By Gerald F. Combs, Jr.
An Asian minister of health once remarked to me how difficult he found the job of convincing his government to invest in solving problems caused by shortages of "micro-nutrients." The term, he implied, belied their importance to good health. "Couldn't we come up with a better name?" he asked.
There is a lot in a name. New parents, marketing specialists, political strategists, college presidents and restaurant owners all know this. The Chinese once had a philosophical school based on names.
The vitamins and essential minerals are, in fact, "micro-nutrients." After all, when we add them up - nearly two dozen of them - they comprise less than two-tenths of a gram of our bodies. Even if we also consider the "macro" minerals (calcium, phosphorus, magnesium), and an adult's total need is still less than 4 grams per day - of the more than 500 grams of food Americans eat each day. The origin of the name is clear; so, why the fuss?
Whoever put the "micro" in "micro-nutrient" was thinking quantitatively. But, like the pinch of pepper that makes the sauce, "micro-nutrients" can have "macro" health impacts: only 30 milligrams of vitamin C each day can prevent scurvy in an adult; only 60 milligrams of retinol given every 6 months can prevent blindness in a vitamin A deficient child; only 4 milligrams of folate per day can reduce the risk of a neural tube defect pregnancy; only 40 micrograms of selenium per day can keep selenium-dependent enzymes expressed at optimal levels; only 1 milligram of copper per day can prevent high cholesterol in individuals with low copper intakes.
That we at the Grand Forks Human Nutrition Research Center are researching the roles of micronutrients in supporting good health is appropriate.
First, it is the logical progression - indeed, the necessary complement - to our long established leadership in mineral nutrition. Accordingly, Eric Uthus's work on the role of selenium in affecting single-carbon metabolism and, thus, cancer risk, naturally led him to working with another effector of that metabolism, the vitamin folic acid. Janet Hunt's work on the bioavailability of dietary iron led her to consider vitamin C, which can affect iron absorption. Their work on the effects of copper and boron in calcium utilization has led Fariba Roughead and Curtiss Hunt also to include vitamin D in their studies of dietary support of bone health.
Second, micronutrients are likely to be the most important determinants of health values of foods and, in many cases, their most variable constituents. Hence, John Finley is working to elucidate how selenium-fertilization of broccoli can affect the plant's ability to produce cancer-protective substances, and how high-selenium pulses and grains can be produced through field-source selection; Henry Lukaski and Phil Reeves are using animal models to determine the anti-diabetic potential of buckwheat carbohydrates.
Third, micronutrient deficiencies are prevalent across the globe - 40% of all women are anemic due to insufficient bioavailable iron; 250,000 children go blind each year due to insufficient vitamin A; at least 40% of the world's soils are deficient in zinc; rickets occurs in more than 22 countries due to deficiencies of calcium and/or vitamin D.
The essential minerals and vitamins are indeed keys to good health affecting every aspect of our cellular and physiological functioning. Optimizing micronutrient nutrition, therefore, is certain to play an important role in our national effort to support healthy body weights and prevent the emerging epidemic of obesity and its attendant morbidities, particularly diabetes, heart disease, stroke and certain cancers. While such efforts must address the central issue of energy - balance, intake and expenditure - they must also address food access, attitudes and behaviors; nutrient adequacy and utilization; and metabolic efficiency, all issues related to the "micronutrients" and, thus, to foods.
What's in a name? The term "minerals" connotes that they are obtained from the earth, mined. "Vitamins" was coined to connote that they are vital for health. Do we lose communicative power, as my foreign colleague suggested, by bundling these critical nutrients together as "micronutrients"? Perhaps. But, at the Grand Forks Human Nutrition Research Center we are not as much concerned with the name as with the outcome. To us, and to your health, micronutrients are big deals!