Health Guide

Limestone

You might be surprised to see 'Limestone' on a health guide, but you likely consume it regularly without knowing! Limestone is a sedimentary rock composed primarily of **Calcium Carbonate**. In the nutritional world, we refer to this as **Calcium**. It is the most abundant mineral in the human body. While we don't eat rocks, we consume the purified mineral extracted from them (often found in supplements or fortified foods) to build strong bones, teeth, and ensure our muscles and nerves fire correctly. Think of it as the 'cement' that holds your body's structure together.

Evidence BasedDietary Supplement

VERIFIED SOURCE

Bio-Activity Analysis

Calcium Absorption Efficiency

SCIENTIFIC DATA VISUALIZATION

Y-Axis

Absorption Rate (%)

Intake Amount →

Health Benefits & Sources

Why You Need It

Strong Bones & Teeth: It is the primary building block for your skeletal system.
Heart Rhythm: Helps regulate the pumping of your heart.
Nerve Signaling: Essential for transmitting messages between your brain and body.
Muscle Contraction: Required for muscles to contract and relax properly.

Deep Dive

Calcium is not just about density; it is dynamic. About 99% of the calcium in your body resides in your bones and teeth, acting as a reserve bank. The remaining 1%, found in your blood and soft tissues, is critically active. It acts as a 'gatekeeper' for your cells. When a nerve needs to fire, calcium rushes in; when a muscle needs to contract, calcium triggers it. Without enough dietary calcium (from limestone/calcium carbonate), your body will 'withdraw' calcium from your bones to keep your blood levels stable, leading to osteopenia or osteoporosis over time.

Natural Food Sources

While we often think of dairy, many plant-based sources are excellent. Note that plant sources contain 'non-heme' calcium, which may be absorbed differently.

Food	Amount	% DV (Based on 1000mg)
Fortified Orange Juice	1 cup	30%
Plain Yogurt	1 cup	23%
Collard Greens (cooked)	1 cup	27%
Canned Salmon (with bones)	3 oz	21%
Tofu (calcium-set)	3.5 oz	20%

Supplementation

Dosage: The RDA (Recommended Dietary Allowance) is generally 1000mg for adult women up to age 50 and men up to age 70.

Who Should Take It:

Post-menopausal women (risk of bone loss increases).
Vegans who avoid dairy and fortified foods.
Individuals with lactose intolerance.
Those on long-term corticosteroid medication.

Top Food Sources

Dairy (Yogurt/Milk)

Best absorbed form (Lactose helps)

Bone-in Fish (Sardines)

Provides Calcium + Vitamin D

Fortified Plant Milks

Equal to cow's milk if fortified

Cruciferous Veggies

Cooked kale/broccoli

Limestone (Supplement)

Calcium Carbonate (40% elemental Ca)

Frequently Asked Questions

Chemically, Limestone is Calcium Carbonate. In nutrition, we process this rock into a purified form to provide Calcium. So, yes, it is the natural source of the mineral Calcium.

Yes. Calcium carbonate (derived from limestone) requires stomach acid for absorption. Taking it with a meal significantly improves how much your body actually utilizes.

Calcium is an alkaline mineral. When it isn't fully absorbed, it can interact with fatty acids in your gut, forming 'soap,' which makes stools harder and slower to move through the intestines.

It can be. While spinach is high in calcium, it is also high in oxalates which block absorption. Better plant sources include kale, broccoli, tofu, and fortified plant milks.

Safety & Side Effects

Side Effects: Generally safe at recommended doses. High doses (over 2000mg/day) can cause bloating, gas, and constipation. It may also increase the risk of kidney stones in susceptible individuals.

Interactions: Calcium can interfere with the absorption of certain antibiotics (tetracyclines) and iron supplements. Take these 2-4 hours apart.

Who Should Avoid:

People with hypercalcemia (high blood calcium levels).
Those with a history of kidney stones (specifically calcium-oxalate stones).
Anyone with kidney disease or heart conditions using certain medications (like Thiazide diuretics) without doctor supervision.

Scientific References

[1]National Institutes of Health (NIH) Office of Dietary Supplements: Calcium Fact Sheet for Health Professionals.
[2]Weaver, C. M., & Plawecki, K. L. (1994). Dietary Calcium: Adequacy of a Vegetarian Diet. The American Journal of Clinical Nutrition.
[3]Bristow, S. M., & Gamble, G. D. (2015). Acute and 3-month effects of calcium carbonate on bone turnover markers in postmenopausal women.
[4]Cormick, G., & Belizán, J. M. (2019). Calcium Intake and Health. Nutrients.