Onions and bones…nothing to cry about

Posted by Liz on Apr 17, 2009 in bone health | 0 comments

I love onions. Red onions, scallions, yellow onions, spring onions, shallots; you name it. Sauteed, raw, caramelized, fried, baked. Yum! So, imagine my pleasure when I stumbled across an interesting study in the July issue of Menopause that shows a link between onion consumption and increased bone density. Yowza!

Okay, so your breath might be a bit ripe but your bones will love you for it!

Although calcium, vitamin D supplements and exercise are effective prevention tools against osteoporosis, they have not been shown to add much in the way of slowing bone loss. To address this hole in therapy, researchers have been looking towards phytochemicals, i.e. natural compounds in plants, to examine if they might increase the activity of bone building cells (osteoblasts) and decrease the activity of cells the breakdown bones (osteoclasts).

Spurred by studies in rats, researchers analyzed the bone density (repeated five times) and onion consumption (from 2 or more times daily to 1 to 6 times a year to never) in 507 perimenopausal and postmenopausal non-Hispanic white women, age 50 and older, participating in the National Health and Nutrition Examination Study. Women were divided  into four groups based on their onion consumption:

• Less once/month
• 2 times a month to 2 times a week
• 3 to 6 times a week
• Once a day or more

Because certain variables are considered risk factors for osteoporosis and could influence study findings, the researchers also measured age, smoking status, calcium intake, use of vitamin D supplements, thyroid hormone levels, intensity of exercise regimens (i.e. none, moderate, vigorous), use of estrogen, and body mass index.

The findings? The more onions the women ate, the greater the increase in their bone density. In fact, women who consumed onions at least once daily had an overall bone density of their spine that was 5% greater than women who consumed onions once a month or less.

What the study didn’t tell us was the quantity (e.g. one cup) and type of onions consumed.

Studies comparing the bone density of smokers and non-smokers at different ages have shown that a bone density difference of 4% can confer a 41% greater risk of hip fracture. So while a 5% difference seems marginal at best, the potential reduction in the risk of fractures is great.

The researchers caution that certain compounds in onions, such as quercetin, have been associated with cancer causing properties. However, they note that animal studies have found no evidence of such problems. Although further study is needed to determine if women who ate onions also consume foods other than onions that might contribute to their reduced risk for osteoporosis, they believe that onions hold great promise as an addition to other measures that prevent osteoporosis.

Me? I’m all for erring on the side of onions. Tears and all!