Vitamin C (ascorbic acid) helps tissue and bone grow and repair themselves. While vitamin C supplements are extremely popular, research has yet to establish solid health benefits.
Why do people take vitamin C?
Studies have not found solid evidence that vitamin C helps prevent or treat colds in average situations.
Vitamin C’s antioxidant benefits are also unclear. While some studies of vitamin C supplements have been promising, they have not found solid evidence that vitamin C supplements help with cancer, stroke, asthma, and many other diseases. Some evidence suggests that vitamin C may be helpful in people who have high cholesterol and in preventing cataracts.
Data on vitamin C and heart disease are mixed. Some studies show an association between low levels of vitamin C and heart disease risk, yet many studies have linked the use of vitamin C supplements with an increased risk of heart disease.
Data on taking vitamin C for hypertension are also mixed. Taking vitamin C with antihypertensive medications may slightly decrease systolic blood pressure, but not diastolic pressure. Supplemental vitamin C — 500 mg per day taken without antihypertensives — doesn’t seem to reduce systolic or diastolic blood pressure. Type 2 diabetics who supplemented with vitamin C and remained on their antihypertensive medications seemed to have a reduction in blood pressure and arterial stiffness. Lower levels of vitamin C in the blood are associated with increased diastolic and systolic blood pressure.
Studies have also shown that dietary rather than supplemental sources of vitamin C are more effective in keeping blood pressure in check.
A substantial number of people may have low intake levels of vitamin C due to the inadequate intake of fruits and vegetables.
Vitamin C also seems to help the body absorb the mineral iron.
How much vitamin C should you take?
The recommended dietary allowance (RDA) includes the vitamin C you get from both the food you eat and any supplements you take.
For children under 1, only an adequate intake (AI) is available
- CHILDREN
0-6 months 40 mg/day
7-12 months 50 mg/day
1-3 years 15 mg/day
4-8 years 25 mg/day
9-13 years 45 mg/day
-FEMALES
14 to 18 years 65 mg/day
19 years and up 75 mg/day
- Pregnant 18 years and under: 80 mg/day
19 years and over: 85 mg/day
Breastfeeding 18 years and under: 115 mg/day
19 years and over: 120 mg/day
MALES
14 to 18 years 75 mg/day
19 years and up 90 mg/day
Smokers need 35 mg/day more vitamin C than nonsmokers.
Although many people take much higher doses of vitamin C, some studies have found that doses above 400 milligrams are not utilized by the body. Instead, the extra vitamin C is excreted in urine.
Higher doses might be used to treat vitamin C deficiencies. But don’t take more unless a doctor says so.
Can you get vitamin C naturally from foods?
Many people get enough vitamin C from their diets. All fruits and vegetables have some vitamin C.
Some of the best sources are:
• Green peppers
• Citrus fruits and juices
• Strawberries
• Tomatoes
• Broccoli
• Sweet potatoes
Light and heat can reduce vitamin C levels. Fresh and uncooked fruits and vegetables have the most vitamin C.
What are the risks of taking vitamin C?
• Side effects.
At recommended doses, vitamin C supplements are safe. However, they can cause upset stomach, heartburn, cramps, and headaches in some people. High doses of vitamin C can cause more intense symptoms, such as kidney stones and severe diarrhea.
• Interactions.
If you take any other regular medicines or chemotherapy drugs, ask your doctor if it’s safe to take vitamin C. It can interact with drugs like aspirin, acetaminophen, antacids, and blood thinners. Nicotine may reduce the effects of vitamin C.
• Risks.
People who are pregnant or have gout, liver disease, kidney disease, and other chronic diseases should check with a doctor before using high doses of vitamin C supplements.
