What are fingernails made of?
Before we can explore their nutritional value, it's important to understand what fingernails are. Fingernails and toenails are composed of layers of a hardened, fibrous protein called keratin. This same protein is also the main structural component of your hair and the outer layer of your skin. Nails are formed in the matrix, located at the base of the nail under the cuticle. As new cells are produced, older ones are pushed out and compacted, eventually hardening to form the visible nail plate. Contrary to what some might believe, nails are not made of bone. They are, in fact, non-living extensions of your skin.
The human digestive system and keratin
Keratin's molecular structure makes it exceptionally tough and insoluble. The human digestive system is simply not equipped to break down and process this protein. While some animals, like microbes and certain insects, possess the necessary enzymes, humans do not. This means that if you swallow a piece of a nail, it will pass through your digestive system mostly undigested, just as a strand of hair would. Your body cannot break down the complex bonds within the keratin to release any potential amino acids or caloric energy.
Health risks of ingesting fingernails
Putting aside the lack of nutritional benefit, eating fingernails poses several significant health risks.
1. Infections: Your hands and the areas under your nails are home to a wide range of bacteria and germs. Biting your nails and then swallowing them can introduce these harmful pathogens into your mouth and digestive tract, increasing your risk of infection. Common infections, such as paronychia (a skin infection around the nail), are also a risk due to damage to the nail bed and cuticle.
2. Dental problems: The habit of nail-biting, known as onychophagia, can damage your teeth. Constantly gnawing on a hard substance can chip or crack tooth enamel, wear down teeth, and even lead to dental misalignment or other oral issues over time.
3. Digestive blockages: While most swallowed nail pieces will pass harmlessly, there's a risk they can clump together in the stomach or intestines. This mass is known as a bezoar and can cause a painful blockage that may require medical intervention.
Nutrients that truly benefit nail health
Instead of trying to find nutritional value in your nails, focus on consuming a balanced diet rich in the nutrients your body needs to produce strong, healthy nails. Nutritional deficiencies often manifest as problems with nail strength, growth, and appearance.
Essential nutrients for strong nails
- Protein: Since nails are made of protein, a diet with adequate protein is essential for producing the keratin needed for healthy nails. Good sources include lean meats, fish, eggs, dairy, and legumes.
- Biotin (Vitamin B7): This B-vitamin is a powerhouse for nail health, improving the structure of keratin and making nails less prone to splitting and breaking. Eggs, nuts, seeds, and sweet potatoes are rich sources.
- Iron: Low iron levels can cause brittle or spoon-shaped nails. Iron helps transport oxygen to the nail cells, so incorporating iron-rich foods like red meat, lentils, and spinach can improve nail appearance.
- Zinc: A deficiency in this mineral can lead to white spots on the nails. Oysters, beef, and pumpkin seeds are excellent sources of zinc.
- Omega-3 Fatty Acids: These fats help keep your nails moisturized and prevent dryness and brittleness. Fatty fish, chia seeds, and walnuts are good options.
Comparison: Eating Nails vs. A Healthy Diet for Nail Health
| Feature | Eating Your Nails | Eating a Healthy Diet for Nail Health |
|---|---|---|
| Nutritional Benefit | Zero | Significant and positive impact |
| Digestive Impact | Indigestible keratin; risk of blockage | Provides essential nutrients for the body |
| Health Risks | Infections from bacteria, dental damage, bezoars | Generally none, assuming a balanced diet |
| Nail Appearance | Potential for deformation, damage to nail bed | Promotes strong, healthy, and resilient nails |
| Psychological Effect | Often a sign of stress or anxiety | Feeling of well-being from taking care of your body |
Conclusion
In summary, the notion that there is any nutritional benefit to eating your fingernails is a myth. While nails are indeed composed of protein, the specific type, keratin, cannot be broken down by the human digestive system. Instead of offering sustenance, ingesting fingernails carries a series of health risks, from bacterial infections to potential digestive blockages. For truly healthy nails, the focus should be on a balanced diet rich in essential nutrients like biotin, protein, zinc, and iron. Your nail health is a reflection of your overall nutritional status, and the best way to support them is to nourish your body from the inside out.
For more information on the structure and biology of nails, including how their composition relates to general health, you can refer to the extensive resources provided by the National Institutes of Health.
Can pets digest keratin?
While humans cannot digest keratin, some animals, such as certain insect species or carnivorous animals eating their prey whole, may be able to digest some forms of it or have adaptations for dealing with non-digestible parts. For example, some pet treats like dehydrated chicken feet (which include nails) are sold for dogs because they contain glucosamine and chondroitin, which dogs can benefit from. However, this does not mean it is an appropriate food source for humans. Even for pets, the nutritional value often lies in other components of the treat, not the keratin itself.
