Milk-Alkali Syndrome

The medical advice column in the Hartford Courant is by Joe Graedon and Teresa Graedon and usually contains good-quality advice. So a scary-sounding problem in their February 22 column stopped me in my tracks:

Q: How much calcium is too much? I take 1,500 milligrams a day, and my doctor wants me to add another 500 milligrams for my thinning bones. I drink milk and wonder if I may be overdosing.

A: Too much calcium (2,000 milligrams a day) can lead to "milk-alkali syndrome." The extra supplement might make you vulnerable to this complication, which increases the risk of bone fractures and kidney stones.

In some ways, this answer is technically accurate. Mostly, though, it's extremely misleading, but I have to take it apart piece by piece to explain why.

First, milk-alkali syndrome.

Say that you have too much gastric acidity. You probably would want to neutralize the acid. Chemically, you neutralize an acid by adding an alkali to it. Acids and alkalis combine to produce water, which is neutral. Antacid pills - Tums, Rolaids, and the like - do this well enough that most people don't need anything more. What did people do before Tums? Back in 1915 a physician named B. W. Sippy invented the Sippy cup. No, he didn't, though that sure would make a fun fact. He invented a process that involved giving patients massive amounts of magnesium carbonate, sodium bicarbonate, and bismuth subcarbonate along with lots of milk.

Some of the more sensitive patients responded by having the acid levels in their blood go perilously low (and the alkali levels increase), called alkalosis. They developed kidney problems, renal insufficiency. And the calcium levels in the blood went too high, or hypercalcemia. The three conditions combined began to be called milk-alkali syndrome. It was never a fatal problem, but it sure wasn't something that was helpful.

The Sippy treatment got lost to medical history and by 1985 milk-alkali syndrome was seen in fewer than 1% of cases of hypercalcemia.

Then something odd happened. Doctors found milk-alkali syndrome in patients they were seeing for other problems, like renal disease or those taking calcium for osteoporosis. Suddenly as many as 12% of cases of people with these related problems had hypercalcemia.

The source of the overage in many cases was the easily available over the counter calcium that is everywhere in antacids and vitamin supplements and calcium fortified foods.

Remember that the RDA for calcium depends on age and sex, but the usual range for adults is from 1000 to 1300 mg per day. Suddenly taking 2000 mg a day, just an extra pill or two, would seem to put you in danger.

The full medical journal article on the subject available from eMedicine.com, Milk-Alkali Syndrome by R Hal Scofield, MD,Professor, Department of Medicine, Section of Endocrinology, Associate Member, University of Oklahoma Health Sciences Center, Arthritis and Immunology Program, Oklahoma Medical Research Foundation, admits that "How oral intake of more than 2 g/d [2000 mg per day] of elemental calcium with absorbable alkali results in hypercalcemia and alkalosis is not completely understood."

I can tell you right away that one thing not understood is that 2 grams (2000 mg) a day of elemental calcium is not at all the same thing as taking four 500 mg Tums pills a day. One 2000 is not like the other 2000 and that difference is a source of endless confusion.

See, you can't buy pure calcium in a store. Calcium is too reactive. You buy it in the form of calcium salts: calcium carbonate or calcium citrate or calcium lactate. Each form breaks down in the body to yield the purer calcium. A 500 mg calcium carbonate pill contains 40% calcium, and this 40% portion is referred to as elemental calcium.

Perhaps you already see the confusion. Say that your RDA is for 1500 mg of calcium. You go out and buy three 500 mg calcium carbonate. Do you have enough calcium to meet your dairy needs? Nope, sorry. RDAs are measures of elemental calcium. Your three calcium carbonate pills yielded only 600 mg of elemental calcium. You're not even to half your need. It's worse with other forms. Calcium citrate is only about 20% elemental calcium. You'd need twice as many same sized pills to equal the same calcium need.

Let's cut through the confusion. and go back to the question from the lady who wants to add another 500 mg calcium pills to the three she already takes that provide 1500 mg of calcium. She's buying 2000 mg of calcium, but only 800 mg of elemental calcium. A women over the age of 50 requires 1200 mg of elemental calcium. So she's not in danger of overdosing; she not even getting her full RDA from supplements, so she better hope that she is getting some extra calcium from milk or other foods.

Is she at risk for milk-acidity syndrome from that 2000 mg of calcium pills? Again, no. She would have to consume regularly 2000 mg of elemental calcium. That's 5000 mg of calcium carbonate pills. That's too much. Put a warning flag on taking ten pills a day.

The RDA is expressed in elemental calcium. The warning dose for milk-alkali syndrome is expressed in elemental calcium. But the package amount on a calcium supplement is a higher total amount, only 20-40% of which is elemental calcium. Confusion in a bottle.

The only good part of the confusion is that the way it's arranged, you're not likely to wind up taking too much calcium at any time. And unless you happen to have existing problems that can be made worse by excess calcium, hypercalcemia or milk-alkali syndrome are not high priority worries.

Get enough calcium. Watch your doses. And don't worry about exotic syndromes.