Nail Growth as an Indicator of Aging
The rate at which fingernails reveal insights into biological aging, according to Dr. David Sinclair, a genetics professor at Harvard Medical School. On his podcast Lifespan, Sinclair explained that nail growth serves as a natural marker of how well a person is aging, beyond their chronological age.
Sinclair referred to a 1979 study that monitored the nail growth of 271 individuals over several years. The study found that nail growth slows down by approximately 0.5% per year after the age of 30. This decline suggests that faster-growing nails may be a sign of a more youthful biological age. While frequent manicures do not influence this process, individuals who find themselves trimming their nails more often than their peers may be aging at a slower biological rate.
It is common for nails to become more brittle and discolored with age. However, Sinclair emphasized that changes in nail growth could also indicate underlying health concerns. While nail growth alone cannot determine overall health, significant shifts in nail texture, color, or thickness could be signs of deeper medical issues.
Health Conditions Linked to Nail Changes
Beyond aging, fingernails reveal a great deal about a person’s health. Certain color changes, ridges, or deformities could indicate underlying medical conditions. White or pale nails may be linked to anemia, heart failure, liver disease, or malnutrition. Yellowing nails could be a sign of diabetes, thyroid disorders, or fungal infections.
Vertical ridges, although often a normal part of aging, can also signal nutritional deficiencies or autoimmune diseases like rheumatoid arthritis. Additionally, a condition known as clubbing—where nails become thick and curved—may be a warning sign of lung disease, cardiovascular disease, inflammatory bowel disease, or liver issues.
While the rate of nail growth provides an interesting insight into aging, brittle and weak nails could stem from other causes. Fingernails reveal important information about diet, hygiene habits, and exposure to harsh chemicals, which all play a significant role in nail health.
Maintaining Healthy Nails
Dr. Mary Stevenson, a dermatologic surgeon at NYU Langone, highlighted that diet has a major impact on nail strength. A lack of protein can reduce keratin production, leading to fragile nails. Deficiencies in vitamin B and iron can also contribute to weakened nail structure.
Additionally, frequent handwashing, exposure to cleaning chemicals, and trauma to the nail bed can make nails more prone to breaking. Stevenson cautioned against cutting cuticles during manicures, as they act as a natural barrier against bacteria and fungi. While some believe that letting nails “breathe” between manicures is necessary for health, she clarified that this is not essential. However, excessive use of acetone-based nail polish removers or improper manicures can weaken nails over time.
To promote stronger nails, Stevenson recommended supplements like biotin and iron, though she noted that visible improvements may take months. Fingernails reveal the importance of maintaining a nutrient-rich diet and avoiding harsh chemicals, which can help preserve nail health and possibly slow down biological aging.
