While overall adequate nutrition is important for maintaining healthy fingernails among other things, vitamin B-12 deficiency may be evident in changes to your fingernails. If you notice any changes in your fingernails such as brittleness, discoloration or streaks, speak with your doctor.
Causes of an Uncommon Deficiency
Vitamin B-12 deficiency is not very common in the United States, and people who don't get enough of the vitamin tend to be over age 50 because malabsorption issues are more common as you age. Other people who may have trouble getting enough of the vitamin are those who have digestive disorders, have had gastrointestinal surgery or who have pernicious anemia. Vegans and strict vegetarians are also more at risk for deficiency because animal protein is the only natural food source of vitamin B-12. Vitamin B-12 deficiency can take two to five years to fully develop because, although your body cannot synthesize vitamin B-12, it can store it in large amounts.
According to researchers of an article published in "The Journal of Family Practice" in 2012, vitamin B-12 deficiency can manifest in fingernails as entirely blue nails, bluish-black pigment with wavy longitudinal dark streaks, brownish networklike pigmentation and longitudinal darkened streaks. The researchers also said these nail changes were reversible as they resolved with B-12 supplementation therapy.
Cannot Fix What Isn't Broken
Taking a vitamin B-12 supplement may not improve your nail strength if you are already well-nourished, according to researchers of a review study published in 2007 in "Journal of Drugs in Dermatology." These researchers studied the role of several vitamins and minerals in nail health and found that vitamin B-12 supplements do not improve your nail health or strength if you are not deficient in vitamin B-12.
Getting Enough Vitamin B-12
To ensure healthy nails, eat a healthy diet, which includes consuming adequate vitamin B-12. The recommended dietary allowance for vitamin B-12 is 2.4 micrograms daily. You can obtain vitamin B-12 from animal products including fish, poultry, meat, eggs and dairy, or if you do not eat animal products, you can obtain vitamin B-12 from fortified breakfast cereals or a supplement. Breakfast cereals can be fortified with 100 percent of the daily value of vitamin B-12, while 3 ounces of trout or salmon provide 90 and 80 percent, respectively; 3 ounces of beef provides 23 percent; 1 cup of low-fat milk provides 18 percent; one egg provides 10 percent; and 3 ounces of roasted chicken breast provides 5 percent of the DV.