Diets too high in animal protein and low in vegetable protein: Meat and other high protein foods leave an acid residue in the blood that leads to bone dissolution. To neutralize this acid load, the body calls on its stores of calcium to provide basic calcium salts. Studies show that people with a high animal protein intake can develop a negative calcium balance, regardless of how much calcium is consumed. An important study demonstrated an increased bone loss and risk of hip fracture in those with a higher ratio of animal protein to vegetable protein. The researchers concluded that an increase in vegetable protein and a decrease in animal protein may decrease the risk of hip fractures in the elderly.1 The recommendations are clear: green vegetables, beans, nuts, and seeds should be the major source of protein. It is important to note that later in life (after age 70), it is crucial to pay more attention to protein intake. At that point, both too much protein and too little protein are unfavorable to bone mass.2
High consumption of salt and/or caffeine: The consumption of large amounts of sodium and caffeine leads to unwanted excretion of calcium.3 Exactly how this works is not completely understood, but both salt and caffeine increase the rate at which blood is filtered through the kidney. The increased filtering pressure and flow compromise the kidney’s ability to return calcium supplies to the bloodstream.
Smoking: Nicotine can interfere with hormonal messages to the kidneys, inhibiting calcium re-absorption. The combination of smoking and drinking coffee or soft drinks, together with the dietary factors mentioned, makes the prevalence of osteoporosis in this country quite understandable. Dietary, health, and lifestyle components are working together to cause this drain of calcium.
Vitamin D Deficiency: Recent research studies have corroborated the fact that most Americans are Vitamin D deficient. This deficiency occurred even among a majority of study subjects who were already taking a multivitamin with the standard 400 IUs of Vitamin D. More and more health authorities are recommending that an additional 400 to 800 IUs of Vitamin D be taken over and above the 400 typically present in a multiple vitamin.
Vitamin supplements: In high doses, Vitamin A (retinol) is associated with birth defects, and recent research suggests the dose that causes risk is much lower than previously thought. If Vitamin A is toxic to a person who is pregnant and potentially harmful to the developing baby, it can’t be good for us the rest of the time. Research has shown it is linked to calcium loss in the urine and osteoporosis. For example, an important study found that subjects with a Vitamin A intake in the range of 1.5 mg had double the hip fracture rate of those with an intake in the range of .5 mg. For every 1 mg increase in Vitamin A consumption, hip fracture rates increased by 68 percent.4 Most multivitamins contain about 5000 IUs of Vitamin A, which is equal to 1.5 mg. This means if you conform to the current recommendations, which have become outdated, and get your Vitamin A from supplements, you could be weakening your bones. Instead, the body can naturally self-fabricate Vitamin A by consuming beta-carotene and other carotenoids in real food. Vegetables such as carrots contain beta carotene, not Vitamin A, and the beta-carotene from vegetables does not lead to excessive Vitamin A formation or cause calcium loss.
Poor physical fitness: Our bones are continually dissolving old bone tissue and rebuilding new bone. Interestingly, our bone strength is directly proportional to our muscle strength. Bones, like muscles, respond to stress by becoming bigger and stronger, and, like muscles, bones weaken and literally shrink if not used. It is essential to exercise, and, in particular, to exercise the back. Studies have found that a back-strengthening exercise program can provide significant, long lasting protection against spinal fractures in women at risk for osteoporosis.5
This is an excerpt from Dr. Fuhrman’s book Eat For Health.
1. Sellmeyer DE, Stone KL, Sebastian A, Cummings SR. A high ratio of dietary animal to vegetable protein increases the rate of bone loss and the risk of fracture in postmenopausal women. Study of Osteoporotic Fractures Research Group. Am J Clin Nutr. 2001;73(1):118-122.
2. Devine A, Dick IM, Islam AF, Dhaliwal SS, Prince RL. Protein consumption is an important predictor of lower limb bone mass in elderly women. Am J Clin Nutr. 2005;81(6):1423-1428.
3. Teucher B, Fairweather-Tait S. Dietary sodium as a risk factor for osteoporosis: where is the evidence? Proc Nutr Soc. 2003;62(4):859-866. Rapuri PB, Gallagher JC, Kinyamu HK, Ryschon KL. Caffeine intake increases the rate of bone loss in elderly women and interacts with vitamin D receptor genotypes. Am J Clin Nutr. 2001;74(5):694-700. Hallström H, Wolk A, Glynn A, Michaëlsson K. Coffee, tea and caffeine consumption in relation to osteoporotic fracture risk in a cohort of Swedish women. Osteoporos Int. 2006;17(7):1055-1064.
4. Whiting SJ, Lemke B. Excess retinol intake may explain the high incidence of osteoporosis in northern Europe. Nutr Rev 1999;57(6):192-195. Melhus H, Michaelson K, Kindmark A, et al. Excessive dietary intake of vitamin A is associated with reduced bone mineral density and increased risk of hip fracture. Ann Intern Med. 1998;129(10):770-778.
5. Sinaki M, Itoi E, Wahner HW, et al. Stronger back muscles reduce the incidence of vertebral fractures: a prospective 10 year follow-up of postmenopausal women. Bone. 2002;30(6):836-841.