Fish for Healthy Bones: Preventing Osteoporosis

January 6, 2016 – Nuritas
Contributing Authors: Brendan Molloy

Bones perform a number of functions within the human body, they provide support for our limbs, house bone marrow which produces white blood cells for our immune system and act as a store of calcium. Calcium is essential for many fundamental processes in the body such as blood clotting, cell signalling, muscle contraction and nerve function. The body must therefore be able to regulate and maintain adequate levels of blood calcium to support all of these processes. This is achieved by obtaining calcium from dietary sources and by removing or depositing calcium from bones via osteoblasts and osteoclasts as needed. Osteoclasts are cells present on the surface of bones which secret collagenase enzyme and release calcium and other minerals to the blood stream. Osteoblasts are specialised mesenchymal cells which produce a calcium and phosphate based mineral which is deposited into the bone matrix forming strong connective tissue.

In a healthy person these processes occur unnoticed but sufferers of osteoporosis experience symptoms of weakened bones such as lower back pain and increased susceptibility to fractures. Osteoporosis can affect people at any age, of either gender but it is a condition more commonly recognised in the elderly. Osteoporosis is estimated to affect 200 million women worldwide – approximately 10% of women aged 60, 20% of women aged 70, 40% of women aged 80 and 66% of women aged 90. This increased fragility is caused by excessive activities of osteoclasts resulting in a detrimental loss of calcium from bones.

Current therapeutic agents designed to stimulate bone formation can have undesirable effects such as osteonecrosis of the jaw and hormone replacement therapy induced malignancies.

But all is not lost, natural remedies do exist!

Several recent studies have demonstrated that peptides produced from fish can prevent or delay the onset of osteoporosis. A report published in the Journal of Agricultural and Food Chemistry demonstrated that peptides derived from Antarctic Krill (Euphausia superba) could prevent/delay osteoporosis (Xia et al., 2015). Interestingly, this work was carried out in a model which simulated osteoporosis caused or exacerbated by estrogen deficiency. Estrogen deficiency at menopause activates both osteoblasts and osteoclasts with osteoclast activation being dominant.

It was found in this study that Krill peptides improved bone density and bone biomechanical properties. Bone resorption and genes associated with the expression of osteoclastic activity were decreased. Bone resorption is controlled by the OPG/RANKL/RANK signalling axis. The expression of RANKL and OPG regulate osteoclast differentiation, activation and survival. Rankl promotes osteoclastogenesis (osteoclast production) by binding to its receptor RANK which is expressed on the osteoclast surface. OPG inhibits osteoclastogenesis by inhibiting RANKL-RANK interaction via competitive binding to RANKL (Xia et al., 2015). Therefore, it is the ratio between OPG and RANKL which determines the level of activation of RANK and the extent to which osteoclastogenesis is activated (Xia et al., 2015).

This study demonstrated the ability of fish peptides to promote OPG/RANKL ratio of mRNA expression and serum content thereby inhibiting bone resorption by preventing the formation of new osteoclasts.

Our team at Nuritas™ are working very hard to find new peptides that improve health and prevent the onset of disease. Findings like this by Xia G et al are crucial to advance the area of preventative medicine.

Reference:
Xia G, Zhao Y, Yu Z, Tian Y, Wang Y, Wang S, Wang J, Xue C. Phosphorylated Peptides from Antarctic Krill (Euphausia superba) Prevent Estrogen Deficiency Induced Osteoporosis by Inhibiting Bone Resorption in Ovariectomized Rats. J Agric Food Chem. 2015 Nov 4;63(43):9550-7