McGill Alert / Alerte de McGill

Updated: Thu, 07/18/2024 - 18:12

Gradual reopening continues on downtown campus. See Campus Public Safety website for details.

La réouverture graduelle du campus du centre-ville se poursuit. Complément d'information : Direction de la protection et de la prévention.

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Food Trumps Pills When It Comes to Calcium for Bones

One of the main things that postmenopausal women have to watch out for is osteoporosis, a condition characterized by weakened bones that can fracture easily. Contrary to common belief, bones are not static. They are constantly being broken down and rebuilt.

One of the main things that postmenopausal women have to watch out for is osteoporosis, a condition characterized by weakened bones that can fracture easily. Contrary to common belief, bones are not static. They are constantly being broken down and rebuilt. Osteoblasts are cells that form new bone tissues and deposit calcium into bones; whereas osteoclasts break down old bone tissues and deport calcium away from bones, a process called bone resorption. These cells are controlled by several hormones, one of them being estrogen. So when a woman reaches menopause, her ovaries stop producing estrogen, which in turn lead to osteoblast death and calcium deportation from the bones. As bones lose their calcium, bone mineral density decreases, rendering bones more and more brittle. Scary thought indeed... now you understand why milk isn’t just for kids! Unfortunately, many ladies don’t like dairy products or simply don’t have the time to drink 3 glasses of milk a day. So in our world of convenience, pills have been invented to suit our busy (or lazy) lifestyle.

Most postmenopausal women are instructed to take calcium and vitamin D supplements, the latter serving to increase the absorption of calcium. Theoretically, calcium from food and calcium from pills are identical, hence should have the same benefit in the body. To test this theory out, Reina Armamento-Villareal, M.D., of Washington Univeristy, and colleagues, decided to investigate. The study comprised of 183 postmenopausal white women who were divided into three groups. Group one relied mainly on dietary sources (primarily dairy) to get their calcium; group two got their calcium from food and supplements; group three obtained their calcium from supplements only. Not surprisingly, women in the diet-plus-supplement group had the highest calcium intake, averaging at 1,620 mg/day, and they also had the highest bone mineral density. The unexpected result was that the milk and cheese eaters had a better bone density at the spine and hip than pill-poppers, even though the latter group had a higher calcium intake. The women relying on dietary calcium took in about 830mg/day of calcium while those relying on supplements consumed 1,033 mg/day. 

Furthermore, women who obtained calcium primarily from food or from both food and supplements had also a higher concentration of active estrogen metabolites than women who relied on supplements only. It is possible that other nutrients found in calcium-rich foods cause a shift in estrogen metabolism, or that dairy products contain active estrogenic compounds that can influence bone density and the amount of estrogenic metabolites in the urine. In any case, a low dose of estrogen helps calcium uptake by the bone, thereby decreasing the risk of osteoporosis. One other concern with over-the-counter calcium supplements is that their solubility and bioavailability are highly variable and may be affected by the presence of other compounds in the supplements or by when the pills are taken. For example, some supplements must be taken during a meal so that stomach acids can facilitate absorption. The study does, however, have some caveats. One of them being that it does not reflect lifelong calcium intakes but only uses one seven-day dietary record to assess dietary habits. It is possible that women who eat more calcium-rich foods have a healthier lifestyle overall. But regardless of these limitations, unless you are allergic to dairy, it is a good idea to consume more milk, cheese and yogurt, as long as they are low in fat and sugar. As the marketing team of Quebec milk Le Lait puts it so beautifully: “One glass of milk is good, but two is better.”

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