Bottomline: A  high omega-3 fat diet with a low ratio of omega-6 to omega-3 Fat,  resulted in significant benefits for bone health. Griel S. et al.Nutrition Journal 2007, 6:2.

In a small, but very controlled study, 23 people were put on one of three diets: typical American Diet, Linoleic Acid Diet (LA) and a High Alpha Linolenic Acid (ALA Diet ) during a 24 week period.

Blood tests screened for two biological markers of bone health, one that indicates bone formation
and one that indicates bone resorption or breakdown. The biomarker for bone resorption, N-telopeptides, decreased significantly while eating the ALA diet and marginally during the LA diet compared to the average American diet.  This means more of the bone is being retained.

Notably, the ALA diet had the lowest omega-6 to omega-3 fat ratio of 1.6 to 1.  The researchers caution that it is unknown if the observed effects are due to increased ALA or conversion of ALA to eicosapentaenoic acid, EPA.

Comment: An important part of this study, is that benefits were accrued on the diet with the lowest omega-6 to omega-3 fat ratio, summarized below, in the chart. Notably, the people on this diet had more EPA in their bodies, than the other two diets. Some scientists believe that balancing the ratio of omega-6 and omega-3 fatty acids is an important factor for the body's ability to accrue EPA, which is the type of omega-3 fat found in fish. Chart: Amount of Fats in three experimental diets, listed as percent of calories:

Type of Fat in Diet	American Diet	Linoleic acid Diet	ALA Diet
Omega-6 Fat Linoleic Acid	7.7%	12.6%	10.5%
Omega-3 Fat	0.8	3.6	6.5
Fat Ratio Omega-6:3	9.5 to 1	3.5 to 1	1.6 to 1

Full Text Link
Griel S. et al.A n increase in dietary n-3 fatty acids decreases a marker of bone resorption in humans. Nutrition Journal 2007, 6:2 doi:10.1186/1475-2891-6-2