As part of their sales pitch for milk and other dairy products, the dairy industry flaunted the fact that milk contains high levels of calcium. This worked very successfully, because when asked to name a good source of calcium, most people answer with 'milk and other dairy products'.
It appears to be a common view in the Western world that an adult diet devoid of dairy is unhealthy and will lead to weak bones and teeth. Unfortunately this means that other foods also high in calcium are not recognised as such, and many people have no idea that a wide variety of vegetables, fruits, nuts, pulses and fish contain it. This is good news for people who are lactose intolerant, allergic to milk, vegan or choose to avoid dairy produce for other reasons.
Calcium is an essential mineral. Ninety-nine percent of the body's calcium is stored in the bones and teeth and the rest has other functions in the body such as muscle contraction (including heart muscle), the transmission of nerve impulses, blood clotting, the regulation of blood pressure and metabolic reactions. Calcium also has an important role to play in the development of bone mass.
The RNI, or reference nutrient intake (the minimal amount required to prevent deficiency) for calcium is set at 700mg per day for UK adults. Three portions of dairy each day, such as a glass of milk, yogurt or piece of cheese provides this. Fish eaten with the bones, such as sardines and pilchards is also a good source.
Some good non-animal sources of calcium include green leafy vegetables, such as kale, collard greens, broccoli, cabbage and watercress, leeks, parsnips, sea vegetables, beans and lentils, tofu and Soya products, sesame seeds, dried apricots, dried figs and dates, blackcurrants, blackberries, oranges, currants and almonds. Calcium is also found in drinking water in hard water areas.
It is fair to say that non-dairy foods are likely to contain less calcium than dairy foods, for example, a portion of broccoli contains about a third as much as a glass of milk. However, this does not mean it is impossible to get adequate amounts of calcium with a dairy-free diet, especially if a wide variety of calcium-containing vegetables, fruits, nuts, seeds and pulses (as well as small-boned fish if not vegetarian), are eaten regularly and in plentiful amounts. If in order to accomplish this it means paying more attention to our diets, it can only be a good thing, after all, this is something we should all be doing regardless of whether we choose to eat dairy or not.
While the amount of calcium in different foods is an important consideration, so is the amount we actually absorb. While calcium is easily absorbed from milk, due to the presence of lactose sugar, high amounts of protein actually cause calcium to be lost in the urine. Milk is an animal protein, therefore a diet consisting of large amounts of dairy, as well as meat, (which is typical of the US and UK populations) also means large amounts of calcium are lost.
As more meat and dairy is consumed, the need to take in extra calcium becomes greater (the RNI for calcium is set at 1000mg for US adults). Other foods that cause calcium to be lost and therefore increase the need for more calcium include those high in fat and salt, as well as alcoholic, caffeinated and carbonated drinks.
The main cause for concern regarding calcium deficiency is osteoporosis, a disease in which bones become brittle and more likely to break due to loss of calcium in later life. The Dairy Council of the United Kingdom advocates eating dairy as the easiest way to get enough calcium to protect our bones against this disease. This is an interesting idea, especially since countries such as Britain and the United States where the prevalence of osteoporosis is high, consume large quantities of milk and milk products. If dairy produce helps to prevent this disease, then surely the inverse would be true?
Putting the 'dairy or not to dairy' argument to one side, calcium is not the only factor involved in whether or not someone will develop osteoporosis. The action of sunlight on the skin stimulates the production of vitamin D, which is required for the absorption of calcium. If the skin is not exposed to the sun or little time is spent outside low levels can be a problem, especially during the winter months. Food sources of Vitamin D include oily fish and eggs, but if sufficient levels of vitamin D are likely to be compromised, fortified foods, such as breakfast cereals and margarines as well as supplements are available.
There are also other lifestyle factors to consider regarding bone health; regular weight bearing exercise boosts bone strength, while smoking and excessive alcohol consumption has an adverse effect.
If you choose not to consume dairy products it is no reason to be alarmed - dairy will not necessarily protect you from a calcium deficiency or osteoporosis. Dairy produce may well be higher in calcium than most other food sources, but that does not automatically make it the best source. Calcium-rich foods that are vegetable in origin, sufficient exposure to sunlight and plenty of weight bearing exercise will go a long way in protecting our calcium stores and future bone health.
Not only do we have to make sure that we maintain an adequate intake of a variety of calcium rich foods, we also have to protect the calcium reserves that we already have.
