In the past, humans did not need to take supplements. The diet, when enough food was available, was more or less balanced with all the necessary elements for health. BUT, the Modern Diet not only misses the mark on suppling nutritious foods, it also adds extra demands due to certain growth, processing, and storage factors influencing food nutrients. Next are some of these factor details.
- Potassium to Sodium ratio turned upside down
This is a major change and not one that supplements can fix, dietary changes are necessary. One of the most profound changes in the modern diet is the balance between sodium (Na) and potassium (K). It now has turned upside down. Sodium levels today are greatly increased compared to potassium. 
Since potassium was found abundantly compared to sodium at 10 to 1 levels in past whole foods, the body only developed an evolutionary mechanism to hold onto sodium and not one for potassium, using Kidney functions. Obviously, both minerals are vital to health. article Now, with the modern diet supplying more sodium compared to potassium, this mechanism of holding sodium is having a significantly negative influence on health. As sodium levels build up, potassium and related magnesium levels in cells are reduced. Heart and stroke health are major areas of concern. ref article
Why is this reversal critical? Potassium and Sodium are both electrolytes. They participate in nerve impulse flow, muscle action, heart beat, and metabolism. Plus, they also control cell membranes for fluid movement in and out of cells. The majority of potassium is inside cells and sodium is mainly outside, until a nerve or muscle needs to work, then these minerals reverse positions, this builds energy potential for nerve impulse to travel. Then, after muscle contracts or nerves fire, the minerals have to quickly return to their original positions. There are numerous potassium-sodium pumps on cell walls to quickly accomplish this movement action. They, along with the calcium-magnesium pumps, use most of the energy produced in cells. article
Since potassium supplements at higher amounts are potentially caustic to the intestinal tract cells, like higher amounts of vitamin C in time release tablets, potassium is limited to only 99 milligrams per pill. This is only 3-4 percent of requirement (males 3400 mg. and females 2600 mg). Thus, it is necessary to both increase potassium foods and decrease sodium containing foods to maintain health.
So the question of the day is this: Why did USA Government Health Agencies recently REDUCE the requirement recommendations for potassium by over 30%? Hint: 97% of the population was not able to reach the old levels.
- Changes to the omega 3 to omega 6 ratio (meat, vegetables, and fats, oils)
Pasture grass fed cattle produce beef that has an omega 3 to omega 6 ratio of about 1 to 4. Certain grass loving bacteria produce more omega 3. When cattle are raised in cereal grain feed lots, this grass loving bacteria numbers are reduced. Another type of bacteria dominates that produces more omega 6 than omega 3. Grain lot feed cattle produce beef that can have a ratio of omega 3 to omega 6 between 1- 15 up to 1- 20. Above a ratio of 1-5, health is increasingly more difficult to maintain. ref
Why is this omega 3 to 6 ratio important? One has to look at the body processing steps for both necessary omega 3 and omega 6 fats. Both have about 5 processing steps. A middle step in omega 3 processing generates EPA omega 3. Next is DHA for brain health. 
Nature picked EPA levels to be the regulator or controller for both of these cascading processes. Fish oils supply EPA and DHA.* The same enzymes function in both omega 3 and omega 6 processing steps. When enough EPA is created, nature sends out a message to stop all processing enzymes for both omega groups, sensing there is enough of the different fats processed to maintain balance. article One of the last steps in omega 6 processing creates posteglandins, 1 to 3. While all posteglandins have vital roles to play, there is one that is of concern to maintain at just the right amount. That one is PGE2. Too much PGE2 generates chronic inflammation in the body overall. A little PGE2 is needed for events like sore muscles to use controlled amount of inflammation to promote healing. ref
Historically, in the past, the ratio of omega 3 to omega 6 fats were almost in a one to one balance. But with grain feed lots and vegetable oils dominating, the current ratio of omega 3 to omega 6 is over 1 to 20. The body is not able to control PGE2 at these levels and chronic inflammation runs rampart leading to numerous degenerative diseases. ref Is it really this simple?
Of course NOT! The body has intrinsic wisdom to adapt and counter abuses to ideal systems. Some of these systems use other omega 6 oils for positive controls to overcome a lack of enough omega 3, as EPA. These counter mechanisms often work for some time, but eventually, mother nature comes alive to bite the body.
*Fish oil supplements supplying EPA and DHA are very large molecules. Fish oils, as well as any vegetable oils, dramatically increase the need for antioxidants such as vitamin E family to protect against oxidation and rancidity of oils. ref
- Butter versus Margarine
Then there is the addition of vegetable oils substituting for butter, coconut, olive, or palm oils. 
Watch for more soon!
- The downfall of dairy
- Calcium to Magnesium Balance
- Empty Calorie Refined Foods
- Increase in Simple Sugars
- Modern Diet is changing Gut Bacteria article article
- Dysfunction of Energy System
- Disruption of Hormone systems
- Blood Presssure Control Issues
For more details, see this article.