Healthy Diet, Healthy Skin

The skin is the body’s largest organ, accounting for 20% of body weight and serving primarily as a physical barrier against microorganisms, ultraviolet (UV) light, abrasions, dehydration and pollution. Loaded with sensory nerve endings, skin regulates body temperature, excretes waste and synthesizes vitamin D. Human skin has three layers:

Epidermis. This outer layer actually consists of two layers: (1) the superficial statum corneum, made up of packed skin cells called keratinocytes that are constantly shed and replaced, and (2) the underlying basal or “living” layer, which supplies new keratinocytes. Younger skin has a greater ability to rejuvenate, because the basal layer’s capacity to create new cells declines with age (Stanulis-Praeger & Gilchrest 1986).

Dermis. This inner layer, or foundation, is filled with blood vessels, lymph channels, nerves, sweat and oil glands, hair follicles and structural connective tissues like collagen and elastin. These connective tissues are strong, flexible proteins responsible for skin’s strength, elasticity and stretchiness.

Subcutaneous fat. This layer insulates and stores nutrients.

Finally, muscle provides definition and firmness to skin.

As we age, our ability to replace dead keratinocytes slows, collagen fibers stiffen and break apart, and elastic fibers thicken and fray—all contributing to wrinkles. Fibroblasts that produce collagen and elastin decrease in number, subcutaneous fat begins to disappear, sebaceous (oil) glands atrophy and pigmentation fades (Gilchrest 1996). All these changes yield dry, sagging skin and an ashen skin tone. Although genetics play a role in skin appearance, environmental factors have a profound effect. Skin aging is accelerated by free-radical damage from smoking, sunlight and pollution (Gilchrest 1996).

All these effects show up on our faces, where healthy skin is the most obvious manifestation of overall health. This skin is the most vulnerable to aging—thanks to 24/7 exposure to environmental insults, the constant movements of facial expressions and thin epidermis around the eyes.

You may be familiar with the term “nutricosmetics,” which describes the use of oral and topical agents that boost skin appearance (Draelos 2010). Nutrient-rich peels, creams, fillers and injections can help alleviate Father Time’s signature, but diets rich in certain nutrients may boost youthfulness from the inside out.

Recipe for Healthy Skin

The diet-appearance connection has long fascinated scientists. Studies associating diet with acne, clear skin tone and overall skin health have demonstrated that certain vitamins, minerals and fats may help create a healthy, ageless glow.

1. Cosgrove et al. (2007) assessed the relationship between diet and skin aging in 4,025 middle-aged women. Those whose faces had a wrinkled appearance consumed significantly less protein, potassium, vitamin C and vitamin A. Dry skin was observed in women with lower linoleic acid and vitamin C intake.
2. Boelsma et al. (2003) found in a study of 302 adults that serum vitamin A levels that correlated to sebum content and fat intake were associated with skin hydration.
3. Purba et al. (2001) observed less sun-exposed skin wrinkling in older adults who consumed eggs, yogurt, legumes, fruits, vegetables and olive oil, suggesting that diets rich in antioxidant vitamins and minerals and certain fats may ward off signs of aging.

Here’s a quick look at the top skin-enhancing vitamins and nutrients:

Vitamin C

The most abundant water-soluble antioxidant, vitamin C resides in cellular fluids and plays a key role in collagen synthesis. Citrus fruits, strawberries, tomatoes, bell peppers and baked potatoes are excellent sources. Smoother skin was observed in women who consumed vitamin C foods (Cosgrove et al. 2007).

Vitamin E

The most abundant fat-soluble antioxidant, vitamin E strengthens and protects the vulnerable subcutaneous fat layer against free-radical damage. Whole, unprocessed grains such as wheat, wheat germ, barley and rye—as well as sunflower oil and almonds—are excellent sources of vitamin E.

Vitamin D

Vitamin D is called the “sunshine” vitamin, because UV rays reaching the skin trigger a chemical reaction that releases vitamin D in the body. In keratinocytes, active vitamin D regulates growth and differentiation, and analogs of vitamin D have been used to treat psoriasis (Tremezaygues & Reichrath 2011). Dairy and shiitake mushrooms are good sources of vitamin D; but supplementation is usually required—both to meet the recommended daily allowance and to account for the use of sunscreen, which can block the UV–vitamin D synthesis process.

Plant Nutrients

Fruits and vegetables are packed with potent free-radical scavengers, including phyto- (plant) chemicals like anthocyanidins, polyphenols and flavonoids. Responsible for the rainbow colors of fruits and vegetables, phytonutrients may reduce wrinkles and inflammation from sun exposure (Dinkova-Kostova 2008; Purba et al. 2001).

Carotenoids produce the deep hues found in carrots, sweet potatoes and spinach. As potent antioxidants, carotenoids may prevent skin aging and improve skin tone. Too much beta carotene can leave skin with an orange cast, but just the right amount can give a healthy glow. Faces that carry a hint of orange are perceived as more attractive and healthier (Alaluf et al. 2002). Lycopene, the carotenoid that gives tomatoes and watermelon their red color, is linked to smoother skin. In a study of 20 adults, lycopene was associated with greater skin smoothness (Darvin et al. 2008).

Grains

Whole grains like cereals and bread are great sources of complex carbohydrates and the B vitamins, which are essential for making new skin cells. Skin becomes dry, cracked and flaky, especially around the corners of the mouth, when B vitamins are lacking. Folic acid in dark green leafy vegetables and whole grains is critical to rejuvenating skin.

Minerals

Zinc is essential for wound healing. Summer skin, prone to sunburn, scrapes and abrasions, needs zinc to heal properly. Shellfish and beef are the best sources. Vegetarians may be at risk for zinc deficiency, since zinc from nonanimal sources is not well absorbed (Hunt 2003).

Iron is required for oxygen-carrying red blood cells; too little iron results in anemia and pallor. Women of child-bearing age who shun beef are at particular risk for anemia. Besides beef, dark-green leafy vegetables are a good source of iron.

Water

Adequate hydration is critical to a glowing complexion. The human body is more than 50% water, and with 3 quarts of it lost every day, drinking 8–10 glasses daily is essential for keeping skin soft and pliable. Hot weather, humidity and exercise accelerate the fluid loss that begets sallow complexions and dry skin. Hydration keeps skin plump and rosy, minimizing fine lines and wrinkles. Water is also critical for the skin’s ability to regulate body temperature and remove waste. Drinking plenty of water is an essential part of any healthy skin prescription.

The Right Combination

Healthy skin starts with good eating habits, exercise and a skincare regimen that includes exfoliation, cleansing, moisturizing and using sunscreen. Peter Thomas Roth says, “A regular skincare regimen that includes sunscreen is essential to getting the great skin you want, but healthy diet and activity are key.” A recent study showed that women who tried an anticellulite cream experienced better results if they also received dietary counseling (Escudier et al. 2011).

People can achieve radiant, glowing summer skin by eating a kaleidoscope of foods rich in nutrients that work in harmony to improve tone, texture and clarity. For a healthy glow that lasts all year, the recipe for great skin includes regular exercise coupled with good nutrition.