Protecting Bone Health on a Vegan Diet

Protecting Bone Health on a Vegan Diet 2017-07-12T22:10:26+00:00

You may think of your bones as stable, rigid and steady. But they are actually in a state of constant flux, continuously breaking down and rebuilding. In the early part of life, they rebuild faster than they break down as the skeleton grows. Even after they’ve stopped growing in length, bones continue to accumulate mass well into your thirties.

With aging, though, the balance between bone breakdown and bone formation becomes harder to maintain. The key to protecting bone health in later life is to slow bone loss and to ensure good nutrition for so that bones can rebuild.

As far as we know, vegans have no particular advantage in preventing osteoporosis. But it shouldn’t be any more difficult for us to maintain strong bones, either. Here are the most important things to focus on.

Eat Enough Protein

Several decades ago, vegan health professionals suggested that eating too much protein, like the amount that the average American eats, was bad for bones. The hypothesis was that certain proteins produced acidic conditions that helped dissolve bones. Two observations bolstered this theory.

First, on a world-wide basis, populations eating the most protein have the highest rates of hip fracture(1).   But we now know that those global comparisons of hip fracture rates don’t tell us much about bone health.  In fact, rates of hip fracture don’t necessarily correlate very well with actual osteoporosis (2). Differences in hip fracture rates seem to be due mostly to genetic differences in anatomy and also to risk of falling.

Another part of the theory about protein and bones focused on findings from clinical research. Feeding protein to subjects resulted in increased calcium excretion in the urine. (3).  But more recent research has found that this calcium isn’t necessarily coming from bone breakdown (4).

The most current evidence suggests that protein is good for bones. In fact, in vegetarians, eating more protein-rich foods like beans and veggie meats, is associated with lower risk of fracture (5,6).

It makes sense since bones form around a collagen-rich protein matrix. Protein may also enhance calcium absorption (7). It’s true that protein can also result in increased acid production, but the best way to counter that is to eat a diet rich in fruits and vegetables.

How much protein vegans need for optimal bone health remains a subject of debate.  Some vegans, particularly those who avoid soy and veggie meats, may have slightly higher protein needs than lacto-ovo vegetarians and meat-eaters. So it’s a good idea to err on the side of a generous intake of protein-rich foods – at least three servings per day of legumes which include beans, peanuts, peanut butter, and soyfoods. Vegans over the age of 50 should try to consume at least four servings of these foods. You can read more about protein on vegan diets here.

Get Adequate Calcium

While acute calcium deficiency is rare, many vegans (and non-vegans) don’t consume enough calcium to maximize lifelong bone health. It’s not at all hard to get adequate calcium from plant foods, but new vegans may not know where to look.

One factor that greatly complicates the issue is that absorption of calcium varies dramatically among foods. Calcium recommendations reflect the assumption that humans absorb about 30% of the calcium in their diet. That’s the absorption rate for calcium from cow’s milk, fortified plant milks, and from tofu made with calcium sulfate. But absorption is quite a bit higher for certain leafy green vegetables from the cabbage family like kale, bok choy and turnip greens. In contrast, it’s much lower for some plant foods like spinach, beans and tahini (8-11).

It would be a chore to track the amount of calcium you are absorbing from different foods. An easier approach is to try to eat at least two cups per day of foods rich in well-absorbed calcium. These are cooked Chinese cabbage, turnip greens, mustard greens, collards, calcium-set tofu (this is tofu made with calcium sulfate, which should be listed on the label) and fortified plant milks. People over 50 need more calcium and should aim for 3 cups per day of these foods. Although this provides a good dose of calcium, it’s important to include other calcium-rich foods like beans, almonds, navel oranges, and tahini in your diet.

If you are struggling to consume these foods, another option is calcium-fortified fruit juices. Although juices should generally be minimized in healthy diets, ½ cup per day or so is fine if this helps you meet nutrient needs. Calcium is very well-absorbed from juices. (Note, however, that orange juice is often also fortified with vitamin D and it’s usually D3, the type that comes from animals.)  A small calcium supplement – about 300 milligrams –can also be valuable in helping some vegans meet calcium needs. Focus on food first, and then do whatever you need to do to make up any slack. Read more about calcium absorption here.

Identify a Good Source of Vitamin D

Although humans evolved to make plenty of vitamin D when our skin is exposed to sunlight, this isn’t always a reliable approach in the modern world. Smog, clouds and sunscreen all interfere with production of vitamin D. Older people and those with darker skin need more sun exposure than younger and fair-skinned individuals. Winter sunlight is generally too weak to promote vitamin D synthesis and most people, vegan or not, need a dietary source of this nutrient for at least part of the year (12,13)

Only a handful of foods are natural sources of vitamin D, so most people depend on fortified foods or supplements for this nutrient. Fortified foods usually contain vitamin D3 which is almost always derived from animals. The vegan form of vitamin D is vitamin D2 or ergocalciferol. The evidence suggests that it’s as effective as vitamin D3 when taken as a daily supplement for maintaining adequate vitamin D status (14). However, new research suggests that vitamin D2 may be less effective in reversing a vitamin D deficiency (15). If you are deficient in vitamin D and need to raise your blood levels, there is a vegan vitamin D3 derived from lichen and sold under the brand name Vitashine. The RDA for vitamin D, whether you are taking D2 or D3, is 600 IUs.

Eat Lots of Fruits and Vegetables

Diets rich in fruits and vegetables seem to help protect bone health.  Many of these foods provide vitamin C which is involved in formation of collagen, an important component of bones. It’s also an antioxidant which may be important since oxidative stress could contribute to bone loss (16).  Potassium and magnesium in fruits and vegetables may help to counter effects of the higher acid load associated with a protein-rich diet (17). Vitamin K (in many leafy green vegetables) has been linked to better bone health although the studies don’t consistently show a benefit (18,10).  Since fruits and vegetables vary greatly in their nutrient content, it’s a good idea to eat a variety of them.

Ensure Adequate Vitamin B12

In elderly people in particular, poor vitamin B12 status has been linked to poorer bone health (20).   It’s important for all vegans, regardless of age, to ensure a good source of vitamin B12 in the cyanocobalamin form. Follow the guidelines here to ensure adequate vitamin B12 intake.

Don’t Overdo Alcohol

Some evidence suggests that moderate alcohol intake is associated with greater bone density in postmenopausal women. But heavy alcohol use is associated with poorer bone mineral density and a greater risk of falling (and therefore a greater risk of breaking a bone). It’s okay to drink alcohol if you enjoy it, but there are lots of reasons to avoid more than a drink a day (21).

Engage in Weight-Bearing Exercise

As important as nutrition is, there is nothing worse for bone health than being a couch potato. Exercise that provides impact and that builds muscle mass and strength is crucial for keeping bones strong.  Exercises that improve balance are also important since most fractures are due to falling.

Good Nutrition for Bones in a Nutshell

Chances are, you’re already putting most of these guidelines into practice. But give your vegan diet a quick review to make sure you are doing everything possible to protect bone health. These guidelines are relevant at every stage of the lifecycle.

  • Consume at least three servings per day of legumes (more if you’re over 50)
  • Consume at least two cups per day of foods rich in well-absorbed calcium: cooked Chinese cabbage, turnip greens, mustard greens, collards, calcium-set tofu and fortified plant milks. Aim for three cups if you’re over 50.
  • Take supplements of vitamin D and vitamin B12 or use foods fortified with these nutrients.
  • Eat lots of fruits and vegetables of all kinds.
  • Don’t drink too much alcohol.
  • Stay active to build muscle and maintain good balance

References

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  2. Bow CH, Cheung E, Cheung CL, Xiao SM, Loong C, Soong C, Tan KC, Luckey MM, Cauley JA, Fujiwara S, et al. Ethnic difference of clinical vertebral fracture risk. Osteoporos Int 2012;23:879-85.
  3. Kerstetter JE, Allen LH. Dietary protein increases urinary calcium. J Nutr 1990;120:134-6.
  4. Fenton TR, Lyon AW, Eliasziw M, Tough SC, Hanley DA. Meta-analysis of the effect of the acid-ash hypothesis of osteoporosis on calcium balance. J Bone Miner Res 2009;24:1835-40.
  5. Thorpe DL, Knutsen SF, Lawrence Beeson W, Rajaram S, Fraser GE. Effects of meat consumption and vegetarian diet on risk of wrist fracture over 25 years in a cohort of peri- and postmenopausal women. Public Health Nutr 2007:1-9.
  6. Lousuebsakul-Matthews V, Thorpe DL, Knutsen R, Beeson WL, Fraser GE, Knutsen SF. Legumes and meat analogues consumption are associated with hip fracture risk independently of meat intake among Caucasian men and women: the Adventist Health Study-2. Public Health Nutr 2014;17:2333-43.
  7. Kerstetter JE, O’Brien KO, Caseria DM, Wall DE, Insogna KL. The impact of dietary protein on calcium absorption and kinetic measures of bone turnover in women. J Clin Endocrinol Metab 2005;90:26-31.
  8. Weaver CM. Should dairy be recommended as part of a healthy vegetarian diet? Point. American Journal of Clinical Nutrition 2009;89:1634S-1637S.
  9. Weaver CM, Heaney RP, Connor L, Martin BR, Smith DL, Nielsen E. Bioavailability of calcium from tofu vs. milk in premenopausal women. J Food Sci 2002;68:3144-3147.
  10. Weaver CM, Heaney RP, Nickel KP, Packard PI. Calcium bioavailability from high oxalate vegetables: Chinese vegetables, sweet potatoes and rhubarb. J Food Sci 1997;63:524-525.
  11. Tang AL, Walker KZ, Wilcox G, Strauss BJ, Ashton JF, Stojanovska L. Calcium absorption in Australian osteopenic post-menopausal women: an acute comparative study of fortified soymilk to cows’ milk. Asia Pac J Clin Nutr 2010;19:243-9.
  12. Holick MF, Siris ES, Binkley N, Beard MK, Khan A, Katzer JT, Petruschke RA, Chen E, de Papp AE. Prevalence of Vitamin D inadequacy among postmenopausal North American women receiving osteoporosis therapy. J Clin Endocrinol Metab 2005;90:3215-24.
  13. Binkley N, Novotny R, Krueger D, Kawahara T, Daida YG, Lensmeyer G, Hollis BW, Drezner MK. Low vitamin D status despite abundant sun exposure. J Clin Endocrinol Metab 2007;92:2130-5.
  14. Holick MF, Biancuzzo RM, Chen TC, Klein EK, Young A, Bibuld D, Reitz R, Salameh W, Ameri A, Tannenbaum AD. Vitamin D2 is as effective as vitamin D3 in maintaining circulating concentrations of 25-hydroxyvitamin D. J Clin Endocrinol Metab 2008;93:677-81.
  15. Tripkovic L, Wilson LR, Hart K, Johnsen S, de Lusignan S, Smith CP, Bucca G, Penson S, Chope G, Elliott R, et al. Daily supplementation with 15 mug vitamin D2 compared with vitamin D3 to increase wintertime 25-hydroxyvitamin D status in healthy South Asian and white European women: a 12-wk randomized, placebo-controlled food-fortification trial. Am J Clin Nutr 2017.
  16. Hamidi M, Boucher BA, Cheung AM, Beyene J, Shah PS. Fruit and vegetable intake and bone health in women aged 45 years and over: a systematic review. Osteoporos Int 2011;22:1681-93.
  17. New SA. Intake of fruit and vegetables: implications for bone health. Proc Nutr Soc 2003;62:889-99.
  18. Braam LA, Knapen MH, Geusens P, Brouns F, Hamulyak K, Gerichhausen MJ, Vermeer C. Vitamin K1 supplementation retards bone loss in postmenopausal women between 50 and 60 years of age. Calcif Tissue Int 2003;73:21-6.
  19. Cheung AM, Tile L, Lee Y, Tomlinson G, Hawker G, Scher J, Hu H, Vieth R, Thompson L, Jamal S, et al. Vitamin K supplementation in postmenopausal women with osteopenia (ECKO trial): a randomized controlled trial. PLoS Med 2008;5:e196.
  20. McLean RR, Jacques PF, Selhub J, Fredman L, Tucker KL, Samelson EJ, Kiel DP, Cupples LA, Hannan MT. Plasma B vitamins, homocysteine, and their relation with bone loss and hip fracture in elderly men and women. J Clin Endocrinol Metab 2008;93:2206-12.
  21. Gaddini GW, Turner RT, Grant KA, Iwaniec UT. Alcohol: A simple nutrient with complex actions on bone in the adult skeleton. Alcohol Clin Exp Res 2016;40:657-71