Column: Trace nutrients

Do you take multivitamins? If you do, take a look at the back of the bottle at the ingredients list. Apart from vitamins A, B, C and E, how many of the ingredients do you recognize? Unless you’re a nutrition student, I’m guessing many of the names are unfamiliar.

Most of these compounds are what are called micronutrients. Like the name implies, these are nutrients that people only need in tiny amounts, unlike things like carbohydrates or protein (which are called macronutrients). For the most part, taking more than these tiny amounts usually isn’t necessary and can sometimes be harmful. Any more than small amounts of vitamin C, for example, is usually passed harmlessly but pointlessly through the body into the urine. Overdose of iron, however, can cause black and/or bloody stool, nausea, low blood pressure or even convulsions; this is why iron is often not an ingredient of multivitamins meant for children.

When I was looking at the back of a vitamin bottle, many of the ingredients were either unfamiliar, such as pantothenic acid and lutein, or elements that I didn’t know people needed, such as chromium, molybdenum and boron.

Let’s start with pantothenic acid, also known as vitamin B5. Animals need pantothenic acid to make a very important compound called coenzyme A (CoA). Without causing flashbacks to ninth-grade biology and the TCA cycle, CoA is involved in energy metabolism of a cell; in essence, it’s part of the reason you’re alive. Don’t be too worried about lacking it, though; people with a deficiency of pantothenic acid are usually only the victims of severe starvation. Essentially all the pantothenic acid that you need is in the foods you eat, primarily vegetables, whole grains and meat.

Another ingredient of some multivitamins is lutein, which is made only by green, leafy plants to increase their absorption of blue light. Lutein in the food industry is interesting because the primary reason that it is found in chicken feed (and thus, the eggs they produce) is because of its orange-red coloration, which consumers prefer over the lighter-colored egg yolks and chicken skin without lutein.

In people, lutein is mostly concentrated in the eyes, where it keeps us safe from the stress of high-energy blue light. There’s ongoing research as to whether lutein can help victims of high light-sensitivity or cataracts, but for now, just keep eating your vegetables.

Time to complicate things a little bit. One of the ingredients that I found on the bottle was chromium, which is considered a transition metal on the periodic table; however, there is actually little research that suggests that it does anything beneficial in the human diet at all. Though there isn’t evidence that it does any harm, there are only three cases where its complete removal from the diet caused a deficiency. It is required in trace amounts for lipid metabolism, but you’ll be fine without supplementing it.

Bottom line for chromium: If it’s in your multivitamin, that’s not a problem, but don’t waste your money on dedicated chromium supplements.

Similarly, the metalloid boron is needed in such tiny amounts that studies on deficiency in rats needed to ultra-purify the foods and filter the dust in the air. The corresponding amount needed for the human diet is poorly understood but likely to be extremely small (except for a few studies on postmenopausal women with osteoporosis, in which boron may help them retain calcium). Boron is considered non-toxic, as the dose which causes fatality in 50 percent of animals is about 6 grams per kilogram of body weight (anything above 2 grams per kilogram of weight is considered non-toxic).

Molybdenum, which like chromium is a transition metal, is clearer in its health benefits. Molybdenum is a part of the active site of certain enzymes and is also an ingredient in tooth enamel, which could help prevent tooth decay. There isn’t enough information to say whether too much molybdenum in people could cause problems, but too little molybdenum leads to an increased risk of esophageal cancer. However, molybdenum is found in high amounts in the soil in the U.S. and is found in foods as varied as green beans, cereals, pork and chicken liver, eggs and sunflower seeds, so deficiency isn’t a problem in the U.S.

If you eat well and supplement any vitamins and minerals your doctor tells you to supplement, then your diet should have all the micronutrients you need.

AMY STEWART can be reached at science@theaggie.org.