Cancer prevention and healing are more than skin deep; nutrition plays a role.
Although it is largely preventable, skin cancer is the most common cancer in the United States, with more than 3.5 million people being diagnosed annually. Statistics show that one person dies of melanoma every 57 minutes.
Medical professionals continue to urge people to take prevention measures like wearing sunscreen daily, not tanning, wearing hats and sunglasses, and having a medical skin exam annually.
But increasingly, researchers are examining the link between skin cancer and how we may be exacerbating the risk from the inside out. Definitive links between specific foods and skin cancer remain elusive, but researchers continue to seek connections and have made promising in-roads.
Dr. Doug DiOrio, medical director of integrative medicine for the OhioHealth Bing Cancer Center, says vitamin D appears to have an impact on skin cancer prevention. "There have been some studies on vitamin D levels, and that makes good sense," he says. "We make vitamin D through exposure to the sun, and it is very good for the skin." Increased levels of vitamin D can have an overall positive impact on many body systems, and even people who are actively avoiding the sun can get plenty of the vitamin in supplement form.
Prof. Yael Vodovotz is a member of the cancer-fighting foods team at the Ohio State University Comprehensive Cancer Center, where researchers are studying the vitamin D effect in deeper detail.
"We are looking at vitamin D levels relating to cancer, but it is still very early on," she says. An animal trial has shown vitamin D is effective in the fight against existing cancer cells, so now the team is seeking funding for human trials. They are also looking at adding vitamin D to a soy-based bread that was used successfully in a human study on prostate cancer, she says.
Vitamin C also appears to have a protective effect against skin cancer. "It is one of the best immune enhancers there is," DiOrio says. Many cancers are caused by viruses, and immune-suppressed individuals are very prone to developing cancer. In animal studies, subjects who are provided with vitamin C showed fewer squamous cell changes when exposed to UV light, DiOrio says. Squamous cell carcinoma is the second most common form of skin cancer in the U.S., affecting more than 700,000 people each year.POSITIVE CHANGES
Dietary advice is everywhere and it's often inaccurate or overwhelming, so experts advise people to keep it simple. A diet high in plant-based foods and low in processed foods offers the best chance for good health.
DiOrio says eliminating flours and other highly processed foods from the diet can play a major role in keeping the skin and other body systems healthy.
"Processed flours, sugars and trans-fats cause inflammation," DiOrio says. "That sets the body up for a carcinogenic effect and makes the skin more susceptible to damage."
The exact cause-and-effect relationship is difficult to pinpoint, but experts know it is there.
"It's difficult to study because you can't regress and narrow it down to just one thing," DiOrio says. "But we can look at nutrition in the lab and see that it affects cancer, and extrapolate that and say that good nutrition does good things for the body."
He advises his patients to avoid foods that are breaded, highly processed or full of sugar. Bread, even whole-grain, is a major culprit.
"Today, we have such highly genetically-modified wheat," he says. "The processing has made the gluten so readily available that it really messes with the inflammation reaction. It spikes our blood sugar, and we can see how harmful that is in diabetics over time." DiOrio says he thinks the reaction sugar causes is harmful to all of us, not just those with diabetes. He tells patients, if a food melts in the mouth, it's sugar. He compares a peanut and a potato chip as an example. "If our saliva can break it down, it's basically sugar." While whole grains are considered preferable to highly-processed grains, they can still cause inflammation, therefore opening the skin up to potential damage.
Jennifer Burton, a registered dietician with OhioHealth, works with patients at both the Bing Cancer Center and the McConnell Heart Health Center.
"Few people would refute the benefits of the healthy diet, but we still eat too many processed foods and too few healthy foods," she says. People who have a healthy diet will hold up better during treatment should they develop skin cancer, she says.
"They will have a better environment in the body to begin with," she says. "And what they eat during and after treatment can have an impact on whether the cancer is going to spread or whether they will have a recurrence."
Burton believes that, while supplements can be helpful, whole foods are the best choice in the prevention of disease.
"I educate patients to look at food as a whole," she says. "The components in food have a synergistic effect we don't completely understand yet," she says. "It's a case of one plus one equaling five. In many cases, supplements just can't replicate that."
For skin cancer prevention, she recommends fruits and vegetables above all.
"They are one of our best sources of antioxidants, and when it comes to skin cancer, they are our first line of defense," she says. Scientists have made a link between fruits and vegetables through population studies. In such studies, subjects self-report the content of their diets, and a link between fruits, vegetables and low skin cancer rates has emerged.
"Foods can be either very protective or very harmful," Burton says. Fruits and veggies are on the good team. "Eat lots of them – the more colorful, the better."
Fat is another agent of skin cancer. Good fats like avocado, flaxseed and nuts can help ward off disease. But animal-based fats have a direct link to disease.
"Studies have looked at fat in the diet and cancer, specifically skin cancer," Burton says. "People with diets higher in saturated fats like those from cheese, milk, cream and steak have a higher incidence of cancer recurrence."
Although dietary guidelines typically recommend a fat intake of no higher than 30 percent of the daily calories, Burton says keeping the fat to 20 percent or less of the caloric intake has been shown to lessen recurrence in cancer patients.
The kind of fat counts, though. "I don't feel the need to tell my clients to avoid nuts, avocados, peanut butter and olive oil, but our diet in general is so full of processed foods, it needs a total overhaul," Burton says.
She also recommends green tea for her patients. "It is one of the most powerful antioxidants we can consume," she says. Antioxidants eliminate free-radical particles that can damage skin both in appearance and strength.
DiOrio also recommends green tea. "It has multiple components, but ECGC is the component that decreases inflammation in the system," he says. "It can be taken as a supplement, but it is probably more beneficial as a tea. There may be something about the brewing process or something about taking it as a warm beverage, but that was the way it was made to be done."
Some people may worry about increasing pesticide intake along with their increased veggies, and wonder if the risks outweigh the benefits. Burton says there's little cause for concern. Some fruits and veggies should be bought in their organic forms, including those with very thin skins, like apples, peaches, plums, grapes, peppers, lettuce and berries.
"In that case, it's probably better to buy organic or buy at the local farmer's market," she says. Produce should also be bought domestically, since some other countries have much more lax regulation on the use of pesticides, she says.
Other veggies like broccoli, sweet potatoes, oranges and asparagus don't necessarily have to be grown organically, but all fruits and veggies, organic or not, should be washed thoroughly to remove pesticide residue or other potentially harmful agents. Burton says, whether you go organic or not, choose a few favorites and keep expanding the repertoire.
"Variety is very important, because each food provides us with something different," she says.
Ashley Harris, a registered dietician with a specialty in oncology, works with patients at the James Comprehensive Cancer Center, part of the Ohio State University Wexner Medical Center.
She says population studies support a strong link between fruits, vegetables and low rates of skin cancer. She says the key is the phytochemicals (or phytonutrients) found in plants.
"Many of these studies are done through the American Institute for Cancer Research, and they partner with the World Cancer Research Fund to look at all aspects of diet, exercise and cancer," Harris says. "The food frequency questionnaires look at large populations to see how much of certain foods people are eating. The studies are not perfect, but they give us some kind of a glimpse at the connections."
Carotenoids, found in dark, leafy greens and fruits or veggies that are red, yellow and orange, appear to have a particularly strong impact on skin cancer. Animal studies have shown that a component in garlic could also have protective factors. Soy has shown positive impacts on other forms of cancer, so Harris recommends it for her patients. "If you look at Asian diets, they have a ton of soy and very low cancer rates," she says.
The key is eating the plant in as unprocessed a form as possible, she says. "In certain plant foods, there are hundreds of these phytochemicals," she says. "We are only at the tip of the iceberg in discovering them, but it seems that the benefits come when the food is in its whole form and the nutrients can work synergistically."
Even through the generations, what you eat now could matter much later.
"There is some evidence that the groundwork is laid earlier in life," Harris says. "Skin cancer can be a slower growing cancer, so diet in previous years could have had an impact. It may even be impacted by mom's diet when she was pregnant. So many factors can play into it."
Kristin Campbell is a freelance writer.