As we age, we eat less, cook less, and our metabolism slows. On average, seniors eat 1,200 calories a day. Meals are less likely to be balanced and drug regimens—such as corticosteroids, anticonvulsants, thyroid hormone, antibiotics, laxatives, or diuretics—may interfere with how some vitamins are absorbed by your body. Depending on your health and lifestyle, a multivitamin could be an essential addition to your daily routine.

Older people can easily become deficient in vitamins D, B6, and B12, and minerals like folic acid, iron, zinc, magnesium, and calcium. This is especially true if you lack exposure to sunlight or can’t eat certain foods. Lack of vitamin B12 can occasionally mimic more serious problems like confusion and memory loss, so if you’re experiencing these symptoms, make sure you’re checked for vitamin deficiency as well.

Some studies show that seniors’ immune systems may benefit from vitamin E in levels higher than the recommended daily dosage. But remember, your metabolism has slowed down; vitamin doses that are easily tolerated by younger people may make you sick. Ask your doctor to help you create a personalized vitamin plan. An extra pill or two first thing in the morning can make a huge difference in how you feel.

Lots of people say that life's third act is the best. Want proof? Just look at 89 year-old entertainment legend Betty White. She's spent seven decades in show business–she even helped demonstrate television at the 1939 World's Fair!–and her career is more vital than ever. The Emmy-Award winning actress, best known for her starring roles on The Mary Tyler Moore Show and Golden Girls, is blazing new ground for senior citizens and shows no sign of stopping. Here are some of Betty’s recent career highlights:

– In 2010, Betty became the oldest person ever to host Saturday Night Live. She was such a hit on the show that she earned a Primetime Emmy for Outstanding Guest Actress in a Comedy Series.

– She's now starring in the popular TV Land sitcom Hot In Cleveland, and she has recently held guest spots on a number of top TV shows, including Boston Legal, 30 Rock, That 70s Show and My Name is Earl.

– She appeared in 2009’s The Proposal alongside Sandra Bullock and Ryan Reynolds. Hollywood watchers credited Betty with the movie's massive success.

– She appeared in a now-iconic Snickers commercial with Abe Vigoda during Super Bowl XLIV, which won the top spot on the USA Today Super Bowl Ad Meter.

– In 2011, she appeared in the Hallmark Hall of Fame movie The Lost Valentine, which received the highest rating for a Hallmark Hall of Fame movie in the past four years and won first place in the prime-time slot for that date.

And those are just her ventures on screen! Betty is also America's foremost animal health advocate, and she has authored multiple books. Her latest book, If You Ask Me (And of Course You Won’t), was published in early 2011. Betty White’s life is a source of inspiration for seniors everywhere – her positive energy, her commitment to pursuing her passions, and her dauntless sense of humor. If you want to age with grace and style, there’s no better model than Betty White.

What do senior citizen music superstars like Paul McCartney, Bruce Springsteen, and Mick Jagger have in common? Sure, they share fame, fortune, and talent, but one of their most exciting mutual traits is their commitment to growing older with creativity and stamina. Still bringing down the house in their senior years and loved by fans of all ages, these legends prove that age truly is just a number.

Paul McCartney. Now 69 years old, the former Beatle and founder of Wings recently received the Gershwin Award in Music, which was presented to him at the White House by President Obama. The award is given to a composer for a lifetime of achievement in the music. He is still playing to packed concerts all over the world.

Bruce Springsteen. He's as much “The Boss” as ever. In 2009, he performed at the halftime show of Super Bowl XLII, wowing kids and longtime fans. That same year, he was named one of eight “Artists of the Decade” by Rolling Stone Magazine. In the past 10 years, Springsteen and his E Street Band have enjoyed a creative and commercial renaissance.

Mick Jagger. At the age of 68, he's still sexy, still dangerous. In 2007, The Rolling Stones made the Guinness Book of World Records for the success of their “A Bigger Bang” tour. Jagger recently started a new band, SuperHeavy, featuring acclaimed younger musicians Damian Marley, Joss Stone and others.

These senior rockers have defined what it means to age with style, providing inspiration to older adults all over the world. They don’t plan to slow down anytime soon, and neither should you. Rock on!