Information on Calcium

Updated: February 5th, 2010

What is Calcium? 

Calcium is the most common mineral in the body.  99% of the Calcium is found in the  bones and teeth, the other 1% or so is found in the bloodstream and some soft tissues.  Calcium is an essential mineral that you need on a daily basis to stay healthy.  It takes up around 2 percent of your body weight.  Calcium is regulated in the blood stream and is so important to the body that the body will pull calcium from your bones in order to keep your blood levels accurate within a tight range.  When Calcium levels in the blood start falling, proteins in the parathyroid glands signal the secretion of PTH (Para Thyroid Hormone).  PTH signals the conversion of Vitamin D to its active form, which increases calcium absorption from the small intestine.  PTH and activated Vitamin D together stimulate the release of Calcium from the bone, and increases the kidneys re-absorption of calcium from the blood.  It makes sense how people get Osteoporosis after a lifetime of not having enough calcium going into your bones, doesn’t it?

What does Calcium do in the body?

Calcium is a mineral that plays a role in the development and integrity of bones and teeth, heart rhythm, secretion of hormones like insulin, blood clotting, brain, nerve, eye and muscle function, blood pressure, kidney function, cholesterol levels, and decreases the risk of things like colon cancer and osteoporosis.  Calcium helps make hormones that control digestion and how you use fats and make energy.  Calcium is used to fire impulses in nerve cells, allowing them to turn off and on to send signals.  Calcium is regulated here as well and very closely through calcium pumps in each cell that use a form of energy known as ATP.  Substances called Excitotoxins can cause your brain cells to take in too much calcium, thus causing the cells to over react and die off.  Calcium is needed for activation of several Vitamin K dependant clotting factors having to do with blood coagulation (clotting).  Calcium should be taken at least 2 hours apart from iron supplements because calcium blocks absorption of iron.  Calcium can also lower the absorption of zinc.

What affects Calcium absorption? 

Things like manganese, germanium, chloride, phosphorus, iron, oxalic acid, chromium, bismuth, and zinc can interfere with the absorption of Calcium.  Magnesium, potassium, boron, sodium, CoQ10, Vitamin B5, Vitamin K and Vitamin D are all things that can help with absorption of Calcium.  Calcium supplements should be taken with food, and doses should not exceed 500mg at a time.  Your total daily amount should be spread out into smaller more frequent dosages instead of one large one.  Calcium needs to be taken with magnesium or it may calcify in your artery walls.  Vitamin D works by being converted into a hormone that is needed to control calcium absorption and excretion.  High sodium levels can decrease Calcium absorption and cause urinary calcium levels to increase.  Protein and Caffeine have the same effect as Sodium.  Phosphorus tends to decrease the urinary excretion of Calcium, but may increase fecal calcium levels.  Calcium will bind to your stomach acid, or anything acidic for that matter so some forms should be taken when you eat for better absorption.  Because it binds to acids (making the acid less effective) calcium may cause you to not fully digest your food properly “think of Tums” if you take too much with meals.  Some forms bind to more acid then other forms, and some don’t need much at all.  Calcium citrate is a form that you can easily be tolerated without eating and requires less acid.  Drugs can affect your absorption.  Common over-the-counter drugs rob your body.  Glucocorticoids which are synthetic versions of natural hormones within the body can rob your body, including cortisone, prednisone, Dexamethasone and Hurdocortisone.    Also digitalis, Phenytoin, antibiotics, Calcibind, thyroid drugs, cholesterol drugs, aluminum antacids, alcohol and tobacco can all rob your body of Calcium.

Oxalic acid is the most potent calcium absorption inhibitor and Phytic acid is a less potent calcium inhibitor.  Foods that contain them should not be eaten unless first properly prepared.  Spinach and rhubarb are high in Oxalic, while sweet potatoes and dried beans are low in Oxalic.  Phytate also blocks calcium absorption and can be found in high amounts in wheat bran and dried beans. 

There is something present in animal fat, raw unpasteurized butter and cream called Wulzen Factor, discovered by researcher Rosalind Wulzen.  This substance acts like a hormone and prevents Arthritis and joint stiffness by ensuring that calcium in the body is put into the bones rather than the joints and other tissues.  It also prevents cataracts and calcification of the pineal gland.  Good stuff.

What forms of Calcium are there?

The preferred method of obtaining calcium is through foods.  You cannot buy pure calcium from a store.  Calcium is always combined with another mineral in nature.  The amount of calcium in a tablet is called elemental Calcium.  Forms of Calcium include Calcium Sulphate, Calcium Phosphate, Calcium Carbonate, Calcium Gluconate, Calcium Lactate, Calcium Citrate, Calcium amino acid Chelates, Calcium Orotate, Calcium Aspartate, Calcium Ascorbate.  The first 3 are inorganic forms and the rest are organic forms.  Organic forms are better absorbed than the inorganic forms, with Orotate and Aspartate being the highest absorbable forms.  Forms to avoid are bone meal, dolomite and oyster-shell calcium as they might contain high levels of lead.

What are natural sources that contain Calcium? 

Milk products are usually preferred as they have the most Calcium within them.  Good sources of Calcium are dark-green leafy vegetables, seaweeds, bok choi, nuts, blackstrap molasses, broccoli, beans, oranges, figs and small fish with tiny bones.  English muffins have about 90mg per muffin.  Eggshells can be ground up and made into powder to put in your food as an additional calcium source.  An 8oz glass of real milk (unprocessed) contains about 300mg of Calcium.

How much do you need?

Calcium deficiency can lead to Rickets, poor blood clotting, and Osteoporosis.  The RDI for Calcium depends on how old you are.  The values range from 200mg a day all the way up to 1500mg a day.  Therapeutic levels are obtained at dosages at 1000mg to 5000mg a day.  Lower amounts may help prevent certain ailments like Rickets but are not therapeutic. Too much calcium can lead to Hypocalcemia, which is caused by too much Calcium in the blood.  The Linus Pauling Institute recommends at least 1000mg a day for all ages over 9.

What can Calcium help out with in our day to day health?

Having adequate amounts of Calcium in your diet can help with many things.  Colorectal Cancer is found to have decreased reoccurrences of polyps while supplementing on 1000-2000mg of Calcium a day.  Since Calcium is the most abundant mineral in your bones, it is essential to get proper amounts throughout your life to prevent something like Osteoporosis.  Multiple studies show that higher intakes of dietary calcium reduce your risks of developing Kidney stones. Just because you have more calcium in your body doesn’t mean you have a higher risk of developing stones.  It is when the body excretes high amounts of calcium through the urine that there may be an increase in stones forming.  Meeting the recommended Calcium intake levels per day while pregnant may reduced the incidences of high blood pressure and Pregnancy-induced hypertension.  Increased dietary intake of calcium is known to decrease the gastrointestinal absorption of lead.  1000mg or more a day can reduce PMS symptoms by over 40%.  Calcium has been shown to help keep weight lower by keeping certain hormone levels in check.

MISC facts about Calcium.

Calcium citrate dissolves quicker than Calcium carbonate but has less elemental Calcium.  Calcium Orotate has a 90%+ bioavailability followed by Calcium Aspartate with an 80%+ bioavailability.  Low Calcium blood levels can be caused by kidney failure, vitamin D deficiency, and low magnesium.  Diets high in Phosphorus and low in Calcium have been shown to increase PTH.  High impact exercises and weight exercises help maintain bone strength.  Sources of calcium for supplements can contain lead, so supplements also contain lead.  You want to get a quality Calcium supplement that is “lead free” if you can.  Although Calcium blocks lead absorption in the GI tract, this fact  may or may not pose a huge concern.

Hypercalcemia (high blood calcium) usually only occurs when supplementing.  Hypercalcemia may cause loss of appetite, nausea, vomiting, constipation, abdominal pain, dry mouth, thirst, and frequent urination. Severe Hypercalcemia may result in confusion, delirium, coma, and even death if severe and not treated.

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