04.01.14
Testing of vitamin C supplements by ConsumerLab.com, White Plains, NY, found 27% of products selected for review didn’t contain the amounts listed on their labels. Two high-dose products contained about 40% more vitamin C than listed, and one had 15% less than listed. Taking too much vitamin C may cause stomach upset and diarrhea, and if used long-term, potentially, other negative effects.
Most adults need only 75 mg to 120 mg of vitamin C per day, which is roughly the amount in a glass of orange juice. Children need just 15 mg to 75 mg. A much higher dose (1,000 mg or more) taken daily throughout the cold season has been shown to reduce the symptoms and duration of a cold, which is why many products are designed to deliver amounts ranging from 250 mg to 1,000 mg per unit. However, side effects may occur when daily intake (including that from foods as well as supplements) exceeds just 400 mg for very young children and 2,000 IU for adults.
ConsumerLab.com also found that a common dose of vitamin C from a high-quality supplement can cost as little as one cent, or more than $1.
Products in the report included 11 selected by ConsumerLab.com and 14 others that passed ConsumerLab.com’s voluntary Quality Certification Program, as well as one other vitamin C supplement similar to one that passed testing.
Most adults need only 75 mg to 120 mg of vitamin C per day, which is roughly the amount in a glass of orange juice. Children need just 15 mg to 75 mg. A much higher dose (1,000 mg or more) taken daily throughout the cold season has been shown to reduce the symptoms and duration of a cold, which is why many products are designed to deliver amounts ranging from 250 mg to 1,000 mg per unit. However, side effects may occur when daily intake (including that from foods as well as supplements) exceeds just 400 mg for very young children and 2,000 IU for adults.
ConsumerLab.com also found that a common dose of vitamin C from a high-quality supplement can cost as little as one cent, or more than $1.
Products in the report included 11 selected by ConsumerLab.com and 14 others that passed ConsumerLab.com’s voluntary Quality Certification Program, as well as one other vitamin C supplement similar to one that passed testing.