By Dr. Shawna Darou, ND
It’s amazing that we still hear so much about the importance of dietary calcium and bone density for women, when there have been years of studies showing that our bone health is much more complicated than the number of glasses of milk we drink each day! In fact there is a big contradiction in the research: studies have shown that neither dairy products, nor high-calcium diets prevent or reduce fracture risk in women (1). And, studies show that there is no association between dietary calcium intake and hip fracture risk (1,2).
There are many cultures world-wide who use less calcium supplements, and consume minimal or no dairy, especially in Africa and Asia. Why do they have 50-70% lower rates of bone fracture and osteoporosis than we do in North America?
Diet-wise, what many studies do show, is that eating more fruits and vegetables in the diet is the main factor that improves bone density (3,4,5). A potential reason for this is that a diet higher in fruits and vegetables is protective is that it creates a slightly more alkaline environment in the body which creates optimal bone density.
A diet higher in animal foods (meat, poultry, fish, dairy), grains and high glycemic foods (sugars) makes the blood slightly more acidic. When the body is more acidic, it tries to neutralize it with alkaline material, leeching stored calcium from the bones. It actually takes 3 servings of fruits and vegetables (alkaline) to neutralize 1 serving of animal food, and 2 servings to neutralize 1 serving of grain! Calcium from dairy does add back calcium, but when it comes from an animal source, it is acidic – it is like taking one step forward and 2 steps back.
Of course, this is not the only factor in achieving and maintaining good bone density. There are many other things to consider. A brief summary of lifestyle changes you can make to support optimal bone density:
- Emphasize fruits and vegetables in your diet
- Exercise regularly, with a combination of weight-bearing exercise (like walking), and strength training. In post-menopausal women, two 40 minute sessions per week of weight lifting increased bone density as much as estrogen! This is a fantastic way to combat the changes in bone density that occur as hormones are changing.
- Eliminate soda from your diet – the phosphates in pop directly interfere with calcium absorption.
- Reduce or eliminate coffee – it increases the rates of calcium lost in urine.
- Stop smoking and reduce alcohol: In studies, smokers and women who drink 2 or more alcoholic drinks per day had the highest risk of osteoporosis.
- Watch stress hormones, especially around menopause: high cortisol levels result in increased rates of bone breakdown. Take steps to lower your stress, or ask for recommendations of supplements to lower cortisol levels.
- Remember that vitamin D is required for calcium absorption. Vitamin D deficiency is also associated with higher risk of osteoporosis. In general, at least 2000 IU per day through the winter is required in Canada to maintain adequate vitamin D stores.
- Yes, pay attention to calcium intake, but remember that this is not the only factor involved in maintaining healthy bones! Non-dairy sources of calcium include: dark leafy green vegetables especially kale, spinach beet greens and broccoli; almonds, sesame seeds, seaweeds and fortified milk-substitutes.
Hormones and Bone Density:
The interplay between bone formation and breakdown is a continuous lifelong process which favors bone formation in the early years of life, leading to peak bone mass at approximately 20-30 years of age. From then on, the total bone mass gradually declines. Many women experience a more rapid rate of bone loss in the early postmenopausal years.
Many hormones affect bone density in women: estrogen, progesterone, testosterone and cortisol all have rolls, and there are indicators well before menopause that a woman may be at higher risk of osteoporosis. This is a brief description of the hormonal involvement:
- Estrogen: prevents bone loss in adults; and when estrogen declines there is less bone deposition.
- Progesterone: promotes new bone formation and deposition.
- Testosterone: helps to reduce bone loss and has a role in bone formation.
- Cortisol: high levels result in increased rate of bone loss, regardless of estrogen status. High cortisol levels in early menopause especially are associated with greatly increasing osteoporosis risk.
- FSH: this pituitary hormone starts to increase in the 40’s as a woman approaches menopause. It is used as a marker along with estrogen to determine whether a woman is approaching menopausal hormone changes.
- DHEA: another adrenal gland hormone which enhances bone formation.
Since the best approach to osteoporosis is prevention, especially in women who are at high risk, a close examination of hormone balance is recommended in the late-30’s or early 40’s so that balance can be restored before bone density is lost.
As you can tell, a comprehensive approach is necessary to optimize you bone density: a nutrition plan high in vegetables and fruits, regular exercise, adequate vitamin D intake, stress management, hormone balance and enough calcium to provide the building blocks for bone formation. So, before you automatically take your calcium supplement for your bones, think about what else you can to to really lower your risk!
- Feskanich D, Willett WC, Stampfer MJ, and Colditz GA. Milk, dietary calcium, and bone fractures in women: a 12-year prospective study. American Journal of Public Health June 1997: Vol. 87, No. 6, pp. 992-997.
- Feskanich D1, Willett WC, Colditz GA. Calcium, vitamin D, milk consumption, and hip fractures: a prospective study among postmenopausal women. Am J Clin Nutr. 2003 Feb;77(2):504-11.
- Lin PH, Ginty F, Appel L, et al. The DASH diet and sodium reduction improve markers of bone turnover and calcium metabolism in adults. J Nutr 2003;133:3130–6
- Tucker KL, Hannan MT, Chen H, Cupples LA, Wilson PW, Kiel DP. Potassium, magnesium and fruit and vegetable intakes are associated with greater bone mineral density in elderly men and women. Am J Clin Nutr 1999;69:727–36.
- McGartland CP, Robinson PJ, Murray LJ, et al. Fruit and vegetable consumption and bone mineral density: the Northern Ireland Young Hearts Project. Am J Clin Nutr 2004;80:1019–23.