Even though, you may be trying to eat well with a variety of good foods, you still don't know if you are getting all of the essential elements your body requires daily through eating.  I nutritionally consult people daily and have done this through the years with over 28,000 people in my database.  I have never met with anyone that didn't express some kind of a negative physical or mental manifestation that was causing them concerns.  Some serious and some not too serious.  I have asked many times, since there are 12 essential vitamins, 17 essential minerals, 9 essential amino acids, and essential fatty acids that the body requires daily, are you getting all of these?  We simply don't know in today's culture if the foods we are eating will provide them all.  

We learn somewhat fundamentally what elements food contain in theory in various levels of our education.  Notice the "in theory" words?  Are the theories guaranteeing the various foods have all they are purported to have?  Of course, not.  For many years, we have known that our foods are mineral depleted by assays performed in labs.  Largely due to not reclaiming the ground, re-fertilizing, letting the ground rest for a while, too much rain in some areas of the country, too many pesticides, insecticides, herbicides, etc.  The ground needs selective minerals and supplements to allow crops to grow healthy.  For pasture land to regenerate elements for livestock to get nutrients from their feed into their meat and milk.    There was a study done in one part of the country over a fifty year period to determine the beta carotene content of 8 vegetables grown in that area.  Over the fifty years, the beta carotene content was decreasing to where even carrots grown in the study had zero beta carotene at the end of the study!  How do you take beta carotene out of a carrot? 

We generally reach satiation as we eat and feel satisfied.  Our children and grandchildren fill-up their tummies and we are happy.  We all get filled-up as we finish our meals but did we receive the essential nutrients necessary to avoid various physiological and psychological dysfunctions?  In most cases, we lack the aforementioned daily nutrients in one form or another. 

--Thus, having a good daily multiple vitamin/mineral supplement is a good idea to assure these two areas. 

--Having a fish oil dose as an essential fatty acid in a flavored liquid or in a capsule daily is a good idea.  If we ate good fish 3-4 times each week, we probably wouldn't have to supplement with capsules. But who eats fish that often.

--At least one helping of some kind of meat daily will provide all the essential amino acids required by the body.  (When I mention meat, this would include either fish, or chicken, or turkey, or red meats, or game.)  Unless a person is trying to build muscles such as a weight lifter or a sports person, we generally don't need extra protein supplement powders, etc. 

Since science doesn't really know the fundamental cause of some illnesses such as cancer, mental illness, influenza, M.S., Parkinson's, anxiety, depression and many others, could the answer be as simple as getting the essential nutrients into our systems daily?  Perhaps the answer is more simple and fundamental than we know.      

So many health issues could be resolved if everyone would supplement properly.  Food alone just won't suffice.  Choose a reputable supplement provider and not the cheap pablum often found in the dollar stores and grocery stores.