By Stephen Daniells
Increased intakes of calcium can increase excretion of fat in the feces, and may play a role in weight management and preventing weight gain, says a review of the science.
Increasing daily calcium intakes from dairy by 1241 mg was associated with an increase in fat excretion of 5.2 grams per day, according to a systematic review with meta-analysis of randomized, controlled trials.
Writing in Obesity Reviews, Professor Arne Astrup from the University of Copenhagen and his co-workers concluded: “Dietary calcium has the potential to increase faecal fat excretion to an extent that could be relevant for prevention of weight (re-)gain.”
The review adds to a large body of observational studies linking calcium intake, mainly from dairy products, to weight loss. The topic is a source of controversy with both camps able to quote research that supports their side and undermines the other.
Over 300m adults are obese worldwide, according to latest statistics from the WHO and the International Obesity Task Force. About one-quarter of the US adult population is said to be obese, with rates in Western Europe on the rise, although not yet at similar levels.
Professor Astrup and his co-workers identified 13 studies which fitted their inclusion criteria, including enrolment of healthy participants over six years of age, provision of data on calcium intakes from dairy and supplemental sources, and provision of data on faecal fat changes.
When the studies were taken in their entirety, a wide variation was observed. When the Scandinavian researchers considered only calcium from dairy sources, a good consistency was achieved.
“An increased dairy calcium intake of 1241 mg day-1 increased faecal fat excretion by 5.2 g day-1 compared with low-calcium (less than 700 mg day-1) dairy diet,” they wrote.
“It has been suggested that the effect of increased calcium intake on body weight and composition is most pronounced in subjects with a low habitual intake,” wrote the researchers. “Furthermore, the majority of the studies included in this meta-analysis, which found a significant effect of increased calcium intake on faecal fat excretion, compared a high intake of dietary calcium with a relatively low intake of dietary calcium.
“Thus it is likely that subjects with a low habitual calcium intake will benefit more from an increased calcium intake than subjects with a high habitual calcium intake,” they concluded.
Source: Obesity Reviews
Published online ahead of print, doi: 10.1111/j.1467-789X.2009.00599.x
"Effect of calcium from dairy and dietary supplements on faecal fat excretion: a meta-analysis of randomized controlled trials"
Authors: R. Christensen, J.K. Lorenzen, C.R. Svith, E.M. Bartels, E.L. Melanson, W.H. Saris, A. Tremblay, A. Astrup
Source: Food Navigator