Can You Eat Egg Shells? Benefits, Risks, and How to Use Them Safely

If you’ve ever wondered whether those eggshells you throw away could actually be beneficial to your health, you’re not alone. Many people are curious about the safety and potential benefits of consuming eggshells. The short answer is yes, you can eat eggshells—and they might even offer some impressive health benefits when prepared correctly.

Eggshells are an incredibly affordable and natural source of calcium, making them an attractive option for people looking to boost their mineral intake without spending money on expensive supplements. With growing interest in sustainable living and reducing food waste, using eggshells as a dietary supplement has gained significant attention in recent years.

This comprehensive guide will explore everything you need to know about eating eggshells, including their nutritional composition, potential health benefits, safety concerns, and practical tips for preparing them at home.

What Are Eggshells Made Of?

Eggshells are the hard, protective outer layer of eggs. While they might seem simple, they have a complex composition that makes them particularly valuable as a calcium source.

The primary component of eggshells is calcium carbonate, which accounts for approximately 95% of their composition. This is the same compound found in limestone, marble, and seashells. Calcium carbonate is one of the most common and bioavailable forms of calcium used in dietary supplements.

The remaining 5% consists of various proteins, including collagen, and trace amounts of other essential minerals such as:

• Magnesium
• Phosphorus
• Strontium
• Fluoride
• Selenium
• Iron
• Zinc

These minerals work synergistically with calcium to support various bodily functions, particularly bone health. The protein content in eggshells may also enhance calcium absorption, making them potentially more effective than isolated calcium supplements.

Nutritional Value and Calcium Content

One of the most impressive aspects of eggshells is their exceptionally high calcium content. Understanding just how much calcium eggshells provide can help you determine whether they might be a useful addition to your diet.

Eggshells are composed of approximately 40% elemental calcium by weight. This means that each gram of eggshell powder provides between 380-400 mg of calcium. To put this in perspective, just half a medium eggshell can provide around 1,000 mg of calcium—the entire recommended daily intake for most adults.

The recommended dietary allowance (RDA) for calcium varies by age and gender:

• Adults aged 19-50: 1,000 mg per day
• Women over 50: 1,200 mg per day
• Men over 70: 1,200 mg per day
• Pregnant and breastfeeding women: 1,000 mg per day

This makes eggshells one of the most concentrated natural sources of calcium available, rivaling or even exceeding traditional calcium-rich foods like dairy products.

Health Benefits of Eating Eggshells

Supports Strong Bones and Teeth

Calcium is the primary mineral responsible for building and maintaining strong bones and teeth. Adequate calcium intake throughout life is essential for achieving peak bone mass during youth and preventing bone loss as we age.

Research has shown that eggshell powder can be as effective as commercial calcium supplements in supporting bone health. The calcium from eggshells is readily absorbed by the body, making it an excellent option for people who need to increase their calcium intake.

May Help Prevent Osteoporosis

Osteoporosis is a condition characterized by weak, brittle bones that are prone to fractures. It affects millions of people worldwide, particularly postmenopausal women and older adults.

Studies have demonstrated that eggshell supplementation may help reduce the risk of osteoporosis and improve bone mineral density in people already diagnosed with the condition. When combined with adequate vitamin D and other bone-supporting nutrients, eggshell powder has shown promising results in strengthening bones.

Research involving postmenopausal women with osteoporosis found that those who took eggshell powder along with vitamin D3 and magnesium experienced significant improvements in bone mineral density compared to those who didn’t supplement.

Cost-Effective Calcium Source

For individuals who struggle to meet their calcium needs through diet alone—whether due to lactose intolerance, vegan diets, food allergies, or limited food access—eggshells offer an extremely affordable alternative to commercial supplements.

Rather than purchasing expensive calcium tablets, you can create your own supplement at home using eggshells that would otherwise be discarded, making this option both economical and environmentally friendly.

Environmentally Sustainable

Using eggshells as a supplement is an excellent way to reduce kitchen waste and practice sustainability. Americans discard millions of pounds of eggshells annually, and repurposing them for health benefits aligns with zero-waste living principles.

Potential Joint Health Benefits

The eggshell membrane—the thin layer between the shell and the egg white—contains compounds that may support joint health. This membrane is rich in collagen, glucosamine, chondroitin sulfate, and hyaluronic acid, all of which are known to support cartilage and connective tissue.

While the amounts of these compounds in homemade eggshell powder are relatively small, some research suggests that regular consumption of eggshell membrane may help reduce joint pain and stiffness in people with conditions like osteoarthritis.

Potential Risks and Safety Concerns

While eggshells can be a beneficial supplement when properly prepared, there are several important safety considerations to keep in mind.

Risk of Bacterial Contamination

The most significant concern with consuming eggshells is the risk of bacterial contamination, particularly from Salmonella bacteria. Raw eggs and their shells can harbor harmful bacteria that cause foodborne illness.

Symptoms of Salmonella infection include:

• Diarrhea
• Fever
• Abdominal cramps
• Nausea and vomiting

To eliminate this risk, it’s crucial to properly sanitize eggshells before consuming them. Boiling is the most effective method for killing harmful bacteria.

Risk of Physical Injury

Sharp eggshell fragments can potentially cut or scrape the mouth, throat, or esophagus if not properly ground into a fine powder. Never attempt to eat large pieces of eggshell.

Always grind eggshells into a very fine powder before consumption to prevent any risk of injury to your digestive tract.

Heavy Metal Content

Natural calcium sources, including eggshells, may contain trace amounts of heavy metals such as lead, aluminum, cadmium, and mercury. However, studies have shown that eggshells typically contain lower levels of these toxic elements compared to other natural calcium sources like oyster shells.

The heavy metal content in eggshells is generally considered safe and not a significant health concern when consumed in recommended amounts.

Excessive Calcium Intake

While calcium is essential for health, consuming too much can lead to adverse effects, including:

• Kidney stones
• Constipation
• Interference with the absorption of other minerals like iron and zinc
• Potential cardiovascular concerns (though research is mixed)

The tolerable upper intake level for calcium is 2,500 mg per day for adults up to age 50, and 2,000 mg per day for those over 50. Avoid exceeding these limits from all sources combined.

How to Prepare Eggshell Powder at Home

Making your own eggshell powder is simple, inexpensive, and allows you to create a natural calcium supplement in your own kitchen. Follow these steps for safe preparation:

Step 1: Collect and Clean the Eggshells

Save eggshells from eggs you’ve used for cooking. Rinse them thoroughly under running water to remove any remaining egg white or residue. You can collect shells over several days, storing them in the refrigerator until you have enough to process.

Step 2: Boil the Eggshells

Place the cleaned eggshells in a pot of water and bring to a boil. Boil for at least 10 minutes to kill any bacteria, including Salmonella. This is the most critical step for ensuring safety.

Step 3: Dry the Eggshells

After boiling, drain the eggshells and spread them on a baking sheet. You can either:

• Air-dry them for several hours or overnight
• Bake them in the oven at 200°F (93°C) for about 10-15 minutes to speed up the drying process

Ensure the shells are completely dry before grinding, as this will help them break down more easily into a fine powder.

Step 4: Grind into Fine Powder

Once completely dry, grind the eggshells into a very fine powder using one of these methods:

• Coffee grinder or spice grinder (most effective for achieving fine powder)
• Blender or food processor
• Mortar and pestle (more time-consuming but effective)
• Rolling pin (place shells in a sealed bag and crush)

The powder should be as fine as possible to prevent any sharp edges and ensure easy mixing with food or beverages.

Step 5: Store Properly

Store your eggshell powder in an airtight container in a cool, dry place. Properly stored, it can last for several months. Label the container with the date of preparation.

How to Use Eggshell Powder

Once you’ve prepared your eggshell powder, there are numerous ways to incorporate it into your daily routine:

Mix with Beverages

• Stir into water or juice
• Add to smoothies or protein shakes
• Mix into coffee or tea (the powder is virtually tasteless)

Add to Foods

• Sprinkle over yogurt or oatmeal
• Mix into bread dough or pizza dough
• Add to pasta sauce or soup
• Incorporate into baked goods like muffins or pancakes
• Mix into ground meat for burgers or meatballs

The powder is virtually flavorless when finely ground, so it won’t significantly affect the taste of your food.

Recommended Dosage

A typical serving is approximately half a teaspoon (2-3 grams) of eggshell powder, which provides roughly 800-1,000 mg of calcium. This amount is usually sufficient to meet or significantly contribute to daily calcium requirements.

Start with smaller amounts and gradually increase to assess your tolerance. Remember to account for calcium from other dietary sources to avoid exceeding the recommended upper limit.

Who Should Consider Eggshell Supplements?

Eggshell powder may be particularly beneficial for certain groups of people:

People with Calcium Deficiency

If blood tests reveal low calcium levels or if you have symptoms of deficiency such as muscle cramps, brittle nails, or frequent bone fractures, eggshell powder can help boost your intake.

Individuals with Dietary Restrictions

• People who are lactose intolerant or allergic to dairy products
• Vegans who don’t consume dairy (note: eggs are not vegan, but eggshells don’t contain animal tissue)
• Those with limited access to calcium-rich foods

Postmenopausal Women

Women experience accelerated bone loss after menopause due to decreased estrogen levels, making adequate calcium intake especially important during this life stage.

Older Adults

As people age, calcium absorption decreases and bone loss accelerates, increasing the risk of osteoporosis and fractures.

People with Osteoporosis or Osteopenia

Those diagnosed with low bone density may benefit from additional calcium supplementation as part of a comprehensive bone health strategy.

When to Avoid Eggshell Supplements

Eggshell powder is not appropriate for everyone. Avoid using it if you:

• Have kidney disease or a history of kidney stones (high calcium intake may worsen these conditions)
• Have hypercalcemia (abnormally high blood calcium levels)
• Are taking certain medications that interact with calcium supplements
• Have hyperparathyroidism or other conditions affecting calcium metabolism

Always consult with a healthcare professional before starting any new supplement regimen, especially if you have existing health conditions or take medications.

Eggshell Powder vs. Commercial Calcium Supplements

How does homemade eggshell powder compare to calcium supplements you can buy at the store?

Advantages of Eggshell Powder

• Cost: Virtually free if you already consume eggs
• Purity: No artificial additives, fillers, or preservatives
• Bioavailability: Research suggests the calcium in eggshells may be absorbed as well as or better than purified calcium carbonate
• Additional nutrients: Contains trace minerals and proteins not found in isolated calcium supplements
• Sustainability: Reduces waste and environmental impact

Advantages of Commercial Supplements

• Convenience: Pre-measured doses in tablet or capsule form
• Standardization: Guaranteed calcium content per serving
• Additional nutrients: Often combined with vitamin D, magnesium, or other bone-supporting nutrients
• Quality control: Manufactured under regulated conditions

Both options can be effective—the best choice depends on your personal preferences, budget, and lifestyle.

The Science Behind Eggshell Calcium Absorption

Research has investigated how effectively the body absorbs calcium from eggshells compared to other sources. The findings are quite encouraging.

Studies using isolated cell models have found that calcium absorption from eggshell powder can be up to 64% greater than from pure calcium carbonate supplements. Researchers believe this enhanced absorption is due to the protein components naturally present in eggshells, which may facilitate calcium uptake in the intestines.

Animal studies have confirmed that eggshells are an effective calcium source, with absorption rates comparable to or exceeding those of purified calcium carbonate. These findings suggest that the natural composition of eggshells—with their combination of calcium, proteins, and trace minerals—may be particularly well-suited for human nutrition.

Human clinical trials have also shown positive results, with participants taking eggshell supplements experiencing improvements in bone mineral density similar to or better than those taking conventional calcium supplements.

Other Uses for Eggshells

Beyond human consumption, eggshells have several other practical applications:

Garden Fertilizer

Crushed eggshells can be added to garden soil to provide calcium to plants, particularly beneficial for tomatoes and other vegetables prone to calcium deficiency.

Compost Addition

Eggshells add valuable minerals to compost and help balance pH levels.

Pet Supplements

Some pet owners add finely ground eggshells to their animals’ food as a calcium supplement, particularly for dogs on homemade diets. Consult with a veterinarian before supplementing your pet’s diet.

Natural Cleaning Abrasive

Crushed eggshells can be used as a gentle abrasive for cleaning pots, pans, and other surfaces.

Frequently Asked Questions

Can I eat eggshells raw?

While technically possible, it’s not recommended due to the risk of bacterial contamination. Always boil eggshells before consuming them to eliminate harmful bacteria like Salmonella.

Do I need to remove the membrane?

No, the membrane can be left attached to the shell. It contains beneficial compounds like collagen and glucosamine that may support joint health.

What do eggshells taste like?

When ground into a fine powder, eggshells are virtually tasteless and won’t significantly affect the flavor of foods or beverages.

Are brown eggshells better than white?

No, shell color doesn’t affect nutritional content. Brown and white eggshells have the same calcium content and health benefits.

Can I use eggshells from any type of bird egg?

While chicken eggshells are most commonly used, shells from duck, quail, or other bird eggs can also be used. The calcium content is similar across different species.

How long does it take to see benefits?

Benefits to bone health typically take months to become measurable through bone density scans. However, maintaining adequate calcium intake is a long-term investment in your health.

Tips for Maximizing Calcium Absorption

To get the most benefit from your eggshell supplement, consider these tips:

Take with Vitamin D

Vitamin D is essential for calcium absorption. Get adequate vitamin D through sun exposure, fortified foods, or supplements to ensure your body can effectively use the calcium from eggshells.

Spread Throughout the Day

Your body can only absorb about 500 mg of calcium at once, so it’s more effective to split your intake into smaller doses throughout the day rather than taking it all at once.

Avoid Interfering Substances

Certain substances can interfere with calcium absorption, including:

• Caffeine (in large amounts)
• Excessive sodium
• Phytic acid (found in grains and legumes)
• Oxalic acid (found in spinach, rhubarb, and beet greens)

Maintain Adequate Protein Intake

Protein is necessary for calcium absorption and bone health, so ensure you’re getting enough in your diet.

Include Magnesium

Magnesium works synergistically with calcium for bone health. Good sources include nuts, seeds, whole grains, and leafy green vegetables.

The Bottom Line

Yes, you can eat eggshells—and they offer significant nutritional benefits when properly prepared. As one of the most concentrated natural sources of calcium, eggshells provide an affordable, accessible, and sustainable way to meet your calcium needs.

Research supports the effectiveness of eggshell powder as a calcium supplement, with studies showing it may be as effective as or even superior to commercial calcium supplements in supporting bone health and potentially reducing osteoporosis risk.

However, safety is paramount. Always boil eggshells to eliminate bacterial contamination, grind them into a fine powder to prevent injury, and use them in moderation to avoid excessive calcium intake.

While eggshell supplementation can be beneficial for many people—particularly those with inadequate calcium intake, dietary restrictions, or bone health concerns—it’s important to consult with a healthcare professional before adding any supplement to your routine, especially if you have existing health conditions or take medications.

By following proper preparation methods and using eggshells responsibly, you can transform kitchen waste into a valuable health supplement that supports your bones, reduces your environmental footprint, and saves money on commercial supplements.

Sources:

• National Center for Biotechnology Information – Eggshell Calcium Studies
• National Institutes of Health – Calcium and Bone Health
• Mayo Clinic – Calcium Supplements Guide
• U.S. Food and Drug Administration – Egg Safety
• NIH Office of Dietary Supplements – Calcium Fact Sheet