Theory that antioxidants can reduce skin cancer 'doubtful'

Dermatologists say people should not depend on dietitians theory.

By JUDY SIEGEL-ITZKOVICH
oranges 88 (photo credit: Courtesy)
oranges 88
(photo credit: Courtesy)
Although a Tel Aviv University nutritionist has claimed that eating a diet rich in antioxidants can help prevent skin cancer, two senior dermatologists told The Jerusalem Post this week that the published study is “far from proof” and that until such a connection is made scientifically, people should not depend on it to protect them from melanoma and other skin tumors.
Dr. Niva Shapira, a dietitian from TAU’s School of Health Professions, recently published in the journal Nutrition Reviews a study that the food you eat can affect your risk of skin cancer. In the study, she maintained that a diet rich in antioxidants and omega-3 fatty acids, like the diet eaten in Mediterranean regions where melanoma rates are extremely low, can help protect against skin tumors such as melanoma.
The sun’s rays damage both the skin and the immune system by penetrating the skin and causing photooxidation, she explained, affecting both the cells themselves and the body’s ability to repair any damage.
So she recommended eating olive oil. fish, yogurt and colorful fruits and vegetables to fight the oxidizing effect of the sun – as well as regular applications of sunscreen and appropriate body coverings such as hats, beach coverups, and other sportswear.
Previous research demonstrated that the sun’s UV rays damage the skin by exciting its molecules and causing them to become oxidized, said Shapira. “My theory was that if you prepared the body with sufficient and relevant antioxidants, damage could be reduced.”
She and Prof. Bodo Kuklinski of Rostock University in Germany performed a study at the Baltic sea, dividing participants into two groups – one consumed a drink high in antioxidants, while the other enjoyed soft drinks. They found that those who drank the antioxidant-rich juice had 50 percent fewer oxidation products in their blood at the end of the two-week period, which included five to six hours of exposure to the sun daily. Further studies proved that these antioxidants, especially carotenoids – fruit and vegetable pigments like red from tomatoes and watermelons and orange from carrots and pumpkins that accumulate in the skin – “had delayed” erythema (redness) in the skin from ultraviolet ray exposure that indicates the beginning of damage to the skin and the DNA and can lead to skin cancer. They claimed that foods provide nutrient “synergy” and that many vitamins and antioxidants and bioactive ingredients work to support one another and the body’s natural protective mechanisms.
But Dr. Ronni Wolf, a senior dermatologist at Wolfson Medical Center in Holon, who had not read the article, urged caution. “Testing the blood for oxidative products doesn’t mean the level is the same in the skin. They can’t claim that diet can reduce the risk of skin cancer, because they haven’t proved it. It takes about a decade for skin cancer to develop. Proving a connection takes a long time and many study participants.
There is no doubt that oxygen radicals are not healthful, but this study cannot be used to reach such a conclusion. It is an exaggeration.”
Eating foods rich in antioxidants with the belief that it will help protect against skin cancer can lead to “overconfidence,” warned Wolf, just as many people think sunscreen allows them to sunbathe for long periods even though sun exposure is harmful in general.
Asked to comment, Prof. David Enk, a senior physician in the dermatology department at Hadassah University Medical Center, said the study was “solid research. That lycopene from tomatoes and other betacarotenes have antioxidant activities is well known. The unique part of the study is that systemic ingestion reduces acute sun damage such as sunburn. However, from here to proclaiming that antioxidant cocktails prevent skin cancers and melanoma is a very long step.”