Fingernails and Nutritional Deficiencies

Fingernails and nutritional deficiencies are commonly overlooked in the medical setting.  Fingernails can provide you with telling information about the underlying nutritional status of your body. The visual observation of nails has a long and reputable history providing valuable information to the trained observer.

Fingernails are made of keratin, a tough protein. The average fingernail grows 2-3 mm per month and is considered about 1/3 the growth rate of hair. The actual growth rate is dependent on age, gender, season, exercise level, diet and hereditary factors.

Fingernail facts:

  • Nails grow faster in the summer or warm climates.
  • Nails grow faster when you’re pregnant.
  • Nails grow faster on your dominant hand.
  • Nails grow quicker on men.
  • Nails don’t grow after you die; rather your skin dehydrates and tightens creating the illusion of nail and hair growth.

Fingernails and Nutritional Deficiencies

Ridging:  Vertical ridges on fingernails can be superficial or deep. The superficial ridges may be due to a lack of moisture (proper hydration) or the aging process. The deeper ridges may perhaps indicate arthritis or decreased circulation to the base of the nail.  Nutrient deficiencies such as poor mineral absorption from the GI tract can also play a factor in vertical ridges.

Splitting:  Nails that split are weak.  Not enough nutrients to keep the nails hard is usually the case.  More minerals are usually needed along with amino acids to rebuild the infrastructure.

Dry brittle nails:  These have been linked to thyroid disease. If combined with a yellowish color, it might be due to a fungal infection. Exposure to harsh detergents or chemical cleaners may also cause the nails to split.

Koilonychia: Koilonychia literally means “spoon nails”. These nails lose their convexity and become flat and then concave. This presentation is usually caused by iron deficiency anemia or hypochromic anemia.  People with koilonychias may also suffer from fatigue as this is another sign of iron deficiency. Most routine blood tests don’t include iron levels, so this finding could be missed.  However now that you know this clue, you are one step ahead of the game.

Beau’s lines:  Beau’s lines are depressions that run across the fingernail and are the result of a temporary cessation of cell division in the nail matrix. These lines are definitely notable because they usually run deep in the nail.  Beau’s lines may be caused by an underlying illness where the body has to divert or conserve it’s energy; nail growth stops and ridges develop. Other causes can be heart, liver and diabetes to name a few.  The most common cause is malnutrition; where the body is not absorbing key nutrients such as in Celiac disease, IBS, IBD or other conditions where the individual fails to get the nutrients needed to support healthy nail growth.

Nail clubbing:  Nail clubbing is an enlargement of your fingernails that curve around your fingertips.  This is a clue that there may be low oxygen levels in your blood and may be a sign of underlying lung and/or heart disease. Clubbing may also be a sign of inflammatory bowel or liver disease.

Nail pitting:  Nail pitting looks like a hail storm hit your nails. You’ll see tiny depressions on the surface of your nails. This profile is commonly seen with individuals that have psoriasis. People with psoriasis have an autoimmune disease. People with psoriasis aren’t typically treated for immune system dysfunction but rather are treated with topical medications to decrease the scaly skin patches.

I couldn’t list all of the nail conditions but I can tell you this: Most nail changes occur very slowly and can be subtle to detect. A change in nail texture is may be an indicator of nutrient deficiency and should be investigated as it may be an early sign of underlying health issues.

Image courtesy of ponsulak at