Comments on: Calcium https://veganhealth.org/calcium-part-2/ Evidence-Based Nutrient Recommendations Wed, 08 Apr 2026 00:12:23 +0000 hourly 1 https://wordpress.org/?v=6.9.4 By: JackNorrisRD https://veganhealth.org/calcium-part-2/#comment-5645 Wed, 21 Jan 2026 23:31:41 +0000 https://veganhealth.org/?page_id=869#comment-5645 In reply to Mike.

Mike,
It’s because the research on calcium and health is only based on calcium from food. You can assume calcium from tapwater is “a wash.” In other words, if research shows people need 750 mg of calcium from food, but it’s really 750 mg from food + 60 mg from tap water, then the resulting recommendations would be for a total of 810 mg. But if you know that your tapwater is higher than average, then factoring in the amount above average as part of your daily intake seems reasonable to me.

]]> By: Mike https://veganhealth.org/calcium-part-2/#comment-5640 Thu, 15 Jan 2026 00:54:55 +0000 https://veganhealth.org/?page_id=869#comment-5640 I’m curious why tap water isn’t discussed as a significant source of dietary calcium. Chicago states their tap water has 130 to 150 mg/L of calcium carbonate. Two liters of tap water a day would be 260-300 mg/day of calcium.

https://311.chicago.gov/s/article/What-is-hardness-and-how-many-grains-per-gallon-GPG-are-in-the-city-s-water?language=en_US

]]> By: JackNorrisRD https://veganhealth.org/calcium-part-2/#comment-5582 Wed, 17 Sep 2025 17:09:11 +0000 https://veganhealth.org/?page_id=869#comment-5582 In reply to Kevin.

Kevin,
Unless someone has iron deficiency (in which case they shouldn’t take a calcium supplement with an iron supplement), it probably doesn’t make a lot of difference. It’s best not to take calcium and zinc supplements at the same time.

]]> By: Kevin https://veganhealth.org/calcium-part-2/#comment-5581 Mon, 15 Sep 2025 20:38:57 +0000 https://veganhealth.org/?page_id=869#comment-5581 Hello,
What’s your thoughts on the idea that calcium supplements can inhibit the absorption of iron and zinc? Is that not significant in some way? Do you think calcium should be spaced out from iron and zinc?

]]> By: JackNorrisRD https://veganhealth.org/calcium-part-2/#comment-5537 Fri, 18 Apr 2025 17:02:05 +0000 https://veganhealth.org/?page_id=869#comment-5537 In reply to TZ.

TZ,

Koeder and Perez-Cueto cite Weaver and Plawecki (1994) who compare the difference between calcium absorption from sesame seeds and nonfat dry milk in rats to humans. Since it’s not a direct measurement of calcium absorption in humans, I don’t consider it reliable.

]]> By: TZ https://veganhealth.org/calcium-part-2/#comment-5536 Fri, 18 Apr 2025 11:40:35 +0000 https://veganhealth.org/?page_id=869#comment-5536 In reply to JackNorrisRD.

Hi. I’ve found information about bioavailability of calcium from food. Sesame seeds included (~20% absorption rate).
https://doi.org/10.1080/10408398.2022.2107997

]]> By: JackNorrisRD https://veganhealth.org/calcium-part-2/#comment-5527 Tue, 18 Mar 2025 03:16:41 +0000 https://veganhealth.org/?page_id=869#comment-5527 In reply to Francis.

Francis,

I’d never heard of calcium carbonate nanoparticles until now. I did a quick search using AI and found this:

While research on the long-term effects of calcium carbonate nano- and microparticles in supplements is ongoing, studies suggest that they are generally considered safe and well-tolerated, with minimal evidence of significant harm.

Safety and Tolerability:

Calcium carbonate, a common form of calcium supplement, is generally considered safe for most people when taken in recommended dosages.

Some studies even suggest that calcium carbonate microparticles may reduce gastrointestinal side effects compared to conventional calcium supplements.

The viability of cells was not negatively affected by calcium carbonate nanoparticles, and in some cases, even showed a stimulative effect on cell viability.

]]> By: Francis https://veganhealth.org/calcium-part-2/#comment-5525 Sun, 16 Mar 2025 21:59:48 +0000 https://veganhealth.org/?page_id=869#comment-5525 hi, i’m a new vegan but if i scan the barcode of fortified plant milks with the Yuka app, it gives a warning about calcium carbonate (with more detail if you then click on “learn more”); it explains that calcium carbonate contains calcium nanoparticles that can penetrate biological barriers (so i assume they can also cross the bbb or blood-brain barrier) and therefore accumulate at cellular levels and we don’t know the long term effects of this. what do you think? are you familiar with this issue? it concerns me. on paper, it is the only downside of a well-planned vegan diet that i know of.

]]> By: JackNorrisRD https://veganhealth.org/calcium-part-2/#comment-5516 Sun, 08 Dec 2024 00:17:51 +0000 https://veganhealth.org/?page_id=869#comment-5516 In reply to Suzy.

Suzy,
The WHO’s calcium recommendations are basically the same as the United States DRI, which is 1,000 mg from adults 19 to 50 years old. The DRIs assume an absorption rate from foods of 25%. So, to answer your question, the recommendations are for total calcium rather than bioavailable calcium and they assume that people are getting an average amount of absorbable calcium.

]]> By: Suzy https://veganhealth.org/calcium-part-2/#comment-5515 Sat, 07 Dec 2024 17:06:39 +0000 https://veganhealth.org/?page_id=869#comment-5515 hi! I’ve got a question about something I would like to confirm with you because I’m not sure i understood you or not. If for instance the recommended amount of calcium is 500mg (WHO), does it mean we need 500mg of bioavailable calcium or 500mg of calcium no matter its absorbability?

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