Vitamin C: Everything You Need to Know
Learn the surprising ways that vitamin C supports our health, how much we actually need, and the best food sources.
Vitamin C (also known as ascorbic acid, L-ascorbic acid or ascorbate) is a water-soluble vitamin that was first discovered in 1912, isolated in 1928, and became the first vitamin to be chemically produced in the year 1933. By 1934, it was being mass produced and sold as a dietary supplement under the brand name “Redoxon,” which is now owned by the company Bayer.
Although many animals can produce their own vitamin C from glucose in their kidneys or livers, humans (along with many other primates) lost the ability to do so approximately 61 million years ago. This was due to the inactivation of the gene that produces L-gulono-lactone oxidase (GLO), an enzyme that’s needed to complete the last step of vitamin C synthesis from glucose. Scientists still speculate about the exact reasons this gene became inactivated, but the leading theory is that the habitat of our ancestors was abundant in vitamin C-rich fruits, making it unnecessary to produce the vitamin internally. So, there was no selective pressure to preserve GLO gene function, and random disabling mutations of the GLO gene eventually displaced the functional copy as a result of genetic drift.
Vitamin C has powerful antioxidant properties, along with serving as an enzyme cofactor (for example in collagen synthesis) and playing important roles in immune system and skin health. Higher intakes of vitamin C are linked to reduced risk of heart disease, some forms of cancer, type 2 diabetes, cataracts, age-related macular degeneration, gout, fatigue, chronic kidney disease, osteoporosis, periodontal disease, and more! Plus, Vitamin C can also help regulate the stress response and reduce anxiety, and there’s preliminary evidence that it may also help prevent Alzheimer’s disease.
The foods with the highest vitamin C content include: citrus fruits (oranges, grapefruit, lemons, limes), kiwis, berries, red peppers, guavas, papayas, broccoli, Brussels sprouts, tomatoes, cantaloupe, and leafy greens. Some organ meats (adrenal glands in particular) are also good sources of vitamin C. Cooking can reduce vitamin C levels in foods, with boiling being the worst offender, due to this vitamin being both water-soluble and sensitive to heat; steaming and microwaving lead to the highest vitamin C retention. Prolonged storage, too, causes vitamin C levels in foods to diminish over time.
This article explains the biological roles of vitamin C, the interactions between dietary vitamin C and our risk of over 20 health conditions, symptoms and signs that we’re getting too little vitamin C, how much vitamin C we need by demographic (and how much is too much), and shares the top 25 best common food sources of vitamin C. Paid subscribers also can download a printer-friendly PDF version of this information below!
The Biological Roles of Vitamin C
