What Deficiency Causes Deep Ridges in Nails? An In-depth Guide

October 16, 2025 •

4 min read

According to dermatologists, while faint vertical nail ridges can be a normal part of aging, deep and pronounced ridges often point to a nutritional deficiency or an underlying health issue. This article investigates what deficiency causes deep ridges in nails and distinguishes between different types of nail ridges to help you identify potential health signals.

Quick Summary

Different nutritional deficiencies, particularly a lack of iron and zinc, can cause deep ridges in nails. Horizontal ridges (Beau's lines) and vertical ridges (onychorrhexis) indicate different underlying issues, from systemic illness to chronic deficiency. Identifying the specific cause is crucial for effective treatment.

Key Points

Iron Deficiency: A lack of iron can cause vertical ridges, or onychorrhexis, along with brittle nails and, in severe cases, spoon-shaped nails.
Zinc Deficiency: A severe shortage of zinc can lead to horizontal grooves, known as Beau's lines, which signal a temporary interruption in nail growth.
Protein Insufficiency: Because nails are made of keratin protein, an overall protein deficiency can cause deep grooves and weaken the entire nail structure.
Aging is a Factor: While deficiencies cause deep ridges, faint vertical ridges are also a common and often harmless sign of the natural aging process.
Other Health Conditions: Beyond nutrition, deep ridges can be a sign of underlying systemic issues like thyroid disease, diabetes, or psoriasis.
Direction Matters: The orientation of the ridge—vertical vs. horizontal—provides important clues about the potential cause, from chronic deficiency to acute illness.
Address the Root Cause: The most effective treatment involves addressing the specific nutritional gap or health condition rather than simply treating the nail cosmetically.

Deep ridges in nails can be a cause for concern, but they are also a common symptom that can be addressed once the underlying cause is identified. While nutritional deficiencies are a primary suspect, it's important to understand the different types of ridges and their specific triggers. The orientation of the ridge—vertical or horizontal—provides important clues about what's happening inside your body.

The Role of Key Nutrients in Nail Health

Nails are made of keratin, a protein that requires specific nutrients for healthy development. When your body lacks these essential vitamins and minerals, the keratin production is disrupted, leading to visible changes in the nail plate. The deficiencies most commonly associated with deep nail ridges include iron, zinc, protein, and B vitamins.

Iron Deficiency and Vertical Ridges (Onychorrhexis)

Iron is critical for hemoglobin production, which carries oxygen to all cells, including the nail matrix where nail growth begins. An iron deficiency, which can lead to anemia, can result in:

Vertical Ridges: These lines run from the cuticle to the tip of the nail.
Brittle Nails: The nails may become thin, fragile, and prone to breaking.
Spoon Nails (Koilonychia): A more severe sign of iron deficiency where the nail becomes concave, or spoon-shaped.

Zinc Deficiency and Horizontal Ridges (Beau's Lines)

Zinc is a vital trace mineral for cell growth and repair. A shortage of zinc can interrupt the growth process, causing distinct horizontal depressions across the nail plate known as Beau's lines. Other signs of zinc deficiency can include hair loss and delayed wound healing.

Protein Deficiency and Nail Grooves

Since nails are primarily protein, a severe protein insufficiency can significantly impact their integrity. The body prioritizes protein for more critical functions, diverting it away from nail and hair growth. This can lead to horizontal grooves and overall weakening of the nail structure.

B Vitamin Deficiencies

Deficiencies in certain B vitamins, such as Biotin (B7) and Folic Acid (B9), are also linked to nail issues.

Biotin Deficiency: Can cause brittle, weak nails and ridges.
Folic Acid (Vitamin B9) Deficiency: May contribute to anemia and irregular nail formation.

Distinguishing Between Different Nail Ridges

It's important to know the difference between vertical and horizontal ridges, as they often signal different underlying issues.

Vertical Ridges (Onychorrhexis) vs. Horizontal Ridges (Beau's Lines)


Feature	Vertical Ridges (Onychorrhexis)	Horizontal Ridges (Beau's Lines)
Direction	Run from the base of the nail to the tip	Run horizontally across the nail plate
Cause	Primarily associated with aging, iron deficiency, thyroid disease, or trauma	Caused by a sudden, severe interruption in nail growth
Associated Factors	Psoriasis, eczema, rheumatoid arthritis	Severe illness (e.g., high fever, pneumonia), chemotherapy, severe zinc deficiency
Prognosis	Often benign and can be improved with addressing nutritional gaps; may be a sign of chronic conditions	Grow out over time as the nail matrix recovers
Medical Action	Medical evaluation recommended if accompanied by other symptoms or is very pronounced	Seek medical attention if new lines appear repeatedly

What to Do About Deep Nail Ridges

If you have deep nail ridges, a visit to a healthcare provider or dermatologist is the best first step. They can perform tests, such as a blood test for iron levels, to determine the exact cause.

Lifestyle and Dietary Changes:

Increase Iron Intake: Incorporate iron-rich foods like red meat, poultry, fish, beans, lentils, and fortified cereals. Combining these with Vitamin C-rich foods (citrus fruits, bell peppers) can boost absorption.
Boost Zinc Consumption: Add oysters, beef, pumpkin seeds, and legumes to your diet to increase zinc levels.
Ensure Protein: Eat high-quality protein from sources like lean meats, eggs, fish, and dairy.
Stay Hydrated: Dehydration can exacerbate brittle nails and make ridges more prominent. Drink plenty of water throughout the day.

Nail Care Practices:

Moisturize: Keep your nails and cuticles moisturized with nourishing oils (like jojoba) or hand cream to prevent dryness.
Protect Nails: Wear gloves when doing housework or using harsh chemicals to prevent further damage.
Avoid Trauma: Be mindful of repetitive trauma, as it can worsen nail integrity.

The Bottom Line

While deep nail ridges can be a concerning cosmetic issue, they are most often a signal from your body that something is out of balance. By paying close attention to the type of ridges and consulting a healthcare professional, you can effectively diagnose and address the root cause, whether it's a simple nutritional deficiency or a sign of a more complex health condition. Restoring your nutrient levels and adopting healthy nail care habits can significantly improve the health and appearance of your nails over time. A balanced diet and good overall health are the best defenses for strong, smooth nails.

Conclusion

In summary, deep ridges in nails are not a disease but a symptom of an underlying issue, frequently a nutritional deficiency. Key deficiencies include iron, linked to vertical ridges (onychorrhexis), and zinc, associated with horizontal ridges (Beau's lines). Factors like aging, severe illness, and certain medical conditions can also contribute. Addressing these deficiencies through a balanced diet rich in essential nutrients like iron, zinc, protein, and B vitamins is crucial for restoring nail health. Consulting a healthcare professional is recommended for a proper diagnosis and tailored treatment plan.

The Relationship Between Deep Nail Ridges and Underlying Health Conditions

While nutritional deficiencies are a common cause of deep nail ridges, it is important not to overlook other underlying health conditions that can present with similar symptoms. Conditions such as thyroid disease, diabetes, and certain autoimmune disorders can also cause disruptions in nail growth. For instance, uncontrolled diabetes can impair blood flow to the extremities, affecting nail formation. Psoriasis, a skin condition, is also known to cause nail changes, including vertical ridging and thickening. Always consult a medical professional for an accurate diagnosis, especially if nail changes are accompanied by other symptoms, to ensure proper treatment of any systemic disease.

Visit the Cleveland Clinic website for more information on nail ridges and their causes

Frequently Asked Questions

The most common nutritional causes are deficiencies in iron and zinc. Iron deficiency often leads to vertical ridges (onychorrhexis), while zinc deficiency is a known cause of horizontal ridges (Beau's lines).

No, faint vertical ridges can be a normal part of the aging process. However, deep or very pronounced vertical ridges, especially when accompanied by other symptoms, may indicate an underlying deficiency or health issue like iron deficiency or thyroid disease.

Horizontal ridges, or Beau's lines, indicate a severe disruption in nail growth. This can be caused by severe illness with high fever, chemotherapy, significant emotional stress, or a severe zinc deficiency.

Yes, since nails are made of keratin, a protein, a severe protein insufficiency can lead to nail abnormalities, including horizontal grooves and general weakening of the nail structure.

It can take several months for the nails to grow out and the ridges to disappear after the underlying deficiency is treated. Nails grow slowly, so patience is required to see improvement.

Other causes include chronic medical conditions like diabetes and thyroid disease, skin conditions like psoriasis and eczema, trauma to the nail matrix, and even severe stress.

You should see a doctor if the ridges are deep, change in appearance, or are accompanied by other symptoms like changes in nail color, brittleness, or pain. A healthcare provider can diagnose the root cause and recommend appropriate treatment.