Amy Burkhart, MD, RD

Amy Burkhart, MD, RD

Amy Burkhart, MD, RD, is a board-certified emergency medicine physician and registered dietitian. She also trained in integrative medicine with Dr. Andrew Weil at the University of Arizona Center for Integrative Medicine. Her practice is located in Napa, CA.
1100 Lincoln Ave. Suite 200
Napa, CA 94558
(707) 927-5622 Office


A Window to Your Health

Hand in black and whiteFingernails can be an expression of who you are – they may be adorned with jewels, be a helpful tool for day-to-day activities or provide a window to hidden stress. However, if you suffer from digestive issues such as celiac disease, irritable bowel syndrome (IBS), FODMAP intolerance or gluten sensitivity, they may also reveal more about your health than you realize. When you are experiencing digestive woes and looking for answers, the following five changes to your fingernails may provide clues to an underlying cause.

1. White Lines

White lines are common and can be a benign sign of previous trauma such as a slammed door or incidental hit on the nail. If trauma is the cause, the lines are typically only on the injured nail and the lines grow out with time. If trauma is not to blame, the two most common types of white lines are Muehrcke’s and Mee’s lines. Both may indicate underlying systemic distress.

Muehrcke’s Lines

Muehrckes Lines2These are paired white lines that occur horizontally across the nail bed and do not move with nail growth. They typically cross the entire nail bed and are homogenous in appearance. In contrast to traumatic lines, they usually appear on more than one nail and fade with compression.

In people with digestive disorders, low albumin (a protein in the blood), niacin (vitamin B3) deficiency, zinc deficiency or malnutrition may be to blame for Muehrcke’s lines.

Less common causes: Chemotherapy, kidney or liver disease.

Mee’s Lines

Mees LinesThese are also horizontal/transverse lines but differ from Muehrcke’s in that they grow out with the nail and do not fade with compression. They are most commonly associated with arsenic toxicity. Since rice can contain high levels of arsenic and the gluten-free diet is often rice-based (including rice flours in baked goods), this is important. See my previous article Arsenic in the Gluten-Free Diet: Facts and Tips.

Less common causes: Hodgkins, leprosy, heart failure, chemotherapy, carbon monoxide poisoning


2. Split, Weak and Bendable Fingernails

Split nailsThese changes can occur due to aging, excessive picking of nails and repeated exposure to water. But when coupled with digestive or other health symptoms, nutrient deficiencies and hypothyroidism must be considered as causes. Iron deficiency and low protein levels may also cause those pesky splitting nails. Levels are easily evaluated by a blood test.

Less common causes: Low folate, vitamin C, vitamin D or calcium. Low stomach acid has also been implicated by some practitioners, but more research is needed to determine this correlation. If fingernails are bitten or chewed frequently, anxiety levels may need to be assessed, as chronic health issues often worsen and cause anxiety and depression.

3. Ridges

Vertical ridgesVertical ridges are common and not typically of concern. They occur with aging due to loss of water under the nail bed. They are equivalent to wrinkles on your skin. They can be minimized by moisturizing your nails regularly, especially near the cuticle.

Less common cause: Rheumatoid arthritis

Horizontal ridges deserve more attention than their vertical counterparts, as they can be indicative of more serious conditions. A single horizontal ridge may indicate trauma or a disruption in nail growth due to a temporary illness. If horizontal ridges recur or persist, a person should be evaluated for zinc deficiency, diabetes or vascular disorders.

Horizontal ridges

4. Scoop or Spoon Nails (Koilonychia)

Scoop nailsSpecific reasons for spoon-shaped nails or “scoop” nails in people whose digestion is compromised include iron deficiency with or without anemia and, conversely, hemochromotosis (, a genetic disorder that causes the body to absorb too much iron. Both conditions are easily assessed by blood tests.

Less common causes: Raynaud’s, lupus (usually along with other symptoms of lupus), trauma, nail-patella syndrome

5. White Spots (Leukonychia)

White spotsSmall white spots are common and most often due to incidental trauma such as bending the nail or banging it. If spots are multiple and frequent, or coupled with additional symptoms, other factors must be considered.

Deficiency of zinc and calcium may occur on restricted diets or if malabsorption is present. Both have been implicated to cause white spots on the nails. Fungal infections are another cause and typically cause spots at the base or tip of the nail. The nail may split or break in addition to the spots if this is the case. Many people with digestive issues suffer from other allergies and may also have an allergic reaction to nail products. If a new product has been started and spots begin to occur, consider stopping the product to assess causality.

Less common but serious conditions such as infections can also cause white spots. If fevers or severe systemic symptoms occur, immediate evaluation is needed.

Pay Attention

Pay AttentionThese 5 changes are the most common I see with digestive disorders such as celiac disease, IBS, FODMAP intolerance and gluten sensitivity. If you experience any of these or other nail abnormalities, please don’t ignore them. Consult with your healthcare provider and assess the need for further evaluation. Those fingernails you thought were just for performing daily tasks and accessorizing may be hinting at a simple way to improve your health.