Nail Health:

What Your Nails Tell You About Your Blood Circulation and Overall Health Status

By Dr. Ben Kim

It takes about 6 months for the average adult to grow a complete fingernail. In contrast, it takes about 18 months to grow a complete toenail.

There are plenty of reasons why your toenails grow at a slower clip than your fingernails do, the main one being that your toenails are further away from your heart, and therefore receive less overall and quality blood supply - I mentioned this earlier in a post on how to promote good blood circulation in your legs and feet.

Your nails actually serve a number of helpful functions, the most obvious ones being:

  1. The ability to work with small objects, like when you're peeling an orange, tying or untying a knot, or working at removing a sliver from your skin.
  2. The ability to get a sense of an object's weight and texture; when your fingers or toes touch an object, sensory receptors in your nails register a change in resistance, and the degree of change in resistance is what gives your brain an idea of the weight and texture of the object that you are touching.

Your nails also provide a quick look at your overall health status. A simple test that I do during every comprehensive patient evaluation is the capillary refill test, performed by pressing down on a person's fingernail, maintaining this pressure until blood circulation is compromised enough to turn the nail white, and then releasing the nail and observing the length of time that's required for the nail to fill up with blood and turn a healthy pink again.

If blood circulation is reasonably strong, a person's nail should turn pink within 2 seconds or less. If blood circulation is compromised, capillary refill time increases.

If several nails are yellow, hard, and curved, this may be indicative of significant lung disease or congestion within the lymphatic system.

Brittle, spoon-shaped or ridged nails may be a sign of anemia that is caused by being deficient in iron.

Black splinter-like lesions may indicate heart or lung disease.

Nails that appear to be lifting off or separating from the nail bed is often a sign of a hyperactive thyroid gland.

Weak and brittle nails in the hands and feet may simply be a sign of malnutrition - my experience has been that this is common among strict vegans who don't get enough healthy fat, healthy protein, and certain minerals from their diet.

Why You Shouldn't Chew on Your Nails

One final note about your nails: it's best to avoid the habit of biting on your nails or cuticles - doing so can transfer bacteria from your mouth to the rich supply of blood that exists under your nails.

This is more dangerous than you'd think, since the lack of fatty tissue between your nails and the underlying bones (phalanges) makes these bones quite susceptible to getting infected.

The fatty, subcutaneous layer of tissue that exists under your skin throughout most of the rest of your body provides a layer of protection against bone infections by common bacteria like streptococci and staphylococci.

For this reason, if your work requires handling of raw meat, it's best that you wear gloves while you work to reduce the risk of infection.

Dr. Ben KimImprove Your Health With Our Free E-mail Newsletter

Join thousands of people from all over the world who receive our natural health newsletter.

  • 100% free. You can unsubscribe anytime.
  • No spam. We respect and protect your privacy at all times.
  • Valuable information that you can use to improve the quality of your health and life.
First Name:


Just a note to let you know how much I appreciate your newsletter. As a fellow health care provider (optometrist) and medical researcher, I find your distillation of the literature into lay terms to be accurate and very understandable. I really enjoyed your contribution regarding macular degeneration. Keep up the good work. - Kristine Erickson, OD, PhD, FAAO

I get a lot of e-mailed newsletters and yours is the only one I read thoroughly from top to bottom. Your advice is enlightening, educational, easy to follow and it works! Thank you so much for all that you offer. - Lisa Abramovic

Thanks for your excellent health newsletter. I look forward to it every week. Thanks for providing the best online health resource I have found. - Anonymous

I'm sure as a doctor you hear your share of complaints. I just thought you'd like to know that there's at least one person in your "e-audience" that appreciates the time and effort you put into sending the emails. I really look forward to them. - Linda H., Raleigh, North Carolina

Many of my adult ESL students are Korean, and enjoy bits and pieces from your newsletter that I have shared with them. In addition to your logical approach to health, I enjoy sharing your newsletter because your English is unfailingly correct as well as easily understood. Thank you for your beautiful approach to life. - J. Zetterstrom

I thank you and your staff for such a great website. I am former National Level Bodybuilder so I know a thing or two about health and fitness. Your site is very valuable and I do my best to pass it on to friends and people I train. It is also a helpful resource in my career as a human service provider working with clients who need to recover from substance abuse. I believe a major part of recovery is getting your body and mind feeling healthy and strong. Thank you again! Great Website! - Michael Christopher, MSW

I truly appreciate your wonderful newsletter - your balanced and professional way of looking at issues is so helpful! - Erica H.

First Name:

Disclaimer: Throughout this entire website, statements are made pertaining to the properties and/or functions of food and/or nutritional products. These statements have not been evaluated by the Food and Drug Administration and these materials and products are not intended to diagnose, treat, cure or prevent any disease.