Calcium Supplements Do Not Prevent Fractures
The recommendation for consumption of calcium over the typically recognised minimum official recommendations in the UK and Nordic countries of 700-800 mg/day of dietary calcium for adults appears to have no substantive benefit on fracture prevention. There is currently little, if any, firm evidence that higher intakes prevent bone loss, falls, or fractures in middle aged and older women and men living in the community.[1],[2]
Other considerations associated with serum levels of Vitamin D, a nutrient/hormone recognised internationally as being in a generally precarious status in people in developed countries, appears on its own to have no immediate relationship of value.[3] In part there is risk of error because of the variables in the various study groups, but simply consuming more calcium (no surprise here for Nutritional Medicine Practitioners) has little or no relevant effect on the prevention of fracture development.
This is not news to the well-read, but will be to millions of people routinely recommended or prescribed calcium and vitamin D for fracture prevention, yet these reviews, whilst welcome would do well to explore other nutrient co factors necessary for bone resorption as well as lifestyle and behaviours that also have a direct impact on bone remineralisation. Knowing what is worth doing is as important as rediscovering what isn’t!
Multiple studies indicate that certain nutrients are consistent with healthy ageing; for example, omega-3 fatty acids are helpful for cognitive health, whereas combinations of calcium, vitamin D and K, copper, zinc, selenium, phosphorus, magnesium, strontium and other vitamins and minerals are linked with better bone health. In other words bones and their durability rely on more than the presence of two nutrients, they need a range of bioavailable nutrients from differing foods, and if required from well manufactured food supplements that use bioavailable forms.
Micronutrients play a prominent role in bone health. The emerging theme with supplementation trials seems to be that habitual intake influences the efficacy of the intervention. In other words, correcting a deficiency and meeting the NRVs of micronutrients involved in bone health will improve bone mineral density (BMD) and benefit the skeleton. To realise lasting effects on bone, the intervention must persist throughout a lifetime. At all stages of life, high impact and resistance exercise in conjunction with adequate intake of nutrients involved in bone health are critical factors in maintaining a healthy skeleton and minimising bone loss.
References
[1] Tai V, Leung W, Grey A, Reid IR, Bolland MJ. Calcium intake and bone mineral density: systematic review and meta-analysis. BMJ. 2015 Sep 29;351:h4183 View Full Article
[2] Bolland MJ, Leung W, Tai V, Bastin S, Gamble GD, Grey A, Reid IR. Calcium intake and risk of fracture: systematic review. BMJ. 2015 Sep 29;351 View Full Article
[3] Moyer VA; U.S. Preventive Services Task Force*. Vitamin D and calcium supplementation to prevent fractures in adults: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2013 May 7;158(9):691-6 View Abstract
Data presented in this metaanalysis is worth a discussion for the following:
1. no sub group analysis of different calcium salts, organic salts (citrates) are more bioavailable than the mostly used calcium carbonate
2. no data on metabolic effectiveness of calcium supplementation like parathyroidal hormone, phosphate level, D-status (Calcitriol/Calcidiol-Quotient), this would give a hint on bioavailability of the calcium form used
3. no subgroup analysis for accompanying medication, like proton pump inhibitors, which reduce bioavailability of calcium due to decreased solution of calcium carbonate
4. no differentitation for diets, since phytates and phosphates bind calcium and reduce bioavailability, have supplements been taken on empty stomach?
In my opinion, this metaanalysis lack biochemical and pharmacological reasonableness, so it is only a statistical effect with no clinical relevance.