The Hidden Benefits of a Mediterranean Diet
How Skin Cancer Could Be Prevented Through Diet
Oct 15, 2008
Eating a Mediterranean diet can halve the risk of the most dangerous form of skin cancer. Findings from an Italian skin disease hospital might explain why skin cancer is lower among Mediterranean people than those in northern Europe, the US and Australia.
The study behind this news report looked at patients with malignant melanoma at a hospital in Rome. Adopting elements of a Mediterranean-style diet (rich in vegetables, fruit, fish, nut and seed oils) might promote good overall health.
The Science Behind The Hype
This was a case-control study based in the inpatient wards of a dermatological hospital in Rome (IDI San-Carlo). All Caucasian patients aged over 18 who were admitted to the hospital with malignant cutaneous melanoma (skin cancer) between May 2001 and May 2003 were included.
People who did not have skin cancer were used as controls and selected from the same hospital during the same time period, matched to the cases according to age and gender.
A food frequency questionnaire was then used to assess the participants’ diet in the year leading up to the interview. It was this that was used to determine whether a person’s diet was a Mediterranean one.
Results of the Study
304 cases and 305 controls agreed to participate, and were interviewed and clinically examined. The researchers collected various pieces of information from the participants in an attempt to rule out non-dietary factors that might cause melanoma.
When the researchers took some of these factors into account, they found that:
- Consumption of vegetables (five or more times a week) and fruits (more than once a day) reduced likelihood of skin cancer.
- Other protective elements of diet included a high consumption of cruciferous vegetables (brassicas), leafy green vegetables, carrots, citrus fruit, fresh herbs, nuts, salad and exclusive use of olive oil for dressing (although some of these results were not very precise).
- High consumption of fish rich in n-3 fatty acids was also protective, as was consumption of shellfish.
- Tea drinking was also protective.
- There was no association with alcohol, high meat intake, liver, offals, cheese, butter, eggs and milk.
- There was little difference between men and women in these results.
Interpretation of the Results
The researchers conclude that after careful control for individual characteristics and sun exposure, the Mediterranean dietary profile (use of fresh herbs, citrus, cruciferous and dark green vegetables, and high consumption of fish rich in n-3 fatty acids and shellfish) might give protection against cutaneous melanoma.
Limitations of the Findings
The main limitation of this study is the possibility that bias (systematic error) associated with recollection has been introduced (namely ‘recall bias’). The participants were asked to describe their exposure to sunlight, etc. from years, possibly decades before, which could lead to confusion over details or instances.
A Cautiously Optimistic Link Between Diet and Health
The findings of this study support a link between foods that are rich in polyphenols and n-3 fatty acids and a reduction in risk of malignant melanoma. However, even the researchers are cautious in their conclusion, saying that ‘some dietary factors present in the Mediterranean diet ‘might’ protect from cutaneous melanoma’.
Until then, excessive sun exposure remains the most important risk factor for these types of skin cancers, and those with fairer skin types should be particularly careful.
However, the balanced intake of vegetables, fruit, fish, nut and seed oils in a Mediterranean-style diet can help promote general health.
Source:
C Fortes, S Mastroeni, F Melchi. A protective effect of the Mediterranean diet for cutaneous melanoma. Int J Epidemiol 2008; 37: 1018-1029
