Vitamin C – Recommended Daily Allowance

The U.S. government recently raised the recommended daily allowance (RDA) of vitamin C for adults from 60 milligrams to 80 milligrams. The following table offers RDAs for specific age and risk groups:

It’s important to note that RDAs are based on the amount of vitamin C the body needs to prevent a deficiency that would cause scurvy, rather than the amount needed to prevent disease and promote optimal health. Based on the results of many studies, some scientists now recommend a daily intake of 400 milligrams for healthy adults.

People with Special Requirements

Some people need more vitamin C because of health, nutrition, and lifestyle concerns. People who are depressed or over-stressed; who drink more than two alcoholic drinks per day; who only et cooked and processed foods; or who take analgesics, antidepressants, steroids or anticoagulants are well advised to consider a daily vitamin C supplement. Additionally, people who smoke and people older than 65 can benefit from supplemental vitamin C.


Symptoms of vitamin C deficiency include bleeding gums, easy bruising, joint pain, poor digestion, slow healing of wounds, weight loss and poor resistance to cold, flu, or other infectious diseases. Vitamin C deficiency is rare in the United States today.

Vitamin C and Disease

Many scientific studies conducted throughout the world over the past 50 years have produced solid evidence correlating adequate vitamin C intake or high levels of vitamin C intake with a reduced risk of many serious diseases and health conditions, including the following:

• Asthma
• Cancer
• Cardiovascular disease
• Cataracts
• Common cold
• Diabetes
• Hypertension
• Parkinson’s disease
• Poor immune system function

While the daily doses of vitamin C used in research studies range from 40 milligrams to nine grams (9,000 milligrams), a daily intake from 400 milligrams to 1,000 milligrams should provide maximum benefits in preventing disease and promoting optimal health. If you think you may benefit from additional quantities, please discuss your specific needs with your health care professional.


Vitamin C is typically nontoxic in oral doses, but excessive quantities may cause the following symptoms:

• Bloating
• Diarrhea
• Frequent urination
• Flatulence
• Nausea
• Upset stomach

If you are taking supplemental vitamin C and are experiencing any of the above symptoms, reduce your dosage or consult with your health care professional.

Vitamin C Fast Facts

Uses and benefits: Vitamin C plays an important role in the formation of collagen and other structural components of the body. Vitamin C is also a powerful antioxidant that supports healthy metabolism and immune system function. Vitamin C may reduce the risk of many serious diseases, including cancer and cardiovascular disease.

Sources: Rich food sources of vitamin C include citrus fruits and juices, melons, strawberries, kiwi, mango, papaya, pineapples, bell peppers, tomatoes and tomato juice, Brussels sprouts, cabbage and broccoli. Vitamin C is a fragile vitamin, so concentrations are highest in fresh, uncooked servings of these foods. Vitamin C is also available in multivitamins and as a single nutrient in tablet, capsule, powder, liquid, effervescent and even chewing gum forms.

Special considerations: Vitamin C is generally considered safe, as the body excretes excess quantities in the urine. However, too much vitamin C many cause bloating, diarrhea, frequent urination, flatulence, nausea or upset stomach.

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