Key Concepts

  • RDA – 90mg/day (adult males); 75 mg/day (adult females) – this will prevent scurvy
  • 400-500 mg/day appears to be the maximum the body can utilize – any excess is excreted
  • Doses of 1 gram+ may increase risk of kidney stones in susceptible individuals
  • At doses of 2 grams+ nausea and diarrhea may occur
  • High Intravenous (IV) doses (50-100 g) appear well-tolerated in individuals and is being explored in cancer research
  • Sources: Red pepper, green pepper, broccoli, & strawberries are great sources of vit C – camu camu is off-the charts for vit C!
  • Vitamin C enhances non-heme iron absorption – good to know for vegetarians and vegans 🙂
  • No one form of supplement has been proven to be superior to another
  • Vitamin C – $0.25/serving – 2/day = $0.50/day

Intro

Ever wonder why pirates had wooden peg legs? Other than being fashionable in the days of pirates, the coveted peg leg was a sign of a serious vitamin C (ascorbic acid) deficiency which led to scurvy. The body cannot produce vitamin C, so it must be obtained from the diet. If you do not obtain vitamin C from the diet, wound healing is seriously delayed. This delayed wood healing can occur with less than 10mg of vitamin C in as little as a month. Some pirates may have lost their limbs directly in battle, but many lost them to scurvy – a wound that does not heal is prone to infection, and an untreated infection can lead to amputation. Now, I doubt many pirates actually had wooden peg legs as an unsanitary amputation would likely result in death.

Deficiency

Anywho, vitamin C! Luckily, scurvy is much more rare to see these days. An individual with scurvy would exhibit the four H’s – hemorrhagic signs (including easy bruising and petechiae (red or purple spots on the skin caused by a minor bleed from broken capillary blood vessels)), hyperkeratosis of hair follicles (thick hair), hypochondriasis (cognitive impairment), and hematological abnormalities (iron malabsorption along with impaired copper and iron metabolism).

Recommended Dietary Allowance 

The recommended dietary allowance for vitamin C is 90 mg/day in adult males and 75 mg/day in adult females. For smokers, 35 mg/day more is recommended by the Food and Nutrition Board. For other age groups, click here. This standard is set to prevent scurvy, but some studies indicate that higher doses of vitamin C may be warranted to prevent coronary heart disease, stroke, hypertension, multiple forms of cancer, cataracts, and gout. The exact amount to provide these preventive benefits is still debated.

In normal, healthy individuals, 400-500 mg/day appears to be the maximum the body can utilize. Any excess of 400-500 mg each day is excreted and therefore appears to provide no additional benefit. This is equivalent to about half a gram of vitamin C. The body actually down regulates absorption after meeting its requirement.

Toxicity

At doses of 2 grams or above, nausea and diarrhea may occur. Doses above 1 gram may increase the risk of kidney stones and is not advised in the literature for those predisposed to kidney stone formation.

Functions

Vitamin C has anti-histamine effects, serves as an antioxidant, a cofactor in collagen synthesis, neurotransmitter synthesis (serotonin, norepinephrine), and carnitine synthesis. Because of vitamin C’s role in collagen synthesis, it is essential for the development and maintenance of bone, dentin, skin, tendons, cartilage, and capillaries.

Vitamin C and Iron

Vitamin C enhances non-heme iron absorption. Non-heme iron is that which is found in non-animal sources like vegetables. This is important to note for vegetarians and vegans because non-heme iron is typically not well-absorbed.

Food Sources of Vitamin C

  • Camu camu – 100 g – 2145 mg
  • Red pepper, sweet, raw, ½ cup – 95 mg
  • Green pepper, sweet, raw, ½ cup – 60 mg
  • Strawberries, 1 cup – 85 mg
  • Broccoli, cooked, ½ cup – 85 mg
  • Broccoli, raw, ½ cup – 65 mg
  • Lemon, 1 whole – 37 mg
  • Orange, 1 medium – 117 mg
  • Spinach, cooked, ½ cup – 9 mg

*It is important to note that a lot of the vitamin C in these foods (such as oranges, lemons, peppers) is found in the pith (the white part). Eat the pith, eat the pith!

Supplements

There are many forms of vitamin C but not much evidence indicating that one form is superior to another.

  • Vitamin C – $0.25/serving – 2/day = $0.50/day

References/Resources

  1. http://www.pnas.org/content/93/8/3704.short – Vitamin C pharmacokinetics in healthy volunteers: evidence for a recommended dietary allowance
  2. http://lpi.oregonstate.edu/mic/vitamins/vitamin-C
  3. https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/
  4. https://www.livescience.com/45057-oranges-nutrition-facts.html 

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