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Just How Important Is Calcium?

Monday, February 24th, 2014

Through every stage of life, calcium is an important component of a woman’s diet. Calcium is involved in many aspects of overall health. It is believed to be important for bone health, prevention of cardiovascular disease, blood pressure regulation, weight management, and prevention of some types of cancer.

How Much Calcium Do You Need?

The recommended daily allowance of calcium for women between 19 and 50 years of age is 1,000 mg. That recommendation does not change when you are pregnant, but meeting it does become even more important, because you are providing nutrition for your baby as well, and his or her bones and teeth need calcium for proper development. In addition, when you don’t get enough calcium for a long period of time, you are at risk for developing osteopenia, which can lead to osteoporosis.  What’s the difference? Osteoporosis is a disease that breaks down the tissue in our bones, making them fragile and more likely to break. Osteopenia is not a disease, but a term that describes low bone density. Both can lead to painful fractures.  While osteopenia is not considered a disease, being diagnosed with osteopenia requires further monitoring. Preventive measures should be taken since osteoporosis may develop if bone density loss increases.

Actually, the real protection against osteoporosis begins when one is a teenager, because porousness of the bones is the end stage of a long process. Continuing to drink milk after childhood through the teenage years is like putting calcium in the bank to be drawn on later. Unfortunately, teenagers favor sodas over milk and not many drink the two glasses of milk a day that would allow them to meet more than half their daily calcium needs.

Which food has more calcium?  A cup of collard greens or a cup of whole milk?  The answer is collard greens!  Eight ounces of skim milk contains almost 300 mg – even more than whole milk, and in a healthier, fat-free package. Yogurt and cheese are good sources of calcium too, but remember that dairy products are just one of many ways to get the calcium you need. Salmon, kale, broccoli, and calcium-fortified orange juice are just a few of the other many places to find calcium.  I don’t believe that my orange juice should be calcium-fortified, but the manufacturers are offering the option.  Just drink milk!

What about calcium supplements? Their safety is often called into question, although for now they appear to be harmless. The real issue is that supplements are not a stand-in for natural foods that contain calcium, because they lack the protein, vitamins, and minerals that you, and your growing baby if you are pregnant, both need. With just a little effort you can get all the calcium you need easily through a healthy diet.

Calcium need during menopause is 1200 milligrams per day. After menopause, it increases to 1500 milligrams per day.  We once thought that calcium and Vitamin D supplementation should be taken to prevent bone fractures in postmenopausal women.  However, the United States Preventive Services Task Force, an independent panel of experts in prevention and primary care, recently issued a draft statement in June, 2012, recommending that healthy postmenopausal women should NOT take low doses of calcium or Vitamin D supplements to prevent fractures.  Why?  Because the supplements were found NOT to prevent fractures and only increased the risk of other problems, such as kidney stones.  So the risks outweighed the benefits and taking these supplements may actually be harming you.


Lactose Intolerance

Lactose intolerance is a common condition in which unpleasant symptoms such as bloating or diarrhea occur after consuming lactose, milk’s natural sugar. This happens when an individual does not produce enough of the enzyme lactase to properly break down the lactose. Lactose intolerance can unsurprisingly make it more of a challenge to consume enough calcium. However, some individuals can consume a small amount of milk without issue. Yogurt is often a good alternative.  However, there are many products today designed for lactose-intolerant individuals. In addition, there are many non-dairy sources of calcium available such as kale, broccoli, collards, and foods fortified with calcium.

Can You Get Too Much Calcium?

Like anything other good thing, too much calcium can present potential problems. Hypercalcemia can cause renal and vascular problems, as well as kidney stones. It can also cause constipation. However, it’s important to realize that you would have to consume more than three times the recommended daily allowance of calcium for problems to begin to occur. Given the average American diet, this is just not a real concern. So drink plenty of skim milk and enjoy lots of other calcium-rich foods as part of your balanced nutritious diet, especially while you are pregnant, lactating or postmenopausal.

For more information about the risk factors associated with postmenopausal osteoporosis, I refer you to my health book, Inside Information for Women.

– Yvonne S. Thornton, M. D., M. P. H.

Osteoporosis Cannot Be Prevented By Calcium Alone

Thursday, February 14th, 2013

Everyone knows how important calcium is in the long-term prevention of osteoporosis. By drinking dairy in your youth, you are building strong bones that will hold up longer against the disease in adulthood. However, few people understand how calcium is absorbed into the body. When you drink a glass of milk, the calcium doesn’t simply soak into your bones on the way down. It must interact with other molecules in your system and bond to them in a way that makes them part of your digestion. Without this bonding, the calcium will simply be flushed out. Unfortunately, many people who try to get enough calcium in their diet don’t get as much as they think they do because it is not properly absorbed. To absorb calcium, your body also needs vitamin D.

Think of vitamin D like the doorman. You can make sure calcium pays a visit to your body by eating an adequate amount, but it will be turned away if no one is there to let it in. To make sure your body actually absorbs calcium and transfers it into your bones, you need to also get enough vitamin D. Studies show that vitamin D and calcium on their own do not effectively prevent fractures in people with osteoporosis.

To learn how much vitamin D you should be getting at your age, make sure you talk to your doctor. He or she will perform tests to first find out whether or not you are deficient in the first place. You can get vitamin D from sun exposure, but you should be careful to avoid too many UV rays at a time. You can also get it from dietary supplements and certain foods such as egg yolks, liver, and fortified milk.

Calcium is certainly important in the prevention of osteoporosis, but vitamin D is equally so. Don’t assume that just because you are getting a lot of calcium, you are safe from weakened bone strength in old age. To prevent the pain and inconvenience of fractures later in your life, start increasing the amount of vitamin D you get today.

– Yvonne S. Thornton, M. D., M. P. H.

Osteoporosis and Alcohol

Monday, July 16th, 2012

Like any reputable physician, I don’t condone heavy drinking, but that doesn’t mean I don’t necessarily partake in a glass of my favorite wine every now and then.  The truth is, a little alcohol once in a while never hurt anyone.  While recent studies suggest that a little bit of drinking may actually help our bones, my personal opinion is that one might be jumping the gun a bit.  Nevertheless, in the “spirit” of being complete and open, I wanted you to know about the recent research that has been covered by the media.

As odd as the connection may seem, a study by the College of Public Health and Human Sciences at Oregon State University found that even small amounts of alcohol have an impact on bone metabolism.  Their study of 40 postmenopausal women who drank moderately did show some benefit.  In fact, according to the principal investigator, “moderate alcohol [use] may slow bone loss by lowering bone turnover.”  That can help to reduce a woman’s risk for osteoporosis later in life.  Urzula Iwaniec, associate professor at OSU, explained that bones are living tissue with old bones constantly being replaced by new bone.  This is why increasing the metabolism of bones helps to stimulate the growth of new bone and keep older, thinning bones at bay.  One of the problems I had with this study is the sample size.  The number of patients studied was way too small to arrive at such a conclusion.  The three main mechanisms by which osteoporosis develops are an inadequate peak bone mass (the skeleton develops insufficient mass and strength during growth), excessive bone resorption, and inadequate formation of new bone during remodeling. An interplay of these three mechanisms underlies the development of fragile bone tissue.  This study only addresses one aspect of osteoporosis and fails to investigate the other possibilities.

Women who are postmenopausal are normally most at risk for bone thinning because of their reduced estrogen.  With that said, researchers did warn against drinking by young adult women, whose bones are still building and that excessive drinking is not a healthy idea for anyone.  However, even the lead author concluded that “the study doesn’t prove that moderate alcohol consumption wards off osteoporosis; it merely shows an association between the two.”  Those who drank one or two alcoholic beverages per day showed increased bone metabolism, and when they stopped drinking for two weeks, the risks for osteoporosis immediately began to show in their blood.  When they resumed drinking again, researchers were amazed to see their bone marker turnover rate return to previous levels.  Unfortunately, the researchers did not test any other hypothesis or mechanism for this change. They believe the reason for this effect is the ability for alcohol to act like estrogen, but it may not be due to this mechanism with respect to bone turnover.

We once thought that calcium and Vitamin D supplementation should be taken to prevent bone fractures.  However, the United States Preventive Services Task Force, an independent panel of experts in prevention and primary care, recently issued a draft statement in June, 2012 recommending that healthy postmenopausal women should not take low doses of calcium or vitamin D supplements to prevent fractures.  Why?  Because the supplements were found not to prevent fractures and only increased the risk of other problems, such as kidney stones.   So the risk outweighed the benefit and taking these supplements may actually be harming you.

While this seminal study about imbibing alcohol doesn’t give us an excuse to throw our healthy calcium- and vitamin D-rich diets out the window, it may be another factor to consider when it comes to our bones.  We already know that red wine may help prevent heart disease, so perhaps, in time, larger studies may support the conclusions of this research and that we may pour ourselves a drink and raise a glass to women’s health.

– Yvonne S. Thornton, M. D., M. P. H.