"Doctor, this seaweed calcium is much better, isn't it?" I hear that almost every week

Last week, Marisa, 58 years old, arrived at the consultation with a bottle of supplement in her bag before I even asked how she was doing.

"Doctor, I bought this seaweed calcium. The shop assistant said it's 100% natural, much better absorbed than regular calcium. It's worth double the price, but she guaranteed it's worth it."

I took the bottle, read the label and asked the question I always ask in these moments:

"Who told you that? Was it a doctor or was it the shop assistant?"

Silence.

And that's exactly what I want to talk about today, because Lithothamnium calcareum is not a scam, it's not poison, it's not a miracle, but it's also not what they're selling to you. And I, as a doctor who sees this type of situation practically every week, feel I need to put this conversation back on the right track.

The data and clinical case cited in this article are fictitious and are for illustrative purposes only, serving to facilitate understanding of the topic addressed.

What exactly is this seaweed

Lithothamnium calcareum is a red marine alga that lives in the freezing waters of the North Atlantic. When it dies, what's left is a skeleton full of minerals, mainly calcium, magnesium and traces of zinc, manganese, selenium, boron and copper. This skeleton is ground up and becomes the powder, or the capsule, that you see on the pharmacy shelf.

Up to this point, in my view, there's no problem. It's a real source of calcium, of natural origin. What bothers me comes next, in the way this product is sold to you.

Is Lithothamnium calcareum better than regular calcium?

In my assessment, honestly, no.

I know this answer bothers anyone who's already spent money thinking they were taking home premium calcium. But, from what science shows us so far, this superiority simply doesn't hold up.

Yes, Lithothamnium has a more varied mineral composition than traditional calcium carbonate or citrate. But in clinical practice, the heavy lifting is still done by calcium itself, and there are no robust studies showing that it's absorbed better or that it brings superior benefits in healthy people.

Translating it the way I like to explain it: the pretty label doesn't change your body's physiology.

So why does everyone speak so highly of it?

In my opinion, it has a name: marketing.

"Organic calcium." "100% natural." "Much better absorbed." "Much better than regular calcium." These are catchy phrases meant to sell, not phrases based on evidence. And here's a maxim I repeat quite often with my patients: natural is not synonymous with effective. Hemlock is also natural, and that doesn't mean I'd recommend it to anyone.

Who can really benefit

This doesn't mean the supplement is useless, far from it. It can make sense for people with low calcium intake in their diet, for people with osteopenia or osteoporosis as part of a treatment guided by a doctor, and for postmenopausal women and elderly people, who have increased calcium needs.

But, in my view, this applies to any well-indicated calcium supplement, it's not exclusive to seaweed.

And who needs to be extra careful

Not every body reacts well to more calcium, and that's something I always emphasise. Special attention is worth paying if you have a history of calcium kidney stones, elevated calcium in your blood, advanced chronic kidney disease, or any condition that affects calcium metabolism.

And a detail that few people know about, and which I consider essential: calcium can interfere with the absorption of medicines like thyroid hormone and some antibiotics, when taken together.

"But it's natural, there's no risk, right?"

There is, and that's what I try to make clear whenever someone asks me.

Excess calcium, from any source, seaweed included, can cause constipation, abdominal discomfort, increased risk of kidney stones in those already predisposed, and in more serious cases, hypercalcemia.

The way I usually put it: more calcium is not synonymous with more health, it's synonymous with more calcium, and the body doesn't cope well with excess of anything.

So is it worth spending more on this seaweed?

In my opinion, it depends much more on your individual context than on what's written on the label.

If your diet already covers your daily calcium needs, you probably won't notice any difference at all, you'll just feel the weight on your wallet. Now, if you have a real deficiency or increased need, Lithothamnium can indeed be an interesting option. It's just not, in my assessment, the only "real" option like the market insists on making it seem.

How I would explain it to my patients:

Strong bones aren't built with a miracle capsule. They're built with adequate calcium, vitamin D up to date, sufficient protein in your diet, impact exercise and weight training, and genuine medical follow-up.

And that's what I want you to take from here: no supplement does this work on its own, not this one, not any other.

What I think, in summary

Lithothamnium calcareum is a legitimate source of marine calcium and can, yes, have its place in specific situations. But to date, in my reading of the available evidence, there's nothing of quality that proves it's superior to traditional calcium supplements.

Before paying more because of a pretty label, talk to your doctor. In my experience, a balanced diet solves, in most cases, what no capsule can solve on its own.

This content is informative in nature and does not replace individualised medical consultation, diagnosis or treatment. Always seek professional guidance before starting any supplementation.

Dr. Rebeca Soares Andrade CRM- GO 39335