(20-09-07) Eating More Fish Might Build Stronger Bones

As people live longer, the prevalence of osteoporosis increases and with it the occurrence of bone fractures. The suffering and setbacks caused by fractures, especially among the elderly, exact an enormous toll on health, quality of life and the cost of care. As osteoporosis is the leading cause of fracture, it has become urgent to halt the deterioration of bone health that leads to this condition. According to the National Osteoporosis Foundation, 1 in 2 women over the age of 50 will fracture a bone in her lifetime. So will 1 in 4 men.

Osteoporosis is a bone disease resulting from the loss of bone mineral density and deterioration in bone architecture (Figure). It affects 4 times more women than men. This is because after menopause, the lack of estrogen facilitates the loss of bone mineral. Men lose bone mineral too, but because they have more dense bones to begin with, osteoporosis develops in them later in life.

Because the consequences of osteoporosis are so great, and because millions of older adults are at risk, it is important to slow the loss of bone mineral in older adults. Diet, physical activity, quitting smoking and medication to increase bone calcium are the most common tactics.

Eating well for bone health means having plenty of calcium and vitamin D (from sunshine or dietary supplements), abundant fruits and vegetables and consuming moderate amounts of protein. This list may grow to include long-chain omega-3 polyunsaturated fatty acids, if the findings from research in animals and people continue to expand. In the report described here, young men with higher intakes of long-chain omega-3s had higher spine bone densities than young men with low intakes.

Researchers at Umea University in Sweden decided to investigate the effect of long-chain omega-3 consumption in young men whose bone density was still increasing. They recruited 17-year-old volunteers from schools and sports clubs and monitored them for 8 years. At enrollment, the investigators measured the men?s bone mineral density in several locations and collected blood samples. Eight years later, they repeated the bone density and blood fatty acid measurements. Then, they analyzed the data for relationships between blood fatty acids and changes in bone mineral density.

After 8 years, the increase in bone density in spine was significantly related to higher blood levels of total omega-3s and DHA, one of the main long-chain omega-3s found primarily in fish. Bone density was greater in men with higher blood levels of arachidonic acid, a long-chain omega-6 fatty acid. Upon further analysis, taking into consideration the volunteers? weight, height and physical activity, total bone mineral density was related only to total omega-3s, DHA and EPA, another long-chain omega-3.

These observations are important for several reasons. The study is one of only a few in humans and it relied on the gold standard measurement of bone health, bone mineral density. The study also related bone density to blood fatty acid measurements, a more reliable indicator of omega-3 status than dietary assessments. Third, the study observed that dietary factors could positively affect bone mineral density in young men. This observation indicates that adolescence is an ideal time to boost mineral deposition in bone. Greater bone density means stronger bones and more mineral reserves to see one through the changes that come later in life.

It is tempting to speculate that long-chain omega-3s might increase bone mineral density in older people, too. This possibility remains to be fully evaluated, but there is some evidence they might. In older adults, the dynamics of bone metabolism changes so that bone removal exceeds bone building. It would strengthen the march against osteoporosis if omega-3s were to tilt the balance toward greater bone density.

Source: Clinical Conditions: Bone Health

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