Vitamin C - Ascorbic Acid

Question 1

Vitamin C- Ascorbic Acid

Answer 1

• Vitamin C functions as a key antioxidant, and as an enzyme cofactor. In both of these functions vitamin C is a potent reducing agent, meaning that it readily donates electrons to recipient molecules.
• Most animals can synthesise vitamin C: ascorbic acid / ascorbate. Some scientists postulate this has made humans more susceptible to viral illnesses , raised cholesterol, cardiovascular disease and cancer, and less resistant to stress.
• Vitamin C does not need to be modified by the body to function.
• Until the ‘cure’ for the vitamin C deficiency disease ‘Scurvy’ was found, more sailors died of scurvy than of any other cause (estimated 2 million sailors or 50% of any major voyage

Question 2

Vitamin C: Food Sources

Answer 2

• All fresh raw fruit and vegetables, particularly peppers, kiwi fruit, papaya, currants, berries, citrus, crucifers, mangoes and tomatoes.
• Very significant losses occur as vegetables wilt, or when they are cut as a result of the release of ascorbate oxidase from the plant tissue.
• Ascorbate oxidase is why lemon or lime juice can prevent the browning (oxidising) of other foods (e.g. sliced apple) the vitamin C creates an antioxidant barrier from oxygen until it is all used up.

Question 3

Vitamin C: Absorption

Answer 3

• Absorbed in the mouth and in the small intestine (by active and passive means). Up to 100% absorption per 200mg serving.
• Transported into cells by glucose transporters; so high blood glucose levels can inhibit vitamin C uptake significantly. Think about diabetics and clients with sugar laden diets. High doses of vitamin C can also skew blood glucose test results.
• Vitamin C concentrates in the adrenal glands, white blood cells, thymus and pituitary although there is no specific storage site .
• Factors that increase breakdown or excretion of vitamin C include: Stress: psychological, chemical, emotional or physiological, and fever and viral illnesses. Alcohol, smoking, heavy metals, aspirin, OCP.

Question 4

Vitamin C: Roles

Answer 4

Anti-Oxidant (immune boosting)
Cholesterol Lowering
Iron Absorption
Endocrine Functions
Collagen Synthesis
Neurotransmitter Synthesis
Energy Production

Question 5

Vitamin C: Anti-oxidant - Functions

Answer 5

• Primary water soluble antioxidant in blood and tissues protecting proteins, lipids, carbohydrates, RNA & DNA from damage from free radicals.
• Recycles other antioxidants such as vitamin E and glutathione making them usable again as antioxidants.
• Up regulates interferons, natural killer cells and T cells

Question 6

Vitamin C: Anti-oxidant - Therapeutic Uses

Answer 6

• Cancer
• Cardiovascular disease
• Alzheimer’s
• Asthma/COPD
• Cataracts
• Immune support e.g. cold sores (2g per day can halve healing time)

Question 7

Vitamin C: Cholesterol lowering - Function

Answer 7

• Conversion of cholesterol to bile acids (lowering blood LDL levels)

Question 8

Vitamin C: Cholesterol lowering - Therapeutic use

Answer 8

Cardiovascular disease

Question 9

Vitamin C: Iron Absorption - Function

Answer 9

• Enhances iron absorption by protecting iron from oxidation. It keeps it in Fe2+ form, not allowing it to become Fe3+,
which is not a bioavailable form.
• A dose of 25mg of vitamin C taken together with a meal increases iron absorption by 65%. Optimum iron absorption may require more than 100mg/day.

Question 10

Vitamin C: Iron Absorption - Therapeutic uses

Answer 10

Anaemia

Question 11

Vitamin C: Endocrine Functions - Function

Answer 11

• Synthesis of thyroxine and adrenal steroid hormones.

Question 12

Vitamin C: Endocrine Functions - Therapeutic uses

Answer 12

• Adrenal fatigue

* Hypothyroidism

Question 13

Vitamin C: Collagen Synthesis - Functions

Answer 13

• Vitamin C is a co factor required for collagen synthesis.

* Important for forming strong tendons, ligaments and bones, repairing wounds, improving gum health.

Question 14

Vitamin C: Collagen Synthesis - Therapeutic uses

Answer 14

• Osteoarthritis
• Cartilage injuries
• Ligament injuries
• Gum diseases
• Bruising
• Fracture repair
• Blood vessels

Question 15

Vitamin C: Neurotransmitter synthesis - Functions

Answer 15

A co-factor for the production of serotonin.

Question 16

Vitamin C: Neurotransmitter synthesis - Therapeutic uses

Answer 16

Weak digestion

Question 17

Vitamin C: Energy Production - Functions

Answer 17

• Transport of long chain fatty acids into the mitochondria for ATP production

Question 18

Vitamin C: Energy Production - Therapeutic use

Answer 18

• Fatigue

* Chronic fatigue

Question 19

Vitamin C: Deficiency Signs and Symptoms

Answer 19

• The two most notable signs of vitamin C deficiency reflect its role maintaining blood vessel integrity:
- The gums bleed easily around the teeth.
- Capillaries under the skin break spontaneously producing pinpoint haemorrhages
• When intake falls to about 1/5 of its optimal store size (approx. 1 month on a vitamin C depleted diet), Scurvy symptoms appear:
- Further haemorrhaging from inadequate collagen synthesis.
- Muscle degeneration and rough, brown scaly skin
- Wounds do not heal . Bone rebuilding falters fractures develop.

Question 20

Vitamin C: Deficiency States

Answer 20

• During stress, the adrenals release vitamin C with other hormones into the blood. The exact role of vitamin C in stress is unknown, but it is known that stress raises vitamin C needs likely due to additional free radical damage.
• Burns, infections, toxic metal intakes, chronic use of medications and cigarette smoking are among the stresses that increase vitamin C demand.
• Smokers have lower levels of serum vitamin C 25mg of vitamin C is lost with every cigarette smoked.
• Subclinical deficiency is common: susceptibility to infections, poor wound healing, fatigue, skin and gum degeneration, petechiae.

Question 21

Vitamin C: Dosage and Tolerance

Answer 21

• 500mg/day+ vitamin C is a sound general dose.
• A high dietary intake of vitamin C is cancer protective, and can be
mega dosed (e.g. 25-75g intravenously) for cancer support.
• 250mg - 1g of vitamin C prophylactically can reduce the incidence of colds by 50% in those who undertake strenuous exercise - potential support in sports nutrition .
• Unabsorbed ascorbate from very high doses (3g/day plus) is a substrate for intestinal bacterial metabolism causing
gastrointestinal discomfort and diarrhoea ( bowel tolerance)
• No high doses in third trimester of pregnancy. The baby becomes
accustomed to high doses that are unsustainable when born.

Question 22

Vitamin C - Toxicity

Answer 22

• Vitamin C is non toxic , even at extremely high doses. No reliable scientific evidence of toxicity in adult doses up to 10g per day. No credible scientific evidence that supplemental vitamin C promotes oxidative damage in humans.
• People with kidney disease and those with a tendency toward gout are prone to forming kidney stones if they take large doses of Ascorbic Acid beyond a few months
• Be mindful of high dose vitamin C with haemochromatosis.

Question 23

Vitamin C: Drug interactions

Answer 23

• May reduce effectiveness of warfarin, statins, some cancer drugs.
Increases oestrogen therapy effects. Skews diabetes test results.