Charles Russo M.D., FACCMy personal history with vitamin C actually begins at my medical school graduation when the Nobel prize-winning scientist Linus Pauling addressed my medical school class at our commencement ceremony. At that time he was well into his 80s and had been using approximately 9000 mg of vitamin C a day for years. His theory was that atherosclerosis was due to a vitamin C deficiency that actually caused a scurvy-like condition of our blood vessels and promoted the inflammation of these blood vessels that resulted in a fatty buildup that clogged them.

Today we know that atherosclerosis is indeed a chronic inflammatory condition of the blood vessels but it has nothing to do with vitamin C deficiency. Indeed, the ingestion of more than 9000 mg of vitamin C a day has resulted in significant intestinal problems including gastroesophageal reflux and chronic diarrhea. I wonder if Dr. Pauling already knew this.

Vitamin C is one of the water-soluble vitamins. However, contrary to popular opinion, although you do not store this vitamin, you can still have a toxic reaction to too much taken at one time or on a daily basis. Vitamin C is also called ascorbic acid. It was first noted as a valuable nutrient by Dr. James Lind, a physician in the British Navy, who conducted an experiment in 1747 with a group of British sailors. One group was given lemon juice to prevent scurvy and the other was not. Scurvy at that time manifested in the sailors as loose teeth, bleeding gums and hemorrhages under the skin. Dr. Lind published his results in 1753 and it took the British Navy more than 40 years to add either lemon or lime juice as standard rations for British sailors. That is how the British received the nickname "Limeys".

Vitamin C is what is called a co-enzyme. These are certain molecules that combine with other proteins in the body to form a more effective active enzyme. Enzymes are protein compounds that help to grease or enhance the metabolic machinery of our body inside cells to produce various other compounds more quickly and efficiently for energy as well as for building blocks of larger structural proteins.

If your diet contains only 50% of the daily recommended allowance of vitamin C, you will develop a deficiency within four weeks. Vitamin C is needed for the production of amino acids as well as multiple structural proteins such as collagen. It helps protect cell membranes against damage and has a significant role in cartilage, bone and tooth development. You can see how if the structural proteins are not made quickly and efficiently a condition like scurvy can develop in a short period of time. In addition, it is needed for norepinephrine production (a key neural transmitter in the body). It is also a catalyst for hormone production and enhances iron absorption in the first part of the small intestine.

Where do we get vitamin C from? We get this valuable nutrient primarily from fruits and vegetables. Citrus fruits in particular are very high in vitamin C (oranges, grapefruit) but so are honeydew, mango, papaya, watermelon, strawberries, brussel sprouts, cabbage, kale, plantains, peppers, potatoes, tomatoes... you get the idea.

The recommended daily allowance for vitamin C does vary with age and goes from 45 mg in children up to 90 mg in the elderly. Obviously infants, pregnant women and nursing women may require higher amounts.

Because this vitamin is so essential for the formation of structural proteins at the time of major illness or injury our requirements may increase dramatically because of our need to repair damaged tissue. Since this vitamin cannot be stored in significant amounts, our daily intake should dramatically increase at these times. It is thought that a burn victim may need as much as 2000 mg of vitamin C a day. That is one of the highest requirement situations a person can find themselves in and, as you see, it is a far cry from 9000 mg a day.

While vitamin C is relatively non-toxic, we have already talked about bowel irritation from excessive doses but, in addition, one of its metabolites called oxalate may increase the incidence of kidney stones in some people. Also, African-Americans and some people of Jewish and Asian descent may actually have a genetic metabolic deficiency that causes "hemolytic anemia" from excessive vitamin C intake. This is a condition where the red blood cells in the body break down prematurely and in great numbers. Vitamin C can also interfere with certain diagnostic tests the most famous of which is to give a false positive test for blood in the stool. It can also interfere with the urine test for blood sugar.

What about the common cold? Over 30 studies involving more than 10,000 episodes of respiratory infection have been evaluated with people who have taken extra vitamin C. These studies have shown about an 8% decrease in the incidence of upper respiratory tract infections in adults and up to 13 to 14% in children. Mostly what vitamin C does is to shorten the duration of the cold but not necessarily the intensity of it. Vitamin C may also be effective in reducing what is called age-related eye disease along with other antioxidants and zinc.

The recommended dose for cold prevention or shortening is not more than 2000 mg a day and for the prevention of age-related eye disease is 500 mg a day.

Lastly some studies have suggested that vitamin C can interfere with certain prescription drugs such as warfarin (Coumadin) making them less effective. Recent studies from Sloan-Kettering in NYC indicate that vitamin C could reduce the effectiveness of many standard chemotherapeutic regimens for cancer by up to 70% because of its ability to accumulate inside cells as an antioxidant. In this case the chemotherapy is trying to kill those cells and the vitamin C is protecting them! Therefore you should always ask your physician if you should be taking supplemental vitamin C.

So what is my recommendation? We should be eating plenty of fruits and vegetables every day and getting our vitamin C naturally. If you have other conditions that you think may require vitamin C supplementation check with your doctor first. Hopefully, you understand after reading this that taking large amounts of water-soluble vitamins such as vitamin C is not always safe or wise and can have serious negative side effects in certain circumstances and individuals.

Charles Russo M.D., FACC, is Board certified in internal medicine and cardiovascular disease. He lives in Fort Lauderdale with his wife and 4 children and obtained his medical degree from New York Medical College with his Cardiology degree from the University of Miami and has advanced degrees in nuclear Cardiology and Lipidology (the study of blood fats).