There are 2 measurements normally associated with vitamin and mineral intake
These values are useful for determining how many nutrients are in a specific amount (a serving size- 100 grams, 1 cup, etc). This is helpful if we want to add up the nutrients in our diet. If instead we want to determine if a food is generally high or low in a nutrient (nutrient dense), we have to do some math with those values. With just the knowledge that a food provides 5% of the daily value for vitamin C, we don’t actually know if it is high in vitamin C. If the food has just 20 calories, it would be high in vitamin C. However, if the food contains 200 calories it would be low in vitamin C. We can calculate the nutrient density by the formula:
Daily Value of food serving * 2000 calories / calories in food serving
A 100% nutrient density means this food helps us exactly meet the DRI. Our 20 calorie food has a vitamin C density of 500%. Our 200 calorie food has a vitamin C density of 50%.
In the past, humans were often able to be healthy by simply hunting and gathering and otherwise living their life. Today there is an endless variety of food available in any quantity desired, ironically making it easier to make bad choices. Foods are now marketed to us, often in misleading ways, and otherwise incorrect information about food is easy to come across. We are stressed out, inactive, and consuming large portions of our calories in the form of processed, nutrient depleted foods like sugar. While our modern environment has benefits, it stacks the deck against us achieving great health. Also the food we eat today may be much more lower that in the past. 1
Scientific tools like this site can be used to assist in making more nutritious food choices and wiser forms of supplementation.
The human body is extremely complex and poorly understood. This site uses the DRI to help you determine your needs, however the DRI is a best effort by a particular group of scientists that have limited information. 2
Many processed foods are enhanced with vitamins and minerals to make the food look good on paper. However, it is unlikely this makes them better food choices. Artificial forms of nutrients may not be absorbed well or may cause side effects. 3
The goal of this site is to help people meet their nutritional goals primarily by eating whole foods. A more cautious approach to health is to minimize artificial supplements, but this site can also assist with accurate supplementation where nutritional goals are not being met.
One aspect of nutrients in food is freshness - I will try to cite some evidence here in the future. Another concept is soil depletion. This idea is not without controversy. Here is one example of supporting evidence: The mineral depletion of foods available to us as a nation (1940-2002)–a review of the 6th Edition of McCance and Widdowson full text pdf
However, there are also examples where researchers have found no significant change in soil composition over time. Interestingly, even if the soil is not being depleted, our modern high-yield crop varieties can have far fewer nutrients. The Broadbalk Wheat Experiment is over a hundred years old, high quality, and well controlled. A recent paper publishes their measurements, showing that the modern dwarf wheat varieties result in lower concentration of minterals, and that increased yield was a suspected cause. Fan MS, Zhao FJ, Fairweaterh-Tait SJ, Poulton PR, Dunham SJ, McGrath SP. Evidence of decreasing mineral density in wheat grain over the last 160 years. J Trace Elem Med Biol. 2008;22(4):315-24.↩
The certainty of DRI values have been criticized by many, even in official settings. For example, In 2007, the Institute of Medicine held a workshop entitled The Development of DRIs 1994–2004: Lessons Learned and New Challenges.. In a panel discussion during the meeting:
Dr. Stoecker noted that the public has a false sense of confidence about the knowledge available for setting the DRIs. She commented that, of course, the data on many nutrients are scarce.