& Joannie Dobbs Sunday
January 15, 2006
All calcium sources not created equal
WE ARE ALL at risk of developing osteoporosis if we live long enough.
Excessive bone loss and bone fractures are likely to develop in both men and women who live into their 80s and 90s if they don't take steps to avoid it throughout their lives. Some people will develop serious bone loss earlier in life if their intake of nutrients needed for bone health is inadequate.
Although many nutrients are related to life-long bone health, calcium is clearly one of the most important. Unfortunately, there is a lot of confusion about what foods provide adequate calcium.
Question: How much calcium does the body need?
Answer: Adults need to absorb about 300 mg of calcium from their diet each day. To do this, it is recommended that the daily diet contain 1,000 to 1,200 mg of calcium.
Q: Why must a person consume three to four times the amount of calcium that the body needs?
A: For the body to absorb calcium from the intestines into the blood, it must be separated from its chemical companions. If the calcium is in a form that is resistant to being released, it just passes through the intestines and is not available to the body. Due to this, a simple list of foods high in calcium only tells you half of the story and can be misleading.
Q: How do the commonly listed food sources rank?
A: Although a cup of cooked spinach contains almost as much calcium as a cup of milk, the body can absorb only about 5 percent of the calcium. Consequently, you would have to eat more than 8 cups of cooked spinach for your body to absorb as much calcium it would get from 1 cup of milk.
Similarly, 4 ounces of almonds contain as much calcium as 8 ounces of milk, but meeting daily calcium needs requires eating more than 3,000 calories of almonds compared with less than 300 calories of nonfat milk. Sesame seeds require more than 6,000 calories and beans 3,000 to 6,000 calories, depending on type. Unfortunately, more than 1,000 calories of ice cream are needed to meet daily calcium needs.
Foods that contain a significant amount of calcium per serving and are known to be well-absorbed include milk, yogurt and cheese, some types of tofu, canned fish that includes the bones, choy sum (Chinese flowering cabbage), kai choy (Chinese mustard greens) and turnip greens.
Alan Titchenal, Ph.D., C.N.S. and Joannie Dobbs, Ph.D., C.N.S.
are nutritionists in the Department of Human Nutrition, Food and Animal Sciences,
College of Tropical Agriculture and Human Resources, UH-Manoa.
Dr. Dobbs also works with the University Health Service
© 2006 Honolulu Star-Bulletin -- http://starbulletin.com
Human Nutrition, Food & Animal Sciences · University of Hawai`i at Mānoa
1955 East-West Road · Honolulu, HI 96822
Page was last updated on: