Higher omega-3 intake builds bone density from ages 16 to 22; omega-6 rivals tend to tear it down
by Craig Weatherby
Some novel findings in young men add to the evidence that higher omega-3 intake helps build stronger bones.
And they reinforce the idea that bone health also improves when people limit intake of omega-6 fatty acids, which predominate in most cooking oils, dressings, meats, poultry, and packaged, prepared, or fast foods (see “Omega-3s Seen as Stellar Bone-Builders”).
Researchers at Sweden's Umeå University report that young men with higher blood levels of omega-3s have denser, stronger bones (Hogstrom M et al 2007).
Surprisingly, no one had ever examined the association between body levels of dietary fatty acids and standard markers of bone strength such as bone mineral density or BMD.
In previous studies, researchers relied on food intake questionnaires to estimate people's intake of fatty acids relative to their bone density: a factor associated with bone strength, though not always synonymous with reduced fracture risk.
What the study found
A team led by Magnus Högström, PhD recruited 78 healthy young men (average age of 16.7 years) from high schools and sports clubs, measured total body bone mineral density (BMD), and took blood samples to measure their levels of omega-3 and omega-6 fatty acids.
About eight years later, Dr. Högström's group found that the young men with the highest tissue levels of omega-3s had the best (highest) total-body BMD and spinal BMD, and the greatest growth in BMD between the ages of 16 and 22.
Of the two omega-3s—DHA and EPA—levels of DHA had the closest associations with these two measures.
As Chaim Vanek, M.D. and William Connor, M.D. of Oregon Health & Science University said in an accompanying editorial, “The study by Högström et al. nicely adds to a growing body of evidence that n-3 fatty acids are also beneficial to bone health” (Vanek C, Connor WE 2007).
Drs. Vanek and Connor hypothesized that the apparent benefits might relate to the opposite effects of omega-3 and omega-6 fatty acids with regard to cell receptors for a genetic switch called PPAR-gamma, excessive activation of whose cell receptors is associated with lower bone mass:
- Omega-6 fatty acids, in excess, weaken bone because they activate PPAR-gamma cell receptors in bone marrow. Americans consume far too many omega-6s.
- Omega-3 fatty acids conserve bone density, because they do not activate PPAR-gamma cell receptors in bone marrow.
Although Drs. Vanek and Connor say that omega-3s do not activate PPAR-gamma cell receptors in bone marrow, diabetes studies indicate that marine omega-3s do activate PPAR-gamma receptors in fatty adipose tissue found under the skin and around internal organs (see Abedin M et al 2006 and other PPAR-omega-3 papers, below).
We haven't been able to confirm or resolve this apparent contradiction, so we welcome any enlightening communications.
Suffice it to say that higher omega-3 intake clearly helps build and conserve bone health, no matter how.
If diets higher in omega-3s than average promote better bone density they could help prevent many fractured bones throughout life, and in later years, help prevent the broken major bones that lead to disablement and many premature death spirals.
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