Do Calcium Supplements Increase Heart Attack Risk?

Written by Dr. Steve Chaney on . Posted in current health articles, Supplements and Health

 

Calcium Confusion

Author: Dr. Stephen Chaney

 cardiovascular-disease

Should you avoid calcium supplements? Do calcium supplements increase heart disease risk? If you’ve been reading some of the recent headlines in magazines, newspapers and current health articles, that’s exactly what you might think.

And, after years of telling us that calcium supplements may be important for bone health, even some doctors are now recommending that their patients avoid calcium supplements. So what’s the truth? What should you believe?

Calcium Confusion

While some headlines and blogs have been telling you to avoid “killer calcium” supplements at all cost, the actual literature on the subject is much more confusing. Some studies claim that taking over 1,000 mg of supplemental calcium is associated with a slight (20-24%) increase in heart attack risk (Bolland et al, BMJ, 341: c3691, 2010; Bolland et al, BMJ 342: d2040, 2011; Xiao et al, JAMA Internal Medicine, 173: 639-646, 2013). Other studies find no association between supplemental calcium intake and heart attack risk or decreased heart attack risk (Lansetmo et al, J Clin Endocrinol Metab, 98: 3010-3018, 2013; Wang et al, Am J Cardiovasc Drugs, 12:105-116, 2012).

Why the confusion? It turns out that most of these studies had some significant limitations – particularly the studies reporting increased heart attack risk. For example:

  • Some studies were too small or the follow-up was too short. As a consequence the total number of cardiovascular deaths was so small that it was difficult to have confidence in small differences between the group supplementing with calcium and the one that was not supplementing.
  • Some of the papers represented a re-analysis of the data from studies that were actually designed to measure whether calcium supplements decreased risk of bone fracture, not whether they increased the risk of cardiovascular death. That is a concern because it means that cardiovascular deaths were not systematically recorded at the time the studies were performed.

And when studies like that are poorly designed, you end up with some pretty bizarre findings. For example:

  • One study reported that calcium supplementation increased the risk of heart attack only in women who were using no calcium supplements prior to the study. A second study by the same authors reported that calcium supplementation increased heart attack risk only women who were taking calcium supplements prior to the study. Obviously, both studies couldn’t be correct.
  • One study has reported that calcium supplementation increases heart attack risk in women, but not in men. Another study reports that calcium supplementation increases heart attack risk in men, but not in women. A third study claims that calcium supplementation reduces cardiovascular death in women, but not in men. Again, all of those studies can’t be true.

Are you confused yet? If so, I have good news for you. The definitive study on calcium supplements and heart attack risk in humans has just been published.

 

Do Calcium Supplements Increase Heart Attack Risk?

A group of scientists from Brigham and Women’s Hospital in Boston and Harvard University analyzed the relationship between supplemental calcium use and cardiovascular disease in 74,245 women with no previous history of heart disease who were enrolled in the Nurses’ Health Study (Paik et al, Osteoporosis International, doi: 10.1007/s00198-014-2732-2, 2014). This was a very well designed study that avoided the flaws of the previous studies. For example:

  • There were a large number of women in the study (74,245) and a long follow-up (24 years). As a consequence there were a large number of adverse cardiovascular events (2,709 deaths and 1,856 strokes). This allowed for a very precise statistical comparison of calcium supplement users and non-users.
  • This study was designed to measure cardiovascular disease and cardiovascular deaths
  • This study was also designed to measure calcium intake. In fact, calcium intake was measured every 4 years.

The results were pretty clear cut:

  • Women taking >1,000 mg of supplemental calcium/day had an 18% decrease in cardiovascular deaths.
  • Women taking >1,000 mg of supplemental calcium/day had a 29% decrease in cardiovascular disease.
  • When they looked at total calcium intake (dietary and supplemental) women consuming >2,000 mg/day had an 18% decrease in cardiovascular deaths compared to women consuming <500 mg/day (about the average dietary intake for American women).
  • It didn’t make any difference whether the women were at high or low risk of heart disease (smokers versus non-smokers, high blood pressure versus normal blood pressure, high cholesterol versus normal cholesterol, heart healthy diet or poor diet, pre- or post-menopause, etc)
  • It also didn’t make any difference if the women started supplementing with calcium during the last 4 years of the study or had been supplementing with calcium for 24 years. The results were essentially the same.

 

The Bottom Line

1)     You can ignore the “Killer Calcium” headlines and the warnings that taking calcium supplements will increase your risk of heart disease. The definitive study for women has just been published, and it shows that >1,000 mg/day of supplemental calcium reduces your risk of cardiovascular disease by 29% and cardiovascular death (primarily heart attacks) by 18%.

2)     The definitive study for men has not yet been published, but it is likely that the results will be similar to those for women.

3)     On the other hand, there is clear evidence that calcium intake in the 1000 to 1300 mg per day range (the current RDA recommendations) decreases the risk of osteoporosis, and osteoporosis can significantly decrease quality of life and even lead to increased mortality. Most people aren’t getting enough calcium in their diet. For these people appropriate calcium supplementation is clearly advantageous.

4)     Finally, as I discuss in my book “The Myths of the Naysayers” (available for free to subscribers of “Health Tips From the Professor”), some poorly designed calcium supplements could indeed have the potential to increase heart disease risk. My recommendation is to make sure that your calcium supplement contains 800 to 1200 IU of vitamin D per day plus RDA levels of the other nutrients needed for bone formation (vitamin C, vitamin K, magnesium, zinc, copper and manganese).

 

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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Comments (4)

  • Helen

    |

    Thank you for this professional and timely information you provide. Most appreciative of your work and effort.

    How does one get your book re: Naysayers?

    HTG

    Reply

    • Dr. Steve Chaney

      |

      Dear Helen,

      When you go to https://www.healthtipsfromtheprofessor.com and register to receive my health tips on a weekly basis you will receive an email with instructions on how to receive your free Naysayers eBook.

      Dr. Chaney

      Reply

  • sharry zacharia

    |

    Thank you for clearing the confusion on CA intake and heart disease.

    Reply

  • Mary Ahrens

    |

    thank you Dr. Chaney for simplifying the results for each of these studies! It’s incredibly helpful!

    Reply

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Latest Article

High Protein Diets and Weight Loss

Posted October 16, 2018 by Dr. Steve Chaney

Do High Protein Diets Reduce Fat And Preserve Muscle?

Author: Dr. Stephen Chaney

Healthy Diet food group, proteins, include meat (chicken or turkAre high protein diets your secret to healthy weight loss? There are lots of diets out there – high fat, low fat, Paleolithic, blood type, exotic juices, magic pills and potions. But recently, high protein diets are getting a lot of press. The word is that they preserve muscle mass and preferentially decrease fat mass.

If high protein diets actually did that, it would be huge because:

  • It’s the fat – not the pounds – that causes most of the health problems.
  • Muscle burns more calories than fat, so preserving muscle mass helps keep your metabolic rate high without dangerous herbs or stimulants – and keeping your metabolic rate high helps prevent both the plateau and yo-yo (weight regain) characteristic of so many diets.
  • When you lose fat and retain muscle you are reshaping your body – and that’s why most people are dieting to begin with.

So let’s look more carefully at the recent study that has been generating all the headlines (Pasiakos et al, The FASEB Journal, 27: 3837-3847, 2013).

The Study Design:

This was a randomized control study with 39 young (21), healthy and fit men and women who were only borderline overweight (BMI = 25). These volunteers were put on a 21 day weight loss program in which calories were reduced by 30% and exercise was increased by 10%. They were divided into 3 groups:

  • One group was assigned a diet containing the RDA for protein (about 14% of calories in this study design).
  • The second group’s diet contained 2X the RDA for protein (28% of calories)
  • The third group’s diet contained 3X the RDA for protein (42% of calories)

In the RDA protein group carbohydrate was 56% of calories, and fat was 30% of calories. In the other two groups the carbohydrate and fat content of the diets was decreased proportionally.

Feet_On_ScaleWhat Did The Study Show?

  • Weight loss (7 pounds in 21 days) was the same on all 3 diets.
  • The high protein (28% and 42%) diets caused almost 2X more fat loss (5 pounds versus 2.8 pounds) than the diet supplying the RDA amount of protein.
  • The high protein (28% and 42%) diets caused 2X less muscle loss (2.1 pounds versus 4.2 pounds) than the diet supplying the RDA amount of protein.
  • In case you didn’t notice, there was no difference in overall results between the 28% (2X the RDA) and 42% (3X the RDA) diets.

Pros And Cons Of The Study:

  • The con is fairly obvious. The participants in this study were all young, healthy and were not seriously overweight. If this were the only study of this type one might seriously question whether the results were applicable to middle aged, overweight coach potatoes. However, there have been several other studies with older, more overweight volunteers that have come to the same conclusion – namely that high protein diets preserve muscle mass and enhance fat loss.
  • The value of this study is that it defines for the first time the upper limit for how much protein is required to preserve muscle mass in a weight loss regimen. 28% of calories is sufficient, and there appear to be no benefit from increasing protein further. I would add the caveat that there are studies suggesting that protein requirements for preserving muscle mass may be greater in adults 50 and older.

The Bottom Line:

1)    Forget the high fat diets, low fat diets, pills and potions. High protein diets (~2X the RDA or 28% of calories) do appear to be the safest, most effective way to preserve muscle mass and enhance fat loss in a weight loss regimen.

2)     That’s not a lot of protein, by the way. The average American consumes almost 2X the RDA for protein on a daily basis. However, it is significantly more protein than the average American consumes when they are trying to lose weight. Salads and carrot sticks are great diet foods, but they don’t contain much protein.

3)     Higher protein intake does not appear to offer any additional benefit – at least in young adults.

4)     Not all high protein diets are created equal. What some people call high protein diets are laden with saturated fats or devoid of carbohydrate. The diet in this study, which is what I recommend, had 43% healthy carbohydrates and 30% healthy fats.

5)    These diets were designed to give 7 pounds of weight loss in 21 days – which is what the experts recommend. There are diets out there promising faster weight loss but they severely restrict calories and/or rely heavily on stimulants, they do not preserve muscle mass, and they often are not safe. In addition they are usually temporary.  I do not recommend them.

6)    This level of protein intake is safe for almost everyone. The major exception would be people with kidney disease, who should always check with their doctor before increasing protein intake. The only other caveat is that protein metabolism creates a lot of nitrogenous waste, so you should drink plenty of water to flush that waste out of your system. But, water is always a good idea.

7)     The high protein diets minimized, but did not completely prevent, muscle loss. Other studies suggest that adding the amino acid leucine to a high protein diet can give 100% retention of muscle mass in a weight loss regimen – but that’s another story for another day.

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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