Vitamin C

Vitamin C or ascorbic acid, is a colorless crystalline compound with an acidic taste, soluble in water, destroyed by cooking, oxidation and the action of bases, resistant to freezing.
It is found in rosehips, peppers, lemons, kiwi, green vegetables, black currants, green walnuts, potatoes. It is essential as a catalyst for cellular metabolism, for oxidation processes in the body and the function of many organs, plays a significant role in the formation of teeth and bones, wound healing and fracture repair. It improves iron circulation through the body, promotes collagen formation and body resistance. Its deficiency causes general body weakness, anemia, scurvy and promotes the development of osteoporosis.
Daily requirements for this vitamin: 50-60 mg in healthy individuals, and in people who smoke, are exposed to pollution, stress, diseases, surgical procedures, etc. around 2 g daily.
In living organisms, ascorbate acts as an antioxidant, protecting the body from oxidative stress. It is also a cofactor in at least six enzymatic reactions, including several collagen synthesis reactions, whose dysfunction manifests as symptoms of scurvy. Long-term deficiency of this vitamin manifests as the development of scurvy. Vitamin C is one of the most widely used food additives.
Ascorbic acid is well known for its antioxidant activity, acting as a reducing agent that neutralizes oxidation in fluids. When the human body contains more free radicals (reactive oxygen species, ROS) than antioxidants, the body is in a state called oxidative stress. This affects cardiovascular diseases, hypertension, chronic inflammatory diseases, diabetes, as well as critically ill patients and people with severe burns. People experiencing oxidative stress have blood ascorbate levels below 45 µmol/L, compared to healthy individuals whose ascorbate levels range from 61.4-80 µmol/L.
It is still not known with certainty whether vitamin C and antioxidants in general prevent diseases associated with oxidative stress. A meta-analysis of numerous antioxidant studies, including vitamin C supplementation, found no relationship between vitamin C and mortality. About 50 times higher concentration of vitamin C is found in lymphocytes, which rapidly consume it during infections. Vitamin C is an important factor in all stressful situations associated with inflammatory processes. It has been known for decades that chronic inflammation is the cause of various diseases. Vitamin C is an essential immune system stimulator and increases body endurance – its immunostimulative, anti-inflammatory, anti-viral and anti-bacterial properties are well known.

Sources of Vitamins

The richest natural sources are fruits and vegetables, and among them, kakadu plum and camu camu fruit contain the highest concentrations of vitamin C. It is also present in some types of meat, especially in liver. Vitamin C is one of the most widely consumed nutritional supplements. It is available in numerous forms, including tablets, drink mixes, and crystals in capsules. Vitamin C is absorbed in the intestines through sodium-dependent channels. It is transported through the intestinal system via glucose-dependent and independent mechanisms. The presence of large amounts of sugar either in the intestinal system or blood can slow absorption.

Plant Sources

Plants are generally good sources of vitamin C. Its amount in plant-based foods depends on the plant source, soil conditions, climate in which the plants grew, length of time after harvest, storage conditions, and preparation methods. The following table is approximate and shows the relative content of various raw plant sources. Some plants were analyzed fresh, while others were dried (artificially increasing the concentration of individual components like vitamin C), so the data is subject to variations and comparison difficulties. Amounts are given in milligrams per 100 grams of fruit or vegetable. This data represents rounded averages from multiple authoritative sources.

Animal Sources

Goats, like many other animals, produce their own vitamin C. An adult goat, weighing approximately 70 kg, produces more than 13,000 mg of vitamin C per day under normal health conditions, and levels are many times higher when exposed to stress. A large number of animal species and plants synthesize vitamin C. Therefore, some animal products can be used as dietary sources of vitamin C. Vitamin C is most present in the liver and least present in muscles. Since muscles make up the largest part of meat in the diet, animal products are not a reliable source of vitamin C. It is present in breast milk but not in raw cow’s milk. All excess vitamin C is eliminated through the urinary system. The following table shows the relative content of vitamin C in animal-based foods. Amounts are in milligrams of vitamin C per 100 grams of food:

Recommended Daily Dose

The scope of its effects, as well as the recommended daily dose, are topics of ongoing debate. Recommended doses range from 45 to 400 mg per day.
The North American Dietary Reference Intake recommends 90 milligrams per day, and no more than 2 grams per day. Other related animal species that share the common inability to produce vitamin C and the necessity of exogenous vitamin C intake consume 20 to 80 times greater amounts than the human reference intake. There are different opinions about the optimal dosing schedule (amount and frequency of intake) of vitamin C for maintaining optimal human health.
It is believed that a balanced diet without supplements contains sufficient vitamin C to prevent scurvy in the average healthy person, while pregnant women, tobacco smokers, and people under stress require somewhat larger amounts. However, the amount of vitamin C needed to prevent scurvy is less than the amount needed for optimal health. There are numerous other chronic diseases whose risk is increased with low vitamin C intake, including cancer, heart disease, and cataracts. A 1999 review suggested a dose of 90-100 mg of vitamin C daily as the necessary daily intake for optimal protection against these diseases, while the dose necessary to prevent scurvy is 45 mg daily. High doses (thousands of milligrams) can produce diarrhea in healthy adults, which is a consequence of the osmotic effect of retaining unabsorbed water in the gastrointestinal tract (similar to cathartic osmotic laxatives). Proponents of orthomolecular medicine claim that the occurrence of diarrhea is an indication of the dose where true bodily requirements lie, although this has not been clinically confirmed.

Recommended Amounts of Vitamin C in the USA:

• Recommended Dietary Allowance (adult male): 90 mg per day
• Recommended Dietary Allowance (adult female): 75 mg per day
• Upper Tolerance Level (adult male): 2 g per day
• Upper Tolerance Level (adult female): 2 g per day

Recommendations for Vitamin C Intake Have been Issued by Numerous National and International Agencies:

• 45 milligrams per day: World Health Organization
• 40 milligrams per day: British Food Standards Agency
• 90 mg/day (men) and 75 mg/day (women): Health Canada 2007