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How Healthy is too Healthy?
Certain nutrients have an intake limit for a reason; too much of one thing can actually harm the body.

By Erin McHenry

 
Do you get enough calcium? Vitamin C? Iron? There are pills for that. There’s a pill for about everything. But more is not always better. Exceeding the upper limit of recommended nutrients is potentially harmful.

“In general if you take a vitamin or a one-a-day time supplement, you’re not going to get into trouble,” said Carol Haggans, a scientific and health communications consultant for the National Institute of Health’s Office of Dietary Supplements. “But if you start taking individual supplements, you know, where you’re taking a bottle of vitamin A and a bottle of vitamin D and adding those up or you’re taking more than the recommended amount, that’s when you get into trouble.”

Calcium strengthens bones and vitamin A improves vision and strengthens the immune system, but too much vitamin A could harm the liver and an excess of iron could even be fatal.

So, just how much does it take to overdose on a nutrient? It’s different for everyone, but here are a few examples of how much the body can handle before it reacts badly.

Vitamin A
“There’s what’s called ‘pre-formed vitamin A,’ which is present in animal products, and then there’s ‘vitamin A beta-carotene,’ which is present in things like carrots or other vegetables,” Haggans said.

The beta-carotene is virtually harmless, so there isn’t really a limit, but eating too many carrots could turn skin orange.

The pre-formed vitamin A, however, can cause serious liver damage or birth defects in infants. Three ounces of beef liver contains more than 20,000 micrograms of vitamin A. Eat that every day and some negative effects are sure to appear. A more common vitamin-A-rich food: French vanilla ice cream. It would take 10 cups of French vanilla ice cream a day to overdose on pre-formed vitamin A. Challenge accepted!

Iron
Haggans said she’s heard of kids getting into bottles of chewable vitamins — the ones that taste like candy — and eating enough to kill them. While snacking on Flintstones vitamins is not recommended, overdosing on iron is pretty difficult. According to the University of Maryland Medical Center, it takes 50-to-100 times the normal levels of iron to overdose. The daily-recommended amount of iron is 45 milligrams. Each Flintstones vitamin has 18 milligrams of the stuff. So do the math … that’s 250 candy-coated chewables to scarf down. Gross.

Calcium
There’s a reason most people fail the gallon challenge — chugging a gallon of milk in 60 minutes — and it’s not just because it’s like swallowing a liquid brick. Drinking half a gallon (between eight and nine cups) of milk in a day goes beyond the Federal Drug Administration’s recommended limit. More importantly, though, more than nine cups can start to make things messy. Too much calcium can cause constipation or kidney stones. Got milk?

Caffeine
It’s not a vital nutrient, but on a dull Monday morning, it feels like it should be. The recommended limit of caffeine per day is 400 milligrams, about four or five cups of coffee. Coffee drinkers who regularly exceed that limit beware, because the body adjusts to having caffeine in its system. Drinking less than what the body expects can have dose-dependent effects like shaky hands, jitters and headaches. “Drinking too much can even be fatal if you actually take an extremely high amount of it,” Haggans said. Depending on your weight, though, you might have to quickly drink over 100 cups of coffee to get to that “extremely high amount,” and even then, you’d die from ingesting all the water before the caffeine gets you.

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Photo courtesy of Sarah Korf

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