Dear Dietician: Excess calcium

Dear Dietitian,

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 heart attack. Is this true? Also, how much is too much?

Mary

Dear Mary,

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, then we must consume adequate amounts of calcium in our diet or use supplements in order 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 about the link between excess calcium and heart attacks is that when a calcium supplement is taken, there is a lot of calcium floating around in the blood waiting to be absorbed by the body. 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 to the heart 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 not a sharp decrease in this hormone as there is with 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 important 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 your calcium needs met in your diet. One simple reason for this is that 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. It's important to get into a habit of consuming these foods day-in and day-out.

When selecting a calcium supplement, know that calcium citrate is better absorbed. It's also important to select 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:

Good health to you!

Dear Dietitian

Leanne McCrate, RD, LD, CNSC, aka Dear Dietitian, is an award-winning dietitian based in Missouri. Her mission is to educate the public on sound, scientifically-based nutrition. Do you have a nutrition question? Email her today at [email protected].