20 Nov 09

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Author: Dr. Karen (8 Articles)

Patient: A couple of my fingernails are curling downward as they grow. Is this due to a poor diet?

Optional Information
Gender: female
Age: 60
Already Tried: nothing

Doctor: Fingernail changes are due to SO many things, it is hard to say without a picture.

But in general, if your fingernails are strong, but curling this is less of a concern than if they are weak and “bendy”.


Curling down is very much associated with respiratory problems- asthma, chronic bronchitis, emphysema and the like.

Iron deficiency will produce pale nails which can curl.

There are many other causes-

See this site at Mayo-


There has not been shown that any dietary change can produce real changes.

However, it depends on what exactly is wrong.

Here is a site talking more about nutrition- but in general, protein, calcium, Vit, B and C have all been used to give better nail health.



You want to be examined- think of the nails as the windows to your body-

Some blood tests or even a chest Xray may be needed (esp if you smoke).

After this- you can rest easy than nothing major is wrong.

Feel free to ask anything else regarding this-

I am happy to add more color where you think it may be relevant

Patient: My nails are not weak or bendy. It is just within the last year that they have started to grow in this curved way. I have no respiratory problems although I do smoke. My mother’s nails did the same thing in her later years and she never smoked.

Doctor: It may be nothing- but with a history of smoking, you just want to make sure the lungs are OK. That is numero uno.

Aside from that, simply checking the nails general health and related lab tests if needed is the next step.

I misspoke- it is NOT just when they are weak and bendy that there is a concern with curling. Typical curling nails with lung disease (called clubbing) usually show thicker curling nails.

Make an appointment and ease your (and my) concerns.

The best to you

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  • salli says:

    I have a toenail that is bending over, is there a way you straighten it back out over time?
    Thank you.


    i have my fingernails bending over and weak,what could be the problem.

  • Teresa Kiernan says:

    I have noticed for awhile now that my middle fingernails bend and they are not that long…they are soft …I thought it was from years of biting them previously …but as a smoker and reading about curved nails was wondering if its worth visting my doctor!

  • Rhonda says:

    My nails curl also, I have actually gone to the doctor about it and been tested and what I found out is that it was a vitamin d deficiency. I have only been taking the vitamin d for a couple of months now and I can notice a little change but not much as of yet. And by the way I am a smoker also and my doctor knows this so I don’t think it has anything to do with smoking.

  • Mystica says:

    My fingernails have curled over the ends of my fingers most of my life. I was diagnosed as asthmatic at age 19 (I’m now 55). my fingernails are pink, but without the little “half-moon” shapes at the bottoms (except my thumb nails). One thumb nail is very strong and solid; the other one tends to separate and peel. Most of my nails have longitudinal stria (lines and ridges). I recently began taking a women’s multivitamin, which seems to have fixed the peeling/separating of the one nail, and some of the stria seem to be smoothing out. Most of the nails still curl over, though, either in the center (ring fingers) or to the inside (medial) sides of the nail. At least, now I understand the curling, so thank you! :-)

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