HEALTH TIPS

Healthy Lifestyle Tips

• Professor Linus Pauling proposed that humans' inability to make ascorbic acid and the decrease in C content of our diet over the years, particularly as early humans shifted from an all vegetarian diet to a partly meat diet, has placed us at risk for getting less vitamin C than we need for optimum health. Some vitamin C advocates are quick to point out that animals that make their own vitamin C produce the human equivalent of 10 to 20 per day. The average human diet, on the other hand, contains only 30 mg per day. They also point to apes, which get an average of 5 g of vitamin C a day in the wild. 

   This theory is disputed by many nutritional experts, who claim the humans' diet was probably never strictly vegetarian and has always contained both meat and vegetables. Conventional wisdom tells us that if the ability to make vitamin C had been needed in our species' early history, it would have been carried down to today's human through own genes. Some evidence indicates that animals make their own vitamin C in large amounts because they use it up much faster than we do. Perhaps humans are more efficient than most members of the animal kingdom in that we efficiently absorb and can store small amounts of vitamin C. why carry the machinery to make vitamin C when you can let plants do it for you? Both sides of this debate are pure speculation, and no one can conclusively prove any of these points. Nevertheless, as knowledge of the importance of antioxidants in the diet grows, increasing vitamin C intake seems like a good idea.

  FUNCTION

  Vitamin C is a modified sugar molecule that is water soluble. One of the important functions of vitamin C is to serve as a water-soluble antioxidant and free-radical scavenger. It is one of the compounds in the body that protects us from oxidative free-radical damage. It is also known that vitamin C is necessary in the synthesis of hydroxyproline and hydroxylysine. These hydorxylated amino acids are building blocks of collagen, the main supporting component in connective tissue, which is the tissue that holds us together. Some types of connective tissue are cartilage, tendons, and fibers.

  A lack of vitamin C causes defects in the formation of mucous membranes and interferes with the normal healing of wounds. Without sufficient vitamin C, the tissue that surrounds and supports capillaries breaks down, and the capillaries themselves then break from lack of support. This results in back - and- blue bruise marks as blood leaks into tissue and clots there. The hallmark of scurvy, the vitamin C deficiency disease, is a lack of collagen synthesis.

  Vitamin C also stimulates the adrenal glands to manufacture cortisone and other body hormones involved in helping us cope with stresses of daily life. Vitamin C levels are high in the adrenal glands. Vitamin C is known to participate in the hydroxylation of a chemical called dopamine in the adrenal gland to form the neurotransmitter norepinephrine. Norepinephrine is essential to life because it affects many parts of the central nervous system and all of our major organs. Another important chemical in the body whose synthesis is dependent on vitamin C is carnitine. Carnitine is needed to move sugars into the mitochondria of the cells so that they can be metabolized to yield energy.

  Vitamin C increased the amount of iron absorbed from non-meat sources through the intestines by chemically reducing and chelating the iron. To be effective, the vitamin C must be taken at the same time as the iron. If you have iron-deficiency anemia, taking the iron tablet simultaneously with 100 to 200 mg of vitamin C will increase absorption by 30 to 40 percent. The vitamin C is involved in the conversion of folic acid to its active form, dihydrofolic acid, in the body. 

  In fact, one of the features of vitamin C deficiency is an anemia similar to the kind found in people deficient in folic acid. Small amounts of ascorbic acid are also needed to break down cholesterol in the blood. 

  White blood cells contain relatively large amounts of vitamin C, and it seems to be key to the ability to these cells to attack and engulf invading bacteria. Immune function is diminished in vitamin C deficiency. Deficient individuals are more susceptible to viral and bacterial infections. Interferon production by cells is stimulated by vitamin C, which may account for its importance in the defense against viruses. In addition, vitamin C is involved in the manufacture of a group of enzymes that are essential to the body's ability to break down drugs and other chemicals the body considers foreign. 

  DAILY REQUIREMENTS

  Only about 10 mg a day of ascorbic acid is enough to protect against scurvy, which is the disease resulting from a deficiency of vitamin C. Nevertheless, the average adult RDA for ascorbic acid has been set at 60 mg to provide an extra margin of safety during times of illness and stress. In the United States it is estimated that 20 to 30 percent of adults consume less than the RDA value. A current controversy is whether levels of vitamin C over the RDA value are needed for optimal health. Given the importance of this vitamin as a water-soluble antioxidant we believe that a higher levels would be beneficial. In considering what intakes might be optimal, it is important to note that 200 mg will provide about 80 percent of complete saturation of blood. Because vitamin C is "pumped" into cells by an enzymatic process, blood cells and body tissues are completely saturated at this dose. Doses of 500 mg to 1,000 mg will saturate blood. Vitamin C intakes of RDA amounts will not saturate.  Thus if you believe that for optimum health, you want to saturate your body with vitamin C, you will need to take in more than 200 mg per day. If five portions of fruits and vegetables were consumed each day, as recommended by nutrition authorities, vitamin C intake would be in the 100 to 300 mg per day range. Researchers at the National Institutes of Health note that 100mg to 200 mg of vitamin C daily will benefit most healthy Americans. Intakes higher than 300 mg will be difficult to achieve without taking supplements.