Skin is pretty important to your appearance — it's part of that "first impression." There is a lot riding on the story your face tells, so I asked some top skin and nutrition experts a few questions.

What can you change in your diet that will show results in your skin?

Green tea and red wine: Wrinkles are caused by a loss of three vital skin structures: collagen, elastin and hyalur-onic acid. The goal in wrinkle treatment is to increase levels of these three substances, says Dr. Leslie Baumann, professor of dermatology at the University of Miami and author of "The Skin Type Solution" (Bantam, 2006). Drink two to four cups of green tea per day.

"It has a high content of flavonoid/catechins, (which can help to strengthen collagen) and of theanine — an amino acid associated with relaxation and cortisol control. Too much cortisol can induce disruptions in blood sugar and inflammation," says Shawn M. Talbott, author of "Cortisol Control and the Beauty Connection" (Hunter House, 2007). Red wine has a flavonoid/collagen effect similar to green tea and is known for its relaxation effects and blood flow promotion, he adds.

Water: Of course you need to drink water to prevent dehydration. "However, as far as skin is concerned, it is not how much water you drink but how well your skin holds onto the water. Skin needs adequate levels of fatty acids, ceramides (a type of fat) and cholesterol to hold on to water. This is why vegans and people on low-cholesterol diets or cholesterol-lowering drugs have dry skin.

"Any liquid you drink can provide skin hydration; however, water consumption should be increased when drinking caffeine and alcohol, both of which can dehydrate you," says Baumann.

Omega-3s: "Healthy omega-3 fatty acids help maintain cell membranes so that they are effective barriers — allowing water and nutrients in and keeping toxins out. Omega-3s also seem to protect skin against sun damage. In a study of skin cancer, people who ate diets rich in fish oils and other omega-3 fats had a 29 percent lower risk of squamous-cell cancer than those who got very little omega-3 fats from food," says Joy Bauer, author of "Joy Bauer's Food Cures" (Rodale, 2007). They are also anti-inflammatory, so they help reduce acne and facial redness. "Good food sources include oily fish, sardines, Pacific oysters, lake trout, flaxseeds, walnuts and omega-3 fortified eggs," adds Bauer.

Grains: Eat whole-grain carbs (as opposed to refined carbs), which don't cause the blood sugar spikes that lead to the glycation (sugar breaking down) of skin proteins that accelerates wrinkling, says Talbott.

Vitamin C: It's involved in collagen production and protects cells from free radical damage. "Scientific studies found that when lab animals ate vitamin C-fortified food, their skin was better able to fight off oxidative damage," says Bauer. Baumann adds that getting the proper amount in your diet can help reverse wrinkles. Good sources include oranges, strawberries, lemons, broccoli and peppers (red/green/yellow).

Vitamin E: This helps protect cell membranes and guards against UV radiation damage. "Some research suggests that vitamin E may work in combination with vitamin C to provide an extra boost of anti-aging skin protection.

Beta carotene: "Beta carotene/vitamin A is involved in the growth and repair of skin tissue and may protect against sun damage. In extremely high doses, straight vitamin A from supplements can be toxic, but ample beta carotene from foods like sweet potato, pumpkin, carrots, mangoes and apricots is entirely safe and great for your skin," says Bauer.

Selenium: "This helps safeguard the skin from sun damage and delays aging by protecting skin quality and elasticity," says Bauer. Food sources include Brazil nuts, tuna (canned light in water), crab and wheat germ.

Coenzyme Q10: According to Baumann, research at the University of Miami has demonstrated a positive result from using a coenzyme Q10 supplement to treat skin cancers. She recommends 200 milligrams every morning because it has a caffeine-like effect.

Glucosamine: Available as a dietary supplement, it increases hyaluronic acid levels, which helps skin hold on to water and gives it plumpness, Baumann says.

What foods can actually damage your skin?

Sugar: Sugar is the most detrimental to skin. It increases acne and may speed aging by causing glycation — the result of sugar breaking down and bonding with protein molecules, which reduces the elasticity of the collagen and leads to tougher, wrinkled skin, says Baumann.

According to Talbott, "Sugar is very bad for the same reason that poorly controlled diabetics have more heart disease and blood vessel damage (due to glycation of these tissues). The same effects can occur to the skin."

Spicy foods: "If you are prone to facial flushing, hot (temperature) or spicy foods will increase flushing, leading to dilated visible blood vessels on the face," says Baumann.

Caffeine: It can dehydrate you, but it also has an anti-inflammatory and anti-aging effect. It is the most popular ingredient in cellulite creams and is a hot ingredient in many skin-care products, adds Baumann.

Alcohol: Red wine has two substances that prevent aging — grape seed extract and resveratrol. However, too much alcohol ages the skin, says Baumann.

Chocolate and greasy foods: Most of the research says chocolate doesn't specifically affect your skin; however, foods that are high in saturated and trans fats have been shown to do so.

Stress: "This can increase oil production in the skin (via cortisol overexposure) — leading to clogged pores and an environment suitable for bacteria-overgrowth," says Talbott.

Charles Stuart Platkin is a nutrition and public-health advocate, and author of "Breaking the FAT Pattern" (Plume, 2006). Sign up for the free Diet Detective newsletter at www.dietdetective.com.