I’ve been confused about calcium and the role it plays in my diet. What foods are best? Is dairy a good source or not? Can I get enough calcium if I don’t eat dairy? And the most puzzling: Why does the US have the highest rate of hip fractures in the world? So I did a little research.
T. Colin Campbell and The China Study initially sparked my curiosity. The book was hugely instrumental in my decision to cut way back on my consumption of meat and dairy as well as processed foods, and instead embrace a plant-based whole food diet.
Campbell has much to say about calcium and osteoporosis. His position centers on the fact that eating animal protein causes our blood to become acidic. To balance the blood’s PH, the body leaches calcium from our bones (similar to what a Tums does for stomach acid). Keep in mind this “robbery” from the bones is a normal and highly controlled bodily function. The only danger may be to those whose dietary calcium is almost exclusively from milk, cheese, eggs and meat. And the likely reason why their calcium intake fails to meet the minimum requirements is a corresponding lack of leafy greens, beans, and other whole plant foods.
There’s no doubt Americans get a pretty hard sell from the dairy industry on the supposed benefits of milk consumption. It does a body good, right? Yet, how do we explain the results of a 12-year Harvard study of 78,000 women? Those who drank milk three times a day actually broke more bones than women who rarely drank milk. Is it the result of our high protein diets, and the acidity from animal protein? The evidence is not entirely conclusive, but we do know that western, industrialized countries have higher calcium requirements.
There is consensus among the experts on bone health and calcium in that our body’s absorption and retention of the mineral is key. Calcium is not only vital to bone health; it’s needed for nerve signal transmission, production of enzymes and hormones, and blood vessel contraction and expansion. And wouldn’t you know, as we age, the rate of calcium absorption in our bodies falls.
The most healthful source of calcium is green leafy vegetables and legumes. Think broccoli, Brussel sprouts, and various greens like kale, Swiss chard, and spinach. Legumes such as white beans and soybeans (tofu) are winners because they also contain magnesium, which the body uses in conjunction with calcium to build bones. The calcium in fortified orange juice (300 milligrams per cup) is highly absorbable since it is paired with vitamin D. Cereals and almonds are other good bets. Unless you’re vegan or lactose intolerant, dairy in moderation supplies plenty of calcium. Just don’t let it be the dominant source, and stick to options that are lower in fat and cholesterol and free of antibiotics and hormones.
Active people keep calcium in their bones while sedentary people lose it. Weight-bearing exercise–anything that forces you to work against gravity–promotes bone density and strength.
Limit Salt Intake
When calcium leaches from the bones it enters the bloodstream and is excreted in the urine. Salt increases the rate at which calcium is lost. Processed foods provide 75% of the sodium we eat, so by avoiding them, you’ll cut your sodium intake and boost your calcium.
You lose about 6 milligrams of calcium for every 100 milligrams of caffeine you take in. Like salt, it increases the rate of calcium excretion.
Cola also increases calcium loss. Sprite, Mountain Dew, etc. don’t seem to have the same effect. It’s likely due to the phosphoric acid found in colas.
Vitamin D controls your body’s absorption of calcium, so if you lack vitamin D, your bones are going to suffer. It’s hard to get vitamin D from food sources (some fish, fortified cereals, milk, and orange juice), but sun exposure triggers vitamin D synthesis.
If you’re concerned about osteoporosis and calcium levels, talk to your doctor about your diet and possible supplementation. Meanwhile, I like WebMD’s approach: “The safest strategy is eating a diet that’s low in salt and rich in fresh and minimally processed whole grains, fruits, and vegetables. Include enough calcium and vitamin D from foods, and supplements if necessary, and be sure to limit caffeine and carbonated drinks.” There it is again, the plant-based whole food lifestyle, and another important reason to live it.
Jack Norris, RD, Does (Animal) Protein Leach Calcium from Bones?
Livestrong.com, What Affects Calcium Absorption?, by M. Gideon Hoyle.
U.S. National Library of Medicine, National Institutes of Health, NCBI, Pub Med, Acid Diet (High-Meat Protein) Effects on Calcium Metabolism and Bone Health, by Cao JJ, Nielsen FH.
U.S. National Library of Medicine, National Institutes of Health, NCBI, Pub Med, Epidemiology of Hip Fracture: Worldwide Geographic Variation. by Dinesh K Dhanwal, Elaine M Dennison, Nick C Harvey, and Cyrus Cooper.
U.S. News and World Report, Health, 5 Non-Diary Foods with Calcium, by Caitlin Yoshiko Kandil.
WebMD.com, Living with Osteoporosis. Osteoporosis Diet Dangers: Foods to Avoid, By Elizabeth M. Ward, MS, RD.
The World’s Healthiest Foods, Calcium, The George Mateljan Foundation.
excellent article. I love the “China Syndrome” too
I also want to mention the recent flurry in the media over calcium supplementation and a possible increased risk of heart disease. I found two good articles addressing this issue.
– – http://well.blogs.nytimes.com/2013/04/08/thinking-twice-about-calcium-supplements-2/
– – http://www.mayoclinic.com/health/calcium-supplements/AN01928
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