A German study followed 24,000 men and women, ages 35 to 64, for 11 years and found that those who took calcium supplements were 86 percent more likely to suffer heart attacks than those who do not (Heart, published online May 23, 2012). More than 60 percent of North American women over 60 take calcium supplements to help prevent bone fractures (U.S. Centers for Disease Control and Prevention's National Center for Health Statistics, 2011).
In the study from Germany, there was no significant
difference in death from stroke or heart attack no matter how much
calcium people got FROM FOODS. There was even a suggestion that
increased calcium intake from foods was associated with increased
heart attack risk. Other factors that increase heart attack risk
were excluded from the study.
Another study showed that calcium pills may reduce
fractures by 10 percent, but can INCREASE risk for heart attacks
by 25 percent (British Medial Journal, published online July
2010). Thus if 1,000 people were given calcium for five years,
there would be 26 fractures prevented but there would also be 14
heart attacks, 10 strokes and 13 deaths more than in people not
taking calcium pills.
OTHER STUDIES SHOW THAT TOO MUCH CALCIUM FROM FOOD AND PILLS
INCREASES HEART ATTACK RISK: Eight studies followed more than
10,000 patients, average age of 68 years, for an average 3.8
years, taking 500 to 1400 mg calcium daily. They had 1.3 times the
chance of suffering a heart attack as people taking no calcium
pills. Those taking more than 805 mg calcium per day from food
without pills were 1.86 times more likely to suffer heart attacks
(British Medical Journal, 2010;341:3691).
HOW TOO MUCH CALCIUM CAN CAUSE HEART ATTACKS: Calcium
supplements raise blood calcium levels which increases chances of
forming clots, a major cause of heart attacks and strokes (J Bone
Miner Res. 1997;12:1959-70). Calcium supplements can thicken neck
artery plaques (Atherosclerosis, 2007;194:426-32) and calcify main
arteries (J Bone Miner Res, 2010;25:505-12). Taking calcium
without also taking vitamin D increases heart attack risk even
further, because calcium blocks the activation of vitamin D to
cause a relative deficiency of that vitamin.
TOO MUCH VITAMIN D RAISES CALCIUM: Vitamin D markedly
increases calcium absorption to raise blood calcium levels.
Researchers at the University of Copenhagen followed almost
250,000 people and found that people with blood levels of hydroxy
vitamin D below 10 nmol/L were 2.3 times more likely to die
prematurely and those with levels above 140 nmol/L were 1.42 times
more likely to die prematurely (Journal of Clinical Endocrinology
and Metabolism, published online May 2012). So both low and high
calcium levels are harmful.
GET YOUR CALCIUM FROM FOOD, NOT PILLS: Adult men and women
need 1,000 to 1,200 milligrams of calcium daily, according to the
National Institutes of Health. You get that amount from a cup of
yogurt, a glass of milk and a slice of cheese. If you avoid dairy
products, you could meet your calcium requirement with a bowl of
enriched cereal, a glass of fortified orange juice, half a cup of
tofu and a piece of salmon.
GET YOUR VITAMIN D FROM SUN OR PILLS: You cannot meet your
needs for vitamin D from foods. You have to depend on the sun or
pills. Get a blood test for hydroxy vitamin D. If it is above 75
nmol/L, you are fine. If it is above 140 nmol/L, you are taking
overdoses of vitamin D and should reduce your intake of vitamin D
If your blood level of hydroxy vitamin D is below 50 nmol/L,
you need more sunlight or you can try taking up to 2000 IU of
vitamin D per day for a month. Once blood levels of vitamin D are
above 50 nmol/l, you should reduce your intake of the pills to
1000 IU per day or less.