How Researchers Came Up With Nutrition Requirements (It's More Interesting Than You Think)

"Volunteers," by which we mean prisoners, were deprived of nutrients and then given the bare minimum they needed to be restored to health.

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My Tuesday question from student readers of NYU's Washington Square News:

Question: How can we determine our individual caloric, vitamin, carbohydrates, fats and other intake requirements per day based on our own individual weight, height and lifestyle?

Answer: You can't. You will have to be satisfied with estimates based on measurements performed years ago on a small number of study subjects.

We require calories and nutrients -- 40 to 50 separate substances that our bodies cannot make, we must get from food. Because these interact, studying one at a time gives results that may well be misleading.

Early nutrition scientists got "volunteers"-- in quotes because study subjects often were prisoners -- to consume diets depleted in vitamin C, for example. They waited until the subjects began to develop scurvy, a sign of vitamin C deficiency. Then they fed the subjects the smallest amount of vitamin C that would eliminate symptoms.

Because individuals vary in nutrient requirements, scientists used this data to estimate the range of nutrient intake that would meet the needs of practically everyone.

The Institute of Medicine compiles such data into Dietary Reference Intakes and presents the estimates by sex and age group. You can look up your requirements in DRI tables. DRIs account for the needs of 98 percent of the population. If your requirements are average, you will need less.

Few American adults show signs of nutrient deficiencies, but if you are worried about your own intake of nutrients, you can take a multivitamin supplement. Note, however, that we have no evidence to show supplements make healthy people healthier.

You can estimate calories by looking up everything you eat or drink in food composition tables, but it is easier to weigh yourself at regular intervals. If you are gaining weight, you are eating too many calories for your activity level.

With nutrition, it's best to get comfortable with estimates and probabilities.

Fortunately, eating a healthy diet takes care of nutrients without your having to give them a thought. Eat your veggies!

A version of this article appeared in the Tuesday, May 1 print edition. Marion Nestle is a contributing columnist. Email her questions at dining@nyunews.com.

This post originally appeared on Food Politics, an Atlantic partner site.

About the Author

Marion Nestle is a professor in the Department of Nutrition, Food Studies, and Public Health at New York University. She is the author of Food Politics, Safe Food, What to Eat, and Pet Food Politics.

The shooting at the compound in Amman may be related to recent protests over the Al-Aqsa Mosque.

Two people were wounded and one person died Sunday after a shooting at the Israeli embassy in Jordan’s capital, Amman. There are few details on the incident, and the motive is still under investigation. Police said one of the injured was an Israeli, and the other two victims were Jordanians, one of whom died. Both Jordanians worked for a furniture company and had entered the embassy’s compound just before the shooting and were working in one of the residential buildings on site.

Israeli authorities evacuated staff at the embassy, which is located in a wealthy neighborhood and is heavily guarded. Israeli authorities are not commenting on the shooting.

Nothing has been confirmed, but the attack could be linked to recent protests over the Al-Aqsa Mosque in Jerusalem. The site has been at the heart of mass protests, started after the Israeli government installed metal detectors at the mosque’s entrance. Israel says they’re necessary for protection after three militants earlier this month attacked and killed two Israeli guards. Muslim leaders see the metal detectors as a challenge to a pact, under which a Muslim organization based in Jordan controls the holy site.