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Jo-Anne M. Rizzotto, M.Ed, R.D., L.D.N., C.D.E.

Jo-Anne Rizzotto, MEd, RDN, LDN, CDCES, is Director of Educational Services at the Joslin Diabetes Center and Harvard Medical School in Boston, MA. She is a registered dietitian and a certified diabetes educator with over 25 years of clinical, research, management and industry experience and is a key member of the clinic leadership team. Jo-Anne is co-chair and an active member of the National Certification Board of Diabetes Educators Exam Board. Jo-Anne has a proven track record of managing many facets of quality assurance and improvement with documented outcomes including advancing the use of technologies in the clinic for the management of diabetes. Jo-Anne establishes, directs and manages all aspects of diabetes education programs including overall direction, content, design, delivery, budgeting and staff management. She ensures all programs and staff delivering education meet the highest quality standards and do so with the highest level of efficiency and effectiveness. Jo-Anne participates in and has been the co-principle investigator in numerous clinical research studies. Jo-Anne chairs and participates in a variety of high level selection committees, clinical guideline committees, publication review committees and academic promotion committees. She also chairs the quality committee with the General Counsel at the Joslin in addition to the Clinic policy and procedure committee.

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Vitamin supplements and fresh lemon

Difference Among Vitamin C Supplements

Ask the Expert


What is the difference among different vitamin C supplements? How do they compare to each other and to whole foods, such as oranges?


Vitamin C is an essential nutrient required for growth and repair of tissues in our bodies. It is also needed to form collagen, an important protein and component of blood vessels, tendons, ligaments and bone. In addition, vitamin C is an antioxidant, a disease-fighting molecule that helps prevent disease by fighting free radicals, substances that can attack and damage the body's cells and tissues. Free radicals are formed by normal bodily processes as well as by environmental contaminants like cigarette smoke. Because our bodies can't make and store vitamin C, we must obtain this nutrient through our diet.

Vitamin C deficiency can cause dry hair and skin, bleeding gums, decreased wound healing and bruising. A more serious, severe deficiency can lead to scurvy, but this is uncommon; however it can occur in malnourished individuals, and those with increased vitamin C requirements, such as pregnant and breastfeeding women and infants receiving unsupplemented milk diets.

The Orange Route
The recommended daily intake of vitamin C for women older than 18 is 75 milligrams (mg)/day. Women who smoke need even more vitamin C - 110 mg/day. And women who are breastfeeding need closer to 95 mg/day. The best way to meet the daily vitamin C requirement is by eating a healthy, balanced diet that is rich in fruits and vegetables. Some of the best sources of vitamin C include green and red peppers, citrus fruits and juices, berries, tomatoes, broccoli, leafy green vegetables, sweet and white potatoes and cantaloupe. The following are rich sources of vitamin C that are easy to incorporate into your daily diet:

Source Vitamin C (mg) 1 medium orange 68 1-cup orange juice 82 1-cup cooked frozen broccoli 74 1 medium fresh tomato 16 1-cup low sodium V8 67 1-cup cubed cantaloupe 59

When Fruit Isn't Enough
Taking a vitamin supplement may be a healthful option if you can't meet the recommended vitamin C intake through diet alone. Vitamin C supplements come in two basic forms: ascorbic acid and ascorbate. Although ascorbic acid is the most inexpensive and standard form of vitamin C, many people find it to be too acidic. Supplements made with ascorbate, on the other hand, are more expensive, but are better tolerated because the ascorbate is attached to minerals, such as sodium, calcium or magnesium. Despite the cost, you may get more bang for your buck with ascorbate-containing supplements because they are also good sources of minerals, such as calcium.

Ester-C is a more costly, yet innovative form of vitamin C. In addition to calcium ascorbate, this product also contains other vitamin C metabolites. Manufacturers of such products suggest the added metabolites help the body absorb the vitamin C and keep the vitamin C in the cells longer. Beware, however, these claims are made by the manufacturers and have not been substantiated by scientific data.

No matter how you meet your vitamin C requirement, you should not consume more than 2000 mg/day. High doses can lead to stomach upset, kidney stones and severe diarrhea.

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