Maintaining healthy teeth does get a little more challenging as we get older: Over time, acid exposure, bacteria, staining agents, and other culprits can sabotage your smile. 

When you want to measure how healthy you are, you probably think about how many fruits and veggies you have each day or whether you get winded when you climb the stairs. But the answer could be right under your nose. Conditions like diabetes, anemia, or immune or nutritional deficiencies can show up as bleeding gums, rampant tooth decay, or swelling or discoloration of the tongue and gum tissue. Likewise, gum disease has been linked to an increased risk of heart disease and hardening of the arteries.

It's never too late to adopt healthy dental habits -- find them on the following slides, along with tips for keeping your lips looking their best.

Sports drinks, sodas, seltzers, citrus fruits, and fruit juices can erode enamel and soften the hardened matrix by dissolving the tooth's protective covering. You don't have to steer clear of these foods and beverages entirely, but you should rinse your mouth with water to neutralize the acids after consuming them.

The counterintuitive advice: Rinse, but don't brush your teeth within an hour of eating or drinking acidic foods, because you'll actually be abrading your teeth with the acid. Or chew a sugarless gum (such as Spry) sweetened with xylitol, which decreases oral acidity.

They not only cause cavities, gum disease, and bad breath -- they also produce acid, which then causes more decay. Sugar is like jet fuel for bacteria -- it's what bacteria feast on, and it causes tooth decay and gum disease to develop much faster.

To get rid of harmful bacteria, thoroughly remove plaque by flossing once a day, brushing at least twice a day, and using an oral irrigator. Also cut back on sugary or starchy foods that stick to the teeth, and drink lots of water, especially after a carb-heavy meal.

If the edges of your teeth look thin or worn down, or if you frequently wake up with a sore jaw or a headache, you may be clenching or grinding your teeth at night. This can wear down or put pressure on the teeth, resulting in cracks and receding gums, which can really age your smile.

Wear a mouth guard at night, and make sure you're getting enough calcium -- a deficiency can cause muscle cramps that may make you clench. To relax your jaw before bed, try pressing your fingers against the large muscles in your cheeks that you use for chewing for 10 seconds while squeezing your teeth tight, then relax the muscles and jaw for five seconds. Repeat six times.

Crunchy raw apples, celery, carrots, and nuts can mechanically clean teeth as you chew them, so they make good desserts or snacks. Also, probiotics -- beneficial bacteria in certain yogurts, kefir, and tempeh -- can reduce acidity and bad bacteria in your mouth.

Make sure you're getting plenty of calcium, vitamin D, phosphorus, and magnesium to help your teeth resist decay and stains and strengthen the bone that holds them. For gums, be sure you're incorporating foods or supplements with vitamin C and omega-3 fatty acids for healing and anti-inflammatory effects.

Don't use too much pressure or rake the brush back and forth, which leads to gum recession and loss of enamel. Instead, slant your toothbrush up and toward the gumline at a 45-degree angle and brush gently for at least two minutes.

Flossing is also crucial to remove plaque and particles that stick to the teeth and gums and to polish the tooth's surface: Wrap the floss around the tooth in a C shape, then glide it up, down, and around each tooth to really clean each side. Try flossing before you brush; you'll loosen up debris that you can then brush off.

Dry mouth is one of the most common side effects of many prescription and over-the-counter medications, including allergy and asthma drugs, antacids, antidepressants, antianxiety meds, and blood pressure drugs. Some vitamins -- such as A, C, D, and E -- have been linked to dry skin and dry mouth; check the side effects of all nutritional supplements before taking them.

Because saliva has calcium ions in it, it bathes your teeth in that protective solution, which buffers them from developing cavities. If you're experiencing dry mouth, drink plenty of water and avoid toothpastes with sodium lauryl sulfate and mouth rinses that contain alcohol, since they can be drying.

Certain foods and drinks -- including beets, red wine, cola, coffee, and most forms of tea (even many herbals) -- can cause tooth discoloration.

The key to preventing this is to keep your mouth super clean and avoid the buildup of plaque, which attracts stains. If possible, brush right after eating or drinking these culprit items to minimize the chance of stains setting on your teeth and to help your saliva naturally wash the stain away.

Outfit your medicine cabinet with these must-haves to keep your teeth and gums in great shape.

The right toothpaste: To keep teeth healthy and bright, look for a toothpaste that targets your dental issues -- for instance, a formula that whitens, offers tartar control, or is designed for sensitive teeth.

Dental floss: Unwaxed floss does a better job of cleaning because it's not slick. However, if your teeth are too tight to accommodate the unwaxed variety, go with a waxed or silky-coated floss.

Electric toothbrush: This moves fast and strokes the teeth more than you could do yourself.

Tongue scraper: Often a bumpy surface on the back of a toothbrush, this scrapes and dislodges odor-and cavity-causing bacteria from the tongue and cheeks.

Oral irrigator: Using pressurized water to dislodge plaque and bacteria between the teeth and under the gumline, an irrigator can flush bacteria from hard-to-reach places.

Fluoride protects the teeth from damage caused by acid and helps strengthen enamel. Some consumers have raised concerns that getting too much fluoride could lead to fluorosis (white spots on the teeth), especially in kids.

Problems like these really come from ingesting too much fluoride in foods, water, and other beverages. There are no fluorosis risks associated with fluoride in toothpaste, unless you're swallowing it regularly. If you have dry mouth or gum recession, a fluoride toothpaste can help make your teeth more resistant to decay.

Our lips age differently than the rest of our skin does: Because the muscles of the lips are in a circle around the mouth, every time the lips contract they get smaller and wrinkle, causing the formation of unwanted vertical lines. Keep your lips looking their best with these preventative tips.

Protect your pucker: The ravages of smoking and sun can be found in the form of vertical pucker lines on the lips. When it comes to smoking, the solution is simple: Don't. When it comes to sun, just protect your lips as you protect your skin: with moisturizer, in the form of a lip balm with SPF.

Get your vitamins: Antioxidants can help reverse sun damage and protect your lips from accelerated aging by encouraging collagen production and inhibiting inflammation from sun exposure. Products that contain a combination of vitamins C and E and melatonin have been shown to prevent and correct the signs of aging by directly targeting free radical damage.