The health benefits of egg whites and yolks are widely known, but what about eggshells? While the majority of us simply bin these outer layers without a second thought, there have been suggestions that the shells carry some serious nutritional worth.
Eggshells are made up of 95% calcium carbonate, with a single shell providing around two grams of calcium. Comparatively, a glass of orange juice provides just 11 milligrams. Not only does this promote bone and muscle health, but it can also help relieve common issues such as heartburn, acid indigestion and stomach problems.
Frida Harju, in-house nutritionist at health app Lifesum, gives further insight.
"Eggshells are thought to be good sources of calcium, with almost double the recommended daily calcium in one egg shell. There have also been studies which found that egg shell powder could be useful for bone health and even reducing the pain of osteoporosis."
The risks
Recycling your eggshells also carries environmental benefits, as it is estimated that the US alone is responsible for 150,000 tones of shell waste. However, while the benefits of dietary calcium cannot be disputed, you might want to think twice before making use of any leftover 'raw' eggshells. Frida warns:
"Eggshells can be covered in bacteria and even carry salmonella, so I would recommend getting your daily dose of calcium from other sources. Another alternative for egg shells could be to use powdered egg shells in flower pots and vegetable patches by adding it to the soil, in order to enrich the plants."
Still keen?
If you are thinking of adding eggshells to your diet, then you need to make sure that they are properly prepared to get rid of any bacteria, as well as buying organic eggs in the first place, Frida says.
"In order to make sure that the eggs are free of bacteria, you should boil them first, then dry them out in an oven for one hour. For human consumption, make sure that the shells are ground into a fine powder which can then be integrated into your morning smoothie, or a sprinkling can be added to pasta dishes along with dinner."
Calcium-rich alternatives
The good news is that there are plenty of other nutritious foods that can provide you with that much-needed calcium boost. Frida says:
"You can get your daily calcium requirement from other food sources, especially dairy products like cheese, milk and yoghurt. However, if you don't consume dairy, then soy-based products like soy milk is often fortified with calcium, but make sure to read the labels before you buy to make sure the product contains enough calcium. Similarly, vegetables like cabbage and broccoli contain calcium, as do foods like nuts and certain types of fish."However, too much calcium can be as dangerous as too little, so make sure you don't overdo it – adults only need one gram per day.