidative-stress period following a meal.6,13

Vitamin C has shown many beneficial effects in preventing cardiovascular disease:

  • Vitamin C preserved crucial cardiac stem cells, required for healing damaged heart tissue, in a lab study.14
  • Two grams per day of vitamin C fully restored an important cardiovascular repair system in smokers after just 2 weeks of supplementation, giving them the same healing capacity as non-smokers.15
  • A meta-analysis of 44 clinical trials showed that vitamin C supplementation improved endothelial function. The effect was stronger in those with higher cardiovascular risk.16
  • Vitamin C reduces the tendency to form harmful plaque and clots. A modest 500 mg per-day dose for 3 months in overweight and obese subjects triggered the release of a natural clot-busting protein, tissue plasminogen activator (tPA) in endothelial cells.17
  • A human double-blind study found that vitamin C supplementation for 6 weeks resulted in a 37% reductionin the numbers of monocytes sticking to endothelial cells—reducing the risk that atherosclerotic plaque would form.18
  • A clinical study of older men showed that a dietary intervention to increase vitamin C levels slowed the progression in thickening of the carotid artery.19

The overall impact of vitamin C on cardiovascular disease risk is potentially life-saving, and studies suggest that daily supplementation with ample amounts can optimize protection of the heart and major arteries.

Boost immune function, cut infection risk

Vitamin C is especially beneficial to the immune system, helping to prevent viral respiratory infections like the common cold.20,21 Immune system cells accumulate vitamin C, using it to create chemical “weapons” which destroy invading bacteria and viruses.22,23

Diminished levels of vitamin C leave us vulnerable to specific disease-causing microbes.21

Vitamin C’s immune-boosting effects arise from multiple mechanisms:21,22,24-27

  • Promoting the actions of phagocytes, the cellular “eating machines” that chew up bacterial and fungal cells.
  • Activating T-cells, white blood cells, that scan the body for abnormalities and infections and direct both antibody-producing cells and killer cells to work against viruses and bacteria.
  • Mitigating oxidative stress and reducing unneeded inflammatory responses.

In addition, vitamin C slows the gradual shrinkage of the thymus gland in mice.25 A shrinking thymus is closely associated with immunosenescence, in which a declining immune system leaves older people at higher risk for infection and autoimmune disorders.28

A meta-analysis of 7 randomized, controlled trials found that, at the onset of an upper respiratory tract infection such as a cold, the addition of doses greater than one gram of vitamin C per day, on top of an ongoing daily preventive vitamin C regimen, significantly shortened the duration of illness and the severity of symptoms.29

Support healthy collagen production 

Collagen, a structural protein abundant in connective tissue and found throughout the body, makes up 30%of all body protein. Collagen provides strength and durability to bone, skin, tendons, ligaments, blood vessels, and more.39

The strength and resilience of much of our collagen decreases with age, contributing to age-related changes to skin, bone, and even our cardiovascular and respiratory systems.40,41

Vitamin C plays a critical role in the synthesis of collagen. Studies have consistently shown that vitamin C supplementation improves collagen production and supports healing of tissues following injuries.39,42-45

For example, there is evidence that vitamin C may accelerate bone healing after a fracture, and increase the quality and amount of collagen in connective tissues.42

Additionally, vitamin C also protects against skin aging and prevents damage caused by ultraviolet radiation.46,47 In aging mice, it blocked wrinkle formation, loss of elasticity, and thinning of the skin by augmenting production of both collagen and elastic fibers.47

Bone health

Large population studies have found that higher vitamin C intake is associated with greater bone mass, and that lower vitamin C intake correlates with bone loss.30 And clinical studies have shown positive associations between vitamin C supplementation and improved bone mineral density.31-33

A 2018 systematic review and meta-analysis found that overall, greater vitamin C intake was associated with a 33% lower risk of osteoporosis, a lower risk of hip fractures, and greater bone mineral density.34 This isn’t surprising, given that vitamin C is required by enzymes that produce the protein matrix in bones. Thus, vitamin C is required for healthy, strong bones.31

The study used mice with genetic defects that make them reliant on dietary vitamin C, as humans are. Multiple bone abnormalities were uncovered when the animals were fed a C-deficient diet. However, when vitamin C supplements were given, those abnormalities were resolved.30,35-37

Vitamin C has a tremendous impact on bone, including restoring normal development of critical bone-forming cells (osteoblasts).38

May help boost mood, fight depression

Clinical studies are revealing that supplemental vitamin C, alone or in combination with anti-anxiety drugs, improves mood-related disorders.

In a randomized, controlled trial, two weeks of vitamin C treatment reduced anxiety compared to a placebo.48 In another controlled, clinical trial, 6 weeks of supplementation with vitamin C at a dosage of 1,000 mg daily significantly reduced anxiety levels.49

Another placebo-controlled clinical trial in children with major depression found that with the addition of vitamin C to fluoxetine drug therapy the children had lower depression scores than those who received the fluoxetine plus a placebo.50 Remarkably, a short-term trial found that a single dose of 1,000 mg of vitamin C significantly reduced anxiety, compared to baseline levels, among the subjects in the top one-quarter of anxiety scores.51

Several mechanisms are being explored to explain vitamin C’s mood-improving effects — beyond its ability to combat oxidative stress. One recent animal study showed that vitamin C may activate receptors for the neurotransmitter GABA, which boosts mood.51 Another provided evidence that vitamin C modulates human opioid-like receptors as it exerts its anti-depressant effects.52

Summary

Multiple, large studies have shown that individuals with higher blood levels of vitamin C are less likely to die from any cause. Vitamin C has important preventive effects on a range of age-associated disorders.

Studies show that vitamin C supplementation can help prevent many kinds of cancers, protect the heart and blood vessels, boost the immune system and fight immune senescence. It has even shown the ability to help prevent osteoporosis and promote healthy bone formation.

Daily vitamin C supplementation plays a vital role in optimizing our body’s ability to combat oxidative stress and protect against many of the diseases associated with aging.

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