Friday, June 15, 2012

Calcium Pills May Increase Heart Attack Risk

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 pills.

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.