The idea of whether to supplement can be quite controversial. Ideally, we want to get all our nutrients from the foods we eat. But, for people who have been following the Standard American Diet (SAD) for many years, or are suffering with an acute or chronic illness, food just sometimes (actually, most of the time) just isn't enough! I've outlined a few reasons below:
The SAD is full processed grains and packaged products with the intent to try manage caloric intake, increase intake of grains/fiber, and reduce fat intake. By doing so, the recommendations often lead us to a path of over eating due to lack of nutrient intake and eventually poor health because we increase our intake of poor quality fats, foods with additives, preservatives, and synthetic colors to entice people to buy. We are also intrigued by quick and easy, fast food at home, and boxed meals. These are packaged in a way to conform to the SAD recommendations and this makes them seem healthy and that you're making a great choice. Overall, the SAD eventually leads to nutrient deficiencies.
Modern farming practices deplete our soil of nutrients. Eventually, the produce we buy in the grocery stores contain far less nutrients than before. In addition, our fruits and vegetables travel a large distance to get where we buy them and the quality and freshness declines. And, these products are grown to increase sugar content and not necessarily more nutrient dense. Basically, our produce is artificially sweeter and contains less nutrients.
Conventional animal farming methods are known to be much lower in key nutrients like zinc, omega 3s, and some antioxidants. Grain only fed meats and farm raised seafood is also known to carry more toxins. Toxins greatly reduce our body's ability to utilize the nutrients from our foods and/or supplements.
If you are someone who exercises regularly, GOOD for you! And you should keep doing that. But remember, regular exercise increases your need for nutrients. This doesn't always equate to needing more calories so the focus should be on quality food versus quantity of food for most exercisers. Now, if you're an ultra K marathoner or elite athlete, you'll need more of both.
CURRENT HEALTH STATUS
If you are chronically ill (or even have an acute health crisis), your nutrient demands will increase. Quality foods and/or supplementation is so important.
In summary, the above outlines some key reason why it may be necessary for you to supplement. There are some instances where this can be for regular maintenance of health if you know you're not getting the nutrients you need OR it can be through a season of poor health, stress, or acute illness. There are some conditions where long term or even lifetime supplementation is necessary but that should be done under the guidance of a healthcare practitioner.