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To Your Health:
To Your Health:
Calcium and Weight Management
By Nancy DiMarco, Ph.D.
Calcium performs a myriad of functions in the body — the most well known
is its relationship to maintenance of bone density. But calcium also is involved
in many life-sustaining functions including heart beat, blood clotting, enzyme
and hormone function and transmission of messages to change metabolism.
A growing body of evidence indicates that calcium also may play a role in weight
management. Let’s take a little journey through some important studies
that demonstrate this link.
The current statistics for the obesity epidemic, coming from the Centers for
Disease Control, estimate that 64 percent of adult Americans and 20 to 25 percent
of our children are overweight or obese. In 40 years, the number of overweight
and obese individuals has doubled in the United States. In a recent anecdote
from the British, they are alarmed at the recent increase in overweight and
obese Brits to 16 percent! In the U.S., we would be thrilled if our numbers
were that low.
Now, what about that link between calcium intake and weight?
One of the earliest pieces of this puzzle was uncovered in the late 1980s when
a group of obese African-American men with high blood pressure added two cups
of yogurt (replacing other foods with an equal number of calories) to their
diet. Their calcium intake increased from 400 mg to 1,000 mg daily and just
by making that simple change, these men over a year’s time lost 11 pounds
of fat. They did nothing else to change their diet or exercise habits.
At the same time, a study was done using data collected from the Nationwide
Food Consumption Survey (1987-88) and it showed that as calcium consumption
increases, body weight decreases.
A similar study showed that among all ethnic groups, African Americans consume
the least amount of calcium and exhibit the greatest prevalence of obesity.
The idea that calcium was somehow involved in regulation of fat stores and
mobilization was studied by Michael Zemel at the University of Tennessee. Along
with animal and human cell laboratory research he conducted which supported
that hypothesis, Zemel also analyzed data from the National Health and Nutrition
Examination Survey and found that people who eat the most dairy products have
the lowest body fat — even when taking into account number of calories
consumed, sex, age and amount of physical activity.
More studies have been conducted on children and obese individuals and the
results have remained constant: Those individuals who consume the greatest amounts
of dairy products (not calcium supplements) do a better job with weight management.
How much calcium is enough? Well, the majority of Americans, including children,
do not consume enough calcium in their diets.
Among children ages 9-12, the average daily calcium intake is approximately
half of the recommended 1,300 mg. With the epidemic of childhood obesity ever
increasing, parents would do well to stop the over consumption of soft drinks
(they contain “nothing of social redeeming value,” according to
one of my children’s swim coaches) and focus instead on foods rich in
calcium.
One of the arguments frequently raised against increased dairy in the diet,
especially by teenage girls, is the increased fat and calories that accompanies
milk consumption. But parents can purchase lower fat dairy products that actually
have a little bit more calcium in them.
Mom and Dad also would benefit from increasing dairy sources in their diets.
Dr. Nancy DiMarco is a research professor in the Department of Nutrition
and Food Sciences, the nutrition coordinator for the Institute for Women's Health
and coordinator of the master's program in Exercise and Sports Nutrition at
Texas Woman's University. She can be reached at ndimarco@twu.edu.
Calcium Facts
- Recommended intake of calcium for individuals ages 4- 8 is 800 mg/day; ages
9-18 is 1,300 mg/day; ages 19-50 is 1,000mg/day; and ages 51 and older is
1,200 mg/day
- Best sources of dairy calcium include, low-fat yogurt (up to 400 mg calcium/8
oz) and non-fat milk (300 mg/8 oz)
- Other sources of calcium include calcium fortified orange juice (350 mg/8
oz); salmon with edible bones (180 mg/3 oz); soy milk (80-200 mg/ 8 oz); tofu
(258 mg/4 oz); calcium fortified ready to eat cereals (100-1,000 mg/ 6 oz-10
oz)
- Lactose, the sugar present in milk, promotes calcium absorption in the gut
in infants but not adults
- Oxalic acid found in spinach, chard and rhubarb ties up calcium in the gut
and decreases its absorption
- Estrogen increases calcium absorption
- Calcium absorption decreases as we age
For Further Information Contact:
Roy Kron
Director of News and Information
Tel: (940) 898-3456
e-mail: rkron@twu.edu
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