Anything in excess is harmful to your health even if it is a calcium supplement or foods rich in calcium that you need to boost bone health. According to the Indian Dietetic Association, an average Indian adult requires approximately 1000 to 1300 mg and 1500 to 1800 mg of calcium per day for pregnant women and lactating mothers. If you exceed that amount, of course, your body will react in one way or the other. The most common side-effect of going overboard with calcium either through food or supplements is the formation of kidney stones.
Can calcium rich diets increase risk of kidney stones?
There are various studies done to establish the link between kidney stones and calcium intake, however, most of them have been inconclusive till date. There are a lot of incidences where we see people who are on a high calcium supplementation or have a high intake of calcium through diet, suffering from kidney stones. However, it is not the calcium alone that needs to be blamed; these people also have a low intake of water and other essential minerals that might lead to an excess of calcium in the body and hence stone formation in kidneys, says renowned dietician Niti Desai, Cumbala Hills Hospital, Mumbai.
Some studies pointed out that low calcium intake can in fact increase one s risk of forming first kidney stones [1]. Calcium is an important mineral for the body; low calcium intake can, in fact, increase one s chances of forming kidney stones and deteriorate bone health. But for people who have a tendency to form stones more than once, they are asked to follow some generic precautions like limit calcium intake and increase water intake, among other things, says Dr Anup Ramani, Uro-Oncological & Robotic Surgeon, Lilavati, Breach Candy, Saifee Hospital. The same study also suggested that urinary calcium increases the risk of kidney stone formation, especially in stone-formers (people who form stones more than once). However, avoiding dietary calcium isn t advisable even for stone-formers [1]. Even for people who are under treatment for kidney stone, having dietary calcium in moderation is fine, says Dr Ramani. Calcium supplementation, in this case, should be avoided or discussed with the doctor before taking them. People with kidney stones can have diary products in moderation.
Another hypothesis is that women who are given calcium supplements to prevent osteoporosis post menopause are at greater risk of developing kidney stones. However, a study published in Journal of American Nutrition in 2008 showed that there is an inverse relationship between calcium intake (either through diet or supplementation) and kidney stone formation [2]. Even though the studies say otherwise, experts still believe that going slow with calcium especially for people who have experienced stone more than once is better.
Can calcium rich diets increase risk of cardiovascular diseases?
There are also studies that claim excess calcium can lead to calcification of arteries and increase the risk of cardiovascular diseases. However, recent studies have also pointed out that there is no relation between calcium intake and heart health. A study published in journal Osteoporosis International showed that after 24 years of follow-up, the risk of cardiovascular disease in women who took calcium supplements and those who didn t was marginal [3]. Another hypothesis was that having calcium supplementation without Vitamin D could lead to the same. However, this claim was also dismissed after another study showed that calcium supplementation with or without Vitamin D didn t affect the heart health of elderly women who are advised supplementation post menopause. This is not to say you don t need vitamin D for calcium absorption [4]. Adequate vitamin D is necessary to help the body absorb calcium for proper functioning, informs Niti.
The take home message
In a nutshell, there are no studies that can conclusively say that excess calcium could be a risk. What experts are worried at the moment is not an excess of calcium intake but meeting the daily calcium requirements. We Indians, lack adequate calcium in our diet and the dangers of going overboard with calcium is not the concern at the moment. In fact, we encourage people to eat calcium rich foods or put them on supplementation to meet the basic needs. There are very fewer chances for people to go overboard with calcium through diet unless you drink say more than one litre of milk a day, says Niti Desai. Also, choosing the right sources of calcium through diet is important. A glass of buffalo milk has 300 mg of calcium while cow s milk has half of it; two servings of pulses and green leafy vegetables can give you 150 to 200 mg of calcium. So it is necessary to chart out your calcium intake if you depend on it solely from diet sources, concludes Niti Desai. However, if your doctor has put you on supplementation, check on your intake every two months to know you are not going overboard with it.
References:
1: Heller HJ. The role of calcium in the prevention of kidney stones. J Am Coll Nutr. 1999 Oct;18(5 Suppl):373S-378S. Review. PubMed PMID: 10511317.
1: Heaney RP. Calcium supplementation and incident kidney stone risk: a systematic review. J Am Coll Nutr. 2008 Oct;27(5):519-27. Review. PubMed PMID:18845701.
1: Paik JM, Curhan GC, Sun Q, Rexrode KM, Manson JE, Rimm EB, Taylor EN. Calcium supplement intake and risk of cardiovascular disease in women. Osteoporos Int. 2014 Aug;25(8):2047-56. doi: 10.1007/s00198-014-2732-3. Epub 2014 May 7. PubMed PMID: 24803331; PubMed Central PMCID: PMC4102630.
1: Lewis JR, Radavelli-Bagatini S, Rejnmark L, Chen JS, Simpson JM, Lappe JM,Mosekilde L, Prentice RL, Prince RL. The effects of calcium supplementation on verified coronary heart disease hospitalization and death in postmenopausal women: a collaborative meta-analysis of randomized controlled trials. J Bone Miner Res. 2015 Jan;30(1):165-75. doi: 10.1002/jbmr.2311. Review. PubMed PMID:25042841.
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