“Drink your milk! Then you will have strong bones.” I’m sure many of us grew up hearing this. And when asked why, we would always be answered with: “Milk has calcium, and calcium helps your bones become stronger.” But first, what is calcium and what is its real purpose in our body?
Calcium is a mineral that is essential in our body for various functions, most notably for the growth and maintenance of strong teeth and bones, but also for nerve signalling, muscle contraction, and the secretion of certain hormones and enzymes.
Of all the minerals in our body, calcium ranks highest in terms of quantity, and as much as 99 percent of this calcium is stored in our teeth and bones, and the rest in our blood, muscles, and the fluid between body cells.
With such a high percentage in our bones, you can definitely deduce that calcium is much needed to maintain bone health, and research has long proven that the mineral is needed by both children and older adults for this.
Bones undergo continuous remodelling, that is, there is constant resorption (removing mature bone tissue) and deposition of calcium into new bone (to form new bone tissue). This enables bones to heal from injury if need be, grow in new areas (as with children), and allow for proper weight distribution.
As such, children with a deficiency in calcium would be predisposed to stunting; they would not have enough calcium for their bones to grow properly and will not reach their full potential adult height as they grow older. In older adults, this can lead to a decrease in bone mass, which would then predispose them to osteoporosis.
Calcium is not a mineral that the body can generate, i.e. we need to get them from other sources. This means the diet that we consume daily should include calcium-rich foods, and if our diet excludes the mineral, especially for an extended length of time, the body does what it needs in order to get this required calcium: it pulls calcium from our bones instead.
This is what typically happens with adults as they reach ages where they are “too old to drink milk” and often do not consume a balanced diet due to hectic lifestyles or poor dietary choices. This results in ‘porous bones’, also known as osteoporosis, where there is a weakening of bones caused by an imbalance between bone building and bone destruction. In older adults and seniors, weaker bones make it more dangerous when they fall; even a light fall can result in fractures or more serious injuries.
Where To Get It?
Calcium can be obtained from many foods, and good sources include dairy products which have the highest concentration per serving of highly absorbable calcium. This explains why children are highly encouraged to drink a lot of milk from a young age. Yoghurts or cheeses such as mozzarella, Swiss or cheddar are also other dairy sources for calcium.
However, calcium is not limited to just dairy products. Dark leafy greens such as watercress, kale, dandelion greens and turnip greens are also rich in calcium. Fish are also a good source of calcium, namely sardine and salmon.
For the lactose-intolerant, vegan/vegetarian populations, or just people looking for healthier non-dairy sources for calcium, they can turn to nuts like almond, or seeds like chia and sesame for their daily dose of the mineral too.
There are also recommendations for the best cooking method to keep as much calcium in your foods as possible, such as steaming or sautéing instead of boiling. Subjecting foods to small amounts of water for the shortest possible time in this way can help to retain the mineral.
Also, the other types of food you consume can influence calcium absorption in your body. For example, eating fibres such as wheat bran or foods with oxalic acid like spinach and rhubarb, can bind with calcium and prevent it from being absorbed into the body. This is also why leafy greens are not always considered as good sources of calcium as though they may be rich in the mineral, the body is not always able to utilise the entire calcium content they contain.
Other than foods, of course it is also possible to obtain the mineral through dietary supplements. Calcium absorption is best when no more than 500 mg is taken at a time. Dietary supplements typically contain two forms of the mineral: calcium citrate and calcium carbonate.
Calcium citrate is a more expensive form of the mineral, and research suggests that it is absorbed better on full or empty stomachs. In contrast, calcium carbonate is better absorbed when taken with food. Other forms of calcium available include calcium lactate, calcium gluconate, and calcium phosphate.
The recommended daily allowance (RDA) for minerals is the average daily level of intake sufficient to meet the nutrient requirements of the average person. However, this figure differs depending on the person’s gender, age and thus needs.
According to the Food and Nutrition Board at the Institute of Medicine of the National Academies, children can require from as little as 200 mg of calcium (at 0-6 months old) to as much as 1,300 mg (from 9-18 years). Adults (19-50 years) typically require 1,000 mg of calcium per day, while older adults (51 years and older) need 1,200 mg for daily functions.
Though seemingly little, when translated into food proportions, it is easy to see why adults may not meet the RDA for calcium. A typical adult would need to consume about three or four glasses of low-fat milk a day (each contains about 380 mg of calcium) or almost 10 servings (each 100 g) of cooked vegetables (kai lan, spinach or chye sim) which vary from about 140-195 mg of calcium per serving.
Calcium is therefore often fortified in foods so as to enable adults to reach their RDA. This includes high-calcium soybean milk (450 mg per 250 ml glass), calcium-fortified orange juice (350 mg per 240 ml glass), and enriched bread (100 mg per two slices). Other foods that are often fortified with the mineral include tofu, breakfast cereals, energy bars, grain or even bottled water.
Research has also promoted that vitamin D be taken in with calcium, as the vitamin also plays an important role in maintaining bone health. At lower levels of calcium in the body, vitamin D is converted to its active form, which encourages greater absorption of calcium into the blood.
The easiest way to intake vitamin D is through exposure of the skin to sunlight, but in this day and age, often adults and even children now spend less time outdoors. As such, calcium-fortified foods and beverages or calcium supplements often also contain vitamin D, so as to promote healthier and increased calcium absorption.
Addressing Deficiencies In Asia
Micronutrient deficiencies are common in Asia and Southeast Asia. Being traditionally vegetarian in some countries, the region typically has a low intake of micronutrient-rich foods, particularly meat and animal source foods, but also certain vegetables and fruits. Of particular concern for the region are the deficiencies in iron, zinc, vitamin A, iodine and calcium.
In 2013, the vitamin D and calcium deficiency among women and children in Vietnam was first brought to light by researchers at the IRD and the National Nutrition Institute of Hanoi. They revealed that women and children involved in their study consumed only one percent of the RDA of vitamin D, and just over 40 percent of that of calcium. These statistics likely reflect that of many other Southeast Asian and Asian countries, and are likely still persisting today.
It is therefore of no surprise that Asia was recorded in 2011 as the region with the highest percentage of children under five who are underweight, wasted and stunted, standing at 76.6 million, 39.2 million and 103.5 million respectively.
According to a report published by the Food and Nutrition Technical Assistance III project (FANTA), low birth weight and maternal malnutrition are likely strong contributors to early development of wasting and stunting in these countries. Improving the nutritional status of women of reproductive age is therefore important in improving child nutrition indicators.
Possible solutions for these include great attention and support for care and nutrition of mothers during and after pregnancy, an increase in emphasis on education for mothers in terms of multi-micronutrient supplementation and as well on proper nutrition for their children from birth onwards.
For manufacturers, more foods are already being fortified with necessary nutrients such as calcium and vitamin D, for the consumption of both children and adults alike. However, there should also be regulations to ensure that the amounts of nutrients fortified in a product are sufficient to address micronutrient deficiencies in consumers, without excessively providing them to the point that it could endanger consumers’ health.
Educating consumers on the need for supplementation, especially for adults and their hectic lifestyles, could be another solution. Taking vitamins and minerals as they are in a single pill or even a couple of tablets would serve to help maintain our health in a more convenient manner.
Needless to say, a healthy, balanced diet and lifestyle could also prove to be a natural solution to any deficiencies, if we have access to and knowledge of the right foods, and will help us achieve healthy ageing in the process.