“Even though we cannot precisely separate the various factors that influence bone health, and heredity is predominant, it is still very important, especially for teenage girls, to build the best” bone capital â €? ? possible, ”says Claudine Blanchet, kinesiologist and osteoporosis specialist.

Indeed, until the end of her twenties, the bone mass increases, then it stabilizes, then it inexorably decreases. We can only slow down the decline, not completely prevent it.⁴. “During adolescence, we must therefore put all the chances on our side,” insists Claudine Blanchet. With this in mind, a sufficient supply of calcium and vitamin D is fundamental.

L’physical exercise would also be very important. A study⁵ has in fact shown that girls who had been physically active from 12 to 18 years of age found themselves at this age with a considerably higher bone density than those who had been sedentary. The most beneficial exercises for bone health are those that impact the bones, support body weight, or support loads. Walking, running, dancing, skiing, soccer, snowshoe sports and weight lifting are, from this point of view, more beneficial than cycling or swimming.^3,4,6,7. In addition, as Claudine Blanchet reminds us, it is important to vary your activities. Otherwise, the bones “get used” to the beneficial stress of exercise and benefit much less.

• On cannot affirm that the calcium in dairy products is more beneficial for the bones than that of other sources.
• In developed countries, dairy products are the privileged sources calcium. They are easily accessible, varied (milk, cheese, yogurt, etc.), relatively economical, their taste is appreciated and they also provide a host of other nutrients.
• Research, at least in Canada, shows that the majority of people who do not consume the recommended servings of dairy products have calcium deficiencies. It seems that they generally do not find the means to obtain their calcium in any other way.
• You can reach your calcium intake without consuming dairy products, but you have to be much more vigilant. However, calcium fortified soy drinks make it easier than ever before. (See the table of foods rich in calcium below, and our Calcium sheet. Most of the specialists we interviewed recommend consulting a dietitian-nutritionist if you are not consuming dairy products.
• La vitamin D is essential calcium absorption and bone health. If you consume little or no vitamin D fortified milk, you must ensure that you get your daily dose of vitamin D in other ways: by sunning or eating other foods such as oily fish (see our sheet Vitamin D).
• If our main calcium intake comes from dairy products, nutritionist Nathalie Jobin, of the University of Montreal, suggests that half of the recommended daily servings consist of vitamin D fortified milk, especially if you live in a northern region where reduced exposure to the sun does not allow you to synthesize enough vitamin D.

On this point, the experts are far from agreeing.

• According to a joint WHO / FAO report³, a minimum intake of 400 mg to 500 mg per day is needed to prevent osteoporosis (a glass of milk provides about 300 mg).
• In North America, the official recommendations are 1 mg for people aged 19 to 50, while they are 700 mg in Great Britain.
• According to a report from the Harvard School of Public Health⁴, long-term studies support the importance of minimal calcium intake for maximizing bone strength, but they question the claimed benefits of high recommended intakes for adults.

• WHO believes that calcium needs could vary from culture to culture for genetic and geographic reasons, and depending on eating habits and lifestyle³. In other words, we would therefore need two kinds of recommendations, one for countries where we consume little animal protein and another for Western Europe and North America.
• It therefore seems that the minimum threshold would be between 400 mg and 600 mg per day, according to the various studies. a insufficient intake, especially in adolescence, would be clearly harmful. A large American study has also compared the consumption of milk in 3 women between the ages of 250 and 5, and their fracture rate up to the age of 17. Those who drank less than a glass of milk per day (50 mg of calcium) in childhood had lower bone mass and a greater risk of fractures⁸.
• On the other hand, it seems that we can only say that consuming more than 600 mg per day (the equivalent of two servings of dairy products) provides increased bone health benefits^4,9. This would be particularly clear after menopause. An American study¹⁰, lasting 18 years, involving 72 postmenopausal women, found that those who consumed 000 mg of calcium per day rather than 1 mg did not have a lower rate of hip fracture.

The official recommendations – which are rarely below 700 mg – were designed to meet the needs of the majority of the population in a given country, and they take into account the lifestyle habits of the average person. By following them, we generally make sure to benefit from a sufficient intake. You can adapt the number of servings of dairy products according to your own lifestyle. For example, a sedentary smoker, who eats a lot of meat and salty foods, will need more calcium than an athletic person who favors fruits and vegetables in their diet and outdoors. (The sun provides vitamin D which helps in the absorption of calcium.)

When we ingest a food, only a certain percentage of its calcium is metabolized by the body and becomes “usable” by the body. This is called the bioavailability. The recommended nutritional intakes have been established on the basis of an average bioavailability of around 35%, which is moreover roughly that of milk.

To know if a food will provide us with a lot of calcium, we must of course take into account the overall amount it contains, but also its percentage of bioavailability. The following table lists the number of servings of various foods needed to obtain the same amount of “usable” calcium that 250 ml of milk provides, or approximately 96 mg of calcium.

Bioavailability of calcium from certain foods compared to milk^11-13

Here is a summary of the main steps you can take to build and maintain good bones.^3,4.

• Get enough calcium on a regular basis throughout your life.
• Get enough vitamin D and vitamins K and A.
• Consume lots of fruits and vegetables.
• Be physically active.
• No smoking.
• Don’t consume too much alcohol, salt and caffeine.
• Consume little animal protein.