12 January - 20 June 2016

Calcium and vitamin D intake from food vs supplements – are there any differences?

Calcium and vitamin D are often recommended for osteoporosis prevention and treatment, with calcium absorption in the small intestine declining with age. In America 60% of women take a calcium supplement, although many nutritional experts encourage patients to consume calcium via food. A crossover trial published in the journal Bone Reports investigates whether 4 servings/day of dairy foods increase Ca retention more than the same amount of calcium and vitamin D from supplements.

Calcium and vitamin D are often recommended for osteoporosis prevention and treatment, with calcium absorption in the small intestine declining with age.  In America 60% of women take a calcium supplement, although many nutritional experts encourage patients to consume calcium via food.  A crossover trial published in the journal Bone Reports investigates whether 4 servings/day of dairy foods increase Ca retention more than the same amount of calcium and vitamin D from supplements.  

Researchers from the USDA, University of California and Lawrence Livermore National Laboratory recruited 12 healthy, low dairy consuming (consuming ≤2.5 servings per day) women who were two years post-menopausal. For the first 180 days of intervention, the participants received an oral dose of 100 nCi of 14 Ca, a radioisotope calcium-41 which allowed the team to measure changes in bone resorption with different dietary interventions.  During this period the subjects were told to continue their low dairy diet and lifestyle.  At day 0 (before intervention) and then during intervention at 90, 120, 150 and 180 days, subjects provided 24 hr urine collections.

After this period the participants were randomly assigned to one of two 42 days interventions followed by a 42 day washout period, with women then continuing the second intervention.  The dairy intervention consisted of the women consuming 20 servings of milk (1 serving 237 ml containing 400 mg calcium and 100 IU cholecalciferol (vitamin D3)/serving) per week and 8 (8oz) servings of low fat vanilla yogurt containing 200 mg calcium and 100 IU vitamin D3 per serving. The supplement intervention included a 600 mg calcium tablet to be taken twice daily and a vitamin D supplement (400 IU vitamin D3 per tablet) once daily.  Energy intake was adjusted to account for the energy associated with the dairy servings.  Twenty four hour urine collection was taken at baseline, at weekly intervention for each intervention and washout period.  Blood was taken at the beginning and end of each intervention. The subjects also recorded a 3 day weekly food intake during each intervention. Body composition as well as bone mineral content and density were measured.

The team measured changes in 41/40 Ca in urine and found that calcium and vitamin D from either dairy foods or supplements exert equal effect on calcium metabolism.  Both interventions demonstrated a significant retention of 41Ca within 1-2 weeks with the washout period showing a significant decrease returning to pre-intervention or untreated levels.  The study found no differences in the “anti-resorptive effect of the calcium supplement versus dairy foods, but the advantage of dairy food becomes evident when dietary intake data are examined.”  The authors note that during the dairy intervention participants will have consumed significantly greater amounts of protein, carbohydrate, vitamin A, zinc and potassium.  Compared to the washout period they also had increased dietary intake of folate, phosphorus and magnesium, which are all nutrients recognised as bone-enhancing.  They state “a longer duration may result in a shift toward a significant difference between food and supplement treatments.” A six-week time frame is reported by the researchers to perhaps be too brief to observe mineralisation changes, noting that a previous 16-week trial comparing 1200 mg/day calcium from semi-skimmed milk vs no milk supplement found significant changes in certain bone formation markers. 

RSSL provides vitamin analysis in a wide range of matrices including drinks, fortified foods, pre-mixes and multi-vitamin tablets. 
For more information please contact Customer Services on +44 (0) 118 918 4076 or email 
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