Published by Paul Thompson |
Fact-checked against peer-reviewed sources | Updated March 2026
Health Guide

# What Your Nails Reveal: Signs of Deficiency & Health

Your nails are more than just a canvas for polish - they're a window into your overall health and wellness

Healthy nails are typically smooth, uniform in color, and free from spots or discoloration. When something changes in your body - whether it's a nutritional deficiency, hormonal imbalance, or health condition - your nails often show the first signs.

## Nails as Health Indicators

The nail plate is made of keratin, a protein that requires various vitamins and minerals for proper formation. As new cells form at the nail matrix (beneath the cuticle), they push older cells forward, creating the visible nail. This continuous growth process means your nails reflect your nutritional status from weeks to months ago.

#### Important Note

While nail changes can indicate health issues, they're not diagnostic on their own. Always consult a healthcare provider for persistent changes or concerns about underlying conditions.

Healthy nails reflect your overall wellness and nutritional status

## White Spots: The Zinc Deficiency Myth

Small white spots on nails, medically known as leukonychia, are one of the most common nail concerns. Popular belief attributes these spots to zinc deficiency, but the reality is quite different.

### What Really Causes White Spots

In most cases, white spots are caused by minor trauma to the nail matrix:

- Bumping your nail against a hard surface
- Aggressive manicuring or cuticle pushing
- Nail biting or picking
- Using your nails as tools

These spots are harmless and will grow out with the nail over several weeks. True zinc deficiency is rare in developed countries and would present with many other symptoms beyond white spots.

White spots (leukonychia) are usually caused by minor trauma, not zinc deficiency
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## Ridges: Vertical vs Horizontal

Nail ridges are extremely common and their significance varies based on their direction and severity.

#### Vertical Ridges

Run from cuticle to tip. Typically harmless and become more prominent with age. Part of the normal aging process. Can be more noticeable with dehydration or vitamin B12 deficiency.

#### Horizontal Ridges (Beau's Lines)

Run across the nail side to side. More concerning - indicate nail growth was temporarily disrupted. May be caused by illness, infection, malnutrition, or systemic conditions.

### Causes of Beau's Lines

- Serious illness or high fever
- Severe infection
- Chemotherapy
- Malnutrition or extreme dieting
- Uncontrolled diabetes
- Peripheral vascular disease

## Brittle Nails: Iron, Biotin & Thyroid

Brittle nails that split, peel, or break easily are one of the most frustrating nail problems. While external factors play a role, internal health issues often contribute.

Understanding the cause of brittle nails helps you find the right solution

### Iron Deficiency

Iron deficiency anemia is a leading cause of brittle nails. Iron is essential for producing hemoglobin, which carries oxygen to tissues including the nail matrix.

- Fatigue and weakness
- Pale skin
- Shortness of breath
- Cold hands and feet
- Hair loss

### Biotin Deficiency

Biotin (vitamin B7) is crucial for keratin production. While true biotin deficiency is rare, marginal deficiencies may contribute to brittle nails.

- Poor diet lacking eggs, nuts, and whole grains
- Long-term antibiotic use
- Excessive raw egg white consumption
- Certain genetic conditions

### Thyroid Dysfunction

Both hypothyroidism and hyperthyroidism can affect nail health. The thyroid regulates metabolism, including nail growth and cell turnover.

#### Hypothyroidism Signs

Slow-growing, brittle nails. Thick, discolored nails. Nail separation from the nail bed (onycholysis).

#### Hyperthyroidism Signs

Fast-growing, soft nails. Nail separation (onycholysis). Nail thinning.

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## Yellow Nails: Multiple Causes

Yellow nails can result from various factors, ranging from benign to serious.

### Common Causes

- Nail polish staining - most common cause, especially from dark or red polishes without base coat
- Fungal infections - cause yellowing, thickening, and crumbling of nails
- Smoking - nicotine and tar stain nails yellow or brown

#### Prevention Tip

Always use a quality base coat before applying colored polish to prevent staining. Give your nails occasional polish-free breaks.

## Spoon-Shaped Nails (Koilonychia)

Koilonychia refers to nails that curve inward, creating a concave or spoon-like appearance. This distinctive change is most commonly associated with iron deficiency anemia.

### Causes of Koilonychia

- Iron deficiency anemia - most common cause in adults
- Hemochromatosis - iron overload disease
- Raynaud's disease - reduced blood flow to extremities
- Lupus and other autoimmune conditions
- Trauma or injury to the nail

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## When Nail Changes Signal Health Problems

While many nail changes are benign, certain patterns warrant medical attention.

#### Dark Lines or Spots Under the Nail

A dark brown or black line under the nail, especially on a single nail, could indicate melanoma (skin cancer). This is particularly important for people with darker skin tones. Seek immediate medical evaluation.

### Other Serious Nail Changes

- Clubbing - fingertips and nails become enlarged and rounded; associated with lung disease, heart disease, liver disease
- Nail separation (Onycholysis) - nail lifts from nail bed; caused by thyroid disease, psoriasis, fungal infection
- Pitting - small depressions in nail surface; associated with psoriasis, alopecia areata, eczema
- White nails (Terry's nails) - most of nail appears white; can indicate liver disease, kidney disease, heart failure

## When to See a Doctor

When to see a doctor about your nail health concerns

Schedule an appointment if you notice:

- Sudden or rapid changes in nail appearance without obvious cause
- Dark lines or spots under the nail, especially on a single nail
- Nail separation from the nail bed
- Painful, red, or swollen skin around nails
- Thickened, yellow nails that aren't improving
- Clubbing of fingertips and nails
- Persistent brittleness despite improving nail care habits
- Spoon-shaped nails developing in adulthood

#### Professional Diagnosis Matters

A dermatologist can perform a physical examination, take nail clippings for analysis, or order blood tests to identify the underlying cause. Many nail conditions respond well to treatment when caught early.

## Supplements for Nail Health

Support your nails from within with these quality supplements

### Sports Research Biotin 5000mcg

High-potency biotin to support keratin production. Promotes healthy nails, hair, and skin.

$17.95
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### NOW Silica Complex

Supports connective tissue and collagen formation. Essential for strong, healthy nails.

$44.00
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### Nordic Naturals Ultimate Omega

1280mg omega-3s reduce inflammation and support nail health.

$64.00
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### Listen to What Your Nails Tell You

Your nails are remarkable indicators of your overall health. While many changes are harmless and age-related, others can signal nutritional deficiencies or underlying medical conditions that deserve attention.

Pay attention to changes, especially those that are sudden, progressive, or accompanied by other symptoms. When in doubt, consult a healthcare provider. Remember that beautiful nails start from within - proper nutrition, adequate hydration, and good overall health create the foundation for strong, healthy nails.