Do Calcium Supplements Prevent Bone Fractures? – Part2: Preventing Osteoporosis

Written by Dr. Steve Chaney on . Posted in current health articles, Drugs and Health, Exercise, Food and Health, Health Current Events, Healthy Lifestyle, Supplements and Health

Creating A “Bone Healthy” Lifestyle

Author: Dr. Stephen Chaney

prevent bone fracturesA recent study (Tai et al, British Medical Journal, BMJ/2015; 351:h4183 doi: 10.1136/bmj.h4183)reported that calcium supplementation for women over 50 resulted in only a very small increase in bone density, which translated into a very small (5-10%) decrease in the risk of bone fractures. They concluded that the standard RDA recommendation of 1,000 – 1,200 mg/day of calcium for adults over 50 is unlikely to help in  preventing osteoporosis or reducing the risk of bone fractures.

In last week’s issue of “Health Tips From the Professor,” I discussed the many flaws of the study. In brief:

  • The study was a meta-analysis of 51 published clinical studies. Normally, meta-analyses are very strong, but they have an “Achilles Heel” – something called the Garbage-In, Garbage-Out Simply put, this means that the meta-analysis is only as strong as the individual studies that went into it. The authors included 40 years of clinical studies in their meta-analysis, and most of those studies had an inadequate design by today’s standards.
  • The study also made a number of what I would call apples to oranges comparisons that were of questionable validity.

In this week’s issue of “Health Tips From The Professor”, I would like to explore the other side of the coin. I would like to consider the possibility that the study might be correct and discuss what that might mean for you.

What Is A “Bone Healthy” Lifestyle?

Despite the concerns I just mentioned, let’s assume for a minute that the study might just be correct in spite of its many flaws. Let’s assume that the “one size fits all” RDA recommendation of 1,000 – 1,200 mg/day of calcium if you are over 50 may actually be flawed advice. If so, perhaps it’s time to say good riddance! It may finally be time to put away the “magic bullet”, “one size fits all” thinking and start seriously considering holistic approaches.

Now that I have your attention, let’s talk about what you can do to prevent osteoporosis – and the role that supplementation should play. Let’s talk about a “bone healthy” lifestyle.

#1: Let’s start with supplementation:  Bone is not built with calcium alone. Bone contains significant amounts of magnesium along with the trace minerals zinc, copper and manganese – and all of these are often present at inadequate levels in the diet. Most of us know by now that vitamin D is essential for bone formation, but recent research has shown that vitamin K is also essential (Kanellakis et al, Calcified Tissue International, 90: 251-262, 2012). An ideal calcium supplement should contain all of those nutrients.

vegetable#2: Next comes diet:  Many of you probably already know that some foods are acid-forming and other are alkaline-forming in our bodies – and that it is best to keep our bodies on the alkaline side. What most of you probably don’t know is that calcium is alkaline and that our bones serve as a giant buffer system to help keep our bodies alkaline. Every time we eat acid-forming foods a little bit of bone is dissolved so that calcium can be released into the bloodstream to neutralize the acid. (My apologies to any chemists reading this for my gross simplification of a complex biological system).

Consequently, if we want strong bones, we should eat less acid-forming foods and more of alkaline-forming foods. Among acid-forming foods, sodas are the biggest offenders, but meat, eggs, dairy, and grains are all big offenders as well. Alkaline-forming foods include most fruits & vegetables, peas, beans, lentils, seeds and nuts. In simple terms, the typical American diet is designed to dissolve our bones. Calcium from diet or supplementation may be of little use if our diet is destroying our bones as fast as the calcium tries to rebuild them.

#3: Test your blood 25-hydroxyvitamin D level:  25-hydroxy vitamin D is the active form of vitamin D in our bloodstream. We need a sufficient (20-50 ng/mL) blood level of 25-hydroxy vitamin D to be able to use calcium efficiently for bone formation. We now know that some people who seem to be getting adequate vitamin D in their diet still have low 25-hydroxyvitamin D levels. In fact, various studies have shown that somewhere between 20-35% of Americans have insufficient blood levels of 25-hydroxy vitamin D. You should get your blood level tested. If it is low, consult with your health professional on how much vitamin D you need to bring your 25-hydroxy vitamin D into the sufficient range.

#4: Beware of drugs:The list of common medications that dissolve bones is a long one. Some of the worst offenders are anti-inflammatory steroids such as cortisone & prednisone, drugs to treat depression, drugs to treat acid reflux, and excess thyroid hormone.

I’m not suggesting that you avoid prescribed medications that are needed to treat a health condition. I would suggest that you ask your doctor or pharmacist (or research online) whether the drugs you are taking adversely affect bone density. If they do, you may want to ask your doctor about alternative approaches, and you should pay a lot more attention to the other aspects of a “bone healthy” lifestyle.

#5: Exercise is perhaps the most important aspect of a bone healthy lifestyle:Whenever our muscles pull on a bone it stimulates the bone to get stronger. I’ll put the benefits of exercise in perspective in the next section.

Exercise Is A Critical Part of  Preventing Osteoporosis

Instead of just quoting more boring studies, I’m going to share a couple of stories that help put the importance of exercise into perspective.

The first is my wife’s story. She ate a very healthy diet with minimal meat and lots of fruits and vegetables for years. She took calcium supplements on a daily basis. She walked 5 miles per day and took yoga classes several days each week. Yet when her doctor recommended a bone density scan in her early sixties she discovered she had low bone density. She was in danger of becoming osteoporotic!

weight lifting exerciseHer doctor prescribed Fosamax. My wife tried it for one day and decided the side effects were worse than the disease. So she started asking holistic health practitioners what she should do. They recommended she find a personal trainer and start pumping iron. That was not an easy solution, but it was the right one. When she went in for her second bone scan 3 months later, her doctor excitedly announced that her bone density had increased by 7%. Her doctor said “We never get results that good with Fosamax”. When my wife told her she wasn’t taking Fosamax, her doctor became even more excited. (Most doctors actually do prefer holistic approaches. They just don’t recommend them.)

The moral of this story is that you can be doing everything else right, but if you’re not doing weight bearing exercises – if you’re not pumping iron, everything else you are doing may be for naught. Weight bearing exercise is an absolutely essential part of a “bone healthy” lifestyle!

But, can exercise do it alone? Some people seem to think so. That brings up my second story. About 30 years ago one of my  UNC colleagues, who was an expert on calcium metabolism, was doing a bone density study on female athletes at UNC. One of the tennis players was nicknamed “Tab.”   Tab was a popular soft drink at that time, and Tab was all she drank – no milk, no water, only Tab. When my colleague measured the bone density of her playing arm, it was normal for a woman of her age. When he measured the bone density of her non-playing arm, it was that of a 65 year old woman. The reason is simple. When we exercise a particular bone, our body will add calcium to that bone to make it stronger. If we are not getting enough calcium from our diet, our body simply dissolves the bones elsewhere in our body to get the calcium that it needs.

The moral of this story is that exercise alone is not enough. In terms of bone health, we absolutely need exercise to take advantage of the calcium in our diet, and we absolutely need sufficient calcium in our diet to take advantage of the exercise.

This is the most glaring deficiency of the meta-analysis I described last week. None of those studies included exercise. No wonder the increase in bone density was minimal!

Putting It All Together –  A “Bone Healthy” Lifestyle

bone healthy lifestyleIf you seriously want to minimize your risk of osteoporosis, there are a few simple steps you can take (simple, but not easy).

  • Consume a “bone healthy” diet that emphasizes fresh fruits and vegetables, minimizes meats, and eliminates sodas and other acidic beverages. For more details on whether your favorite foods are acid-forming or alkaline-forming, you can find plenty of charts on the internet.
  • Minimize the use of medications that adversely affect bone density. You’ll need to work with your doctor on this one.
  • Get plenty of weight bearing exercise. This is an absolutely essential part of a bone healthy lifestyle. Your local Y can probably give you guidance if you can’t afford a personal trainer. Of course, if you have physical limitations or have a disease, you should consult with your health professional before beginning any exercise program.
  • Get your blood 25-hydroxy vitamin D level tested. If it is low, take enough supplemental vitamin D to get your 25-hydroxy vitamin D level into the sufficient range – optimal is even better. Sufficient blood levels of 25-hydroxy vitamin D are also absolutely essential for you to be able to utilize calcium efficiently.
  • Consider a calcium supplement. Even when you are doing everything else correctly, you still need adequate calcium in your diet to form strong bones. “I’m not necessarily recommending a “one-size fits all” 1,000 to 1,200 mg/day. Supplementation is always most effective when you actually need it. For example:
  • If you are not including dairy products in your diet (either because they are acid-forming or for other health reasons), it will be difficult for you to get adequate amounts of calcium in your diet. You can get calcium from other food sources such as green leafy vegetables. However, unless you plan your diet very carefully you will probably not get enough.
  • If you are taking medications that decrease bone density, that may increase your need for supplemental calcium. Unfortunately, we don’t yet have guidelines on how much is needed.
  • If you do use a calcium supplement, make sure it is complete. Don’t just settle for calcium and vitamin D. At the very least you will want your supplement to contain magnesium and vitamin K. I personally recommend that it also contain zinc, copper, and manganese.
  • Unfortunately, we don’t really have good guidelines for how much calcium you need. Studies like the one described above are challenging the old RDAs, but we don’t yet have enough studies to know how much calcium we need to build strong bones when we are following a “bone healthy” lifestyle that includes proper diet, sufficient 25-hydroxy vitamin D blood levels and plenty of exercise.

What About Medications For Preventing Bone Loss?

The danger is that, as the conclusions of this meta-analysis get widely publicized and doctors stop prescribing calcium supplements, they probably aren’t going to recommend a holistic approach. They probably won’t recommend a “bone healthy” lifestyle. Instead, they will most preventing osteoporosislikely recommend drugs to prevent bone loss. In fact, the authors of the study described last week specifically praised the use of bisphosphonate drugs (Fosamax and Zometa), and a related drug (Xgeva) that works by a similar mechanism because they increased bone density by 5-9% over 3 years.

However, these drugs have a dark side, and it’s not just the acid reflux, esophageal damage and esophageal cancer that you hear about in the TV ads. These drugs all act by blocking bone resorption, the ability of the body to break down bone. In the short term, this prevents the bone loss associated with aging and reduces the risk of bone fractures.

However, you might remember from last week’s article that bone resorption is also an essential part of bone remodeling, the process that keeps our bones young and strong. When these drugs are used for more than a few years you end up with bones that are dense, but are also old and brittle. Long term use of these drugs is associated with jaw bones that simply dissolve and bones that easily break during everyday activities. This is yet another example of drugs with side effects that look a lot like the disease you were taking the drug for in the first place.


The Bottom Line

  1. A recent study has reported that the RDA recommendation of 1,000 – 1,200 mg/day of calcium for people over 50 provides only a minimal increase in bone density (0.7-1.8%) over the first year or two. This translates into a very small (5-10%) decrease in risk of bone fractures. It did not matter whether the calcium came from dietary sources or from supplementation. The authors concluded that adding extra calcium to the diet, whether from foods or supplements, was not a very efficient way to increase bone density and prevent fractures.

2. This study suffers from some serious flaws, which I discussed in last week’s “Health Tips From the Professor

3. Unfortunately, many doctors are likely to take this study to heart. They are likely to stop recommending calcium and other natural approaches and start relying even more heavily on drugs to preserve bone mass. That’s bad news because, while the most frequently proscribed drugs do increase bone mass and prevent fractures short term, they also cause your bones to age more rapidly. After a few years you end up with bones that are dense, but are also incredibly brittle and fracture very easily. That’s right. If you use these drugs long enough, they will cause the very condition you were trying to prevent.

4. We should also consider the possibility that this study may just be correct. Let’s assume for a minute that the RDA recommendation of 1,000 – 1,200 mg/day of calcium for everyone over 50 may actually be flawed advice. If so, it may finally be time to put away the “magic bullet” thinking and start seriously considering holistic approaches to preserving bone mass.

5. A far better choice is to follow a “bone healthy” lifestyle.

  • Start with a “bone healthy” diet. Avoid acid-forming foods like sodas, meats, eggs, dairy, and grains. Instead choose alkaline-forming foods like most fruits & vegetables, peas, beans, lentils, seeds and nuts.
  • Check on the medicines you are using. If they are ones that adversely affect bone density, ask your health professional if there are bone-healthier options.
  • Check your blood level of 25-hydroxy vitamin D on a regular basis. If it is low, consult with your health professional on the amount of vitamin D you need to take to bring your 25-hydroxy vitamin D into the optimal range.
  • Get plenty of weight bearing exercise. This means pumping iron. It is an absolutely essential part of a bone healthy lifestyle. Of course, if you have physical limitations or have a disease, you should consult with your health professional before beginning any exercise program.
  • If you are not getting sufficient calcium from your diet, consider a complete calcium supplement. In addition to calcium and vitamin D, a bone-healthy calcium supplement should at the very least contain magnesium and vitamin K. I also recommend it contain zinc, copper, and manganese.

Just don’t rely on a calcium supplement alone to keep your bone density where it should be. If your 25-hydroxy vitamin D isn’t where it should be and/or you aren’t doing weight bearing exercise on a regular basis, your calcium supplement may be almost useless.   All the aforementioned may aid in preventing osteoporosis.  In my opinion, that may be the biggest take-home lesson from the recent meta-analysis.


These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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Latest Article

A Low Carb Diet and Weight Loss

Posted January 15, 2019 by Dr. Steve Chaney

Do Low-Carb Diets Help Maintain Weight Loss?

Author: Dr. Stephen Chaney


low carb dietTraditional diets have been based on counting calories, but are all calories equal? Low-carb enthusiasts have long claimed that diets high in sugar and refined carbs cause obesity. Their hypothesis is based on the fact that high blood sugar levels cause a spike in insulin levels, and insulin promotes fat storage.

The problem is that there has been scant evidence to support that hypothesis. In fact, a recent meta-analysis of 32 published clinical studies (KD Hall and J Guo, Gastroenterology, 152: 1718-1727, 2017 ) concluded that low-fat diets resulted in a higher metabolic rate and greater fat loss than isocaloric low-carbohydrate diets.

However, low-carb enthusiasts persisted. They argued that the studies included in the meta-analysis were too short to adequately measure the metabolic effects of a low-carb diet. Recently, a study has been published in the British Medical Journal (CB Ebbeling et al, BMJ 2018, 363:k4583 ) that appears to vindicate their position.

Are low carb diets best for long term weight loss?

Low-carb enthusiasts claim the study conclusively shows that low-carb diets are best for losing weight and for keeping it off once you have lost it. They are saying that it is time to shift away from counting calories and from promoting low-fat diets and focus on low-carb diets instead if we wish to solve the obesity epidemic. In this article I will focus on three issues:

  • How good was the study?
  • What were its limitations?
  • Are the claims justified?


How Was The Study Designed?

low carb diet studyThe investigators started with 234 overweight adults (30% male, 78% white, average age 40, BMI 32) recruited from the campus of Framingham State University in Massachusetts. All participants were put on a diet that restricted calories to 60% of estimated needs for 10 weeks. The diet consisted of 45% of calories from carbohydrate, 30% from fat, and 25% from protein. [So much for the claim that the study showed low-carb diets were more effective for weight loss. The diet used for the weight loss portion of the diet was not low-carb.]

During the initial phase of the study 161 of the participants achieved 10% weight loss. These participants were randomly divided into 3 groups for the weight maintenance phase of the study.

  • The diet composition of the high-carb group was 60% carbohydrate, 20% fat, and 20% protein.
  • The diet composition of the moderate-carb group was 40% carbohydrate, 40% fat, and 20% protein.
  • The diet composition of the low-carb group was 20% carbohydrate, 60% fat, and 20% protein.

Other important characteristics of the study were:

  • The weight maintenance portion of the study lasted 5 months – much longer than any previous study.
  • All meals were designed by dietitians and prepared by a commercial food service. The meals were either served in a cafeteria or packaged to be taken home by the participants.
  • The caloric content of the meals was individually adjusted on a weekly basis so that weight was kept within a ± 4-pound range during the 5-month maintenance phase.
  • Sugar, saturated fat, and sodium were limited and kept relatively constant among the 3 diets.

120 participants made it through the 5-month maintenance phase.


Do Low-Carb Diets Help Maintain Weight Loss?

low carb diet maintain weight lossThe results were striking:

  • The low-carb group burned an additional 278 calories/day compared to the high-carb group and 131 calories/day more than the moderate-carbohydrate group.
  • These differences were even higher for those individuals with higher insulin secretion at the beginning of the maintenance phase of the study.
  • These differences lead the authors to hypothesize that low-carb diets might be more effective for weight maintenance than other diets.


What Are The Pros And Cons Of This Study?

low carb diet pros and consThis was a very well-done study. In fact, it is the most ambitious and well-controlled study of its kind. However, like any other clinical study, it has its limitations. It also needs to be repeated.

The pros of the study are obvious. It was a long study and the dietary intake of the participants was tightly controlled.

As for cons, here are the three limitations of the study listed by the authors:

#1: Potential Measurement Error: This section of the paper was a highly technical consideration of the method used to measure energy expenditure. Suffice it to say that the method they used to measure calories burned per day may overestimate calories burned in the low-carb group. That, of course, would invalidate the major findings of the study. It is unlikely, but it is why the study needs to be repeated using a different measure of energy expenditure.

#2: Compliance: Although the participants were provided with all their meals, there was no way of being sure they ate them. There was also no way of knowing whether they may have eaten other foods in addition to the food they were provided. Again, this is unlikely, but cannot be eliminated from consideration.

#3: Generalizability: This is simply an acknowledgement that the greatest strength of this study is also its greatest weakness. The authors acknowledged that their study was conducted in such a tightly controlled manner it is difficult to translate their findings to the real world. For example:

  • Sugar and saturated fat were restricted and were at very similar levels in all 3 diets. In the real world, people consuming a high-carb diet are likely to consume more sugar than people in the other diet groups. Similarly, people consuming the low-carb diet are likely to consume more saturated fat than people in the other diet groups.
  • Weight was kept constant in the weight maintenance phase by constantly adjusting caloric intake. Unfortunately, this seldom happens in the real world. Most people gain weight once they go off their diet – and this is just as true with low-carb diets as with other diets.
  • The participants had access to dietitian-designed prepared meals 3 times a day for 5 months. This almost never happens in the real world. The authors said “…these results [their data] must be reconciled with the long-term weight loss trials relying on nutrition education and behavioral counseling that find only a small advantage for low carbohydrate compared with low fat diets according to several recent meta-analyses.” [I would add that in the real world, people do not even have access to nutritional education and behavioral modification.]


low carb diet and youWhat Does This Study Mean For You?

  • This study shows that under very tightly controlled conditions (dietitian-prepared meals, sugar and saturated fat limited to healthy levels, calories continually adjusted so that weight remains constant) a low-carb diet burns more calories per day than a moderate-carb or high-carb diet. These findings show that it is theoretically possible to increase your metabolic weight and successfully maintain a healthy weight on a low-carb diet. These are the headlines you probably saw. However, a careful reading of the study provides a much more nuanced viewpoint. For example, the fact that the study conditions were so tightly controlled makes it difficult to translate these findings to the real world.
  • In fact, the authors of the study acknowledged that multiple clinical studies show this almost never happens in the real world. These studies show that most people regain the weight they have lost on low-carb diets. More importantly, the rate of weight regain is virtually identical on low-carb and low-fat diets. Consequently, the authors of the current study concluded “…translation [of their results to the real world] requires exploration in future mechanistic oriented research.” Simply put, the authors are saying that more research is needed to provide a mechanistic explanation for this discrepancy before one can make recommendations that are relevant to weight loss and weight maintenance in the real world.
  • The authors also discussed the results of their study in light of a recent, well-designed 12-month study (CD Gardener et al, JAMA, 319: 667-669, 2018 ) that showed no difference in weight change between a healthy low-fat versus a healthy low-carbohydrate diet. That study also reported that the results were unaffected by insulin secretion at baseline. The authors of the current study noted that “…[in the previous study] participants were instructed to minimize or eliminate refined grains and added sugars and maximize intake of vegetables. Probably for this reason, the reported glycemic load [effect of the diet on blood sugar levels] of the low-fat diet was very low…and similar to [the low-carb diet].” In short, the authors of the current study were acknowledging that diets which focus on healthy, plant-based carbohydrates and eliminate sugar, refined grains, and processed foods may be as effective as low-carb diets for helping maintain a healthy weight.
  • This would also be consistent with previous studies showing that primarily plant-based, low-carb diets are more effective at maintaining a healthy weight and better health outcomes long-term than the typical American version of the low-fat diet, which is high in sugar and refined grains. In contrast, meat-based, low-carb diets are no more effective than the American version of the low-fat diet at preventing weight gain and poor health outcomes. I have covered these studies in detail in my book “Slaying The Food Myths.”

Consequently, the lead author of the most recent study has said: “The findings [of this study] do not impugn whole fruits, beans and other unprocessed carbohydrates. Rather, the study suggests that reducing foods with added sugar, flour, and other refined carbohydrates could help people maintain weight loss….” This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.

The Bottom Line


  • A recent study compared the calories burned per day on a low-carb, moderate-carb, and high-carb diet. The study concluded that the low-carb diet burned significantly more calories per day than the other two diets and might be suitable for long-term weight control. If confirmed by subsequent studies, this would be the first real evidence that low-carb diets are superior for maintaining a healthy weight.
  • However, the study has some major limitations. For example, it used a methodology that may overestimate the benefits of a low-carb diet, and it was performed under tightly controlled conditions that can never be duplicated in the real world. As acknowledged by the authors, this study is also contradicted by multiple previous studies. Further studies will be required to confirm the results of this study and show how it can be applied in the real world.
  • In addition, the kind of carbohydrate in the diet is every bit as important as the amount of carbohydrate. The authors acknowledge that the differences seen in their study apply mainly to carbohydrates from sugar, refined grains, and processed foods. They advocate diets with low glycemic load (small effects on blood sugar and insulin levels) and acknowledge this can also be achieved by incorporating low-glycemic load, plant-based carbohydrates into your diet. This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.
  • Finally, clinical studies report averages, but none of us are average. When you examine the data from the current study, it is evident that some participants burned more calories per hour on the high-carb diet than other participants did on the low carb diet. That reinforces the observation that some people lose weight more effectively on low-carb diets while others lose weight more effectively on low-fat diets. If you are someone who does better on a low-carb diet, the best available evidence suggests you will have better long-term health outcomes on a primarily plant-based, low-carb diet such as the low-carb version of the Mediterranean diet.

For more details read the article above.



These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.