Preventing osteoporosis: building strong bones over a lifetime.WE OFTEN TAKE OUR BONES FOR GRANTED--they're just a part of us--keeping us standing, walking, running, sitting a lot, maybe skiing or biking. We don't think about them much until something goes wrong--one breaks or bends or somehow interferes with what we want to do. As we age, we're less able to be complacent about our bones. Maybe we're more worried about slipping on a throw rug and breaking a hip, or maybe we've been diagnosed with osteoporosis or have noticed a decrease in height. While following a vegan diet vegan diet (vē´g  n),n the strictest form of vegetarian diet, which prohibits the consumption of all animal products, including can promote bone health, it does not guarantee healthy bones. We've received notes like this one from a VRG VRG Varig (Viacao Aerea Rio-Grandense, Brazil, ICAO code) VRG Vegetarian Resource Group VRG Ventral Respiratory Group VRG Vaccinia-Rabies Glycoprotein (gene) VRG Vision Research Group VRG Vortex Ring Gun member: "I'm a 58-year-old woman, vegan, post-menopause, and I've found out that I have osteoporosis, I don't understand why this is happening to me. I take long walks every day and eat lots of grains and tofu. I thought vegans didn't get osteoporosis because of their healthy diets ..." This article was written to explain what osteoporosis is, what causes it, and what vegans The following is a list of notable people who practise (or practised) veganism. Entertainers
Osteoporosis is a disease that affects more than 25 million Americans. In 2001, the estimated national direct expenditure for osteoporosis and fractures related to this condition was $17 billion, and this cost is rising. Osteoporosis simply means porous bones. It is a condition in which the bones become less dense and fragile, and they can break easily. It affects women more than men, although men are also affected as they get older. If osteoporosis leads to a bone fracture, it can seriously affect function and even lead to death. To understand osteoporosis, we'll need to look more closely at bones. Although bones seem very simple, they are actually fairly complicated. The scaffolding for bone is made from a protein called collagen. As bones form, calcium and phosphorus combine to make hydroxyapatite hydroxyapatite /hy·droxy·ap·a·tite/ (-ap´ah-tit) an inorganic calcium-containing constituent of bone matrix and teeth, imparting rigidity to these structures. , a mineral-rich substance that crystallizes on the collagen scaffold, making a strong, rigid material. Bone minerals do not remain in the bone forever. Even after bones are formed, they are constantly changing. When another part of the body needs calcium, it is taken from the bone to meet the need. When more calcium is available, it is used to rebuild the bone. Early in life, more bone is being built than is being broken down. After about age 30, though, more bone is being broken down than is being built, resulting in a net loss of bone. Although bone loss is inevitable with aging, if you have larger, stronger bones at the start, the normal loss of bone mass will not be as severe. Also, anything that can be done to slow the rate of loss helps to spare bones. Women are at much greater risk for osteoporosis than men because women start out with less bone and lose bone mass more quickly, particularly in the years immediately after menopause. Women between the ages of 20 and 29 have about 76 percent the bone matter of men; by their 70s, this decreases to about 60 percent. (1) Thus, when women age and start losing bone mass, they develop very fragile bones. Genetics also appears to play a role in that osteoporosis runs in families. Factors like gender and genes can't be changed. Others are within our control, though, and can have a marked effect on risk of osteoporosis. These include dietary factors, such as calcium, vitamin D vitamin D Any of a group of fat-soluble alcohols important in calcium metabolism in animals to form strong bones and teeth and prevent rickets and osteoporosis. It is formed by ultraviolet radiation (sunlight) of sterols (see steroid) present in the skin. , protein, sodium, caffeine, phosphorus, fluoride, vitamin A vitamin A also called retinol Fat-soluble alcohol, most abundant in fatty fish and especially in fish-liver oils. It is not found in plants, but many vegetables and fruits contain beta-carotene (see , and vitamin K vitamin K Any of several fat-soluble compounds essential for the clotting of blood. A deficiency of vitamin K in the body leads to an increase in clotting time. In 1929 a previously unrecognized fat-soluble substance present in green leafy vegetables was found to be required , as well as weight-bearing activity. Calcium, the main mineral in bones, plays an important role in bone health. Children whose diets are low in calcium may develop osteoporosis as adults and have a greater risk of breaking bones. (2-4) Some studies, (5-7) although not all, (8) have shown that older adults with a high calcium intake have stronger bones and a lower fracture risk. There is a limited number of studies of vegans, most of which find low bone density as well as low calcium intakes. (9-10) One study11 where vegans had calcium intakes close to recommended levels found that calcium was well-absorbed from a vegan diet. Sources of well-absorbed calcium include calcium-fortified soymilk soy·milk n. A milk substitute made from soybeans, often supplemented with vitamins. Noun 1. soymilk - a milk substitute containing soybean flour and water; used in some infant formulas and in making tofu and juice, calcium-set tofu tofu Soft, bland, custardlike food product made from soybeans. Believed to date from China's Han dynasty (206 BC–AD 220), tofu is today an important source of protein in the cuisines of East and Southeast Asia. , soybeans and soynuts, bok choy bok choy or Chinese mustard Brassica chinensis, one of two types of Chinese cabbage. It has glossy dark green leaves and thick, crisp white stalks in a loose head. Its yellow-flowering centre is especially prized. See also brassica; mustard family. , broccoli, collards collards: see kale. , Chinese cabbage Chinese cabbage Either of two widely cultivated members of the mustard family, bok choy and Brassica pekinensis. The latter vegetable, also called celery cabbage, forms a tight head of crinkled light green leaves. It has long been grown in the U.S. as a salad vegetable. , kale kale, borecole (bôr`kōl), and collards, common names for nonheading, hardy types of cabbage (var. , mustard greens Noun 1. mustard greens - leaves eaten as cooked greens Indian mustard, leaf mustard, mustard cruciferous vegetable - a vegetable of the mustard family: especially mustard greens; various cabbages; broccoli; cauliflower; brussels sprouts , and okra okra: see mallow. okra Herbaceous, hairy, annual plant (Hibiscus esculentus or Abelmoschus esculentus), of the mallow family, grown for its edible fruit. Okra leaves are deeply notched; flowers are yellow with a crimson centre. . (12) Grains, beans (other than soybeans), fruits, and vegetables other than those listed can contribute to calcium intake but cannot replace the key foods mentioned above. Nevertheless, it's not enough to have a high-calcium diet. Adequate vitamin D is needed for calcium to be absorbed. Vitamin D is necessary throughout life to help build strong bones in childhood and adolescence and to maintain bones throughout adulthood. (8,13,14) Our skin produces Vitamin D with sun exposure, but many factors, including season, time of day, age, sunscreen sunscreen /sun·screen/ (-skren) a substance applied to the skin to protect it from the effects of the sun's rays. sun·screen n. use, and pollution, can interfere with this production. Therefore, dietary sources of vitamin D are important for most people. Since there are only very small amounts of naturally-occurring vitamin D in plant foods, vegans--both children and adults--should rely on foods fortified fortified (fôrt  ´fīd),adj containing additives more potent than the principal ingredient. with vitamin D, including fortified non-dairy milks, juices, and breakfast cereals This is a list of breakfast cereals. Many cereals are trademarked brands of large companies such as Kellogg's, General Mills, Malt-O-Meal, Nestlé, The Quaker Oats Company, and Post Cereals, but similar equivalent products are often sold by other manufacturers and as store own . Vitamin D supplements are another option. Some popular publications suggest that vegans don't have to be concerned about bone health because the lower animal protein content of vegan diets will minimize calcium losses. In reality, vegans do need adequate calcium and vitamin D, and they should also be sure that they are getting adequate, but not excessive, protein. Vegan diets generally contain adequate amounts of protein unless they are very low in calories or do not contain a variety of whole plant foods. Protein's effect on bones remains uncertain. Some studies show that diets that are high in protein, especially animal protein, do cause increased losses of calcium in the urine (seen at 0.45 grams of protein per pound of body weight and at 0.95 grams of protein per pound) (15) and may even increase fracture risk. (16,17) The effects of protein may be especially important in those with low calcium intakes. (18) Other studies suggest that a higher protein intake (as much as 0.95 grams per pound of body weight) is needed to promote calcium absorption, (19) reduce the risk of fracture, (20) and increase bone density. (21,22) Additional research is needed, but at this time it seems that both an adequate intake adequate intake (AI), n the consumption and absorption of sufficient food, vitamins, and essential minerals necessary to maintain health. See also dietary reference intakes; estimated average requirement; recommended dietary allowances; and upper intake of calcium and protein (near the RDA RDA abbr. recommended daily allowance Recommended Dietary Allowance (RDA) The Recommended Dietary Allowances (RDAs) are quantities of nutrients in the diet that are required to maintain good health in people. of 0.8 grams of protein per kilogram or 0.36 grams of protein per pound) can optimize bone health. In addition, phosphorus, fluoride, vitamin A, and vitamin K are important for bone health. Phosphorus, like calcium, is a major part of bone. Phosphorus is found in many foods and is abundant in vegan diets. Fluoride promotes the accumulation of calcium and phosphate in bone. It comes primarily from fluoridated water. Vitamin A is needed for bone growth, although excessive amounts of retinol retinol: see Vitamin A under vitamin. (the form of vitamin A found in many animal foods) can increase fracture risk. (23) Beta-carotene, the vitamin A precursor found in plant foods, does not appear to increase the risk of fracture. Vitamin K, a vitamin that comes from green vegetables and other plant foods, is needed to make a protein that strengthens bones. Many substances that support bone health have been mentioned. Caffeine and sodium have the opposite effect--excesses of these can be harmful to bones. Large amounts of caffeine increase calcium losses in urine. This is especially problematic for those with low calcium intakes. (24,25) Excess sodium can also increase urinary calcium and compromise bone health. (26,27) Any exercise that makes bones support weight-walking, running, dancing, weight-training, or roller-blading--can stimulate an increase in bone size and strength. For elementary school elementary school: see school. children, even 30 minutes of this type of exercise a couple of times a week can contribute to an increase in bone strength, which should lead to a reduced risk of osteoporosis later in life. (28) It won't hurt teens (29,30) or adults, (31) either. Besides helping strengthen bones, exercise can also improve balance and flexibility, both important factors in preventing and recuperating from falls. In conclusion, vegans of all ages can promote bone health by: * Consuming enough calcium and protein * Getting adequate vitamin D from diet, sunlight exposure, and/or supplements * Being sure to eat fruits and vegetables that supply beta-carotene and vitamin K * Limiting use of sodium and caffeine * Getting regular exercise, especially weight-bearing exercise.
Plant Sources of Calcium
Below is a list of plant sources that provide calcium and the amount
that a serving of each food yields:
Calcium
Food/Serving Content (mg)
LEGUMES, 1 cup, cooked
Black beans 46
Chickpeas 77
Great Northern beans 60
Kidney beans 50
Lentils 38
Lima beans 54
Navy beans 64
Pinto beans 82
Vegetarian baked beans 64
SOYFOODS
Soybeans, 1 cup, cooked 175
Soybeans, green, 1 cup, cooked 261
Tofu, 1/2 cup 120-430 *
Tempeh, 1/2 cup 92
Texturized Vegetable Protein 80
(TVP) **, 1/2 cup, rehydrated
Soymilk, 1 cup 40-100 *
Fortified soymilk, 1 cup 200-300 *
Soy yogurt, 1/2 cup 350
Soynuts, 1/4 cup 59
NUTS AND SEEDS, 2 Tablespoons
Almonds 46
Almond butter 86
Brazil nuts 31
Sesame seeds 176
Tahini 128
VEGETABLES, 1/2 cup, cooked ***
Bok choy 79
Broccoli 36
Collard greens 178
Kale 90
Mustard greens 76
Okra 88
Butternut squash 42
Sweet potato 35
Turnip greens 78
FRUITS
Dried figs, 5 137
Orange, 1 large 74
Raisins, 2/3 cup 53
Calcium-fortified orange juice, 300
1 cup
BREADS, CEREALS, GRAINS
Cereal, ready-to-eat, fortified 55-315 *
Cornbread, 2-ounce piece 141
Corn tortilla, 6-inch diameter 42
English muffin, enriched, 1 99
OTHER FOODS
Blackstrap molasses, 1 Tablespoon 172
Fortified rice milk, 1 cup 250-300 *
Notes:
* Indicates a range of calcium found in different tofu products,
fortified soymilks, fortified rice milks, and fortified cereals.
** TVP is a trademark of Archer Daniels Midland Company and is a
textured soy protein.
*** Oxalic acid, found in spinach, rhubarb, chard, and beet greens,
binds with the calcium in those foods and reduces its absorption. Thus,
these foods (which are not in the chart) cannot be considered good
sources of calcium.
Source: Data from USDA National Nutrient Database for Standard
Reference, Release 15, 2002 and manufacturers' information.
References: (1) Widdowson EM. 1992. Physiological processes of aging: are there special nutritional requirements nutritional requirements, n the food and liquids necessary for normal physiologic function. for elderly people? Do McCay's findings apply to humans? Am J Clin Nutr 55:1246S-1249S. (2) Sandier RB, Slemenda CW, LaPorte RE, et al. 1985. Post-menopausal bone density and milk consumption in childhood and adolescence. Am J Clin Nutr 42:270-74. (3) Halioua L, Anderson JJ. 1989. Lifetime calcium intake and physical activity habits: independent and combined effects on the radial bone of healthy premenopausal pre·me·no·paus·al adj. Of or relating to the years or the stage of life immediately before the onset of menopause. premenopausal adjective Caucasian women. Am J Clin Nutr 49:534-41. (4) Kalkwarf HJ, Khoury JC, Lanphear BP. 2003. Milk intake during childhood and adolescence, adult bone density, and osteoporotic fractures in US women. Am J Clin Nutr 77:257-65. (5) Chevalley T, Rizzoli R, Nydegger V, et al. 1994. Effects of calcium supplements on femoral femoral /fem·o·ral/ (fem´or-al) pertaining to the femur or to the thigh. fem·o·ral adj. Of or relating to the femur or thigh. bone mineral density bone mineral density n. See bone density. bone mineral density A measurement of bone mass, expressed as the amount of mineral–in grams divided by the area scanned in cm2. See Bone densitometry. and vertebral ver·te·bral adj. 1. Of, relating to, or of the nature of a vertebra. 2. Having or consisting of vertebrae. 3. Having a spinal column. fracture rate in vitamin-D-replete elderly patients. Osteoporos Int 4:245-52. (6) Dawson-Hughes B, Harris SS, Krall EA, Dallal GE. 1997. Effect of calcium and vitamin D supplementation on bone density in men and women 65 years of age or older. NEnglJMed337: 670-76. (7) Pecker R, Hinders S, Davies KM, et al. 1996. Correcting calcium nutritional deficiency prevents spine fractures in elderly women. J Bone Miner Res 11:1961-66. (8) Feskanich D, Willett WC, Colditz GA. 2003. Calcium, vitamin D, milk consumption, and hip fractures: a prospective study among postmenopausal post·men·o·paus·al adj. Of or occurring in the time following menopause. postmenopausal Change of life Gynecology adjective Referring to the time in ♀ when menstrual periods stop for ≥ 1 yr women. Am J Clin Nutr 77: 504-11 (9) Marsh AG, Sanchez TV, Michelsen O. 1988. Vegetarian lifestyle and bone mineral density. Am J Clin Nutr 48 (suppl):837-41. (10) Chiu JF, Lan SJ, Yang CY, et al. 1997. Long-term vegetarian diet and bone mineral density in post-menopausal Taiwanese women. Calcif Tissue Int 60:245-49. (11) Kohlenberg-Mueller K, Raschka L. 2003. Calcium balance in young adults on a vegan vegan /veg·an/ (ve´gan) (vej´an) a vegetarian whose diet excludes all food of animal origin. ve·gan n. and lactovegetarian diet. J Bone Miner Metab 21:28-33. (12) Weaver CM, Plawecki KL. 1994. Dietary calcium: adequacy of a vegetarian diet. Am J Clin Nutr 59 (suppl): 1238S-1241S. (13) Dagnelie PC, Vergote FJRVA, van Staveren WA, van den Berg Van den Berg is the surname of:
(14) Dawson-Hughes B, Dallal GE, Krall EA, Harris S, Sokoll LJ, Falconer G. 1991. Effect of vitamin D supplementation on wintertime and overall bone loss in healthy postmenopausal women. Ann Intern Med 115:505-12. (15) Kerstetter JE, O'Brien KO, Insogna KL. 2003. Low protein intake: the impact on calcium and bone homeostasis homeostasis Any self-regulating process by which a biological or mechanical system maintains stability while adjusting to changing conditions. Systems in dynamic equilibrium reach a balance in which internal change continuously compensates for external change in a feedback in humans. J Nutr 133:855S-861S. (16) Frassetto LA, Todd KM, Morris RC, Jr., et al. 2000. Worldwide incidence of hip fracture in elderly women: relation to consumption of animal and vegetable foods. J Gerontol A Biol Sci Med Sci 55:M585-92. (17) Sellmeyer DE, Stone KL, Sebastian A, et al. 2001. A high ratio of dietary animal to vegetable protein increases the rate of bone loss and the risk of fracture in postmenopausal women. Am J Clin Nutr 73:118-22. (18) Meyer HE, Pedersen JI, Loken EB, et al. 1997. Dietary factors and the incidence of hip fracture in middle-aged Norwegians. A prospective study. Am J Epidemiol 145:117-23. (19) Kerstetter JE, O'Brien KO, Caseria DM, et al. Nov 16 2004. The impact of dietary protein on calcium absorption and kinetic measures of bone turnover in women. J Clin Endocrinol Metab [Epub ahead of print]. (20) Munger RG, Cerhan JR, Chiu BC. 1999. Prospective study of dietary protein intake and risk of hip fracture in postmenopausal women. Am J Clin Nutr 69:147-52. (21) Kerstetter JE, Looker AC, Insogna KL. 2000. Low dietary protein and low bone density. Calcif Tissue Int 66:313. (22) Promislow JH, Goodman-Gruen D, Slymen DJ, et al. 2002. Protein consumption and bone mineral density in the elderly: the Rancho Bernardo Study. Am J Epidemiol 155:636-44. (23) Feskanich D, Singh V, Willett WC, Colditz GA. 2002. Vitamin A intake and hip fractures among postmenopausal women. JAMA JAMA abbr. Journal of the American Medical Association 287:47-54. (24) Rapuri PB, Gallagher JC, Kinyamu HK, et al. 2001. Caffeine intake increases the rate of bone loss in elderly women and interacts with vitamin D receptor genotypes. Am J Clin Nutr 74:694-700. (25) Massey LK. 2001. Is caffeine a risk factor for bone loss in the elderly? Am J Clin Nutr 74:569-70. (26) Matkovic V, Ilich JZ, Andon MB, et al. 1995. Urinary calcium, sodium, and bone mass of young females. Am J Clin Nutr 62: 417-25. (27) Devine A, Criddle RA, Dick IM, et al. 1995. A longitudinal study longitudinal study a chronological study in epidemiology which attempts to establish a relationship between an antecedent cause and a subsequent effect. See also cohort study. of the effect of sodium and calcium intakes on regional bone density in postmenopausal women. Am J Clin Nutr 62:740-45 (28) Bachrach LK. 2000. Making an impact on pediatric pediatric /pe·di·at·ric/ (pe?de-at´rik) pertaining to the health of children. pe·di·at·ric adj. Of or relating to pediatrics. bone health. J Pediatr 136:137-39. (29) Lloyd T, Chinchilli VM, Johnson-Rollings N, et al. 2000. Adult female hip bone density reflects teenage sports-exercise patterns but not teenage calcium intake. Pediatrics 106:40-44. (30) Bailey DA, McKay HA, Mirwald RL, et al. 1999. A six-year longitudinal study of the relationship of physical activity to bone mineral accrual in growing children: the University of Saskatchewan The University of Saskatchewan (U of S) is a coeducational public research university located on the east side of the South Saskatchewan River in Saskatoon, Saskatchewan, Canada. The University is celebrating its centennial year in 2007. bone mineral accrual study. J Bone Miner Res 14:1672-79. (31) Asikainen TM, Kukkonen-Harjula K, Miilunpalo S. 2004. Exercise for health for early postmenopausal women: a systematic review of randomized controlled trials. Sports Med 34:753-58. Sample Menu Providing Adequate Protein, Calcium, and Vitamin D for a Typical 51- to 70-Year-Old Woman Weighing 140 pounds Breakfast: * 1 cup ready-to-eat cereal enriched with vitamin D (like Wheat Chex) * 1 cup calcium- and vitamin D-fortified soymilk * 1 slice whole wheat toast Lunch: * Almond butter and jelly sandwich * Carrot sticks * Grapes * 1 cup calcium- and vitamin D-fortified soymilk Dinner: * 1/2 cup kidney beans with 1 cup cooked pasta and 1/2 cup marinara ma·ri·na·ra adj. Being or served with a sauce of tomatoes, onions, garlic, and spices: spaghetti marinara. n. Marinara sauce. sauce * 1 whole wheat tortilla * 1 medium orange * 1 cup cooked collard greens Noun 1. collard greens - kale that has smooth leaves collards cole, kail, kale - coarse curly-leafed cabbage (frozen or fresh) Snack: * 1/4 cup soynuts * 1 1/2 cups calcium, and vitamin D-fortified orange juice Reed Mangels mangels Beta vulgaris; called also mangel-wurzel. , PhD, RD, is one of VRG's Nutrition Advisors. She is the co-author of Simply Vegan and the most recent American Dietitic Association position paper on vegetarian diets. |
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