What the heck are soluble adhesion molecules, and why should you care?
Well, they're proteins belonging to the family of “cell adhesion molecules” (CAMs), and they're implicated in cardiovascular disease and cancer.
CAMs are markers for specific inflammatory processes that impact white blood cells, blood platelet cells, and endothelial cells … with generally negative effects.
The endothelium (inner layer) of blood vessels is made of endothelial cells, which are very active players in the health of our arteries … and appear to play indirect roles in cancer growth.
Now, two new studies indicate that higher intakes of omega-3s (EPA and DHA) from fish inhibit a specific kind of CAM, with consequent benefits to heart and immune health.
Both studies looked at the effects of omega-3s on blood levels of soluble intercellular adhesion molecule-1 (sICAM-1).
Prior research linked higher blood levels of sICAM-1 to cancer, and to three key precursors of cardiovascular disease:
  • Arterial inflammation
  • Activation of endothelial cells
  • Activation of the immune-system white blood cells called monocytes
Chinese study
Researchers from China's Jilin University analyzed 18 randomized clinical trials that tested omega-3 supplements and collected data on the participants' blood levels of sICAM-1 (Yang Y et al. 2012).
Their analysis indicates that omega-3 supplements can reduce blood levels of sICAM-1 in healthy people and people with unhealthy blood fat profiles.
This seems to reveal a new way in which omega-3s may help prevent atherosclerosis and related cardiovascular disease.
Adding a new insight to the inflammation-moderating effects of omega-3s, the Chinese team found that supplements reduced inflammation by inhibiting activation of monocytes, which proliferate in response to inflammation.
Chronic inflammation drives atherosclerosis, the leading cause of cardiovascular disease.
It's become clear that white blood (immune-system) cells – especially macrophages – are promote arterial plaques, which are prone to rupture, leading to strokes, heart attack, and possible death.
Like macrophages, monocytes appear to promote formation of arterial plaques and fuel their growth via formation of “foam” cells, production of free radicals, and more.
As the researchers wrote, their finding “… supports the notion that omega-3 [supplements can help] to prevent the development and progression of atherosclerosis.” (Yang Y et al. 2012)
French study finds omega-3s' sICAM-1 effects curb cancer
A team from the National Institute of Health and Medical Research in Paris report that higher blood levels of omega-3 may counteract the pro-cancer properties of sICAM-1 (Touvier M et al. 2012).
The Paris group examined the impacts of omega-3 intakes on sICAM-1 levels and cancer risk by comparing data from 408 people with cancer (“cases”) and 760 healthy people (“controls”).
As in the Chinese analysis, their results linked higher omega-3 levels to lower sICAM-1 levels.
This association was seen in people with four kinds of cancer, including breast and prostate cancer.
In addition, higher blood levels of sICAM-1 were linked to higher cancer risk in people with below-average omega-3 intakes.
Conversely, people with higher omega-3 intakes had lower sICAM-1 blood levels and lower risk of cancer.
As they wrote, “These findings suggest that n-3 PUFA intake may counteract the pro-carcinogenic actions of sICAM-1.” (Touvier M et al. 2012)
The researchers proposed two ways in which omega-3s might affect blood levels of sICAM-1:
  1. Omega-3s may decrease the expression of adhesion molecules like sICAM-1.
  2. Omega-3s may interfere with a pro-cancer pathway triggered by sICAM-1 … with, as they wrote, “an anti-carcinogenic action”.
The French and Chinese findings reveal good news … and how much remains to be learned about the roles that omega-3s play in human health.
  • Touvier M, Kesse-Guyot E, Andreeva VA, Fezeu L, Charnaux N, Sutton A, Druesne-Pecollo N, Hercberg S, Galan P, Zelek L, Latino-Martel P, Czernichow S. Modulation of the association between plasma intercellular adhesion molecule-1 and cancer risk by n-3 PUFA intake: a nested case-control study. Am J Clin Nutr. 2012 Apr;95(4):944-50. Epub 2012 Feb 29.
  • Yang Y, Lu N, Chen D, Meng L, Zheng Y, Hui R. Effects of n-3 PUFA supplementation on plasma soluble adhesion molecules: a meta-analysis of randomized controlled trials. Am J Clin Nutr. 2012 Apr;95(4):972-80. Epub 2012 Feb 29.