Vitamin C or L-ascorbic acid has been known since ancient times. People in many parts of the world assumed that such forbidding disease as the Sea scurvy was caused by a lack of fresh plant foods. The British Navy used to adhere to the special sailors’ diets with lemon juice as far back as 1795. Ascorbic acid was discovered in 1933 and synthesized in 1934.
Today vitamin C is well known as an essential nourishment for humans and a large number of higher primate species and other mammalian species (notably guinea pigs and bats) and also a few species of birds, and some fish.
In humans, vitamin C helps to generate collagen in body tissue and builds up blood vessels, skin, teeth and bones; it permits the body to absorb iron from food and it helps to defend the body from free radicals. So it is really necessary for our well-being.
The richest natural sources are fruits and vegetables:
- citrus fruit crops and citrus juices;
- broccoli, brussels sprouts, white cabbage;
- potatoes;
- watercress, punch, fennel, spinach;
- pepper (both sweet and bitter);
- tomatoes;
- blackberry, briar, strawberry.
Vitamin C chemically decomposes under certain conditions, as usual during the cooking of food. For all usual claims to the contrary, boiling water at 100°C does not cause any significant destruction of the vitamin, the necessary for decomposing temperature is about 190°C. Nevertheless, pressure cooking, roasting, frying and grilling food usually lead to the decomposition of vitamin C. Longer cooking time also has this effect.
Recommended daily intake:
Recommended dietary allowance is different in different countries and depends on the particular health services. So the recommended daily intake:
• the United Kingdom's Food Standards Agency - 40 milligrams per day;
• the World Health Organization - 45 milligrams per day;
• Health Canada 2007 - 60 mg/day;
• United States' National Academy of Sciences - 60–95 milligrams per day.
The United States defined Tolerable Upper Intake Level for a 25-year-old male is 2,000 milligrams per day.
So, common sense guides us to suppose that it is permissible and reasonable to pick out an individual dose. But keep in mind: high doses (thousands of milligrams) may result in diarrhea even in healthy adults. Though the supporters of alternative medicine (especially orthomolecular medicine) are committed to adjustment of vitamin dosage and hold to account by the incipient problems for the quality of taken products.