Your brittle nails probably due to dryness

Q. Are brittle nails that break easily a sign that I need more of a specific nutrient?

A. Actually, the most common cause of brittle nails is dryness resulting from frequent exposure to water or from exposure to harsh cleaners or other chemicals. Wearing rubber gloves to protect hands and nails when working in water or with harsh chemicals can prevent this problem.

People who are drastically limiting their calories could also have problems with breaking nails due to inadequate calorie or protein intake. To ensure you are meeting your protein needs, include modest amounts of protein in your diet each day. Good sources include: poultry, seafood and lean meat (about 3 ounces per serving); low-fat dairy products; and plant-based protein sources, like soy products, beans, nuts and seeds.

If nail problems still persist despite dietary changes, you could consider a supplement of the B vitamin biotin. Some research suggests that about 2,500 micrograms (mcg; equal to 2.5 milligrams) can help. However, as this is so far beyond the 30 mcg the Institute of Medicine currently identifies as adequate, be sure to check with your health care provider before initiating supplement use.

Although no adverse effects have been reported even with amounts beyond 2,500 mcg, a safe upper limit has yet to be established for the vitamin, so proceed with caution. If you do start taking a biotin supplement, a three-month course is generally recommended. If you see no improvement, stop taking the supplement. If problem nails get better, try to slowly reduce the amount of the supplement that you take each day.

Q. Do products that help people lose weight while they sleep really work?

A. Remember that if it sounds too good to be true, it probably is. Some of these products contain a diuretic that increases the amount of urine passed. So, although your scale may indeed go down in the morning, you've lost water weight, not fat. Other products instruct users to avoid eating three hours before bed.

For someone who has been doing a lot of late-night eating, cutting out those extra calories could produce weight loss that has nothing to do with the supplement.