Vitamins are parts of enzymes you can't live without, and your body can't make. We take them for granted today, but vitamin deficiency diseases plagued our ancestors and took a long time to figure out.

Vitamin C is found in fruits and vegetables, and Scurvy, caused by lack of vitamin C for many weeks or months, wasn't identified until people were separated from plants for long periods of time and that first occurred when they built ships that could go on long voyages.

The crew of Magellan's voyage around the world in 1519 got scurvy, and in 1600 a British report showed 10,000 sailors had died of scurvy in 20 years. In 1747, James Lind, the ship's physician aboard the HMS Salisbury, conducted an experiment on 12 sick men. He divided them into six groups and fed them all the same diet, but gave each pair a different supplement: apple juice, sulfuric acid, vinegar, a mix of spices, sea water, or citrus fruits.

The two men given the oranges and lemon recovered immediately and were back at work in six days. The men who had apple juice improved, but not enough to work. None of the others got any better. Lind's report led to lemon juice rations on long voyages and sailors called "limeys."

Without vitamin C you don't make collagen, essential to connective tissue, so your gums bleed, teeth loosen, joints and muscles ache, and eventually you die. Any reasonable diet that includes fruits and vegetables gives you enough, so scurvy is rarely seen in North America today.

What about the Eskimos? Most animals, except humans, make their own vitamin C and it's possible to get enough vitamin C to sustain you from fresh meat, especially liver. The word "eskimo" means raw flesh eaters.