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One of the best, cheapest, and most bioavailable sources of calcium is eggshells. Yes, plain old eggshells. From homemade toothpaste, to a calcium-fortified smoothie, to a highly-bioavailable, bone-building supplement for you, your pets, and your vegetable garden—learning how to make eggshell calcium powder has many benefits.
- The Benefits of Eggshells
- The Importance of Calcium
- Eggshell Calcium Powder
- How to Use Eggshell Powder
- How Long Will Eggshell Powder Last?
The Benefits of Eggshells
Eggshells are made almost entirely of calcium carbonate, which is exactly what makes up most of our nails, teeth, and bones. They’re also loaded with collagen protein, magnesium, selenium, strontium, and other nutritious compounds that are very good for your bones and joints.
Additionally, eggshell calcium is a very digestible, bioavailable form of calcium, because it comes from food. In fact, a study found that calcium absorption was up to 64% greater from eggshell powder compared to the calcium found in most commercial calcium supplements.
And using your eggshells makes good use of what is normally thrown in the trash or compost. Simply save your old shells (put them in the refrigerator or freezer until you have enough saved up), and you can help cut down on food waste in your kitchen.
The Importance of Calcium
Calcium is the most abundant mineral in the body. While most of our calcium can be found stored in our bones and teeth, it’s also vital for muscle contraction, heart health, nerve health, enzyme activity, and cell formation.
In fact, humans need large amounts of calcium every day to remain healthy—a minimum of 1000-1500mg. But if we don’t get enough, the body has no problem taking what it needs from storage in our teeth and bones. And when the body has to tap its calcium storage too often, we can end up with health problems like tooth decay or osteoporosis.
Our pets and livestock need calcium, too, to remain healthy. Unfortunately, processed commercial feed often cannot provide the amount of calcium required for healthy teeth, shiny coats or strong eggshells.
And finally, all of the calcium in our food (and our pets’ food) comes from the calcium present in the soil. Calcium is one of the earth’s most abundant minerals, but it can become depleted over time in our gardens and farm fields, so our gardens sometimes need extra calcium, too.
If you feel you or your pets cannot get all the calcium you need from your diet, or if your soil test indicates you need extra calcium in your garden, you can buy ready-made eggshell calcium online, or you can make it yourself for free, using eggshells from your kitchen.
Better Eggs Make Better Calcium Powder
It goes without saying that the healthier a hen is, the healthier her eggs will be. Eggs from hens that are raised on pastures where they are able to get lots of fresh air and Vitamin D from the sun, and forage for a diversity of greens, grubs, and bugs are more nutritious than conventional eggs. Their shells contain more nutrients, too.
For best results, if you can get access to them, make eggshell calcium using shells from hens that are pasture-raised and on organic feed.
Here’s how to make eggshell calcium powder…
Eggshell Calcium Powder
- Coffee grinder spice grinder or mortar and pestle
- Large pot
- Rinse any remaining egg white out of your eggshells as you use them, leaving the membrane. (It's nutritious.) Set shells aside in the fridge or freezer until you have at least a dozen.
- Fill a large pot with 6 cups of filtered water and bring to a boil.
- Carefully put your eggshells into the water, and boil them for 10 minutes. (This will kill any harmful pathogens.) Skim off any white foam that forms.
- Drain the eggshells by spreading them upside down on a cooling rack or a towel-lined stainless steel baking sheet, and let them dry overnight.
- In the morning, put the eggshells in a 200 degree (Fahrenheit) oven for about 10-15 minutes to completely dry them out. Keep an eye on them: You want to just dry them, not bake them.
- Once fully dry, allow to cool for at least 30 minutes.
- Put a few shells into your coffee grinder and grind them until they are pulverized into a fine powder. Continue until all of your shells are powdered.
- Sift the powder through a sieve to remove any larger pieces.
- Store in a tightly sealed jar in the cupboard, away from heat and moisture, for up to a year.
How to Use Eggshell Powder
Eggshell Powder as a Calcium Supplement
Calcium deficiency is a problem worldwide. If you are on a restricted diet due to allergies, health concerns or spiritual beliefs, taking certain medications, or just hate eating green vegetables every day, you are probably not getting enough calcium from your diet.
The truth is, hip fracture due to osteoporosis is one of the leading causes of death in people over 50, so clearly many of us are not getting enough calcium from our meals alone.
The good news is that powdered chicken eggshell contains approximately 380 mg of calcium per gram, so about 2.5 grams of powdered eggshell—about 1 teaspoon—is enough to meet the minimum daily calcium requirements for an average adult.
This makes eggshells an excellent, affordable source of whole food calcium to add to your diet. In fact, a recent study found that calcium absorption was up to 64% greater from eggshell powder compared to the calcium carbonate found in calcium supplement pills—so save your money and make your own.
You can then add your free eggshell calcium to food or mix it with water, smoothie or juice. Because it can be a bit gritty, even when finely pulverized, some of the best foods to add eggshell powder to are bread and baked goods, spaghetti, and breaded, fried meat.
If you really don’t care for the texture, you can put finely powdered eggshell calcium into empty capsules and swallow them whole, like any other supplement.
When measuring your capsules, remember that one teaspoon (or about 2.5 g) of powdered eggshell contains approximately 800-1,000mg of calcium, which is the minimum daily requirement for adults.
Eggshell Powder for Pets
Powdered eggshell calcium can be a beneficial calcium supplement for dogs, cats, rabbits, and other pets, too. Calcium supplements are especially important for animals on raw diets to help balance excess phosphorus.
To give it to pets, simply sprinkle a bit of eggshell powder over their food. Talk to your vet about whether calcium supplementation would benefit your specific pet, and how much you should give them.
Eggshell Powder for Chickens
Egg laying hens need a sufficient amount of calcium in order to produce healthy eggs. Normally chickens get calcium from foraging greens and eating bugs and small animals. But most hens don’t get to range on diverse, open pasture, and often subsist on a vegetarian diet of low-calcium grains.
Therefore, most people who raise chickens need to give them supplemental calcium to keep them healthy and productive. In fact, a chicken pecking at their own eggs is often a sign of calcium deficiency. What better way to help them than to give them back their own shells!
Give coarsely ground eggshells to chickens in a bowl separate from their regular feed, or in a small pile in their coop. That way, if they need it, they can take it. If they don’t, they will leave it alone.
Eggshell Powder in Toothpaste
You will need to grind your eggshell powder is as fine as possible if you want to use it for cosmetic purposes—until it is silky, like chalk. This might require using a mortar and pestle. Then you can use this ultra-fine eggshell calcium in any homemade toothpaste recipe.
Eggshell Powder for the Garden
Calcium is one of the most abundant minerals in the soil and absolutely vital for plant growth, but it can be depleted over many seasons of producing food and flowers. Have your soil tested to assess your calcium levels, and amend as indicated by the results.
Finely ground eggshell calcium can be a great early spring amendment to your garden soil, especially for preventing blossom end rot in your tomatoes, peppers and squash. You can also use eggshell calcium in lieu of powdered lime if you need added calcium without raising the soil pH.
The finer you grind your shells, the faster the calcium can break down and make a difference in your garden. Work eggshell powder deep into the soil in the fall or early spring to give it enough time to become bioavailable to your plants.
Eggshell calcium added to your potting soil mix can help you start healthy, strong seedlings, too.
How Long Will Eggshell Powder Last?
As long as the eggshells are completely dry and kept in a cool, airtight container, eggshell powder will last a year or more. You can put food-grade silica desiccation packets (maybe from your old calcium supplement bottles?!) into your jar to help absorb moisture during long-term storage.