What Builds Bones?
The Quick Answer: Calcium (essential for bone health) deficiency is a problem for adolescent girls, menopausal women, and older men. There is growing evidence that getting calcium from whole foods works better than taking it in pill form. The foods in this picture provide 700 mg.
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In 1939 Dr. Weston Price published a remarkable book, Nutrition and Physical Degeneration. Price studied 13 indigenous civilizations from his expeditions, comparing dental decay in people eating traditional diets to their cousins who had moved to the cities and adopted the modern diet. He concluded that it was possible to prevent dental cavities (or caries) through diet, and that prevention was better than repair. His work was ignored, and the business model for modern dentistry was built on repair rather than prevention. This is a repeating story in nutrition: repair, in our culture, makes a better business than prevention (which requires that so un-American behavior—self-restraint).
I intended to share more about Dr. Price until I discovered that May was National Osteoporosis Awareness & Prevention Month—I almost missed it. Osteoporosis is a lot like dental cavities—repair makes a better business than prevention. Here are a few facts:
• Half of women over fifty will break a bone because of declining bone density; worse, there is the risk of “dowager’s hump.”
• For men the risk of age-related bone fracture is one in four.
• Risk factors for osteoporosis include: insufficient dietary calcium, vitamin D deficiency, excessive intake of protein, sodium, and caffeine, and lack of exercise. (Smoking and heavy alcohol intake are causes also, but if you’re reading this blog you don’t likely have those problems.)
My beautiful wife was upset recently because the doctor gave her a stern lecture for not taking calcium and vitamin D pills. I was puzzled because the doctor had not tested her to see if there was a deficiency, or made a diagnosis of bone loss. He claimed the benefit was well proven; I thought it would be wise to see the proof. My wife is caught between her doctor’s faith in pills, and our faith in wholesome food.
This week the prestigious British Medical Journal reported on a major long-term study that addressed this question; the article was titled “Dietary calcium intake and risk of fracture and osteoporosis: prospective longitudinal cohort study.” (An online digital version is available here.)
The study tracked diet, supplements, and bone fractures in 61,400 postmenopausal Swedish women for nineteen years, starting after they turned fifty. This is the most complete study of diet and bone health to date and the article made these surprising statements:
• There is currently a wide range of daily calcium recommendations: The UK calls for 700 mg; Scandinavia, 800 mg; the U.S., 1200 mg; and 1300 mg in Australia and New Zealand. (These values include dietary calcium and any taken in pill form. Because no one knows how much calcium they get in their diet, these targets are not very helpful.)
• Reviews of prior studies have found little or no benefit to taking calcium in pill form. Eating calcium as part of a healthy diet seems to be best but the optimum amount had not been determined.
• The study concluded that the optimum dietary intake of calcium for postmenopausal women was 700 mg daily. Taking less resulted in more hip fractures; taking more also caused an increase in hip fractures, though at a reduced rate. At lower levels of calcium intake, vitamin D intake was especially helpful.
• Taking calcium in pill form as a supplement did NOT show a benefit.
Based on this major study, we should:
1. Eat more foods rich in calcium. This is critical for adolescent girls, menopausal women, and older men. The most recent data (NHANES 2002-6) showed older women averaging about 560 mg of calcium daily from food sources; men were getting a little more, about 650. Because we already get 51% of our calcium from milk and dairy, getting more from plant sources seems wise as there are other reasons to eat more dark green vegetables, legumes, nuts and seeds. (Plant-sourced calcium also increases estrogen activity in women, and reduces the risk of kidney stones.)
2. Discuss with your doctor the wisdom of taking calcium in pill form; he should be aware of other health considerations. Getting sufficient calcium is a bigger challenge if you avoid milk or dairy. (All this is a tough topic for doctors as they have been guided to push calcium supplements.)
Dietary Calcium
What does 700 mg of calcium from natural foods look like? The picture above tells the story, but here are the details:
• Breakfast of Post Grape Nuts and milk (1/2 cup each): 165 mg.
• Morning snack of cheese (1/2 oz.) and whole wheat cracker: 100 mg.
• Lunch of canned tuna on whole wheat store bread (wheat isn't a significant sourse of calcium; the bread shown is calcium fortified): 87 mg.
• Afternoon snack of yogurt (2 oz.): 100 mg.
• Dinner of spinach salad and a bean dish: 212 mg.
• Evening snack of walnuts, Brazil nuts or sunflower seeds: 30-40 mg.
We’ll come back to bone health in a future post—it’s a complex subject that scientists are still unraveling. Three parting thoughts:
1. Remember that besides dietary calcium, exercise, adequate vitamin D, and avoidance of excessive salt and caffeine are also important to bone health.
2. Strong bones go hand-in-hand with strong muscles. Both peak in our youth; the key to health is to slow the decline.
3. Exercise builds muscles and most muscles are attached at each end to a bone. So besides improving your appearance, exercising your muscles also strengthen your bones.
Please comment on your approach to calcium sufficiency, or your experience protecting bone strength.
Friday, May 27, 2011 at 12:31PM | by Skip Hellewell | 22 Comments | 7 References | Share Article | in calcium, prevention | Email Article 
Reader Comments (22)
I love that you find the actual studies that support my gut conviction that food is better than supplements! Also, thank you for pointing out the plant sources. We try to not eat a lot of dairy (husband is lactose intollerant, daughter is allergic), and I've read enough to be really frustrated by the milk campaigns that have lead most people to believe you have to drink milk for health, and specifically for calcium. I'm not saying it's bad, but there are many routes that can be healthy.
Every post about supplements eases my budget. I'd rather buy a container of organic spinach and some nuts and cheese at Costco totaling about $20 instead of buying calcium and wondering if they are really worth the $20 I pay for them. Thank you for doing research on behalf of many of us. My diet was already doing okay, but there is always room for improvement. As a side note...I bought the expensive eggs at Costco today. I figure if my children are eating them I ought to get the most for my money. Thank you.
Every post about supplements eases my budget. I'd rather buy a container of organic spinach and some nuts and cheese at Costco totaling about $20 instead of buying calcium and wondering if they are really worth the $20 I pay for them. Thank you for doing research on behalf of many of us. My diet was already doing okay, but there is always room for improvement. As a side note...I bought the expensive eggs at Costco today. I figure if my children are eating them I ought to get the most for my money. Thank you.
This is a subject that is quite important to me. I had an enlarged parathyroid gland (we all have 4 of these) in my early 20's. The parathyroid glands control calcium in the blood and bones (in case you didn't know). Being enlarged, it thought I needed more calcium in my blood, pulling it from my bones and teeth. The excess calcium in my blood collected in my kidney, creating a huge kidney stone. I had surgeries to remove both the stones and the enlarged parathyroid. So now I am left with only 3 parathyroid glands, I probably only have about 3/4 of the calcium I should have in my body- on top of already having decreased bone density from losing calcium when my bones should have been at their peak density. So I am at a huge risk for osteoporosis. I actually get a tingly numbness in my fingers and my facial muscles twitch- that is when I can tell I need more calcium. In fact, after the surgery to remove the parathyroid gland, the doctors kept coming by and showing the interns the way my cheek muscles would spasm when they tapped on them because they rarely see cases that bad!
Anyway, I am now trying to figure out how to increase bone density and increase my calcium intake. I am trying to incorporate more calcium rich foods into my diet. It is not the easiest thing for me, but I am trying. I really appreciate the information in the post!
I'm confused about the information you gave regarding the whole wheat bread...you said supplements weren't effective, but isn't bread fortified with what are essentially supplements?
Sandi, you identified an essential issue in modern nutrition—the effectiveness of adding "functional" ingredients to food. You and others who read nutrition articles, blogs and books are the leading edge of the real food movement. The real food movement is a challenge and a threat to the processed food industry, the corporations I call "Food Inc."
To placate us, Food Inc. has seized on what they call "functional foods", which are processed foods supplemented with whatever chemical the public is currently in love with (vitamin C, vitamin E, omega-3, etc). The rising concern about osteoporosis has made calcium—supplied as calcium carbonate or calcium sulfate—a popular chemical for enriching or fortifying food. The effectiveness of this has not been properly studied. There is a surprising amount of calcium added to breads—I saw bread with up to 100 mg per slice.
I wanted to discuss this issue—the benefit of added calcium—but the post had already passed our 1000 word limit, so I made a note to return to it in a future post. You alertly picked up on the issue. Thanks, and best to you.
Thanks for this great post and all of the past posts! This blog is always very interesting, though provoking and motivates me to live a healthier lifestyle.
I have a question about the absorbability of the calcium in spinach and other leafy greens. I remember learning that although they contain a lot of Calcium, it isn't absorbed nearly as well as the calcium in dairy products (part of the problem being that they are also high in iron which hinders the absorption of calcium.) I just did some google searches on this and found conflicting data so I wanted to know what you have found out about this.
Thanks!
Rachel
p.s. I'd love some more info about you being on the Martha Stewart site and how that all came about!
Rachel, your second question is easier to answer. The reason my applesauce recipe (I say "my", but people have been making applesauce forever, haven't they?) is on Martha Stewart's site has to do with the June issue, currently on the newsstands. The lead story in the June issue is about family reunions—a wonderful topic for Martha to present. It was our privilege to be the family in the story. Don't you think our grandchildren are a little above average?
The first question, about the absorption of calcium from leafy greens is more complicated. Some research has been done on the bio-availability of calcium from various sources, including spinach, milk and dairy. My conclusion is that we don't really know enough about the subject—this is a repeating theme in nutrition—and the best approach is to include a variety of sources. Best to you.
Calcium and Vitmain D can only be absorbed with fat intake, so have some butter with those green veggies, and opt for whole milk dairy rather than nonfat.
Loved the post. I remember my midwife recommending calcium supplements a while ago. I bought a bottle and then after I took them for a couple of weeks off and on, they have been sitting in my cupboard, unused. I guess I was just following my gut feeling that food is better than supplements. I don't eat a lot of dairy, but I do eat a healthy, varied diet. Aren't sardines a good source, since they still have the bones in?
Lindsey, yes, sardines are a good source of calcium as well as omega-3, and a good value. Canned salmon also works. Best.
Along with spinach, salmon, white beans and broccoli, in the winter I increase use of brussle sprouts and collard greens/okra. This time of year when prices are lower, rhubarb and peas.
Sure glad I got talked in to buying that big bottle of calcium supplements by my doctor (grumble, grumble). I was getting worried because I haven't drank milk regularly for a few years and my finger nails were showing supposed signs of calcium deficiency. I guess I am back to ramping up my leafy greens.
Thanks for the post. I have to laugh, though....I just bought a bottle of calcium pills on Saturday thinking "I need more calcium."
I do appreciate learning these details. Spinach salad is on the lunch menu today!
If any of you are familiar with chia seeds (a super seed), they contain as much calcium as 1/2 c of milk. Also, I've read that spinach contains an agent (oxalic acid) that binds with the calcium, causing it to pass through the body unabsorbed. Greens w/o this problem include kale, broccoli and collard greens. (My source for this information, along wtih a lot of other information on sources for minerals and vitamins is a book called Super Baby Food by Ruth Yaron). Skip, have you heard of oxalic acid anywhere before? Was just looking up something and ran across this information and thought I would add it to the conversation, since it seems a lot of people are looking to spinach to add their extra calcium.
@Stephanie:
My husband is prone to kidney stones, so he's been told to avoid foods that are high in oxalic acid. Unless you overdose on lots of spinach, it's not a problem for most people, from what I understand. Lots of foods have it, but in much smaller quantities. I think the key is to be balanced and not rely on one "miracle vegetable" for all your nutrients. I don't happen to like spinach, so I'm okay with helping him avoid it!
Stephanie and Sacha, thanks for your comments. It's true that spinach contains oxalic acid (oxylate), and that oxalate can reduce the bioavailability of the calcium so richly found in spinach. It's also true that 80% of kidney stone material is calcium and oxylate. A couple of other points:
1. Doctors are best qualified to guide patients prone to kidney stones so I shouldn't say too much. But, it appears that perhaps only 10-15% of the oxalate in the body comes from the diet, the rest is made by the body. So reducing the risk of kidney stones is more complicated than simply avoiding foods rich in oxalic acid, which has other benefits. Drinking adequate water (not soft drinks) is essential; 10-12 glasses daily are recommended if you have a kidney stone history. That's a lot to drink! A diet high in protein is also problematic. As plants are low in protein, an excess of protein usually requires an excess of meat or meat products (dairy). Another reason to not rely too heavily on dairy for our calcium.
2. We know that plant sources of antioxidants are crucial to health and prevention of cancer and other disease. The plants that are highest in antioxidants, also tend to be higher in oxalic acid. For reasons we don't fully understand, in Nature antioxidants and oxalic acid travel together.
3. A consideration for the husband: In a recent study "of prostate cancer and vegetable intake-including the vegetables spinach, broccoli, cauliflower, cabbage, Brussels sprouts, mustard greens, turnip greens, collards, and kale-only spinach showed evidence of significant protection against the occurrence of aggressive prostate cancer."
4. While the bioavailability of calcium in spinach is reduced by oxalic acid, spinach also offers more calcium than most plants. The important thing is to combine a variety of plant sources of calcium, recognizing that you'll also get lots of antioxidants as well as oxalic acid.
An excellent summary of spinach can be found here: http://www.whfoods.com/genpage.php?tname=foodspice&dbid=43
Best to you.
Thanks for the great information, Skip. My mom (70 years old) was prescribed calcium supplements by her doctor and the longterm effect was that her muscles became "frozen" as she described it. She found that other women have had the same difficulties and there is a lawsuit going on for the particular brand that she used. It took her months of being off the pills before her body started working again. She had given up almost everything (driving, cooking, quilting, holding grandkids) because of the side effects. Luckily, she has regained her movement and strength.
We so much enjoy your blog. My husband would never eat brown rice for me, but he does for you. Even my 14 year old daughter checks in with you regularly. You are known as "Uncle Skip" at our house! Thanks for your wisdom.
I am kind of new to your site, so I don't know if you have commented on the salt issue. There are some interesting studies about the benefits of the 'right' kind of salts. Yes the iodized refined salt in the form that most people are familiar with is not good for you. It has been stripped of the vital minerals needed to assimilate properly.
Tamra, welcome to the site. How did you find us? There will be a post on salt and the benefit of "natural" salts. Best.