By Dr. Joseph Mercola
Your diet has a significant impact on the health of your skin. When it comes to wellness, beauty is more than skin deep. As a general rule, diets that include lots of fresh vegetables and plenty of omega-3 lay the groundwork for a youthful complexion.1,2
However, just as with protecting your overall health, loading up on specific foods to boost your youthful appearance, while still eating some of the most damaging foods, will likely not make a significant impact. For example, those who become resistant to insulin and leptin also realize the effects this has on the aging process.3 These conditions increase skin changes4 and your risk of metabolic disease.5
The most effective way to protect against insulin resistance is by reducing or eliminating processed foods and those that are high in refined sugar, processed fructose, trans fats and other harmful ingredients.
Specific nutrients have the opposite effect, or a protective benefit by helping ward off the damage caused by exposure to the elements. A recent study by researchers from Brown University found foods rich in vitamin A had a specific beneficial effect.6
Vitamin A-rich foods may protect against skin cancer
The researchers’ goal was to determine if there is an association between dietary intake of vitamin A and a reduced risk of squamous cell carcinoma.7 They analyzed data from two studies and found that those eating a diet high in vitamin A had a 17% reduced risk of getting cutaneous squamous cell carcinoma.
The scientists also analyzed results from 48,400 men and 75,170 women over 26 years.8 The original studies prospectively examined the participants’ intake of vitamin A and carotenoids using diet assessments from the Nurses’ Health Study and the Health Professionals Follow-up Study. The researchers’ end point measurement was the incidence of cutaneous squamous cell carcinoma.9
During the study period, 3,978 cases of squamous cell carcinoma were found. The researchers believe the results suggest that those with a higher dietary intake of vitamin A have a lower risk of being diagnosed with squamous cell carcinoma.10 The data supported the following conclusions by the researchers, who wrote:11
“In this large prospective study of U.S. women and men, we found that higher intake of total vitamin A, retinol, and several individual carotenoids, including beta cryptoxanthin, lycopene, and lutein and zeaxanthin, was associated with lower risk of SCC.
The results were generally consistent between men and women. The inverse associations appeared to be more prominent among those with moles and those with burn or blistering sunburn reaction as children or adolescents.”
While the researchers found a lower risk of squamous cell skin cancer with higher levels of dietary intake of vitamin A, Eunyoung Cho, study author and associate professor at Brown University, said taking too much vitamin A from supplementation could lead to an increased risk of osteoporosis and hip fractures.12 Cho commented:13
“These findings just add another reason to have a healthy diet with fruits and vegetables. Vitamin A from plant sources is safe.”
More than one type of skin cancer
According to the American Academy of Dermatology,14 there are four major types of skin cancer. Actinic keratoses are dry scaly patches that form on the skin. They are considered precancerous and may progress to squamous cell carcinoma, so early treatment is important.
Basal cell carcinoma is by far the most common type of skin cancer. These cancers may form anywhere on the body and often are flesh-colored or pinkish patches of skin. Early diagnosis and treatment help reduce the potential it will invade surrounding tissue and cause significant disfigurement.15
Once diagnosed with basal cell carcinoma, 50% go on to experience a recurrence within five years of the first diagnosis. This type typically grows slowly and metastasis is rare. Recurrence is more likely in those with a history of eczema, those who have used tanning beds and those whose original cancer was larger than 2 centimeters or was several layers deep in the skin.16
Squamous cell carcinoma is the second most common type and it may develop anywhere on your body. It presents as a firm red bump or scaly patch. It may appear to be a sore that doesn't heal.17 This cancer develops from the epidermal layer of the skin, or outermost layer.
It often grows slowly; it is uncommon for it to metastasize before being found. However, it is more likely to invade the fatty tissue beneath the skin, causing disfigurement with removal.18
Melanoma is the deadliest form of cancer. This is the type that develops from a current mole or appears as a new spot on the skin. Dermatologists19 recommend you use the ABCDEs to spot a melanoma and seek immediate medical attention if you think you have found one. Any spots that are different, or begin to change, itch or bleed should be evaluated by a dermatologist.
- Asymmetry — One half the dark area is unlike the other half. Most moles are symmetrical.
- Border — The outer edges of the mole will have an irregular or poorly defined border, seeming to fade into your skin.
- Color — An abnormal mole will have varied color from one area of the mole to another. You may notice shades of dark or light colors, including red or blue.
- Diameter — Most malignant melanomas are larger than the size of a pencil eraser.
- Evolving — Melanomas will look different than the rest of your moles and you may notice changes in shape, size or color over time.
Different types of vitamin A
Vitamin A refers to several different but related nutrients that fall into one of two main categories.20Retinoids are the bioavailable form of vitamin A that are found in animal-based foods while carotenoids are previtamin A found in plant foods.
As your body acquires carotenoids from plant sources, it must convert it into bioavailable retinol.21,22This does not pose a major problem if you are healthy. However, there are several factors that may inhibit this conversion including digestive problems, alcohol use23 and certain medications and medical conditions that interfere with the absorption of fat, such as cystic fibrosis and liver disease.24
Your body's ability to convert carotenoids into bioavailable retinol will also depend on your diet, as both absorption25 and conversion are fat dependent. In one study,26 researchers found a high-fat diet improved enzyme activity and the bioavailability of vitamin A in an animal model.
Carotenoids are the water-soluble provitamins found in plant foods, including beta carotene. Xanthophylls are another form of carotenoids; lutein and zeaxanthin are in this category.27 However, retinoids are the biologically active form and are only found in animal foods, including retinol, retinoic acid and retinyl esters.28
Vitamin A helps more than your skin
The featured study demonstrated that those with the highest amount of dietary vitamin A intake also experienced the lowest risk of squamous cell carcinoma. However, other studies have shown vitamin A may also inhibit other types of cancer.
In a study of a drug blocking the breakdown of retinoic acid, the result was a reduced tumor size in mice implanted with human prostate cancer cells.29 Vitamin A is an antioxidant and helps fight inflammation and damage from reactive oxygen species. Benefits from optimal levels of vitamin A obtained from your diet may support:
Immune system function30,31
Slowing the aging process33
Get vitamin A from your food
Vitamin A supplementation carries risks for many people, so your best bet is to make sure you're getting it from real food — both animal- and plant-based. Your best sources of retinoids are from:
- Eggs from organic, pastured chickens;
- Whole raw milk and cream from organic, grass-fed cows and
- Raw, organic butter and cheese from grass-fed cows.40
Other foods containing high amounts include:41