The Better Bones Blog

by Dr. Susan Brown, PhD.

How much magnesium do you need to prevent fracture?

Is magnesium the missing ingredient for preventing bone fracture?

Are you getting enough magnesium? The mineral may not immediately spring to mind when you think about important nutrients for your bones — but two new studies that found a strong relationship between insufficient magnesium and fracture risk could change this.

Low magnesium and hip fracture are connected

The first study (Kunutsor et al, 2017) found that having low magnesium levels in the blood correlated to a 44% higher risk of bone fractures, particularly hip fractures. This was done by looking at serum magnesium levels of 2,245 middle-aged men (age 43-61 years old).

The study noted that none of the men with what they regarded as “high” magnesium levels (more than 2.3 mg/dL) fractured at all. I should mention that the FDA sets the serum magnesium reference range at 1.8-3.6 mg/dL, so 2.3 mg/dL hardly qualifies as a “high” level of magnesium. It’s not even in the middle of the range! And that raises the possibility that chronic, latent magnesium deficiency may have been depleting the study participants’ bones of this needed mineral (Elin, 2011).

How much magnesium do you need to lower fracture risk?

Researchers also continue to reveal the importance of dietary intake of magnesium — especially for women. The second study (Veronese et al, 2017) included 1,577 and 2,071 women with an average age of 60 years. During the 8 year study, 560 participants — almost 15% — had a fracture. The risk of fracture also decreased significantly in the people who had the highest magnesium intake — 53% in the men, and 62% in the women.

One of the important findings was that in women, the effects were only seen to a significant degree in the ones who achieved the recommended daily allowance (RDA) of dietary magnesium, which was 320 mg/day (for men, it was 420 mg/day).

I generally recommend a daily magnesium intake of: 400-800 mg/day (which is somewhat higher than the RDA).

Here’s how to get the magnesium you need

I get two messages from these studies. One is obvious: We need to pay more attention to magnesium for healthy bones! Both studies show that people who lacked adequate magnesium would have benefited from having more, either through changes to their diet or by taking a magnesium supplement. They also show that even a small increase in daily magnesium intake can produce a significant effect. Ideally, though, we want to get enough to keep our bones healthy — and current ideas of what constitutes “enough” are probably too low.

The other message is perhaps less obvious, but no less important: chronic, latent magnesium deficiency is something you can probably fix pretty easily, assuming there’s no hidden disease process that prevents absorption. A good way to start is to try adding more magnesium-rich foods to your diet, like this easy salad recipe that gives you 350 mg of magnesium. You can also learn more about supplementing for magnesium with my Better Bones Basics.

Try this magnesium-rich warm salad

In a bowl, toss:
1 cup steamed or sautéed spinach (157 mg of magnesium)
1 avocado, sliced (58 mg of magnesium)
1/4 cup almonds (105 mg of magnesium)
3.5 ounces of sautéed tofu (30 of magnesium)
Sea salt and pepper to taste (optional)

 

Magnesium rich salad recipe

Magnesium rich salad recipe

References:

Elin RJ. Re-evaluation of the concept of chronic, latent, magnesium deficiency. Magnes Res 2011;24(4):225-227.

Food and Drug Administration. Investigations Operations Manual 2017: Appendix C. Silver Spring, MD: US FDA. Available at https://www.fda.gov/ICECI/inspections/IOM/ (accessed August 7, 2017).

Kunutsor SK, Whitehouse MR, Blom AW, et al. Low serum magnesium levels are associated with increased risk of fractures: a long-term prospective cohort. Eur J Epidemiol 2017; doi: 10.1007/S10654-017-0242-2.

Veronese N, Stubbs B, Solmi M, et al. Dietary magnesium intake and fracture risk: data from a large prospective study. Br J Nutr 2017; doi: 10.1017/S0007114517001350.

Bone Drugs: Are they worthwhile?

Conflicting advice on bone drugs — what does the evidence say?

It’s no secret that I’m no fan of bone drugs in general. I’ve found the arguments for their use deeply unconvincing for decades. And now, European researchers looking at the accumulated evidence about the various drugs’ long-term effects are starting to come to the same conclusion:

Except in extreme cases, bone drugs don’t offer enough benefit in reducing the risk of fractures to be worth the price paid in terms of both short- and long-term side effects.

A European/Canadian research group reviewed the evidence on bisphosphonates like:

  • alendronate (Fosamax),
  • ibandronate (Boniva) and zoledronic acid (Zometa or Reclast)
  • teriparatide (Forteo)
  • denosumab (Prolia)
  • two treatments not used in the U.S.: calcitonins and strontium ranelate

Their findings struck me as good general “lessons” for all of us to learn.

‘Denser’ bones are not always stronger bones

The review found that the majority of osteoporotic fractures happened in those who did not have “osteoporotic bone density.” This helps confirm: Bone density alone cannot predict fracture risk.

Other recent studies show a large percentage of people who fracture have only osteopenia or even normal bone density. Many people with an osteoporotic bone density never fracture.

Not all fractures are created equal

When it comes to assessing bone drugs’ effects, a painless vertebral fracture or a toe fracture (painful, but not life-altering) shouldn’t be considered as clinically important as a hip fracture, which is life-changing.

Yet many drug trials either focus on vertebral fractures or on “non-vertebral” fractures as an endpoint. The stubbed toe becomes equivalent to a hip fracture in determining how effective the drugs are in fracture prevention.

Not surprisingly, when hip fractures are looked at specifically as the endpoint of choice, the researchers discover something different. They found that the data on less serious fractures of toes, wrists and so forth obscure the fact that the drugs don’t do much to prevent the most serious and dangerous osteoporotic fractures.

Bone drugs’ benefits remain inconclusive

The benefits of taking a bone drug must outweigh the costs for it to be worth recommending. And even in high-risk older adults, such benefits have not been shown conclusively.

In weighing the risk-benefits of bone drugs, researchers took a hard line on the importance of evaluating all costs. “Clinical trials evaluating harm-benefit balance in osteoporosis or fracture prevention should be well-powered long-term studies that include hard endpoints,” they note. “Total mortality, total serious adverse events, hip fractures, and functional status are essential outcomes.”

New U.S. osteoporosis guidelines miss the mark

What’s frustrating to me is that experts in the U.S. still focus uncritically on the flawed studies that the review critiques. They glibly parrot the ideas that bone density is the same thing as fracture risk and that drugs offer protection from fractures.

Case in point: The American College of Physicians’ latest osteoporosis guidelines, which were published virtually simultaneously with the European review. They make a “strong recommendation” for the use of bisphosphonate drugs “to reduce the risk of hip and vertebral fractures.” Most galling to me, they openly equate bone mineral density with fracture risk: “most women with normal DXA scores” it notes, “do not progress to osteoporosis within 15 years.”

To which I respond with the European review’s first lesson: Denser bones ≠ stronger bones.

References:
Erviti J, Gorricho J, Saiz LC, Perry T, Wright JA. Rethinking the Appraisal and Approval of Drugs for Fracture Prevention. Front Pharmacol. 15 May 2017 | https://doi.org/10.3389/fphar.2017.00265

Qaseem A, Forciea MA, McLean RM, Denberg TD, for the Clinical Guidelines Committee of the American College of Physicians. Treatment of Low Bone Density or Osteoporosis to Prevent Fractures in Men and Women: A Clinical Practice Guideline Update From the American College of Physicians. Ann Intern Med. 2017;166:818–839.

5 differences between arthritis and vertebral fracture

Arthritis or fracture? Figuring out what back pain means

It’s an unusual person who gets to middle age without a few aches and pains — a little wear and tear is to be expected after a half century or so. But for those at risk of osteoporotic fractures, back pain is particularly worrisome because you can’t really know whether it’s tired muscles, or arthritis, or a vertebral fracture.

Or can you?

Recent research shows that the pain caused by vertebral fractures is different from other causes, such as arthritis of the spine. As a 2016 study published in Osteoporosis International found, vertebral fractures in women produced a number of distinct pain signposts that weren’t present in women who had arthritis of the spinal column.

Recognizing the signs of vertebral fracture vs. arthritis pain

The study looked at 197 British women between the ages of 67 and 84, asking them to report on their experiences of pain (in the back but elsewhere as well) before initiating a spine x-ray to look for vertebral fractures. They found that about a third of the women had vertebral fractures — and the women with fractures had a number of things in common. They were older (average age of 76.9 years versus 71.7 in the women without fractures), were considerably more likely to have had a previous fracture, or a diagnosis of osteoporosis, or both, and had fairly specific attributes to the pain they experienced that differed from the women with arthritis.

Most notably, women with fractures described their pain as recent and brief in duration but “crushing,” whereas women with arthritis said they had intermittent or periodic pain that they were more likely to call “taut” or “sharp.” Radiation of pain to the legs and association with weather changes were common in the women with arthritis but not the women with vertebral fractures. (See table for full comparison.)

Listening to your body

All of this makes sense. Fractures are an acute injury in the bone, which is very different from the kind of slow, gradual, and chronic inflammatory process that is present in arthritis.

What I take away from this study is that our body will tell us what we need to know — if we listen carefully. To start learning more about your bone health and risk for fracture, I encourage you to take our quick and easy Bone Health Profile.

Table: Women’s experience of vertebral fracture pain

Vertebral fractureArthritis
Risk factors
  • Older age
  • Previous fracture (nonvertebral)
  • Diagnosis of osteoporosis
Duration of painShort-term, recent (occurring within days or weeks of the study); episodes are brief or transient with no apparent patternLong-term (present months or years prior to study); episodes are “periodic” or intermittent
OnsetSuddenGradual
Type of pain“Crushing” but localizedPain description varies but it is ongoing or intermittent and may occur anywhere from neck to legs
Other
  • Relieved by lying down
  • Does not radiate to legs
  • No obvious association to weather or temperature
  • No clear effect on pain of keeping still or moving
  • May radiate to legs
  • Some associations with cold, damp, or changing weather conditions
Vertebral Fracture vs Arthritis

Vertebral Fracture vs Arthritis

Reference: 

Clark EM, Gooberman-Hill R, Peter TJ. Using self-reports of pain and other variables to distinguish between older women with back pain due to vertebral fractures and those with back pain due to degenerative changes. Osteoporos Int 2016;27:1459–1467.


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