Seeking the right trace minerals
DEAR DR. BLONZ >>
How many trace minerals are essential for good health? I have been seeking a supplement that includes boron, which I know is essential, but it is not listed on any supplements I've found. I'm also concerned that commercial agriculture produces food that is less healthy because it is grown in mineral-depleted soil. Must farmers put minerals back into the soil after each crop is harvested? — R.T., Haywarda
DEAR R.T. >> There are 17 essential minerals. Seven of them are needed in amounts of more than 100 mg per day: calcium, phosphorous, potassium, chlorine, sodium, magnesium and sulfur. A note about sulfur: While it is essential, it's already present in some amino acids that comprise protein and some of the B vitamins, so there is no recommended intake for sulfur by itself.
The remaining minerals are called trace minerals; these are equally essential, but are needed in smaller amounts — less than 100 mg per day. The essential trace minerals are iron, cobalt, fluoride, zinc, copper, selenium, manganese, iodine, molybdenum and chromium. Cobalt is on the list, but is not needed by itself because it is already present as an integral part of vitamin B12, an essential vitamin. Too much cobalt can be dangerous; if you are meeting your daily requirement of vitamin B12, you are getting the necessary level of cobalt. (Learn about cobalt poisoning at b.link/4ti2aae.)
You ask about boron, which is a trace element that plays a role in several bodily functions and which the body cannot make on its own. And yet, boron is not listed as an essential trace element. Why not, if we know it's needed? “Essential” minerals are identified as indispensable for one or more biological functions. This is usually determined by studies that report how a deficiency causes some type of problem that is relieved when the missing element is supplied. We know boron affects the way the body handles other minerals, but there is no “boron deficiency” disease, so it has yet to be classified as an essential trace element. This points to why I emphasize a plant-based, wholefood diet rather than relying on supplements. (Read more about boron at b.link/6e8249b.)
Now to your question about commercial agriculture and the minerals in soil: If a particular mineral is essential for plant growth, and if that mineral leaves the soil with the plant at harvest, then the farmer would need to replace the mineral, otherwise the soil would become depleted and future plants would fail to thrive. The farmer can replace needed minerals through composting, crop rotation, fertilizer or by adding specific nutrient-rich compounds, such as manure. It's not an exact science — every farmer must determine what works best with the crops in their particular geographical area.