Nutrition-wise blog

Got food questions? We've got answers

By Jennifer K. Nelson, R.D., L.D. and Katherine Zeratsky, R.D., L.D. September 28, 2011

When my family gets together, they quiz me about food and nutrition. They've come up with some great food questions over the years. I thought I'd share a few with you.

Q: Why do beans cause gas?
A: Beans produce gas because they contain the natural indigestible sugars called oligosaccharides. In the large intestine, bacteria ferment the sugars and gas is formed.

Q: Why does soaking beans make them more digestible?
A: Soaking beans releases an enzyme that, along with the water, helps break down the oligosaccharides, making them more digestible. Therefore, fewer oligosaccharides reach the intestine, and less gas is produced.

Q: Why does powdered sugar — but not granulated sugar — clump when you add it to coffee?
A: Most powdered sugar contains cornstarch, which when added to coffee can form a gooey clump. Granulated sugar doesn't contain starch — so it doesn't clump.

Q: Why do pasta recipes recommend adding salt to the cooking water?
A: Tradition has more to do with this than anything else. It is commonly believed that pasta will cook faster because salt increases the temperature at which water boils. From a chemistry standpoint this is true. However, if you add 1 tablespoon of salt (way too much) to 5 quarts of water, you only increase the boiling point of water by 7/100th of 1 degree. Not enough to shorten cooking time.

Q: Whatever happened to cod liver oil?
A: Years ago parents gave their children cod liver oil to stave off rickets and night blindness caused by deficiencies in vitamins A and D. One tablespoon of cod liver oil contains 13,600 International Units (IU) of vitamin A and 1,360 IU of vitamin D. The upper limits are 10,000 IU for vitamin A and 4,000 IU for vitamin D. So, cod liver oil fell out of favor because of concerns about possible vitamin toxicity. Cod liver oil is making a resurgence, however, as a source of omega-3 fatty acids, which is thought to have benefits for heart health.

Do you have food questions? Send them in and we'll do our best to answer them.

- Jennifer

Sept. 28, 2011