Yes, you can be too thin

Whenever I go to one of my son’s school events, or see a group of children in other places, my attention is drawn to the number of very thin, almost frail looking young girls. The anthropologist in me always asks, Why would nature select for such thin, small boned girls? The thin children, I muse, cannot possibly have the same degree of bone strength as the sturdier girls. Will they not in later life fracture more than others?

I’ve asked myself this question dozens of times. Here at the Center for Better Bones we’ve seen that being underweight, and particularly losing more weight as we age, is a significant risk factor for osteoporotic fracture. But now, new research suggests that thinness in childhood is also a critical issue. A large study from Finland has confirmed my speculation. This investigation found that, as they aged, the thinnest Finnish children had more than an 8-fold increased risk of hip fracture as compared to the heaviest group of children. Yes indeed, you can be too thin.

OK, so now you might say that’s all well and good but what about obesity? Does being very overweight help or hinder bone? Well, we don’t have data on children right at hand, but we do have research findings on adults. Recently, Italian scientists asked if obesity offered protection from osteoporosis. In a study of middle-aged women and men they found that being overweight was neutral or protected for bone mineral density. However, being obese was associated with low bone mass, often compatible with a diagnosis of osteoporosis. Their conclusion is that skeletal metabolism is likely to be altered by factors related to obesity. Yes indeed, being really heavy does not help bone either.

Research shows us that obesity is related to many health issues, and that losing weight is often beneficial to our health. When it comes to your bones, this issue is a bit more complicated. I always encourage women to take care with weight loss, especially as they age, because the combination of low weight and advancing age are important risk factors for determining low bone density. We all have a healthy weight at which our bodies thrive, and it’s always best to work toward yours. If this means you have to lose a few pounds, do so with your bones and whole body in mind:
• Exercise in a way that builds muscle
• Strive for an alkaline diet
• Supplement with bone-building vitamins and minerals, especially vitamins D and K

References:
Javaid, MK, JG Eriksson, E kajantie, et al. 2010. Growth in childhood predicts hip fracture risk in later life. Osteopor Int, DOI: 10.1007/s00198-010-1224-3, Pub. online April 9.
Greco, EA, R Fornari, F Rossi, et al. 2010. Is obesity protective for osteoporosis? Evaluation of bone mineral density in individuals with high body mass index. Int J of Clin Prac, 64(6):817-820.