Healthy Bones and Plant-Driven Diets

by Matthew Kadey, MS, RD on Aug 17, 2016

Nutrition

These foods will help you keep a veggie-focused approach without weakening your skeleton.

Many people embracing a more plant-based diet worry they’re setting themselves up for nutritional shortfalls that will weaken their bones. Where will they get their calcium—the best-known nutrient for bone health—if they’re avoiding dairy? And what about other bone builders like high-quality protein and vitamin B12, which are readily available in meat?

Vegetarians and vegans, who focus their eating efforts mainly on plants, still have to build and maintain strong bones to stave off conditions like osteoporosis. After all, nothing slows down a healthy, active lifestyle more than a stress fracture or a broken hip.

Fortunately, there’s good news for kale and lentil lovers everywhere. Eating mostly foods grown in soil need not weaken our skeletons. A 2015 Arizona State University study found no significant difference in bone mineral density (BMD) among young adults who followed a meat-based, lacto-ovo vegetarian (including dairy but no meat) or vegan diet for more than a year(Knurick et al. 2015). And researchers in Greece showed that adhering to the Mediterranean Diet, which emphasizes plant foods, protects against fracture risk (Benetou et al. 2013). Similarly, a 2014 Journal of Nutrition report found that a diet rich in fruits, vegetables and legumes can lessen the risk of suffering a hip fracture (Dai et al. 2014).

When it comes to bone health, sports dietitian and Ironman® competitor Marni Sumbal, MS, RD, CSSD, says you have to look at the big picture and consider overall diet quality. “Achieving and maintaining strong bones requires more than just eating enough of certain nutrients like calcium and vitamin D,” Sumbal says. “Yes, you need these key nutrients, but you also require a number of other important ones, which a well-planned, plant-focused diet can deliver enough of.”

In other words, it takes more than a milk moustache to keep you fracture-free, both now and down the road.

To build a sturdy frame, here are the key nutrients that everyone should make extra efforts to obtain enough of—and the plant foods that can help your clients get their fill.

Calcium

There’s no question that calcium is an important mineral for building snap-resistant bones, as bones account for roughly about 99% of the body’s total calcium stores. “If adequate calcium is not consumed, it’s removed from bones to help meet other needs in the body, and over time [the bones] can grow weaker,” says Sumbal.

The Recommended Dietary Allowance (RDA) for calcium is 1,000 milligrams per day for women up to age 50 and men up to age 70, and 1,200 mg/day for anyone older—levels that are easy to achieve in a diet that includes dairy foods like milk and yogurt.

But it’s not a must to float your morning cereal in milk. Sumbal notes that there are a number of nondairy calcium sources in the supermarket. “The key is to eat a variety of sources so calcium intake adds up to meet needs.” She recommends a food-first approach, as high intakes of calcium supplements may raise the risk for heart problems such as calcified arteries.

Power Plants

Collards. Here’s more proof that it’s important to live and eat a little greener. Just 1 cup of cooked collards has about 266 mg of calcium plus healthy amounts of bone builders like vitamin K, magnesium and carotenoids. Other greens that deliver the most absorbable calcium include mustard, turnip, kale, bok choy and broccoli. Spinach and beet greens in particular are high in oxalates, which can limit calcium absorption. Cooking the greens may help to lessen their oxalate levels, allowing for better calcium uptake (Chai & Liebman 2005).

Tofu. Here’s a good way to get your bone-boosting protein and calcium all in one. Just a 3-ounce serving can provide about half the daily need for calcium. But the key is to choose tofu made with calcium sulfate as a coagulant (sometimes called “calcium-set” tofu).

Tahini. Whether you sprinkle sesame seeds on a stir-fry or use tahini (a paste made by grinding up sesame seeds) to whip up a batch of hummus or creamy salad dressing, you’re getting a shot of calcium. Each 2-tablespoon serving of tahini supplies roughly 130 mg of calcium, while each tablespoon of whole sesame seeds offers up nearly 10% of the daily calcium requirement.

Dried figs. If you’re looking to tame a sweet tooth and help your bones along the way, look no further than dried figs. Each half-cup serving supplies about 120 mg of calcium, along with the bone-friendly nutrients vitamin K and magnesium. Enjoy dried figs sliced and added to salads, oatmeal, trail mix, yogurt, or homemade energy bars and balls.

Vitamin D

You can chow down on all the calcium-rich foods you like, but without enough vitamin D it won’t do you much good. “We need vitamin D for strong bones because it’s necessary for proper calcium absorption,” explains registered dietitian Sharon Palmer, RDN, author of the books The Plant-Powered Diet (The Experiment 2012) and Plant-Powered for Life (The Experiment 2014). That’s why studies show that higher intakes of calcium alone aren’t enough to ward off fractures and osteoporosis (Bolland et al. 2015; Feskanich, Willett & Colditz 2003) and that poor vitamin D status can speed up bone aging (Busse et al. 2013).

The only problem? It’s tough to find much if any vitamin D in food, which is a concern during the winter (or if you’re stuck in an office all day) when your body generates little from the sun. And research suggests that vegetarians and vegans can be at heightened risk for poor vitamin D status compared with those who eat meat and seafood—fatty fish like salmon, mackerel and sardines are naturally good sources (Crowe et al. 2011). So unless your plant-based diet includes plenty of the items outlined below and you’re basking in some sunshine daily, Palmer says supplementation should be considered as a safeguard against a bone-sapping deficiency.

Power Plants

Mushrooms. You can now buy brands of UV-exposed mushrooms like Monterey, which can supply upward of 400 international units of vitamin D in a 3-ounce serving. (The RDA for vitamin D is 600 IU/day for people aged 1–70). Mushrooms behave in relation to sunlight much as humans do, converting a form of cholesterol into active vitamin D (Keegan et al. 2013; Koyyalamudi et al. 2009). This means you can also pick up regular mushrooms from the market, set them out in a sunny location for a couple of hours and likely end up with vitamin D–loaded fungi. Preliminary research suggests that consumption of vitamin D–enhanced mushrooms may indeed improve bone density (Chen et al. 2015). Try sautéing with a bit of oil or butter, since that will improve absorption of vitamin D, which is fat-soluble.

Nondairy milks. From soy to almond to hemp, nondairy milk options have proliferated in the market, and many are fortified with calcium and vitamin D. Most of these no-moo drinks offer up about 30% of the daily value for vitamin D. Just keep in mind that except for soymilk, dairy-free milks contain significantly less protein than cow’s milk, so if you are using them for your smoothies and cereal, you’ll need to make up protein elsewhere in the diet. And if the drink is very low in fat, try serving it with a fat source like a handful of almonds to improve vitamin D absorption. Also seek out those labeled “unsweetened” to side-step added sugars. Some brands of orange juice are also now fortified with the sunshine vitamin.

Protein

For many years, people thought high intakes of dietary protein contributed to weak bones. How? Lofty protein consumption was believed to increase acid in the body, causing calcium to be leached from bones to reset the acid-base balance, and in doing so setting someone up for a skeleton that could buckle like a cheap lawn chair.

But modern research now demonstrates that protein helps, rather than hurts, with respect to bone strength. Case in point: A 2015 study in the Journal of Nutrition, Health & Aging determined that subjects with a consistent protein intake of less than 12% of total daily calories had a higher fracture risk than those with a protein intake at or above 15% of total calories (Langsetmo et al. 2015). Protein is thought to increase intestinal calcium absorption and also to play a role in bone formation (Bonjour 2005). Interestingly, in the study by Langsetmo et al. (2015) subjects with higher protein intakes all reduced fracture risk to about the same degree whether their main source of protein was dairy, meat or plant food. So eschewing steak for tofu can also show your bones some love.

“If adequate energy is consumed along with an assortment of protein-rich plant foods, overall bone health shouldn’t be compromised on a plant-based diet,” says Sumbal. She suggests active people should aim to consume 1.2–1.8 grams of protein for each kilogram of body weight, with ˜ 20–30 g of protein per meal.

Power Plants

Protein powders. For postworkout smoothies, whey no longer rules the roost. From hemp to sprouted brown rice to peas, the options for vegan protein powders have never been greater or better. They offer a convenient way to nail your daily protein quota if there is a concern about meeting needs entirely via whole foods.

Lentils. Packing in about 13 g of protein in a quarter-cup serving, lentils are a fantastically budget-friendly source of bone-friendly protein. The stellar amounts of protein in lentils and other legumes may be one reason why a 2014 Loma Linda University study discovered that higher intakes of this food group were associated with fewer hip fractures among more than 33,000 subjects (Lousuebsakul-Matthews et al. 2014).

Tempeh. Made from a base of fermented soybeans, a mere cup of tempeh supplies a whopping 30 g of protein. Tempeh also provides dietary fiber and probiotics, which may aid in digestive and immune health. The flavor is best described as smoky, nutty and earthy in an umami kind of way. Slabs of tempeh can be marinated and grilled in the same way as steak. Or you can try crumbling tempeh and adding it to chilis, stir-fries, tacos, soups, casseroles and pasta sauce.

Hemp seeds. Hemp (also called hemp hearts) reigns supreme as a protein source among seeds. Each 3-tablespoon serving provides about 10 g of high-quality bone-building protein. So get in the habit of sprinkling hemp seeds on your salads, oatmeal and yogurt.

Vitamin K

When it comes to building break-resistant bones, you don’t hear much about vitamin K, but it’s necessary to help bone-forming proteins like osteocalcin do their jobs better (Weber 2001). Data from the esteemed Framingham Heart Study shows a link between high vitamin K intake and reduced risk of hip fracture in men and women, and increased BMD in women (Booth et al. 2003; Booth et al. 2000). The RDA for vitamin K is 90 micrograms per day for adult women and 120 mcg/day for men.

Power Plants

Dried plums. With about 65% of the daily vitamin K requirement in a half-cup serving, dried plums are sweet, convenient bone builders. And indeed, studies have shown that this parched fruit can help stymie age-related bone loss and encourage bone formation—a benefit that likely also hails from the antioxidants, magnesium and potassium in dried plums (Hooshmand 2016; Hooshmand & Arjmandi 2009; Smith et al. 2014). Try incorporating them into a plant-based diet where you’d use other dried fruits—think granola, yogurt and DIY energy foods.

Kale. For vitamin K, kale is a green giant. A mere 1-cup serving meets nearly seven times the daily need for this bone-strengthening nutrient. For convenience and milder-tasting greens, you can source out ready-to-go baby kale in plastic clamshells alongside other tender greens.

Avocado. Fatty in a good way, the creamy flesh of an avocado supplies a nutritional stew that includes vitamin K, magnesium, vitamin C, dietary fiber and potassium. Beyond guacamole, avocado can up the nutritional ante of smoothies, salads, grain bowls, tacos and an assortment of raw-style desserts that are pasted all over Instagram.

Vitamin B12

Beyond playing a role in forming red blood cells, vitamin B12 appears to work to lower bone turnover in the body (Herrmann et al. 2009; Stone et al. 2004; Tucker et al. 2005). The B vitamin is involved in the synthesis of DNA, the genetic material found in all our cells, including those in bone (O’Leary & Samman 2010). Low levels of vitamin B12 may also boost blood levels of homocysteine, a compound associated with lower BMD (Krivosíková et al. 2010; Van Wijngaarden et al. 2013; McLean et al. 2004).

“Because B12 is found naturally only in foods of animal origin, you have to either source out a steady supply of fortified plant foods if no meat or dairy is consumed in the diet, or consider a daily vitamin B12 supplement, preferably in the form of cyanocobalamin, to make sure to get enough,” says Palmer. Foods can include boxed cereals, certain energy bars and the rising tide of better-than-ever faux meat products like burgers. Keep in mind that in contrast to calcium and vitamin D, few cartons of nondairy milks like almond are fortified with vitamin B12.

Power Plants

Nutritional yeast. The orange-yellow flakes affectionately called “hippie dust” are a dried and deactivated form of the microorganism Saccharomyces cerevisiae. Not only is nutritional yeast a surprising source of protein, but many brands are also fortified with vitamin B12. It has a cheesy, umami flavor, so you can add a generous showering of nutritional yeast anywhere you want cheese-like savoriness; add it, for instance, to pasta, soups, chili, popcorn, salads, beans, steamed vegetables, pizza, mashed potatoes and cooked grains. It’s often used to create dairy-free “cheese sauce” for items like steamed vegetables and macaroni.

Coconut yogurt. Made by inoculating coconut milk with live cultures, creamy coconut yogurt offers up a dairy-free cultured treat to improve digestive health. As a bonus, some brands fortify their products with vitamin B12. Just be aware that sweetened versions can contain high amounts of sugar and you don’t get the protein found in dairy-based yogurt.

Magnesium

Though magnesium is off the radar of most people, studies have linked higher magnesium intakes with improved BMD (Castiglioni et al. 2013; Orchard et al. 2014; Ryder et al. 2005). The mineral seems to regulate parathyroid hormone, which stimulates bone calcium absorption. Though less than half of Americans get enough magnesium (Rosanoff, Weaver & Rude 2012), Palmer says it’s found mostly in foods of plant origin, making it easier to get your fill if adhering to a plant-focused diet.

Power Plants

Quinoa. Once obscure but now in almost every health-oriented pantry, quinoa is a leading source of magnesium among whole-grain options. As a bonus, it’s also higher in protein than typical grains, making it a one-two punch in the fight against a weak skeleton.

Cocoa powder. Here’s another good reason to flaunt being a chocoholic. Each tablespoon of cocoa powder gives you about 10% of the daily magnesium requirement. And if you choose natural cocoa powder (sometimes spelled “cacao”) as opposed to Dutch-processed versions, you’ll benefit from health-hiking antioxidants as well. Try mixing cocoa powder into smoothies, oatmeal and various desserts.

Pumpkin seeds. The jack-o’-lantern castoffs are a surefire way to load up on bone-building magnesium. Each 1-ounce serving meets roughly 40% of the daily need for this nutrient. What’s more, pumpkin seeds (pepitas) are also a source of vitamin K, to further fortify your skeleton.

Potassium

You may know that potassium plays a role in keeping blood pressure numbers healthy, but it’s also an important player in bone strength. In a large review of studies, British researchers determined that higher intakes of potassium, which is found in a variety of plant foods, can limit bone resorption, a process whereby compounds called osteoclasts break down bone and cause calcium to be released into the bloodstream (Lambert et al. 2015). What’s concerning is that the vast majority of Americans aren’t meeting their daily potassium requirements—4,700 mg daily for adults (Cogswell et al. 2012).

Power Plants

Sweet potato. The orange spud is a consistent potassium performer, supplying about 15% of the daily need for this bone protector. It’s also jam-packed with beta carotene, an antioxidant that may play a role in fending off a weak skeleton. Roasted sweet-potato cubes are a delicious addition to salads and grain bowls.

Beans. The United Nations has hailed 2016 as the International Year of the Pulses, owing to their ability to provide an inexpensive and sustainable source of huge amounts of nutrition. Indeed, working more beans—such as black beans and kidney beans—into a diet is a great way to strengthen bones via a nutritional assault of potassium, protein, magnesium and calcium.

Plantains. Popular in Latin American and Asian cuisines, plantain is a big brother to the banana. With a quarter of the daily potassium needs in one fruit, plantains actually have more bone-friendly potassium than their more common counterparts. Starchy green plantains are best for thickening stews (think mole), whereas yellowing plantains with a few black dots can be sautéed, simmered in curries and stews, roasted or even grilled. Once their skin is almost completely black, they’re sweet enough to be blended raw into smoothies, pancake batters and oatmeal.

Omega-3

Emerging evidence suggests mega-healthy omega-3 fats can play a role in overall bone health (Orchard et al. 2013; Orchard et al. 2012; Li et al. 2010). “[The] benefit [is] possibly attributed to limiting inflammation that can accelerate bone loss,” says Palmer. While a number of plant foods supply omega-3 fat in the form of alpha-linolenic acid (ALA), it appears that the long-chain omega-3 fatty acids EPA and DHA found in fatty fish and grass-fed meats are more potent at fortifying bone strength (Farina et al. 2011).

It’s true that ALA is converted inefficiently to EPA and DHA in the body, but Palmer says that eating a variety of ALA sources daily can help maximize your conversion potential. If you don’t cast your line for fish but still want to make sure you are reeling in enough long-chain omegas, try an algae-based EPA and DHA supplement, suggests Palmer.

Power Plants

Walnuts. Among nuts, walnuts lead the way on omega-3 content, supplying about 2.5 g in an ounce serving. What’s more, a 2016 University of California, San Diego, study found that crunching your way through a handful of these benevolent nuts can improve cholesterol numbers, making them not only a bone builder but also a heart protector (Le et al. 2016).

Chia seeds. No longer just for desk pets, chia seeds have experienced a renaissance in recent years as people learned about their impressive nutritional resumé, including laudable amounts of ALA, as well as dietary fiber and even some must-have calcium. When mixed with liquid, chia forms a gel, which is why it’s often used to make healthier versions of fruit jam and pudding. Flax and hemp are other seeds with omega power.

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About the Author

Matthew Kadey,  MS, RD

Matthew Kadey, MS, RD IDEA Author/Presenter

Matthew Kadey, MS, RD, is a James Beard Award-winning journalist, Canada-based dietitian, freelance nutrition writer and recipe developer. He has written for dozens of magazines including Runner’s World, Men’s Health, Shape, Vegetarian Times and Fitness.