3. Vitamin B-12 for brain function

Ewoldt says that as women age, they absorb fewer nutrients from their food. One key nutrient they may not be absorbing enough of is vitamin B-12, which is essential for maintaining both healthy red blood cells and brain function.

"The best sources of vitamin B-12 are eggs, milk, lean meats, fish and fortified foods like cereals and grains," says Ewoldt. "Vegans, in particular, will need to choose more fortified foods, but even elderly people who eat all foods may have difficulty absorbing enough vitamin B-12."

While the recommended daily intake of vitamin B-12 for women over 50 is 2.4 micrograms a day, Ewoldt suggests you talk with your doctor to see if you also need a supplement.

Ewoldt offers three tips to help women over 50 get the nutrition they need.

• Make whole foods the foundation of your diet. "Focusing on whole grains, fruits and veggies will help avoid a lot of common problems that come with age," says Ewoldt.
• Drink before you're thirsty. The way your body detects thirst changes as you age. Says Ewoldt, "Make sure to drink plenty of water, even if you don't feel thirsty. Carry a water bottle, and drink a glass with every meal."
• Make an appointment with food. (And keep it.) Ewoldt often suggests that his clients create concrete plans that lay out exactly how they'll get key nutrients. He adds, "Write the plan on a calendar. By simply making an 'appointment' with that apple, you're more likely to eat it."