Are You Confused About Calcium? You're Not Alone

Calcium supplements

( I recently attended a breakfast meeting called Calcium Confusion presented by Jamieson Vitamins and Argyle Communications on the day before World Osteoporosis Day, which by the way, is October 20th. The purpose of the meeting was to help clear the air of confusion surrounding dietary calcium, calcium supplements and the risk for cardiovascular disease. Admittedly I've been cautious about calcium and the use of calcium supplements because of research that got a lot of press  a few years ago suggesting that higher intakes of calcium, defined as 1000 or more mg per day, might in fact, increase the risk for heart disease.

The majority of research to date, including more recent studies, supports the safety of calcium supplements, I will always emphasize food first. As well, to mainly focus on calcium and vitamin D for the prevention of osteoporosis is 'not seeing the forest for the trees'. Using calcium supplements without regard for the other supporting nutrients is a tad cavalier for my liking and I still feel may prove to be harmful in the long run. Time will tell.

Is Calcium Harmful Or Helpful? Cutting Through The Confusion

Calcium Conundrum. What Is The Latest Research?

Dr Robert Heaney is an osteoporosis expert and Research Chair for Grassroots Health, a public health promotion organization whose mandate is to increase awareness of the importance of vitamin D for all aspects of health, not just bones. He reviewed the article in a 2008 British Medical Journal by Bolland et al, which found an increased risk of CVD with calcium supplements. This came as a big shock to both the public, and health organizations and professionals, because current recommendations support the use of calcium supplements for the prevention of osteoporosis.

Heaney pointed out that since the publication of the study, several groups have reexamined Bolland’s meta-analysis. Some of the problems with the original research include the fact that subjects with the highest use of calcium supplements also had more CVD risk factors; once that was adjusted, the association between CVD and calcium supplement use disappeared. Bolland also only included studies that had subjects with adverse CVD related events, in other words, he used studies that looked at sicker people therefore stacking the odds in favour of finding a problem.

A couple of curious points made by Heaney include his suggestion that calcium supplements couldn't be a problem [as it relates to CVD] due to a lack of biological plausibility. He also stated that high amounts of calcium, regardless of the source, don’t pose a threat because the body has defenses in place to prevent it from absorbing too much calcium.

I find this confusing since everything I've read, and what I know from dialysis patients who are on blood thinners and therefore vitamin K deficient, and often vitamin D deficient, is that calcium supplements [used as a medication in dialysis patients] can increase calcification of the blood vessels.

This is more than biologically plausible without adequate amounts of vitamin D, magnesium and vitamin K2; supporting nutrients that direct the movement of calcium in the body; without them, calcium is less likely to go into the bones and teeth where it belongs and but rather ends up in the soft tissues, like blood vessels. This is beautifully highlighted in the book Vitamin K2 and the Calcium Paradox.

On a very encouraging note, bone repair can start at any age, it really isn't too late to 'get with the program'. Studies have clearly shown that because bones are constantly being remodelled, literally 24 hours a day, 7 days a week, benefits from higher amounts of calcium, vitamin D, and I’d throw in magnesium and vitamin K2, start immediately.

Calcium And The Diet

Lauren Davidson RD spoke about the role of diet in meeting calcium needs. She reminded the audience that Osteoporosis Canada recommends meeting calcium requirements from dietary sources first, and only if that’s not possible, to then use calcium supplements. This makes perfect sense, and is a sound strategy, because food provides a plethora of nutrients. Not only is milk an excellent source of calcium for example, with 300mg per 250ml/1 cup serving, but milk also provides other bone building nutrients such as phosphorus, magnesium, vitamin D [albeit only a whiff, but enough to prevent rickets], vitamin A, protein and vitamin B12. Providing a sample menu illustrated that will little effort, it's easy to get 800 to 1000 mg of calcium from food.

Davidson also stated that along with promoting a calcium-rich diet, she also recommends vitamin D, and with good reason. Research has clearly demonstrated that Canadians are vitamin D deficient most of the year, and that deficiency is the rule and not the exception. In my practice I take it a step further and ensure people are getting enough magnesium [however supplements are recommended more often than not as most struggle to get the 400-500 mg they need every day], and vitamin K2 [not to be confused with vitamin K1 from plants] for optimal bone health. While I am not averse to recommending higher amounts of vitamin D, to do so without regard to magnesium and vitamin K2 intake is potentially problematic; higher intakes of vitamin D can induce a functional magnesium and vitamin K2 deficiency.

The Institute of Medicine recommends 1000-1200 mg of calcium and a paltry 600 IU of vitamin D per day; amounts that have been met with a lot of criticism  For one, with only 600 IU vitamin D per day, about 25-30% of the population will have osteoid tissue, in other words, bone tissue that is un-mineralized and starving for calcium, phosphorus and magnesium. Why this is acceptable is unclear to me. I’m in agreement with Walter Willet from the Harvard School of Public Health who states that the current nutritional recommendations are too generous for calcium and lacking for vitamin D.

This would also make evolutionary sense as well because calcium would be hard to come by since our paleolithic ancestors who would not have been eating dairy, nuts and seeds in any appreciable amount or cooked dark green leafy vegetables. This lower intake of calcium would have also resulted in a more ideal ratio of calcium to magnesium of 1:1. Vitamin D would have been more plentiful given our origins near the equator.

Heaney's own work supports this. With adequate levels of vitamin D, around 75-80 nmol, the body can absorb all the calcium it needs from about 600 mg per day. Granted, if there's evidence of osteomalcia [pre-osteoporosis] or osteoporosis, then more calcium is warranted as the bones will be starving for more calcium to replace what's been lost and 1000-1500 mg makes sense in a treatment setting, but for preventative measure, possibly wasteful.

Davidson also touched on the dietary factors and eating patterns that can affect calcium absorption.

We know that the body can only absorb a certain amount of calcium at one time [that goes for any nutrient], which, is why it’s best to spread one’s calcium intake throughout the day. Thankfully that’s exactly what happens when one eats a diet based on a variety of healthy foods and it’s also how calcium shows up in the food supply; present in varying amounts in many different foods.

Its also well understood that certain compounds in foods called anti-nutrients can inhibit the absorption of all minerals, not just calcium; most notably phytates/phytic acid and oxalates/oxalic acid. Mineral deficiencies are commonly seen in macrobiotic and grain-heavy diets. It will also likely be the case for those following the new diet fad [new in terms of human history], raw veganism.

While it's true that these anti-nutrients and excessive amounts of sodium, inorganic phosphate, caffeine, alcohol and protein may lead to increased calcium losses possibly increasing the risk for osteoporosis, it’s important to temper any messages surrounding this with much needed context. Excess needs to be clearly defined. In practical terms, current general healthy eating guidelines ensure that excesses of sodium, inorganic phosphate, caffeine, alcohol and protein are avoided. The caffeine in a latte will not interfere with the absorption of calcium from the milk. More importantly, calcium balance studies using radio isotopes of calcium have shown this. Regarding anti-nutrients in whole grains, legumes and vegetables, cooking will greatly reduce the negative impact on mineral absorption.

When it comes to preventing osteoporosis, general healthy eating need only be bolstered with adequate amounts of calcium, vitamin D, magnesium, and vitamin K2  if needed. To reiterate, most will need extra magnesium, vitamin D and K2. The other critical factor is weight bearing exercise.

Getting enough calcium

Meeting one’s calcium requirements with food is much easier than you think. Assuming you includes a variety of different foods that are minimally processed, you’ll be getting around 300 mg without even trying. Add a couple of servings of calcium-rich foods and you’re off to the races. To suggest that supplements are absolutely needed is biased and unfounded.

If supplements are needed, I just recommend good old calcium carbonate; in fact dialysis units routinely use Tums, or the generic equivalent, to adequately manage patients' calcium levels all the time – no need for fancy calcium supplements. Tums Extra Strength will have 300 mg of caclium, Tums Extra 400 mg.

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