In many homes, the evening meal looks much the same: a plate of boiled water spinach, a small bowl of fish sauce, a bowl of winter melon soup, a few pieces of braised meat. The milk is kept for the child still in school; the adults gave it up long ago, and some feel bloated whenever they drink it. Often it is only after 50, when they come in for back pain or after a slip and fall, that many people first hear a doctor mention osteoporosis.
At the clinic, we are often asked whether it is worth buying calcium to take at home. The answer depends on how much calcium your everyday meals already bring in, so the doctor usually asks about your eating first and only then talks about tablets.
How much calcium Vietnamese people get each day
In 2021, a survey of 251 women aged 30 to 65 in a suburban district of Hanoi recorded an average intake of about 535 mg of calcium a day (Nguyen and Murimi). Milk and dairy foods supplied only 4% of that amount. The authors also found that 95% of the women surveyed did not know how much calcium they needed, and more than eight in ten did not know the factors that raise the risk of osteoporosis.
Looking more widely across countries, the picture is not very different. When Balk and colleagues (2017) pooled dietary intake data from 74 countries, many Asian countries had an average calcium intake below 500 mg a day, and only the Northern European countries went above 1,000 mg. Women usually take in less calcium than men.
Why years of low calcium go unnoticed
Almost all of the body’s calcium sits in the bones and teeth. The small share carried in the blood is held at a very steady level, because the heart, the nerves and blood clotting need it every minute. Physiology usually describes how, when meals do not bring in enough, parathyroid hormone mobilizes calcium from the bones to keep the blood level steady.
Bone loses calcium slowly, with no pain and no tiredness, sometimes over many years. Usually the problem only comes to light once the bones have already thinned. People get shorter, and the back may gradually stoop; some break a wrist or the neck of the thigh bone (hip fracture) after only a minor fall.
Familiar foods that are rich in calcium
By common nutrition knowledge, a few familiar dishes in Vietnamese meals are fairly rich in calcium: small fish braised until soft enough to eat bones and all, small shrimp stir-fried with their shells on, field crab soup, and tofu. People who feel bloated after fresh milk can switch to yogurt, which sits more easily.
All you need to do is write down your meals for one week and bring the notes to your appointment. From the way you actually eat, the doctor can estimate your calcium intake, and only then work out whether to add more through food or with tablets, sometimes both.
Vitamin D, magnesium and movement go with calcium
Vitamin D is usually described as necessary for the gut to absorb calcium, and the skin makes vitamin D when sunlight falls on it. In a 2016 consensus of two osteoporosis organizations, ESCEO and IOF, Harvey and colleagues noted that calcium supplements taken with vitamin D slightly lower the risk of fractures, while the medical literature does not support taking calcium alone to prevent fractures. This expert group also considered that vitamin D may help reduce falls (see our article on preventing falls in older adults).
Magnesium is often mentioned as a substance involved in building bone. Many people may gradually run low on magnesium because of refined foods and stressful lives; this is covered in our article on magnesium.
Bones also need to be used. People are commonly advised to walk, climb stairs or do light weight-bearing exercise, on the grounds that movement helps the bones hold on to calcium.
Take calcium carbonate tablets with meals
Calcium carbonate is a common tablet form. Recker (1985) measured absorption in people lacking stomach acid, a condition common in older adults. Taken on an empty stomach, they absorbed only about 4% of the calcium carbonate; taken with breakfast, absorption returned to normal.
At Tam Duc, we advise taking calcium carbonate tablets with meals, not on an empty stomach or before eating. Before that, the doctor will ask which calcium you are taking, how long you have been taking it and whether you have a history of kidney stones, and only then discuss how much to take, for how long and whether you need vitamin D as well.
Many people worry that calcium tablets harm the heart. The ESCEO and IOF consensus considered that this claim is not convincingly supported by the current evidence; the side effects named in the consensus include kidney stones and digestive discomfort (Harvey and colleagues, 2016). We still prefer calcium from meals, and add tablets only when meals cannot make up the shortfall.
How the clinic looks at calcium
The consultation begins with everyday questions: what you eat, whether you walk much, whether you get out in the sun, whether you have ever broken a bone, what medicines you are taking, whether you have kidney stones. Besides the clinical examination, the doctor also takes your pulse, looks at your tongue, and listens and asks in the way of traditional medicine. Traditional medicine places the bones under the Kidney, so people whose lower back and knees feel sore and weak, and whose legs grow weaker with age, usually have this part looked at closely. An herbal decoction modified for each person may go together with changes to diet and guidance on exercise.
If you are already taking a calcium product, bring the bottle with you. The doctor may have you hold a small piece of that very tablet in your mouth and then do Applied Kinesiology muscle testing, to see how your body responds to this particular product; the method is explained in our article why doctors use muscle testing. Some people also need blood tests or a bone density scan, and in that case the muscle testing results are read together with those results.
Numbness around the mouth, cramping hands: when to get checked right away
- Numbness around the mouth or in the fingertips, or hands that cramp up on their own: get checked right away, because this may be a sign that the calcium in your blood is dropping low;
- Severe muscle cramps that keep coming back are also a reason to get checked right away;
- A broken bone after a minor knock: get checked for osteoporosis;
- If you have had kidney stones or have kidney disease: ask your doctor before taking calcium tablets.
Worth keeping
- Write down your meals for one week and bring the notes to your appointment;
- Take calcium carbonate tablets with meals, not on an empty stomach;
- Get some gentle sun, and walk or climb stairs regularly every day;
- Bring your calcium and vitamin D bottles and any medicines you are taking to your appointment;
- If you have had kidney stones or kidney disease, ask your doctor before taking tablets.
If you are unsure whether to take calcium, or have taken it for a few years without being sure it helps, Dr. Dinh Ngoc Duc (MD, MSc in Traditional Medicine) will go over your diet, your current medicines and the state of your bones with you before choosing how to supplement.
The right dose of calcium and vitamin D depends on your age, kidney disease, history of kidney stones and the medicines you take. Ask your doctor before starting tablets on your own.
References
- Nguyen B, Murimi MW (2021). Lack of calcium rich foods in the diet, low knowledge on calcium level recommendations and severe food insecurity predicts low calcium intake among Vietnamese women. Appetite 163:105242. https://doi.org/10.1016/j.appet.2021.105242;
- Balk EM, Adam GP, Langberg VN, Earley A, Clark P, Ebeling PR, et al. (2017). Global dietary calcium intake among adults: a systematic review. Osteoporos Int 28(12):3315-3324. https://doi.org/10.1007/s00198-017-4230-x;
- Recker RR (1985). Calcium absorption and achlorhydria. N Engl J Med 313(2):70-3. https://doi.org/10.1056/NEJM198507113130202;
- Harvey NC, Biver E, Kaufman JM, Bauer J, Branco J, Brandi ML, et al. (2016). The role of calcium supplementation in healthy musculoskeletal ageing: An expert consensus meeting of the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) and the International Foundation for Osteoporosis (IOF). Osteoporos Int 28(2):447-462. https://doi.org/10.1007/s00198-016-3773-6.
