The following report is a systematic review and meta-analysis (the highest level of scientific proof) on calcium intake and bone mineral density.
Abstract
Objective To determine whether increasing calcium intake from dietary sources affects bone mineral density (BMD) and, if so, whether the effects are similar to those of calcium supplements.
Design Random effects meta-analysis of randomised controlled trials.
Data sources Ovid Medline, Embase, Pubmed, and references from relevant systematic reviews. Initial searches were undertaken in July 2013 and updated in September 2014.
Eligibility criteria for selecting studies Randomised controlled trials of dietary sources of calcium or calcium supplements (with or without vitamin D) in participants aged over 50 with BMD at the lumbar spine, total hip, femoral neck, total body, or forearm as an outcome.
Results We identified 59 eligible randomised controlled trials: 15 studied dietary sources of calcium (n=1533) and 51 studied calcium supplements (n=12 257). Increasing calcium intake from dietary sources increased BMD by 0.6-1.0% at the total hip and total body at one year and by 0.7-1.8% at these sites and the lumbar spine and femoral neck at two years. There was no effect on BMD in the forearm. Calcium supplements increased BMD by 0.7-1.8% at all five skeletal sites at one, two, and over two and a half years, but the size of the increase in BMD at later time points was similar to the increase at one year. Increases in BMD were similar in trials of dietary sources of calcium and calcium supplements (except at the forearm), in trials of calcium monotherapy versus co-administered calcium and vitamin D, in trials with calcium doses of ≥1000 versus <1000 mg/day and ≤500 versus >500 mg/day, and in trials where the baseline dietary calcium intake was <800 versus ≥800 mg/day.
Conclusions Increasing calcium intake from dietary sources or by taking calcium supplements produces small non-progressive increases in BMD, which are unlikely to lead to a clinically significant reduction in risk of fracture.
Conclusions
In summary, increasing calcium intake from dietary sources increases BMD by a similar amount to increases in BMD from calcium supplements. In each case, the increases are small (1-2%) and non-progressive, with little further effect on BMD after a year. Subgroup analyses do not suggest greater benefits of increasing calcium intake on BMD in any subpopulation based on clinically relevant baseline characteristics. The small effects on BMD are unlikely to translate into clinically meaningful reductions in fractures. Therefore, for most individuals concerned about their bone density, increasing calcium intake is unlikely to be beneficial.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4784773/
4 comments:
Hi Bone Lady!
I have been reading around on your blog and I am very intrigued and inspired by your experiences with strontium citrate! I am 55 years old and was diagnosed with osteoporosis of the spine (-2.9) this year. This score is a significant decrease from -2.1 over the course of just two years. My doc, of course, is encouraging me to take Fosamax followed by Prolia in a couple of years. My biggest concern is not the side effects of these medications, especially Prolia (zero bone turnover for decades? a drug that will never plateau? c'mon), it's the longterm effects of them.
I would like to ask, if you don't mind, do you know the cause of your osteoporosis? Mine is certainly genetic (I also have "risk factors" of being white, female, small boned) and I'm wondering if strontium might work for me.
Thank you,
Victoria
Hi Victoria,
My osteoporosis is considered postmenopausal because I was postmenopausal (age 59) when first diagnosed with only a DXA scan. I had an early menopause (age 42), which most certainly contributed to my decline in BMD. I never took HRT, which may have helped slow the decline. I am also white, female, small boned. I have always been thin. I may have been anorexic during my teen years. The term "anorexic" was not used much at the time, but I was very thin in my teens and purposely ate very little to get even thinner. My tummy has always protruded a bit, and that bothered me then and still does. I don't think I have a genetic predisposition to osteoporosis. My mom never had a DXA scan, but her back was straight, and she never broke a bone, even when she tripped on a sidewalk once. I had two aunts (my mom's sisters) who also never had DXA scans. One aunt went out with a friend when she was 90, fell in a store or parking lot, and broke her arm. Another aunt was in an automobile accident when she was quite elderly and got a hairline fracture in one arm, which went undiagnosed for weeks. I am fairly sure my two aunts on my dad's side never fractured a bone. My grandmothers never fractured.
I see no reason why strontium would not work for you.
Best wishes,
BoneLady
Do you have any idea what kind of supplemental calcium was used in this study? Thanks
Hi suzie,
This study was a meta-analysis of randomized controlled trials and included 51 trials of calcium supplements and 15 trials of dietary sources of calcium. So, you have to read 51 individual trials to know what kinds of supplemental calcium and what dosages were used. Below is the link to the original article, which contains all the references used.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4784773/
For example, reference 7 used 1000 mg of elemental calcium as calcium carbonate with 400 IU of vitamin D3 daily.
https://pubmed.ncbi.nlm.nih.gov/16481635/
Reference 12 used 10-30 mg of sodium fluoride (NaF) and 1 g of calcium, but did not state the type of calcium supplement. https://pubmed.ncbi.nlm.nih.gov/3111669/
Reference 13 used 750 mg calcium or 15 micrograms (600 IU) 25-OH-vitamin D3, but did not state type of calcium supplement. https://pubmed.ncbi.nlm.nih.gov/10999778/
Reference 32 used 1 g of calcium per day, but the kind of calcium supplement was not specified.
https://pubmed.ncbi.nlm.nih.gov/354312/
Reference 50 used 1 g elementary calcium (calcium carbonate) and 14 micrograms (560 IU) vitamin D3.
https://pubmed.ncbi.nlm.nih.gov/9797910/
I checked four references; the rest are up to you. That job should keep you busy for quite a while!
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