Proper diet and nutrition are crucial for maintaining good health. Good nutrition is also reflected in a person’s outward appearance, including that of the skin, hair and nails.

In recent years, researchers have found growing evidence of the link between healthy eating and a variety of positive health outcomes. These include reduced risk of heart disease and cancer. In addition, good eating habits may help prevent worsening of skin conditions such as psoriasis.

Recommended foods for good skin health include:

• Fruits
• Vegetables
• Whole grains
• “Good” fat, such as that found in vegetable oils, fish and nuts

On the other hand, foods containing substances such as sugar, saturated fat, cholesterol, sodium and alcohol should be avoided or consumed in moderation.

Good nutrition is essential for maintaining proper function of the body systems, including the skin, the largest organ. Most health experts recommend eating a balanced diet with a variety of healthful foods to keep skin healthy and glowing, as well as to prevent diseases such as cancer and heart disease. In addition, healthy eating habits may help prevent worsening of some skin conditions, such as psoriasis.

Many substances found in food affect the skin’s health. These include:

• Antioxidants. Chemicals that interact with other chemicals called free radicals, which can damage the skin and other cells. Vitamins A, C, E and beta carotene – as well as certain fruits and vegetables – have antioxidant properties. These are essential for skin health, help in wound healing and may also help protect skin cells against damage by free radicals. Free radicals are toxic molecules, which are naturally produced by oxygen, sunlight (ultraviolet radiation), smoking and pollution.
  
  Some studies have indicated that antioxidants may help slow down skin aging by ridding the body of free radicals. However, the evidence to support these claims remains mixed.
  
  
• Vitamin D. Consuming adequate amounts of vitamin D can aid in calcium absorption, bone formation and skin healing. Lack of vitamin D can lead to softening of the bones. Good sources of vitamin D include egg yolks, herring, sardines, tuna, salmon and fortified milk.
  
  Vitamin D is also naturally formed in the skin when it is exposed to direct sunlight. However, sun exposure should be limited to avoid the damaging effects of excessive ultraviolet radiation on the skin (e.g., skin cancer, wrinkles).
  
  Since the body requires calcium to benefit from vitamin D, foods that contain both nutrients (e.g., fortified milk, salmon) are especially beneficial. Many dietary supplements also contain both vitamin D and calcium.
  
  
• Vitamin A. This vitamin is essential for growth, vision and immune response. A lack of vitamin A can result in skin disorders. It can also cause the nails to split and break.  
  
  
• Fat. Some fat is necessary to maintain healthy skin, hair and nails. For instance, eating foods with omega-3-fatty acids (e.g., salmon, cod, bass, broccoli) can help protect against fungal and bacterial nail infections. However, reducing intake of foods high in certain types of fat and cholesterol can decrease the risk of weight gain and coronary heart disease.
  
  It is more important to reduce the type of fat (such as trans fats and saturated fats) than to reduce the amount of fat. Trans fats are unsaturated fatty acids (building blocks of dietary fats) formed when vegetable oils are processed and made more solid. They are found in fats labeled “partially hydrogenated.” Many margarines and foods in fast food restaurants are sources of trans fats. Saturated fats contain high levels of saturated fatty acids. They can be found in animal products such as cheese, butter and red meat. 
  
  
• Fiber. High fiber intake has been shown to substantially reduce the risk of coronary heart disease and stroke. Fiber is also associated with lower cholesterol levels and improved bowel function, which help promote healthy looking skin.
  
  
• Folate. A type of B vitamin important to the production of skin cells. Natural sources of folate include certain breakfast cereals, orange juice, peas, peanuts, beans and leafy green vegetables.
  
  
• Iron. Iron is essential to proper oxygen transport and regulation of cell growth, including skin cells. A deficiency of iron limits oxygen delivery to cells, causing fatigue, decreased immunity and pale skin. Thin, rigid or easily broken nails may also indicate a lack of iron. Sources of iron include liver, kidneys, red meat, poultry, eggs, peas, legumes, dried fruits and leafy green vegetables (e.g., kale).
  
  
• Protein. Protein helps prevent muscle tissue from breaking down and helps repair tissue that has been damaged, including skin tissue. Sources of protein include meat, fish, poultry, eggs, milk, cheese, dried beans and peas, peanut butter, nuts, bread and cereal.
  
  
• Zinc. Zinc plays a crucial role in promoting cell reproduction and the growth and repair of tissues. Brittle nails with white spots may indicate a deficiency in zinc. Sources of zinc include whole grains, poultry and seafood (particularly oysters).
  
  
• Alcohol. Drinking alcohol causes small blood vessels in the skin to widen (dilate), allowing more blood to flow close to the skin's surface. This results in a flushed appearance and a feeling of warmth, which may worsen skin conditions including acne, rosacea, psoriasis and certain types of ulcers (pressure sores). In addition, excessive consumption of alcohol can deplete the body of water and lead to dry skin.
  
  
• Caffeine. This stimulant and diuretic can be found in coffee, tea, soft drinks, chocolate and some over-the-counter drugs. Excessive consumption can contribute to dehydration, which can lead to sallow, dry skin.

An important step for healthy, radiant skin is to eat a balanced diet with foods known or strongly believed to promote good overall health. In general, it is best to consume:

• Fruits and vegetables. Studies have shown that consumption of fruits and vegetables can decrease the risk of various diseases including heart disease and cancer. Additionally, many of these are rich in antioxidants, which promote skin health. The U.S. Department of Agriculture (USDA) 2005 Dietary Guidelines for Americans recommends that people consume two and a half cups* of vegetables and two cups* of fruit each day. People are urged to choose the following fruits and vegetables:
  
  
• • Cruciferous vegetables. These include broccoli, cabbage, cauliflower and brussel sprouts.
    
    
  • Green, leafy vegetables.
    
    
  • Citrus fruits.
    
    
  • Fruits and vegetables rich in vitamin C - which promotes wound healing - including citrus, strawberries and tomatoes.

* Based on a reference intake of 2000 calories

• Whole grains. Whole grains are foods that have not had their bran removed by milling. They are packed with fiber and nutrients that are stripped from refined grains, which are found in most commercially-produced breads and flours. When selecting foods, look for the words “whole wheat” on the label. The USDA recommends three or more ounce-equivalents* of breads, cereals, rice and pasta each day. Good sources include whole grain versions of:
  
  
• • Breads
  • Pasta
  • Rice
  • Couscous
  • Polenta
  • Bulgur
    
    
  *Based on a reference intake of 2000 calories

In addition, the USDA recommends three cups of fat-free or low-fat servings of milk, yogurt and cheese; and lean, low-fat or fat-free meat, poultry, fish, dried beans and peas, eggs and nuts each day.

On the other hand, it is best to avoid eating too much of the following:

• Foods high in fats, especially saturated fats (foods that contain high levels of saturated fatty acids) and trans fatty acids (unsaturated fatty acids formed when vegetable oils are processed and made more solid).
  
  However, essential fatty acids, such as those found in vegetable oils (e.g., canola, flax seed), fish (e.g., salmon, tuna) and nuts are beneficial to the health of skin. Though fat provides many benefits to the body, consuming excessive amounts of any type of fat can lead to obesity and other health problems.
  
  
• Foods high in cholesterol. Cholesterol is a fat-like substance that helps digest fats. It also strengthens cell membranes and makes hormones. However, too much cholesterol can lead to a buildup on the walls of arteries, increasing the risk for blood clots, heart attacks and stroke. Red meats and foods that contain high levels of animal fats should be avoided.
  
  
• Sugars. Sugars provide calories without nutrients, and can lead to weight gain and tooth decay. In addition, excessive consumption of sugar may promote skin aging. Research indicates that sugar may inhibit the effectiveness of collagen within skin cells, which can result in loss of elasticity. Foods high in sugar include soft drinks, fruit drinks, puddings, ice cream and baked goods.
  
  
• Salt (sodium chloride). High levels of sodium can lead to high blood pressure, which can cause a variety of health problems. In addition, excess sodium is deposited beneath the skin, where it attracts a layer of water, resulting in a bloated appearance.

People should also consume a minimum of eight 8-ounce servings of water throughout the day. This amount increases for people who exercise regularly. This prevents the body from dehydrating, which can lead to dry skin. A person should not wait until they are thirsty before consuming water.

Tips for helping to promote healthy meals include the following:

• Incorporate fruits and vegetables into every meal. For example, add fruit to cereal and vegetables to pasta dishes.
  
  
• Snack on fruits and vegetables instead of sweets. Yogurt is another healthy alternative to sweets.
  
  
• Eat chicken, turkey, fish and beans instead of red meat and cheese.
  
  
• Use olive oil or canola oil, which contain polyunsaturated or monounsaturated fats (fatty acids that do not increase levels of total cholesterol or triglycerides) instead of saturated fats.
  
  
• Use margarines that do not have partially hydrogenated oils. Soft margarines usually have less trans fatty acids than stick margarines.
  
  
• Avoid crackers, cookies and cupcakes that contain partially hydrogenated fats (trans fats formed when hydrogen atoms are added to polyunsaturated fatty acids).
  
  
• Try to avoid fast food meals. Most fast foods are high in fat and calories and low in other nutrients. When ordering fast food, it is best to choose healthier items, such as broiled chicken or a green salad.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions regarding diet and skin health:

1. How is my diet affecting my skin condition?
   
   
2. Is all fat bad for my skin?
   
   
3. What kinds of vitamins and minerals should I consume to help promote skin health?
   
   
4. Which foods should I avoid that might be bad for my skin condition?
   
   
5. What types of foods should I be eating to improve skin health?
   
   
6. How can I change my eating habits to ensure that I am consuming all the nutrients my body needs?
   
   
7. Would limiting my consumption of alcohol benefit my skin?
   
   
8. Are there certain adjustments that I should make to my diet based on my age?
   
   
9. I have heard that drinking water is good for the skin. How much water should I be drinking?
   
   
10. Would taking nutritional supplements improve the appearance of my skin?