Everyone knows vitamins are important in our diet, but what exactly are they? Generally, vitamins are defined as organic molecules that are needed by an organism yet cannot be synthesized by that organism. Different life forms have different needs and synthetic capabilities and thus each species has it’s own specific list of vitamins.
Most of our vitamins are obtained solely from food. One exception to this is Vitamin D; our major source for for this essential nutrient is from our skin, where it is produced/activated using the ultraviolet (UV) energy from sunlight. Vitamin K and biotin are the other special cases. While they can be derived from food, the majority is manufactured inside the intestines by the millions of “good guy” bacteria that reside there.
One important way vitamins are categorized is based on their solubility, which affects the body’s ability to store and excrete them. Water soluble vitamins cannot be “stockpiled” in body tissues, so regular intake of these important entities is necessary to good health . And because these water soluble molecules can be flushed out of the body via the kidneys with ease, there usually is no serious downside to excess intake. Water soluble vitamins include all the B vitamins as well as vitamin C.
Fat soluble vitamins, on the other hand, are not easily excreted and so accumulate in our soft tissues . Daily intake is not needed, as long as there is an overall average sufficient ingestion. With these types of vitamins, excess intake can be associated with significant and long-lasting adverse effects. The fat soluble vitamin family includes Vitamin A, Vitamin D, Vitamin E and vitamin K.
Vitamin A (carotene) is essential to producing the light-absorbing protein of the retina. It makes sense, then, that the first sign of vitamin A deficiency is night blindness; it can then progress to total vision loss. In fact, vitamin A deficiency is one of the top causes of blindness in children. Organ meats, fish oil and carrots are rich sources of this fat soluble vitamin, so kids, eat your carrots! Note that as with other things in life, too much of this good thing can be bad thing, as arctic explorers binging on polar bear livers learned–their super-high levels of vitamin A resulted in developing orange skin and liver failure!
The water soluble B vitamins all basically help the body convert food to energy. Vitamin B1 (thiamine) is particularly important to the nervous system, and a deficiency of thiamine produces a serious neurological disorder called Beri-Beri. Yeast and grains are major sources of B1 in our diet, but unfortunately some common preservatives like sulfites, destroy it, thus illustrating one benefit to preservative-free food. And since alcohol blocks thiamine absorption in the intestines, heavy drinkers have the potential to quickly develop a marked vitamin B1 shortage resulting in dangerous brain complications, such as encephalitis and psychosis. This is why emergency room physicians quickly administer IV fluids supplemented with B vitamins to incoherent/intoxicated patients.
B2, or riboflavin, is another important water soluble vitamin that is important to health skin and mucosa. It is a deep yellow-orange color and is actually used as food coloring; and it is the reason why the urine of vitamin-pill takers takes on a deep gold hue. Run short of this vitamin and you’ll suffer with cracked lips, inflamed mouth lining and irritated skin!
Vitamin B3, also called niacin, matches B2 in its importance for healthy mucosa and skin. It is also essential for normal brain function, and deficiency of this results in a dreaded illness called Pellagra. Pellagra starts with marked cold intolerance, then progresses to diarrhea,dermatitis and ultimately dementia. This alone make niacin important to us, but it is also notable that this vitamin is one of the few that has been proven to have medical use at very high doses. It can help increase the HDL (“good” ) cholesterol and decrease the LDL (“bad”) cholesterol and is actually considered the first prescription treatment for lipid disorders. Unfortunately, niacin’s effect is usually modest, and tolerance is limited by the marked flushing and liver irritation it may produce.
Perhaps the most well-known B vitamin is B12. This vitamin has a rather complex way of entering our system; after ingestion, it is linked to a specially produced protein in the stomach called intrinsic factor and then transported, like a barge being moved by a tugboat, through the small intestines until reaching a special area near the appendix where it is finally able to enter the circulation. There are many points at which this elaborate absorption system can malfunction, making vitamin B12 deficiency one of the most common human vitamin deficiencies. Severely low B12 will cause marked anemia and neurological dysfunction, but even borderline low B12 may provoke fatigue and memory loss.
Vitamin C, previously lauded as a possible cure for cancer as well as the common cold, has lost much of its prestige in the dietary community. Yet the fact remains it is crucial to the body’s primary immune defense mechanism: intact skin. Vitamin C is a critical element in collagen production; collagen is the main structural protein of skin that provides its tensile strength and elasticity. Without vitamin C(ascorbic acid), skin tears,bleeds, ulcerates and will not heal. This horrific condition is called scurvy, and killed many a sailor until food sources of vitamin c , like citrus, were made a regular part of ships’ larders.
The most common vitamin deficiency in the modern world, however, is a deficiency of vitamin D. The main source of vitamin D is sunlight, and the widespread use of sunscreen, as well as changes in air/atmosphere quality, virtually negate that as a source. Foods such as clams, beef liver, trout and salmon have abundant vitamin D, but the many well-fed adults would benefit from supplementation. As vitamin D is fat-soluble, though, overdosing is possible and problematic, so physician–guidance is invaluable.
Our bodies require vitamins to function normally; fortunately, we are able to get most of what we need by eating proper food. Folks that are unable to have a balanced diet,or have a digestive disorder that impairs absorption, or have increased needs (like pregnancy or alcoholism) may benefit from a multivitamin supplement . And even those of us with excellent intake and no confounding issues may require additional vitamin D and/or vitamin B12. Consider asking your doctor what, if any, dietary supplements would be appropriate for you!