Dear Dietitian – Does too much calcium increase the risk of heart attack?
I am sixty years old, and I’ve always been health conscious. I eat right and exercise three times a week. Recently, I’ve read that too much calcium may increase your risk of a heart attack. Is this true? Also, how much is too much?
How many times did you hear “Drink your milk” when you were a child? Milk is a good source of calcium, which is needed for healthy bones. Our bodies will build bone until about age 18. After that point, we must consume adequate amounts of calcium in our diet or use supplements to maintain healthy bones.
There is controversy among experts about the link between excess calcium and heart attacks, and studies have produced mixed results. Some studies have even found a decreased risk of heart disease with calcium, especially when consumed in the diet.
One theory is that when a calcium supplement is taken, the body uses what it needs, leaving excess amounts in the blood. These calcium bits are deposited onto the walls of the arteries, increasing plaque, which narrows the arteries and reduces blood flow to the heart. When blood flow is reduced, so is oxygen. Ultimately, a section of the heart doesn’t get enough oxygen to survive, resulting in a myocardial infarction (MI), or heart attack.
For adults, the Recommended Daily Allowance (RDA) of calcium is 1,000 mg up to age 50. That amount increases to 1,200 mg per day for women over 50 and men older than 70. Why the age difference? When women go through menopause, the amount of estrogen in the body significantly decreases. Estrogen is needed to hinder bone breakdown. While testosterone in men serves the same function, there is no sharp decrease in this hormone as there is estrogen in women.
How much is too much? The Upper Limit (UL) for calcium intake is 2000 mg for men age 51 and over; for women the same age, the UL is 2500 mg.
Remember that vitamin D is essential for calcium absorption. This vitamin can be obtained from sunlight, fortified milk, and fatty fish like mackerel and tuna. It is also added to soy milk, juice, and fortified cereals.
It is always best to get calcium needs met by diet. One simple reason for this is you are less likely to ingest excess amounts of the mineral this way. Most of us don’t drink a gallon of milk a day or eat 10 cups of kale. Another option is a 50/50 plan. Get half your calcium needs in your diet and take a supplement that contains 500 mg of calcium.
When selecting a calcium supplement, remember that calcium citrate is better absorbed. It’s also wise to choose a supplement with USP on the label. This means the United States Pharmacopeia (USP) has tested the product for potency and absorption.
The table below lists good sources of dietary calcium:
|Fortified soy milk||1 cup||80-500 mg (varies with brand)|
|Cow’s milk (2%)||1 cup||295 mg|
|Spinach||1 cup raw||55 mg|
|Kale||1 cup raw||95 mg|
|Cheese, cheddar||1 slice||205 mg|
|Greek yogurt, non-fat||8 oz||200 mg|
|Beans, navy||1 cup cooked||120 mg|
|Tofu, firm||½ cup||260 mg|
Until next time, be healthy!