Doctor, do I need to take vitamins every day?

More often than not was I asked this question.  The answer is depending on who you are.  A healthy individual having a well balanced American diet should do fine without taking any vitamins.  This is not to say that vitamins are not needed by anyone or any situation.  Vitamins, like air and water, are essential to maintain normal life process.  Vitamin is called 維他命 in Chinese, which means “maintain his life,” I would say it is 維我命 （maintain my life).

Photo credit to Harvard Health Letter

Vitamin B12, together with folic acid, is required to make blood (red blood cell), lack of which can lead to a condition called pernicious anemia, which is invariably fatal.  Vitamin B12, taken by mouth, needs to bind with a protein called intrinsic factor in the stomach, so that the complex can be transferred to the small intestine to be absorbed.  One with a defect intrinsic factor cannot absorb vitamin B12.   This is why the inevitably fatal pernicious anemia can be easily “cured” by having vitamin B12 injection once a month.

Vitamin B12 is also required to maintain normal nerve and brain function, check blood vitamin B12 level is part of dementia work up.

A pregnant woman lacking folic acid (also called vitamin B9) can have a dire consequence with baby having spina bifida, a serious neurological defect.  It is so crucial that doctors advise the woman to take folic acid before they begin trying to conceive.

If one searches internet one will find vitamin D is good practically good for all organ systems from Alzheimer disease to prevent all sorts of cancers, in addition to bone health.

Speaking of vitamins none are more important than so-called “eye vitamins” which are antioxidant vitamins that include vitamin A, vitamin C, vitamin E, beta-carotene or carotenoids (lutein, zeaxanthin).  There is one credible study showing taking antioxidant vitamins (lutein and zeaxanthin) can slow down the progression of the age-related macular degeneration (AMD or 黃斑變性),

Our body cannot synthesize vitamins (vitamin D made through skin and sun light is the only exception). As is true, like every thing else, the best source of vitamins is from the Nature：The foods we eat.

Let this post serve as an introduction of vitamins, I will make separate post for each vitamin so that I can go into further details, in which I will list the best sources of each vitamin.

There are two main types of vitamins: water soluble and fat soluble.  Water soluble vitamins (all vitamin B: B1, B2, B3, B5, B6, B7, B9, B12 and vitamin C) will be expelled by the body when it doesn’t use whereas fat soluble vitamins (vitamin A, D, E, and K) will be stored in liver and fat tissue when unused, thus a potential for toxicity.

However, not every one can have a well balanced diet or can be sure whether he or she is having a well balanced diet, in which case vitamin supplements will come into play.  While picking up a vitamin bottle from shell, Dr JoAnn Manson, a nutrition guru, recommends the one with a label showing that it has been tested and certified by independent labs such as US Pharmacopeia, Consumer Lab and NSF International.