Health & Wellness Articles

Calcium

By Jayna Locke

The topic of calcium causes great confusion. So let's cut straight to the core of what it is, why it is important, and how to get the amount you need.

What is Calcium?

We all know calcium is a mineral that is critical to our bone health. Here are some quick facts:

• - Calcium is the most abundant mineral in the body, making up 1.5 to 2 percent of total body weight.
• - Our bones contain more than 99 percent of the body's calcium.
• - Calcium is critical not only to the building and maintaining of bones and teeth, but also to our central nervous system, the contraction of muscles, the release of neurotransmitters, the regulation of heart beat, and the clotting of blood.

Now, let's try to cut through the confusion about sources and absorption!

Quick Facts on Calcium Sources

There are many calcium types and sources. Some sources can contain toxic levels of lead and should be avoided. These include:

• Bone meal
• Dolomite
• Unrefined calcium carbonate

Good sources are both non-toxic and "bio-available," or readily absorbed. These include:

• Calcium citrate
• Calcium sulfate
• Calcium lactate
• Calcium gluconate

Interesting note: While kidney stones can be a concern for people who increase their intake of calcium, the calcium citrate form is not only soluble (ready to be absorbed in the intestine) but it also retards the crystal growth of calcium salts, thus assisting in the prevention of kidney stone formation.

Quick Facts on Calcium Absorption

Calcium is best absorbed when it is in a soluble form, as indicated earlier (e.g. citrate, sulfate, lactate, and gluconate).

Additional factors that can affect absorption include:

• Aging. Stomach acids are reduced as we age, leaving us less capable of assimilating the calcium we consume. For this reason, it is especially critical for elderly people and people with digestive ailments to supplement with highly soluble forms of calcium.
• Hormones. Estrogen aids in the incorporation of calcium into bone. Therefore, post-menopausal women, with lowered levels of estrogen, are at increased risk for calcium deficiency and should take extra measures to include calcium in their diet as well as to consume and/or supplement with the most bio-available forms of calcium.
• Vitamin D deficiency. Vitamin D helps improve calcium absorption. Thus, adequate vitamin D intake from food and sun exposure is essential to bone health. In northern longitudes (such as the upper regions of the U.S.) sun exposure in winter does not provide adequate vitamin D, so it is important to increase dietary vitamin D.
  
  
• Caffeine consumption. Caffeine has a small effect on calcium absorption. It can temporarily increase calcium excretion and may modestly decrease calcium absorption. However, this effect is easily offset by increasing calcium consumption in the diet. For example, adding a tablespoon of milk to a cup of coffee offsets the 2-3 mg of calcium excreted as a result of drinking the coffee.
• Alcohol consumption. Alcohol can affect calcium status by reducing the intestinal absorption of calcium. It can also inhibit enzymes in the liver that help convert vitamin D to its active form, which in turn reduces calcium absorption. Currently, the evidence is conflicting as to whether moderate alcohol consumption is helpful or harmful to bone.
• High-protein diet or high sodium diet. A diet high in protein or sodium will typically increase calcium excretion. However, if a high protein, high sodium food also contains calcium, this may help counteract the loss of calcium.

Who Needs Calcium and How Much Do They Need?

The following recommended daily allowances for calcium were taken from The Dietary Reference Intakes: Elements (see Sources). Notice that calcium requirements do not differ among boys and girls, or men and women. Notice also that calcium requirements do not increase for pregnant and lactating women because calcium absorption is maximized during pregnancy and lactation. In other words, calcium consumption should be steady and reliable in the diets of all groups. A key note, here, is that while calcium requirements do not differ dramatically between the sexes, or over age gaps, absorption does decrease with age (and in women, with lowered estrogen), creating a greater need for soluble, bio-available forms of calcium.

An excellent resource for determining your current calcium intake is the Calcium Calculator.

Calcium Deficiency

Low calcium intake is associated with a variety of health problems, including:

• - Some forms of hypertension
• - Prostate and colorectal cancer*
• - Some types of kidney stones
• - Miscarriage
• - Heart-related birth defects in children when the mother is calcium deficient during pregnancy
• - Menstrual and pre-menstrual problems
• - Joint and periodontal diseases
• - Sleep problems
• - Depression
• - Weight gain
• - Osteoporosis

*Taking calcium supplements helps prevent the recurrence of polyps in the colon, a risk factor for colorectal cancer. In a well-controlled clinical trial, published in the Journal of The National Cancer Institute, calcium supplements reduced growth of polyps which can be a precursor to colorectal cancer.

The Osteoporosis Connection

Osteoporosis is a disorder characterized by porous, weak bones. This condition results when bone is being destroyed at a faster rate than it is being formed. Osteoporosis is a major public health threat for an estimated 44 million Americans, or 55 percent of people 50 years of age and older and is responsible for more than 1.5 million fractures annually. Ten million individuals—men and women—are estimated to have osteoporosis today and almost 34 million more are estimated to have low bone mass (or osteopenia), placing them at increased risk for the disease in the future. The risk of osteoporosis is that weight-bearing bones such as the vertebrae and hip become more susceptible to fracture.

The Link to Weight Management

While the involvement of calcium and dairy products in weight regulation and body composition is complex and not well understood, studies are gaining momentum. From the National Institutes of Health, Office of Dietary Supplements' "Calcium Fact Sheet":

Three small, recently published clinical trials show that calcium-rich dairy products may help obese individuals following reduced-calorie diets to lose some excess weight and fat. In one trial, 32 obese adults were randomized to one of three groups: eating a standard diet providing 400-500 mg calcium, eating a standard diet supplemented with 800 mg calcium, and eating a diet with 3 servings/day of dairy products to provide 1,200-1,300 mg calcium. The subjects ate 500 fewer calories a day over the 24 weeks of the study. All lost weight and body fat, but those taking the calcium supplements lost significantly more than subjects eating the unsupplemented standard diet, and those on the high-dairy diet lost by far the most. Dairy products also favorably affected body composition in a small group of obese African-American adults who followed a weight-maintenance program for 24 weeks. Subjects who ate 3 servings/day of dairy products, which increased calcium intakes to 1,200 mg/day, lost significantly more fat (both total body and abdominal) and preserved lean body mass as compared to those who consumed less than one daily serving of these foods and 500 mg/day total calcium.

Exercise and Bone Health

Getting enough calcium is not as simple as eating well or taking a supplement every day. Exercise also plays an enormous role, and is critical for healthy bone development in children, as well as continual rebuilding of bone mass in adulthood. Increasing peak bone mass in young adulthood through calcium supplementation and exercise can reduce the risk of osteoporosis in later adulthood.

From the National Institutes of Health, Office of Dietary Supplements' "Calcium Fact Sheet":

During childhood and adolescence, bones increase in size and mass. Bones continue to add more mass until around age 30, when peak bone mass is reached. Peak bone mass is the point when the maximum amount of bone is achieved. Because bone loss, like bone growth, is a gradual process, the stronger your bones are at age 30, the more your bone loss will be delayed as you age. Therefore, it is particularly important to consume adequate calcium and vitamin D throughout infancy, childhood, and adolescence. It is also important to engage in weight-bearing exercise to maximize bone strength and bone density (amount of bone tissue in a certain volume of bone) to help prevent osteoporosis later in life. Weight bearing exercise is the type of exercise that causes your bones and muscles to work against gravity while they bear your weight. Resistance exercises such as weight training are also important because they help to improve muscle mass and bone strength.

Good examples of weight bearing exercise include walking, running, skating, and dancing.

Food Sources of Calcium

Dairy products, for those who can tolerate them, have some of the most soluble forms of calcium. Milk is the most recommended source of dietary calcium from the USDA. Milk is also a good source of phosphorus and magnesium, which help the body absorb and use the calcium more effectively. Vitamin D is essential for efficient utilization of calcium. Milk is fortified with vitamin D for this reason. Other dairy products such as yogurt, most cheeses, and buttermilk are also recommended.

Interesting note: Calcium is not contained in the fat portion of milk, so removing the fat will not affect the calcium content. In fact, when you replace the fat portion that has been removed with an equal part of skim milk, you are actually increasing the calcium content. Therefore, one cup of skim or non-fat milk will have more calcium than one cup of whole milk because almost the entire cup of skim milk is the made up of the calcium-containing portion.

Even more loaded with calcium, are green leafy vegetables such as kale, broccoli, collards, mustard greens, turnip greens, and bok choy or Chinese cabbage. While spinach does contain plenty of calcium, it is excluded from the list of good sources because it is high in phytates and oxalates, compounds known to bind with calcium and reduce absorption. The same is true of high fiber whole grains. Note, however, that the negative effect on calcium absorption is restricted to that food itself, and does not extend to the calcium in other foods consumed at the same time.

How Much Calcium is Too Much?

While regular calcium intake from a reliable, soluble source is important, excessively high intakes of calcium (>2500 mg per day) can also have adverse effects. Risks include hypercalcemia (elevated levels of calcium in the blood), impaired kidney function and decreased absorption of other minerals. Note, however, that hypercalcemia from diet and supplements is very rare. Most cases of hypercalcemia occur as a result of advanced malignancy.

If you have a diet rich in calcium, a wise approach is to assess your current calcium intake before adding a supplement.

Thank you for reading. All comments are welcome. I look forward to providing you with more health tips in the future!

To Your Health!

Jayna Locke
email: jayna@xn----9sbif7bbcmdtk.xn--j1aef.xn--p1acf
tel no.: 952-913-6813
toll free msg center: 1-800-556-6436
web: www.newvitalitywellness.com

Sources

• National Institutes of Health, Office of Dietary Supplements' "Calcium Fact Sheet."
• National Institutes of Health, Office of Dietary Supplements', "Vitamin D Fact Sheet."
• Surgeon General's Report on Bone Health and Osteoporosis.
• USDA's "Dietary Guidelines for Americans."
• USDA's "Dietary Reference Intakes: Elements."
• The US Food and Nutrition Information Center's "Vitamins and Minerals" page.
• Murray, N.D., Michael T., Encyclopedia of Nutritional Supplements, Three Rivers Press, 1996.

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