Recent talk that "calcium supplements can kill you," citing a recent European publication, made people very apprehensive, confused and even scared.
No wonder. For decades, we were told that calcium supplements are good for bone health. Now, they say, it can kill you by increasing the incidence of heart attacks and strokes. Is either of the conclusions really true?
A previous article published in British Medical Journal supported the conclusion from this European study that calcium supplements can be harmful. But a study published in Archives of Internal Medicine (the Iowa Women's Health Study, October 2011) came up with the opposite conclusion.
This is nothing new. For years, we have heard opposing conclusions about beneficial health effects of chocolate, eggs, shrimp, several vitamins, many minerals, glucosamine, fish oil, folic acid and even aspirin.
The Iowa Women's Health Study reported that in older women, several commonly used dietary vitamin and mineral supplements, especially iron, were associated with increased mortality risk — except for calcium and vitamin D, which decreased death rate.
Most of the contradictory and controversial conclusions come from observational studies. In these population studies, a lot of information is gathered looking for association between different things. That does not prove cause-and-effect relation between any two particular factors. Many other unrecognized confounding factors can affect the conclusions.
Cholesterol is one of the examples. For decades, the medical community believed that estrogen supplementation can protect against heart attacks in postmenopausal women. Simple observations led to that intuitive conclusion. Fact one: Menstruating women are mostly spared from heart attacks because of the protective effect of estrogen. Fact two: Estrogen tends to reduce bad cholesterol and increase good cholesterol. Fact three: Low levels of bad cholesterol and high good cholesterol reduce the incidence of heart attacks.
A equals B. B equals C. So, A should equal C. So we thought for decades. It works in mathematics, not necessarily in medicine. When tested in controlled clinical trials, costing millions of dollars, the results turned out to be opposite. Hormone supplementation did not decrease heart attacks. It caused more strokes, blood clots and breast cancer.
"Anti-aging agents" are a big tempting business, until one realizes that some of them may prevent aging by killing a person early.
"Natural" is considered the key ingredient for good health. If it is natural, it must be good for you. In reality, so many natural things can literally kill you or disable you. Lead, arsenic, mercury and poison ivy are all perfectly natural.
The human body is complex and nature is very complicated, which makes the practice of medicine difficult. Every body and everybody is different. We thought genes controlled everything. We discovered DNA and decoded the entire genome. We thought we conquered the secrets of nature. Then we found out there are things called epi-genomes that control genes, which are very susceptible to environmental influences, thus altering one's destiny in a very short period of time.
Too much of a good thing is not necessarily better (e.g. salt). Little of a bad thing may not necessarily be that bad. What one person perceives as stress is someone else's stimulus.
So, what is the answer? Can calcium supplements kill you? Maybe, maybe not. It depends who is taking it (age, gender, other medical conditions, etc.), in what form, in what strength and for what reason. That is where your personal physician comes into the picture, to make judgment calls weighing the benefits versus the risks. That is the art of medicine.
We also need expensive and ethical, focused and prospective clinical trials to differentiate between claims and facts. That is the cost of medicine.
Dietary supplementation (at an estimated cost of $20 billion annually) should be reserved for preventing or correcting deficiency rather than promoting wellness. There is definitely no controversy about the beneficial effect of balanced diet with more fruits and vegetables and regular exercise.
Dr. Rao Musunuru, a practicing cardiologist in Hudson, is a member of National Leadership Committee of Clinical Cardiology Council of the American Heart Association and a past member of the advisory council for the National Heart, Lung and Blood Institute at the National Institutes of Health.