"The eyes may be the window to your soul, but your mouth is a reflection of your overall health," says Elisa Mello, D.D.S., a cosmetic and reconstructive dentist with NYC Smile Design in New York.
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, Mello says. Likewise, gum disease has been linked to an increased risk of heart disease, hardening of the arteries, and pre-term delivery during pregnancy.
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.
But it's never too late to adopt healthy dental habits, and there's no need to grin and bear a smile that's anything less than sparkling.
Reduce Acid Exposure
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," says Gigi Meinecke, D.M.D., a fellow in the Academy of General Dentistry. 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," says Craig Zunka, D.D.S., president of the Holistic Dental Association.
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.
Relax Your Jaw
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," says Chris Kammer, D.D.S., president of the American Academy for Oral Systemic Health.
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, Zunka says.
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.
Eat Smile-Friendly Foods
Crunchy raw apples, celery, carrots, and nuts can mechanically clean teeth as you chew them, so they make good desserts or snacks, Kammer says. 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, Zunka says.
For gums, be sure you're incorporating foods or supplements with vitamin C and omega-3 fatty acids for healing and anti-inflammatory effects.
Brush Your Teeth Correctly -- and Gently!
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, Mello advises.
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.
She adds, "I recommend flossing before you brush, because you loosen up debris that you can then brush off."
Learn How Your Meds May Affect Your Mouth
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," Mello says, "so it's important to check the side effects of all nutritional supplements before taking them."
Adds Meinecke, "Saliva has calcium ions in it, and 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.
Watch Out for Staining Agents
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, Mello says. 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.
Read more: 5 Tools to Save Your Smile