Worrying about their bones is not something that teenage girls give high priority to – not in relation to how strong they are going to be in 20 years anyway. Nevertheless, building strong bones in adolescent and teenage years is crucial to having strong bones throughout life and into old age. Some older men and women never recover from hip fractures. Once more, genetics plays a major role, for men and women, but it’s the lifestyle differences that can even things out.
In older people, a decline in hormone status has an impact, but it seems this can be at least delayed or stabilised with appropriate lifestyle application – if you start early enough. You need to do sufficient dynamic, impact exercise at an appropriate intensity, and this is where exercise programs often fail – a few arm curls with light weights and a walk around the block is often not enough.
Recently I had a woman contact me asking for help. She had been exercising, lost some weight, and when she checked her DXA test for bone mineral density (BMD), she had actually lost a little – and she was devastated. I didn’t get too involved with her program but this is likely to be all too common. Middle aged women, perhaps post or peri-menopause, losing weight, are very vulnerable to bone loss – and exercise is not a magic wand.
The exercise program needs to be somewhat physical for best effect, and a threshold of useful intensity may not be achievable for some women (and men). In addition, the catabolism of weight loss does not help in the effort to build or even maintain bone.
At the same time, attention needs to be paid to dietary protein, alkalinity and adequacy of calcium and vitamin D, although the complexities of this are not yet fully understood.
It’s all the more reason for young women to understand the importance of maximising the accumulation of bone in adolescent years, and for their parents to understand this too. Smoking, binge drinking, poor diet, lack of physical activity and extreme dieting in this age group is going to be a disaster for their bone health, especially in later years.
Facts about bone mineral density
- More than a quarter of adult bone mass is laid down between the ages of 12 to 14 years in girls and 13 to 15 years in boys.
- Genetics determine 60 to 80% of peak bone mass.
- Diet and physical activity are predictors of bone building during growth.
- The intensity of an exercise program needs to be sufficient to improve bone mineralisation.
- Dietary calcium predicts 10-15% of skeletal calcium retention during adolescence, although interaction with vitamin D is still not well understood.
- Men retain bone better than women; and black women better than non-black women.
- After menopause, the utility of exercise to increase bone mass depends on adequate availability of dietary calcium.
- Moderate consumption of alcohol may be beneficial to bone in men and women. However, in men, more than 2 drinks/day is associated with significantly lower bone mineral density.
- Caffeine/coffee consumption has no effect on bone economy providing adequate intake of calcium and vitamin D are consumed.
Things that work against bone health
- Menopause and low estrogen status in women
- Low androgen and estrogen status in men
- Low-energy and low-nutrient density diets, especially protein
- Female triad – disordered eating, cessation of periods, bone loss (some women athletes, anorexics)
- Excessive dietary salt; excessive alcohol consumption
- Inadequate fruit and vegetables (acid diet)
- Being underweight and not exercising
What You Need to Know About Bone Density
- Start before puberty with appropriate exercise and healthy eating.
- Maintain normal weight and protect muscle with sports and exercise.
- Eat plenty of fruit and vegetables and vegetable protein — alkaline diet.
- Ensure the recommended intake of protein, especially vegans and vegetarians.
- Eat calcium, vitamin D and K rich foods and avoid carbonated drinks, especially cola drinks.
- Get appropriate sun exposure for safe vitamin D absorption.
- Supplement to get adequate calcium and vitamin D if necessary.
- Exercise for bone health with dynamic exercises including: weight lifting – weighted lunges, steps, jump squats, clap pushups, overhead push-presses, pump classes –plyometrics – bounds, box marches, skips, hops, step classes — running, jogging, fast walking, jumping, basketball, volleyball
- Don’t do very low-calorie dieting and always include exercise in weight loss plans.
- Undereating and weight loss, excessive exercising and cessation of periods is a warning cluster for bone less in active women.
– Sports Med. 2005;35(9):779-830. Physical activity in the prevention and amelioration of osteoporosis in women : interaction of mechanical, hormonal and dietary factors. Borer KT. Asia Pac J Clin Nutr. 2008;17 Suppl 1:135-7. The role of nutrition on optimizing peak bone mass. Weaver CM.
— Tucker KL, Morita K, Qiao N, Hannan MT, Cupples LA, Kiel DP. Colas, but not other carbonated beverages, are associated with low bone mineral density in older women: The Framingham Osteoporosis Study. Am J Clin Nutr. 2006 Oct;84(4):936-42.
— Am J Clin Nutr. 2003 Feb;77(2):504-11. Calcium, vitamin D, milk consumption, and hip fractures: a prospective study among postmenopausal women. Feskanich D, Willett WC, Colditz GA.
— Vandenput L, Ohlsson C. Estrogens as regulators of bone health in men. Nat Rev Endocrinol. 2009 Aug;5(8):437-43.
— Leblanc ES, Nielson CM, Marshall LM, et al. The Osteoporotic Fractures in Men (MrOS) Study Group. The effects of serum testosterone, estradiol, and sex hormone binding globulin levels on fracture risk in older men. J Clin Endocrinol Metab. 2009 Jul 7.
— Am J Clin Nutr. 2003 Feb;77(2):512-6. Vitamin K intake and bone mineral density in women and men. Booth SL, Broe KE, Gagnon DR, Tucker KL, Hannan MT, McLean RR, Dawson-Hughes B, Wilson PW, Cupples LA, Kiel DP.