Sodium nitrite change in US meat curing practices resulted in a 69% decrease in average nitrite content. This event preceded the beginning of a dramatic decline in gastric cancer mortality. Around 1970, it was found that ascorbic acid (vitamin C), an antioxidant, inhibits nitrosamine formation. Consequently, the addition of at least 550 ppm of ascorbic acid is required in meats manufactured in the United States. Manufacturers sometimes instead use erythorbic acid, a cheaper but equally effective isomer of ascorbic acid. Additionally, manufacturers may include α-tocopherol (vitamin E) to further inhibit nitrosamine production. α-Tocopherol, ascorbic acid, and erythorbic acid all inhibit nitrosamine production
Vitamin C infection. The mega-dosing theory is to a large degree discredited. Modest benefits are demonstrated for the common cold. Benefits are not superior when supplement intakes of more than 1,000 mg/day are compared to intakes between 200 and 1,000 mg/day, and so not limited to the mega-dose range. The theory that large amounts of intravenous ascorbic acid can be used to treat late-stage cancer is - some forty years after Pauling's seminal paper - still considered unproven and still in need of high quality research. However, a lack of conclusive evidence has not stopped individual physicians from prescribing intravenous ascorbic acid