What Deficiency Causes Nail Ridges and Other Nail Abnormalities?

January 1, 2026 •

4 min read

While vertical nail ridges are often a harmless sign of aging, studies and dermatologists confirm that nutritional deficiencies, such as low iron and zinc, can also significantly impact nail health and contribute to the formation of ridges. Understanding the specific deficiency causing your nail ridges is key to determining the right course of action for healthier nails.

Quick Summary

Nail ridges can be caused by nutrient deficiencies like insufficient iron, zinc, and B vitamins, though other factors also play a role. The type of ridge, vertical or horizontal, often points toward different potential causes, from aging and trauma to serious systemic health issues. Addressing the underlying problem is the primary solution.

Key Points

Vertical Ridges Often Benign: The most common cause of vertical nail ridges is the natural aging process, as nail cell turnover slows down.
Iron Deficiency Link: Iron deficiency is a notable cause of vertical ridges and brittle nails. In severe cases, it can cause spoon-shaped nails (koilonychia).
B Vitamins are Crucial: Biotin and B12 deficiencies can impact nail health and growth, potentially leading to ridging and other abnormalities.
Zinc and Protein for Horizontal Ridges: Severe deficiencies in zinc or protein can cause horizontal indentations across the nail, known as Beau's lines.
Other Causes Exist: Beyond deficiencies, horizontal ridges can result from trauma, severe illnesses, chemotherapy, or systemic diseases like diabetes and thyroid issues.
Consult a Professional: If you notice significant changes in your nails, it is wise to consult a healthcare provider to determine the cause and get an accurate diagnosis.

The appearance of ridges on fingernails can be a cosmetic concern for many, but they can also be a subtle indicator of underlying health issues. While harmless aging is the most common cause of vertical ridges, other nutritional deficiencies can play a significant role, as can more serious medical conditions. Distinguishing between vertical (longitudinal) and horizontal (Beau's lines) ridges is the first step toward uncovering the root cause, as each type can signal different issues.

Vertical Ridges: Iron, B Vitamins, and More

Vertical ridges, also known as onychorrhexis, run from the cuticle to the tip of the nail. They tend to become more pronounced with age as cell turnover in the nail matrix slows down. However, when they are deep or accompanied by other nail changes, a deficiency might be at fault.

Iron Deficiency and Anemia

One of the most frequently cited nutritional causes of vertical ridges is iron deficiency, which can lead to anemia. Iron is crucial for red blood cell production, which carries oxygen to the nails and other parts of the body. A lack of sufficient oxygen can impair nail growth, leading to brittleness and prominent ridges. In severe cases of iron deficiency anemia, the nails may also become concave or 'spoon-shaped,' a condition known as koilonychia.

Biotin and Other B Vitamins

Biotin, or vitamin B7, is well-known for its role in supporting hair and nail health. It promotes cell growth and is involved in the metabolism of protein-building amino acids essential for strong nails. While a biotin deficiency is rare, it can lead to brittle nails and ridging. A deficiency in vitamin B12 can also affect nail health, sometimes causing ridges along with hyperpigmentation.

Dehydration and Protein

Chronic dehydration can cause the nail plate to dry out, making vertical ridges more noticeable. Adequate hydration is essential for overall nail health. Additionally, since nails are made of keratin, a fibrous protein, a protein deficiency can also weaken nails and contribute to ridges.

Horizontal Ridges: Beau's Lines and Acute Issues

Horizontal ridges, known as Beau's lines, are more indicative of a systemic problem that temporarily disrupts nail growth. They appear as indentations running across the nail plate. Unlike age-related vertical ridges, these lines are often the result of an acute stressor on the body.

Zinc and Protein Deficiency

A severe zinc deficiency can interrupt cell division and cause Beau's lines to appear. Zinc is essential for promoting healthy nail growth, and inadequate intake can lead to visible horizontal depressions. Similarly, a significant protein deficiency can also trigger the appearance of Beau's lines, reflecting a period of malnutrition.

Systemic Health Conditions

Beau's lines are often associated with systemic health issues that cause a severe stress response, halting normal nail production. Common medical culprits include:

Serious illnesses: Such as pneumonia, COVID-19, or high fever.
Uncontrolled diabetes: Leading to reduced blood flow to the nail bed.
Thyroid disease: Both hyper- and hypothyroidism can cause nail abnormalities.
Chemotherapy: This treatment attacks fast-dividing cells, including those in the nail matrix, causing nail growth to pause.

Trauma to the Nail Matrix

Physical trauma to the cuticle or nail matrix can also result in a single Beau's line on the affected nail. This could be from an injury like a jammed finger or aggressive manicuring practices.

Addressing Nutritional and Other Causes

For ridges caused by nutritional deficiencies, a balanced diet is the best defense. Focus on consuming foods rich in the key vitamins and minerals necessary for strong, healthy nails.

Essential Nutrients for Nail Health

Iron: Include lean meats, chicken, fish, eggs, beans, and leafy greens like spinach. Combining plant-based iron sources with vitamin C-rich foods (citrus fruits, bell peppers) can boost absorption.
Zinc: Found in red meat, poultry, fish, eggs, nuts, and seeds. Oysters are a particularly rich source.
Protein: A varied diet with protein from sources like meat, poultry, fish, eggs, dairy, soy, nuts, and beans is vital for keratin production.
Biotin and Other B Vitamins: Foods such as egg yolks, nuts, seeds, avocado, and salmon are good sources. Folate (B9) is in dark green vegetables and citrus fruits.
Hydration: Drink plenty of water throughout the day to prevent dehydration from affecting your nails.

Comparison of Ridge Types and Potential Causes


Feature	Vertical Ridges (Onychorrhexis)	Horizontal Ridges (Beau's Lines)
Appearance	Lines running from the cuticle to the nail tip.	Indentations or grooves running side-to-side across the nail.
Common Cause	Normal aging, minor trauma, dehydration.	Severe illness, major stress, trauma to the nail matrix.
Deficiency Link	Iron, Biotin, B12, general malnutrition.	Severe zinc or protein deficiency.
Other Causes	Psoriasis, lichen planus, thyroid disease.	Chemotherapy, diabetes, thyroid disease, serious infections.
Significance	Often harmless, but deep ridges can signal a nutritional issue.	More likely to indicate a significant, systemic health event.
Timeline	Can appear and become more prominent gradually over time.	Appear after a period of stress and grow out with the nail.

Conclusion

In summary, while the most common cause of vertical nail ridges is the natural aging process, it is important not to dismiss them entirely. Both vertical and horizontal nail ridges can be linked to nutritional deficiencies like iron, zinc, and B vitamins, as well as protein. Horizontal ridges, in particular, often point toward a more acute systemic issue, such as a severe illness, uncontrolled diabetes, or chemotherapy. The appearance of new, deep, or persistent ridges warrants a discussion with a healthcare provider to rule out underlying medical conditions and ensure that any potential deficiency is addressed through diet or supplementation under professional guidance. The best approach to nail health is to maintain a balanced diet and proper hydration and to be vigilant for other accompanying symptoms. For more information on nail changes that might indicate serious conditions, refer to resources like the Cleveland Clinic.

Frequently Asked Questions

Yes, specific vitamin deficiencies, particularly in B vitamins like biotin and B12, can contribute to nail ridges. However, many other factors, such as aging, trauma, and systemic illnesses, can also be responsible.

Ridges caused by a deficiency can improve and grow out over time once the underlying nutritional issue is corrected. Since nails grow slowly, it may take several months to see a complete return to normal appearance.

Vertical ridges (onychorrhexis) run from the cuticle to the nail tip and are often age-related or linked to issues like iron deficiency. Horizontal ridges (Beau's lines) run across the nail and are typically caused by a more significant, acute health event or trauma.

Yes, a severe protein deficiency can disrupt nail growth and is a known cause of horizontal ridges, or Beau's lines. Since nails are made of the protein keratin, insufficient protein can weaken their structure.

Yes, dehydration can cause the nail plate to become dry and brittle, which can make vertical ridges more pronounced. Staying adequately hydrated is important for overall nail health.

Iron deficiency often causes vertical nail ridges and brittle nails. In more severe cases, it can also lead to koilonychia, a condition where the nails become abnormally thin and spoon-shaped.

For most people, vertical ridges are harmless and part of aging. However, if you notice deep, persistent, or new horizontal ridges, or if they are accompanied by other symptoms like changes in color, it is best to consult a healthcare professional.