The study, performed with mice, analysed the effects of a CLA-containing diet with regular or enhanced calcium content and found that the extra calcium improved the effect of CLA on bone mass, especially in males.
“Inconsistent effects of CLA on bone mass may be in part due to various dietary levels of calcium used in different studies,” wrote the researchers in the Journal of Food Science. “Co-supplementation of CLA and calcium may benefit bone health by preserving bone mass.”
Osteoporosis, characterized by low bone mass, leads to an increase risk of fractures, especially the hips, spine and wrists. An estimated 75 million people suffer from osteoporosis in Europe, the USA and Japan.
The researchers, from the University of Massachusetts Amherst and the University of Wisconsin-Madison, reanalysed their two of the earlier studies with mice fed a diet containing 0.5 per cent CLA with a regular calcium content (0.5 per cent) or an enhanced calcium level of 0.66 per cent.
The CLA market is expanding, according to a 2007 Frost & Sullivan report, which said the global market is forecast to reach revenues of US$109.9 million in 2013.
They report that extra calcium improved the effects of CLA effects on bone mass, especially in male mice. No effects of CLA were observed without the additional calcium in the diet, they added.
In an attempt to explain the mechanism behind the apparent effects, the researchers noted that CLA may play a role in calcium absorption, while other studies have reported that CLA may also play a role in bone formation.
“The exact mechanism of either of these CLA isomers on calcium transport in conjunction with bone formation still needs further investigation,” stated the researchers.
The two major isomers of CLA are cis-9,trans-11 (c9,t11) and trans-10,cis-12 (t10,c12) did not appear to be equal for boosting bone health, with the latter singled out for attention.
“It is likely that the trans-10,cis-12 CLA isomer is responsible for improvement of bone mass, although further studies are needed to confirm this,” wrote the researchers.
Potential reduction of osteoporosis has traditionally been a two-pronged approach by either attempting to boost bone density in high-risk post-menopausal women by improved diet or supplements, or by maximising the build up of bone during the highly important pubescent years.
About 35 per cent of a mature adult's peak bone mass is built-up during puberty.
Source: Journal of Food ScienceVolume 73, Number 7, Pages C556-C560“Cosupplementation of Dietary Calcium and Conjugated Linoleic Acid (CLA) Improves Bone Mass in Mice”Authors: Y. Park, M.W. Pariza, Y. Park