Facts
Why vitamin C is good for you
Vitamin C is required to make collagen – the strong connective tissue that holds the skeleton together, attaches muscles to bones, builds strong blood vessels and keeps organs and skin in place. Collagen is the glue that holds the body together and it cannot be made it unless there is enough Vitamin C.
Since collagen is needed to fix damage to the body, it is evident that Vitamin C helps heal wounds of all sorts. Broken bones, sprained joints, cuts, and other injuries heal a lot faster if the body gets plenty of Vitamin C. Vitamin C is also required to manufacture many of the body’s hormones.
Vitamin C is one of the body’s top antioxidants. It not only helps to get rid of the free radicals, it also helps the other antioxidants do their work better. Without enough Vitamin C, some other vitamins (ie folic acid) and minerals (ie iron) are not absorbed as well and cannot be used properly.
The immune system requires a lot of Vitamin C to run at peak levels. A person that does not have enough Vitamin C is likely to get sick more often and to stay sick longer.
People with high levels of Vitamin C have lower blood pressure, which makes them less likely to have a stroke or heart attack.
Another name for Vitamin C is ascorbic acid, which literally means “acid that prevents scurvy”.
Important vitamin C facts
- Antacids, alcohol, antidepressants, birth control pills and steroids all deplete vitamin C
- A healthy person’s body contains about 5,000mg of Vitamin C. Excess vitamin C supplements will be excreted only after the saturation point of 5,00mg is reached. During illness or stress, the body draws down on its reserves of Vitamin C and needs them to be very quickly replenished
- Many of vitamin C’s beneficial effects occur only at levels above 200mg a day
- There is vitamin C in just about every fruit and green vegetable. One food very high in vitamin C is acerola, a large red berry native to the West Indies – one cup of acerola berries has 1,600mg of vitamin C, as opposed to about 80mg for a medium-sized orange
- Vitamin C is water-soluble, so it is everywhere in the body – inside all cells and in the spaces between all cells
- To help preserve the vitamin C in foods, buy the freshest fruits and vegetables, store them in a cool, dark place and use them as soon as possible. A lot of vitamin C is lost when foods are cooked
- Large doses of vitamin C can interfere with medical tests for sugar (glucose) and calcium oxalate in the urine, for blood in the stool and or haemoglobin levels in the blood. Cut back on Vitamin C supplements for a few days before any medical tests
- Vitamin C is needed to make other enzymes that gather and remove toxins (ie lead and pollutants) out the body
- Vitamin C is one of the most important antioxidant in the body. Other powerful antioxidants such as vitamin E and glutathione need Vitamin C to work properly
Vitamin C works best with
Health
Vitamin C and health
- Preventing cardiovascular disease – according to one American study, if every adult in the Australia took an extra 500mg of Vitamin C every day, about 20,000 people would not die of heart disease every year. Not only would all those people still be alive, they wouldn’t be costing billions of dollars in health care costs every year
- Lowering cholesterol levels – studies show that people with high levels of Vitamin C have lower total blood cholesterol levels
- Lowering blood pressure – numerous studies show that people with high levels of Vitamin C have blood pressure readings that are slightly lower than people with low levels of Vitamin C
- Enhancing the Immune System – the immune system helps fight infection and vitamin C enhances the immune system – it helps it fight infection more effectively
- Healing wounds and recovering from surgery – vitamin C levels may be low right after surgery. To help speed up healing and fight off infections, vitamin C level need to be high. Current research shows that taking vitamin C before the operation and after it will make healing faster and strengthen collagen levels
- Allergies and asthma – vitamin C is a natural antihistamine. Vitamin C prevents the immune system from making high levels of histamines and also helps the body remove the histamine out of bloodstream faster, reducing the allergic reaction. Vitamin C is even more effective for asthma if some magnesium is also supplemented at the same time
- Diabetes – diabetics often have low levels of Vitamin C. Insulin, which carries glucose into the cells, to be used for energy, also carries vitamin C into the cells. In diabetics, not enough insulin enters the cells and neither does enough vitamin C.
- Preventing cancer – study after study proves that Vitamin C can help protect against cancer. People with high levels of vitamin C and other antioxidants are markedly less likely to get cancer of the lung, cervix, colon, pancreas, oesophagus, mouth and stomach. Research shows that the antioxidants remove all the free radicals and damaging toxins before they can damage cells/DNA and trigger cancer
- Men’s sperm production – there is some evidence to suggest that taking vitamin C can improve the quality and quantity of men’s sperm so that they can impregnate their partners. This is positive news for “infertile” couples. Studies show that supplementation with Vitamin C markedly raised sperm count
- Cataracts – vitamin C can help prevent cataracts in older adults. A recent study found that taking vitamin C supplements over a long period – over 10 years – lowered the risk of cataracts by over 77%
Talk to a medical professional about vitamin C supplements before taking them.
Deficiency
Groups at risk of vitamin C deficiency
- Smokers – cigarette smoke breaks down vitamin C very quickly and extra is needed to combat the damage smoking does to cells (studies show that people exposed to passive smoking also need extra vitamin C)
- The elderly – older people need more vitamin C in general, especially if they take drugs that interfere with vitamin C absorption
- Pregnant or breastfeeding women – much of the nutrients eaten are passed onto the child and extra may be needed each day to top up supplies of vitamin C
- Allergies and asthma – fighting allergic reactions and asthma attacks use up a lot of the vitamin C reserves, so extra may be required
- Just after surgery – vitamin C helps heal wounds faster and fights infections
- Diabetes – vitamin C doesn’t get into the cells of diabetics very well, so extra may be required.
- Chronic or acute infections/illnesses – the immune system needs plenty of vitamin C when it is in high gear fighting off illness or disease
- Under major stress – when under stress, the body’s systems go into overdrive and use up vitamin C extra fast
- Aspirin, birth control pills, antibiotics and other prescription drugs – these drugs either block vitamin C from being absorbed in the body or break it down too quickly
- Alcoholics – absorb less of some of the vitamin C and may not eat properly
Talk to a medical professional about vitamin C supplements BEFORE taking them.
Symptoms of vitamin C deficiency
Mild vitamin C deficiency will show up with the following symptoms:
- fatigue and tiring easily
- appetite loss
- muscle weakness
- bruising easily
- frequent infections
A shortage of vitamin C weakens the walls of blood vessels – they break easily, causing bruising and even nosebleeds.
After several weeks with no vitamin C in the diet, scurvy will develop.
Food sources
Vitamin C in food
| FOOD | AMOUNT |
Vitamin C (mg)
|
|---|---|---|
| Rose hip | 100g |
1500-2500
|
| Acerola | 1 cup |
1644
|
| Pepper, yellow bell | 1 medium |
341
|
| Papaya | 1 medium |
188
|
| Guava | 1 medium |
165
|
| Orange juice | 1 cup |
97
|
| Strawberries | 1 cup |
85
|
| Orange, navel | 1 medium |
80
|
| Kiwi fruit | 1 medium |
75
|
| Rockmelon (cantaloupe) | 1 cup |
68
|
| Cranberry juice | 3/4 cup |
67
|
| Broccoli, cooked | 1 cup |
58
|
| Mango | 1 medium |
57
|
| Brussels sprouts | ½ cup |
48
|
| Grapefruit, pink | ½ medium |
47
|
| Pepper, green bell | 85g |
45
|
| Honeydew melon | ½ cup |
42
|
| Grapefruit, white | ½ medium |
39
|
| Cauliflower, cooked | ½ cup |
36
|
| Lemon | 1 medium |
31
|
| Kale, cooked | ½ cup |
27
|
| Potato, baked | 1 medium |
26
|
| Tangerine | 1 medium |
26
|
| Pineapple | 1 cup |
24
|
| Tomato | 1 medium |
24
|
| Lime | 1 medium |
20
|
| Blueberries, fresh | 1 cup |
19
|
| Cabbage, raw | ½ cup |
17
|
| Collard greens, cooked | 1 cup |
15
|
| Banana | 1 medium |
10
|
| Spinach, cooked | ½ cup |
9
|
| Turnips, cooked | ½ cup |
9
|
| Apple | 1 medium |
8
|
| Carrot | 1 medium |
7
|
| Peach | 1 medium |
6
|
Daily intake
Vitamin C recommended daily intake (RDI)
| RDA | lifestage | age | amount |
|---|---|---|---|
| INFANTS | 0-6mths 7-12mths |
40mg 50mg |
|
| CHILDREN | 1-3yrs 4-8yrs |
15mg 25mg |
|
| CHILDREN | 9-13yrs male: 14-18yrs female: 14-18yrs |
45mg 75mg 65mg |
|
| ADULTS | male: 19-50yrs female: 19-50yrs |
90mg 75mg |
|
| SENIORS | male: 51+yrs female: 51+yrs |
90mg 75mg |
|
| PREGNANT | <18yrs 19-50yrs |
80mg 85mg |
|
| LACTATING | <18yrs 19-50yrs |
115mg 120mg |
|
| TOLERABLE UPPER LIMIT | lifestage | age | amount |
| INFANTS | 0-12mths | n/a* | |
| CHILDREN | 1-3yrs 4-8yrs |
400mg 650mg |
|
| CHILDREN | 9-13yrs 14-18yrs |
1200mg 1800mg |
|
| ADULTS | 19-50yrs | 2000mg | |
| SENIORS | 51+yrs | 2000mg | |
| PREGNANT | <18yrs 19-50yrs |
1800mg 2000g |
|
| LACTATING | <18yrs 19-50yrs |
1800mg 2000g |
|
| TOXIC LEVELS | Depends on individual’s tolerance – can be >600mg, for some and >25,000mg for others | ||
The tolerable upper limits should only be taken for short periods and only under medical supervision.
* The tolerable upper limit for vitamin C for infants aged 0-12 months has not yet been determined due to a lack of data about the adverse effects in this age group. The only source of vitamin C intake should be from food (breast milk and/or baby formula).
Toxicity
Overdosage, toxicity and cautions for vitamin C
Vitamin C is a relative non-toxic vitamin, except at exceedingly high doses.
Side effects at the high doses (listed above) are:
- gastrointestinal problems – diarrhoea, nausea and abdominal cramps.
These side effects normally stop as soon as the high dosage is reduced or stopped.
Precautions
CAUTION: People with current (or previously diagnosed) kidney stones or kidney disease should NOT take large doses of Vitamin C.
Interactions
References
References
- Carr AC, Frei B. Toward a new recommended dietary allowance for vitamin C based on antioxidant and health effects in humans. American Journal of Clinical Nutrition 1999, Vol. 69, No. 6, 1086-1107
- Enstrom JE, Kanim LE, Klein MA. Vitamin C intake and mortality among a sample of the United States population. Epidemiology 1992, 3(3):194-202
- Hornig B, Arakawa N, Kohler C, Drexler H. Vitamin C Improves Endothelial Function of Conduit Arteries in Patients With Chronic Heart Failure. Circulation Journal. 1998;97:363-368
- Morris MC, et al. Vitamin E and vitamin C supplement use and risk of incident Alzheimer disease. Alzheimer Dis Assoc Disco, 1998. Vol 12(3): 121-6
- Office of Dietary Supplements USA – has the official USA RDI for all vitamins (these are also adopted by Australia), accessed 20 August 2023
- Osiecki, Henry, The Nutrient Bible 2002, BioConcepts Publishing
- Packer JE, Slater TF, Wilson RL. Direct observation of a free radical interaction between vitamin E and vitamin C. Nature Journal 1979. Vol 278, 737-738
- Padayatty SJ, Riordan HD, Hewitt SM, Katz A, Hoffer LJ, Levine M. Intravenously administered vitamin C as cancer therapy: three cases. CMAJ March 28, 2006; 174 (7)
- Ting HH, et al. Vitamin C Improves Endothilium-dependant Vasodilation in Patients with Non-Insulin Dependent Diabetes Mellitus. J. Clin. Invest 1996. Vol 97 (1); 22-28
Last reviewed and updated: 9 May 2024