The Ultimate Guide to Vitamin C

Vitamin C is vital for many reasons. It’s needed to form collagen in fibrous tissues, teeth, and bones. And there’s even research to suggest that vitamin C can help to protect us from a variety of cancers.

How? By disarming the two major types of free radicals.

Free radicals are unpaired atoms that can form when oxygen interacts with certain molecules. These rogue atoms are highly volatile and can be destructive to DNA, protein, and cell membranes they contract. Cancer, Parkinson’s Disease, and aging are all linked to free radicals. But luckily, the body is able to defend itself with antioxidants like vitamin C, beta-carotene, vitamin E, and lutein.

Nowadays, it’s rare to be deficient in vitamin C. But evidence suggests that many people still don’t get enough of it.

• • Scaly skin
  • Bleeding gums
  • Rough, dry, scaly skin
  • Splitting hair
  • Decreased wound-healing rate
  • Easy bruising
  • Nosebleeds
  • Decreased ability to fight off infection.

A well-known symptom of severe vitamin C deficiency is scurvy. The disease is a result of 60–90 days of vitamin C deficiency. But scurvy is a rarity in most developed countries, as there is plenty of vitamin C-rich produce available.

Puts the Breaks on Inflammation

Vitamin C’s direct antioxidant actions protect against bone-destroying chronic inflammation. Regardless of its source(s), chronic inflammation excessively activates osteoclasts — cells that break down and absorb bone during remodeling — and causes bone loss. So vitamin C’s antioxidant actions provide essential protection for our bones.

Restores Glutathione

The antioxidant glutathione is integral in the body’s antioxidant and detoxification defenses. When there are insufficient levels, irreversible cell damage — resulting in cell death — can occur.

As we age, our ability to produce glutathione declines, but our need for it increases.

In women, glutathione requirements increase, particularly after menopause. Postmenopausal women use up their glutathione much quicker due to the loss of estrogen. Estrogen has many anti-inflammatory effects, including boosting our production of glutathione and other key antioxidant enzymes.

The drop in estrogen production that occurs with menopause results in an increase of active free radicals. In turn, there’s an increase in the production of osteoclasts and bone resorption. Studies on rats, however, show that vitamin C increases glutathione levels and can reverse this scenario.

Collagen Formation

Vitamin C’s anti-inflammatory activities ensure its place as an essential bone-health nutrient. But it has many other important bone-building actions too.

Vitamin C is vital to collagen development. And since more than 90% of the protein in bone is made from collagen, vitamin C is an essential nutrient for healthy bone.

Vitamin C also stimulates the production of mesenchymal stem cells (MSMs). MSMs cells are produced in our bone marrow and can develop into different types of cells, including cartilage, muscle, and fat cells, as well as bone-building osteoblasts.

Want to learn more about collagen? Check out our post: A Vegetarian’s Guide to Collagen and Healthy Bones.

There have been many studies to assess vitamin C’s importance for bone health. Most have involved both men and women over the age of 60 and postmenopausal women — not surprising since osteoporosis and the incidence of osteoporotic fracture are highest within these groups. Virtually all studies report significant beneficial effects of vitamin C on bone mineral density and/or risk of fractures.

Over the last decade, hundreds of studies have been conducted on vitamin C revealing its benefits.

The following are eight science-backed benefits of vitamin C:

The Reference Daily Intake (RDI) is considered the daily dietary intake level of a nutrient considered to meet the requirements of 97–98% of healthy individuals in each gender group and life stage.

For vitamin C, the following levels are recommended:

RDIs for vitamin C was set back in 1996 using healthy volunteers. But researchers aren’t convinced they’re on par with the actual optimal intake, which many believe to be much higher.

Vitamin C gets used up much quicker during periods of acute illness, as well as chronic inflammation. Chronic, low-grade inflammation, which affects the majority of people over the age of 50, also plays a major role in osteoporosis. This further indicates that the RDI provides less than optimal support for healthy bones. The tolerable upper limit for vitamin C is 3,000 mg/d, but the research evidence suggests that intakes up to 4,000 mg/d are well tolerated in the general population.

Recent studies show between 10–17% of the US population is vitamin C deficient. This isn’t surprising given the number of very common factors that increase our risk of vitamin C deficiency, which we’ll learn more about in the next section.

• • Insufficient Dietary Intake. Not getting enough from your diet is the major cause of vitamin C deficiency. Even the recommended five servings per day of fruits and vegetables, which few Americans are consuming, only provides around 200 mg of vitamin C.
  • Being Overweight. Carrying extra fat, particularly on your belly, leads to chronic inflammation and increases the need for vitamin C to combat it. The situation is compounded by high cholesterol, high triglycerides, and non-alcoholic fatty liver disease.
  • Exposure to Environmental Toxins. We’re not just talking cigarette smokers here. People exposed to secondhand smoke or other environmental toxins like smog, lead, and pesticide residues are also at increased risk of vitamin C deficiency.
  • Aging. As we age, the likelihood of vitamin C deficiency increases. That’s partly due to age related inflammation. But aging liver cells also produce fewer of the proteins that help us transport vitamin C around the body. In animal studies, production of a key type of liver cell for this process declines 45% with age.

You’ll find that the top vitamin C food sources are all plant foods. While citrus food may be the most common association, there are a whole host of excellent sources of vitamin C.

Acerola Cherry, also known as Barbados cherry, is one of the highest food sources of vitamin C. One cup provides a whopping 1,644 mg! But this berry is most commonly found in supplement form because it decomposes within five days of harvest!

The following are the top food sources of vitamin C:

Vitamin C is available in a number of forms:

• • Ascorbic acid
  • Mineral ascorbates: calcium ascorbate, sodium ascorbate, magnesium ascorbate
  • Ascorbic acid and vitamin C metabolites (Ester-C®)
  • Vitamin C with bioflavonoids
  • Ascorbyl palmitate

Vitamin C supplementation has been intensively studied, so we have a robust database confirming that vitamin C supplements are safe for the general population. Because of vitamin C’s antioxidant and immune boosting effects, many people consume seemingly high quantities of vitamin C. The amounts people often supplement with are above the current recommended intakes, but could actually be well below optimal health intakes.

Numerous studies of vitamin C supplementation have provided no substantive evidence to support concerns about safety other than occasional gastrointestinal upset or mild diarrhea.

Reviews of the medical research conducted by different authors have consistently found that vitamin C is safe at intakes of 2,000 mg/d. The upper limit for vitamin C, set primarily to avoid diarrhea, is 3,000 mg/d.

The list of hypothetical adverse effects you are likely to see on various websites, including claims that vitamin C might increase the chances of forming kidney stones, increase risk of gout, cause excess iron absorption, reduce vitamin B12 concentrations, or even induce “rebound” scurvy, have all have been found to have no substantive basis.

According to the most current review of the research, published by the Linus Pauling Institute at Oregon State, “There is no reliable scientific evidence that large amounts of vitamin C (up to 10 grams/day in adults) are toxic or detrimental to health.”