Home Ingredients CAS (Calcified Atlantic Seaweed Calcium)
Bone Health

CAS (Calcified Atlantic Seaweed Calcium)

Lithothamnion calcareum
Evidence Level
Strong
1 Clinical Trial
3 Documented Benefits
4/5 Evidence Score

CAS is a plant-source calcium from calcified Atlantic red seaweed (Lithothamnion), naturally rich in calcium, magnesium, and 70-plus trace minerals. This marine multimineral supports bone health from a whole-food source.

Studied Dose Commonly 500 to 1200 mg of elemental calcium per day.
Active Compound Calcium (often with vitamin D and trace minerals for bone support).

Benefits

Bone strength

Calcium is the main structural mineral of bone; with vitamin D, supplementation supports bone mineral density and reduces bone loss.

Supported by Trial 1

Bone maintenance with age

Adequate calcium intake is essential throughout life to maintain a strong skeleton and reduce age-related bone loss.

Supported by Trial 1

Muscle and nerve support

Calcium also supports normal muscle contraction and nerve signaling.

Supported by Trial 1

Mechanism of action

1

Bone mineralization

Calcium combines with phosphate to form the hydroxyapatite crystals that give bone its hardness and strength.

2

Calcium homeostasis

The body tightly regulates blood calcium; adequate intake spares calcium from being drawn out of bone.

Clinical trials

1
Calcium and Vitamin D for Bone — Meta-Analysis
PubMed

Systematic review and meta-analysis of combined calcium and vitamin D supplementation on bone in postmenopausal women. (Liu et al. 2020, Food and Function)

Postmenopausal women across trials.

Combined calcium and vitamin D supported bone mineral density and reduced bone loss versus control.

Side effects and drug interactions

Common Potential side effects

Constipation, gas, or bloating can occur.
Take in divided doses (500 mg or less at a time) for best absorption.
Very high intake may raise kidney-stone risk in susceptible people.

Important Drug interactions

Antibiotics (tetracyclines, quinolones), thyroid medication, and bisphosphonates — separate by 2 to 4 hours.
Thiazide diuretics — monitor calcium levels.
Tell your doctor about all medications and your total calcium intake.

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Frequently asked questions about CAS (Calcified Atlantic Seaweed Calcium)

What is CAS?

CAS is a plant-source calcium from calcified Atlantic red seaweed (Lithothamnion), naturally rich in calcium, magnesium, and 70-plus trace minerals. This marine multimineral supports bone health from a whole-food source.

What is CAS used for?

CAS is researched primarily for Bone Health. Calcium is the main structural mineral of bone; with vitamin D, supplementation supports bone mineral density and reduces bone loss.

What is the recommended dosage of CAS?

The clinically studied dose is Commonly 500 to 1200 mg of elemental calcium per day. Always follow the product label and check with a healthcare provider for personal advice.

Is CAS safe, and does it have side effects?

For most healthy adults, CAS is well tolerated at studied doses. Reported effects can include: Constipation, gas, or bloating can occur. Take in divided doses (500 mg or less at a time) for best absorption. It may also interact with some medications. CAS is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does CAS interact with any medications?

Possible interactions include: Antibiotics (tetracyclines, quinolones), thyroid medication, and bisphosphonates — separate by 2 to 4 hours. Thiazide diuretics — monitor calcium levels. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for CAS?

NutraSmarts rates the evidence for CAS as Strong (4 out of 5). It is backed by 1 clinical trial and 1 cited reference summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(1 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Liu C, Kuang X, Li K, et al. Effects of combined calcium and vitamin D supplementation on osteoporosis in postmenopausal women: a systematic review and meta-analysis of randomized controlled trials. Food Funct. 2020;11(12):10817-10827..PubMedUsed to support: Meta-analysis supporting bone benefit of calcium (the mineral in this branded calcium).