Often we meet a friend we haven't seen for a few years, and they've barely changed at all. Others have aged so much we barely recognize them. The difference? Good genes can't be discounted, but the most important elements of aging involve lifestyle, especially eating a healthy diet.

Some foods are better than others in battling Father Time, especially those that fight inflammation. These eight foods have special nutrients that help you turn back the clock:

• Fish. Fatty fish, like salmon, tuna, and mackerel, contain large amounts of omega-3 fatty acids that fight many of the diseases of aging, including cardiovascular disease by preventing the buildup of cholesterol in arteries. Fatty fish, due to its anti-inflammatory properties, also fights Alzheimer's disease, arthritis, cancer, and helps keep skin young. The American Heart Association recommends two servings a week.

• Chocolate. Studies show that chocolate boosts brain function and lowers blood pressure. A German study found that small amounts of chocolate daily could reduce the risk of heart attack and stroke by almost 40 percent. Amounts as small as those in two Hershey's Kisses have been found to be effective, but most experts recommend 1 to 1.5 ounces of dark chocolate. The flavanols in chocolate also help protect against Type 2 diabetes, dementia, and kidney disease.

• Yogurt. Yogurt has been associated with longevity since a 1970s study found that Soviet Georgia had a higher percentage of centenarians than any other country in the world. The seniors attributed their long lives to the high amount of yogurt in their diets. Yogurt, in addition to being rich in bone-strengthening calcium, contains "good" bacteria that help sustain a healthy intestinal tract.

 Berries. Raspberries, blueberries, and other berries contain antioxidants called anthocyanins which give berries their deep color and slow the aging process — the darker the berry, the higher the amounts of antioxidants. Researchers at Tufts University found that rats given blueberry extract for the human equivalent of 10 years out-performed control rats in their old age. A daily cup of fresh or frozen berries fights the inflammation that leads to aging.

• Tomatoes. Lycopene, the antioxidant that gives tomatoes their vibrant color, keeps skin looking young and may also lower the risk of heart disease and several cancers. A two-month trial at Cambridge University tested a lycopene supplement on both healthy volunteers and those with pre-existing heart conditions. Researchers found that the pill lowered the amounts of LDL (bad) cholesterol by as much as 90 percent. Another study found that men who ate 10 servings of tomato-based foods weekly reduced their risk of prostate cancer by 45 percent.

• Broccoli. Broccoli is loaded with vitamins and minerals, including chromium, that slow the aging process and boost brain function. The sulforaphane found in broccoli and other cruciferous vegetables, including cabbage and Brussels sprouts, reduces the risk of heart attack and stroke as well as cancer. Scientists from Texas Tech University found that the chemical diindolylmethane (DIM), which is created in the body after eating broccoli, inhibits the activation of STAT3 — a protein involved in the growth and survival of tumors. It also improved the effectiveness of the chemotherapy drug cisplatin by 50 percent without damaging healthy cells. Some experts recommend two servings of cruciferous vegetables daily.

• Olive oil. Olive oil is a staple of the Mediterranean diet, and an avalanche of studies during the past couple of decades have shown its many health benefits. Olive oil contains powerful antioxidants called polyphenols that have anti-inflammatory properties and fight heart disease, cancer, and Alzheimer's. A study published in the journal ACS Chemical Neuroscience found that a substance in olive oil called oleocanthal helps decrease the accumulation of beta-amyloid in the brain — the abnormal proteins that clump together and cause memory loss.

• Nuts. A handful of nuts of any kind daily — one to two ounces — contains liberal amounts of inflammation-fighting omega-3 fatty acids and offers benefits similar to those of olive oil. One study found that those who ate nuts every day had 60 percent fewer heart attacks than those who ate nuts less than once a month. Nuts also help the production of elastin and collagen, compounds that keep skin looking young.