01 Sep Got Calcium?
More than 75% of Americans don’t get enough calcium in their diet! In fact, the majority of women in a recent study underestimated their calcium intake by at least half! In this month’s newsletter, we review this important mineral.
Calcium is the most abundant mineral in the human body.
Its functions are many:– 99% is stored in our bones and teeth and calcium is crucial to bone and tooth health.- Calcium is required for muscles to contract and relax. This is true for both skeletal muscles and smooth muscles (including those of the heart and blood vessels).- Calcium is needed for the transmission of nerve signals- Calcium is also required for the release of hormones and the activation of enzymes- Calcium is an important player in clot formation
The RDA (recommended daily amount) of calcium is about 1000mg/day for adults ages 25 to 50. For children, 600-800mg a day is recommended (less for those under 1 year of age). For males and females between the ages of 9 and 18, when major growth spurts occur, 1300mg is recommended. As we age, bone breakdown increases and calcium absorption decreases. Men over age 50 and postmenopausal women need between 1000 and 1500mg of calcium a day.
What if I don’t get enough?
When blood levels of calcium drop, calcium is “borrowed” from bones. Therefore, over the long haul, a lack of calcium may result in osteopenia (thinning of the bones) or, even more severe, osteoporosis (literally “porous bones” which are fragile and prone to fracture). Muscle spasms can also be a symptom of inadequate calcium. In addition, high blood pressure (hypertension), due to blood vessel spasms, and irregular heartbeat, can also occur.
Is there such a thing as “too much of a good thing”?
Excessive intake of calcium (more than 4g per day) can cause impaired kidney function; interference with absorption of other minerals (iron, zinc, magnesium, phosphorus); and result in “ectopic” calcium deposits throughout the body. However, since calcium balance is so tightly controlled in the body, calcium toxicity from dietary or supplemental intake is rare.In the past, it was thought that calcium supplementation could lead to kidney stones. More recent studies have demonstrated that the opposite is actually true.
What factors affect calcium absorption and excretion?
- Vitamin D (either from dietary sources or made in the skin when it is exposed to sunlight) is required for absorption of calcium.
- Oxalates (found in green leafy vegetables) and phytates (found in whole grains, seeds, nuts, and legumes) interfere with absorption of calcium from these particular foods. Gentle heating, leavening, sprouting, and soaking activate natural enzymes within these foods which break down these oxalates and phytates so that they are inactive.
- Meals high in sodium or protein may increase calcium excretion.
- Caffeine also decreases absorption and increases excretion of calcium.
- Carbonated drinks (like coke) contain phosphorous which can decrease calcium levels. As can very high fiber diets.
- Alcohol can reduce absorption of calcium and inhibit liver activation of vitamin D which further affects calcium absorption.
- Stomach acid is needed for the absorption of calcium. Since many people over 60 have low stomach acid (called hypochlorhydria), they are especially vulnerable to calcium deficiency. Those who frequently use antacids are also at risk. (Hmm, what does that say for Tums® with Calcium???)- Certain medications (most notably, corticosteroids) can decrease calcium levels.
Milk is not the only source!
Despite the constant barrage of messages from the “Got Milk” campaign founders, adequate calcium can be obtained from sources other than dairy.
- Cooked soybeans contain about 300mg of calcium per cup.
- Tofu and soymilk are also good sources.
- One ounce of almonds (about 22) contains around 80mg of calcium. Other nuts, seeds, and legumes can also help to fill your calcium quota.
- Spinach, broccoli, collard greens, kale, and bok choy are all good sources- especially when lightly steamed.
- Sardines and salmon with bones and skin are excellent sources.
- Many beverages, including orange juice and rice milk, are fortified with calcium, as are a large variety of cereals.
When a conscious effort is made, adequate calcium intake from one’s diet is very feasible.
Not all supplements are created equal.
Calcium citrate or citrate malate are better absorbed than calcium carbonate which is commonly used in supplements. Certain preparations of calcium (e.g. bone meal and dolomite) can have significant contamination with lead and other heavy metals and should be avoided.As with other supplements, it is best to divide your dose of calcium and spread it throughout the day (since absorption of supplements is highest at 500mg or less).
Calcium is used in the treatment of many conditions.
Therapeutic doses of calcium can be used in the care of many disorders.
For example, in some cases, hypertension can be controlled by calcium supplementation.
In addition, there is good evidence to support the use of calcium supplements to prevent colon cancer, by preventing the recurrence of polyps in the intestines.
If you are concerned that your calcium intake is not high enough, speak to a naturopath or nutritionist to find out more information about your current intake and ways to enhance it.
Please Note: This information is for educational purposes only. Consultation with a licensed health care practitioner is recommended for anyone suffering from a health ailment.You are free to use the information in this newsletter or pass it on to others, but please keep it intact and credit it to Dr. Leat Kuzniar, ND.