Why Are My Fingernails So Brittle?

Ask Peggy

Peggy Woodward, RD

DEAR PEGGY: Over the past couple of years my finger nails have become very brittle. They are very thin, flake at the tips, and I am constantly getting snags on them. I am at the very end of the perimenopausal stage in life and am wondering if that has something to do with it or is my diet lacking something? —B.S., Muscatine, IA

Brittle nails can simply be a symptom of aging, but low levels of zinc and iron are often associated with brittle nails, so you're right to be concerned. Most women over the age of 50 need about 8 mg of zinc per day. Zinc deficiency is fairly uncommon in Americans and most often seen in the elderly or strict vegetarians, where there may be nutrient deficiencies. These are some dietary sources of zinc:

  • 4 ounces sirloin steak - 7.4 mg
  • 4 ounces canned crab meat - 4.6 mg
  • 1 cup cooked black-eyed peas - 2.2 mg

Most women over the age of 50 need about 8 mg iron per day. Iron needs for women decrease slightly as they stop menstruating. So if nothing else in your diet has changed, it's unlikely that you are suddenly not getting enough iron. These are some dietary sources of iron:

  • 1 cup cooked spinach - 6.4 mg
  • 5 ounces sirloin steak - 4.8 mg
  • 1/2 cup cooked green peas 1.3 mg

Beef and seafood are rich sources of both zinc and iron. If you are a vegetarian, you may want to take a closer look at your diet and make sure you are getting enough of those nutrients. If you are still concerned you should see your doctor to have your iron checked. Lab tests for zinc do not accurately reflect zinc status but your physician could evaluate other signs and symptoms for a zinc deficiency.