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People whose diets included high levels of vitamin A had a risk of contracting the second most common type of skin cancer by 17%, compared to those who ate small amounts of food and supplements rich in vitamin A.
That's what researchers at Brown University say, which uncovered this discovery after badyzing data from two long-term observational studies.
Cutaneous squamous cell carcinoma is the second most common type of skin cancer in fair-skinned people. Vitamin A is known to be essential for the healthy growth and maturation of skin cells, but preliminary studies on its effectiveness in reducing the risk of skin cancer have been mitigated, said Eunyoung Cho, badociate professor of dermatology and epidemiology at Brown.
"Our study provides another reason to eat a lot of fruits and vegetables as part of a healthy diet," said Cho, also an epidemiologist badociated with Brigham Hospital and Women's. "Skin cancer, including squamous cell carcinoma, is difficult to prevent, but this study suggests that a healthy diet rich in vitamin A may be a way to reduce your risk, in addition to wearing sunscreen and to reduce sun exposure. "
The results were published on Wednesday 31 July in the Journal de la American Medical Association Dermatology.
The research team led by Cho examined the results of feeding and skin cancer participants in two large long-term observational studies: the study on the health of nurses, who followed 121,700 US women from 1984 to 2012, and the follow-up study on health professionals. , which followed 51,529 American men from 1986 to 2012.
Between the two studies, approximately 123,000 participants were Caucasian (and therefore at high risk for skin cancer), had no history of cancer, and had completed nutritional reports multiple times. Of the people included in the team's subsequent badysis, a total of 3,978 cases of squamous cell carcinoma were reported and verified during the 24- or 26-year follow-up periods.
The two studies also asked participants about hair color, the number of severe sunburns they had received in their lifetime, and a family history of skin cancer, and the researchers adjusted these factors. 'other. Studies did not, however, question participants about avoiding the midday sun, considered a major risk factor for skin cancer.
After grouping study participants into five categories based on vitamin A intake levels, researchers found that subjects in the highest average daily vitamin A intake were 17% less likely to contract skin cancer than those in the category with the least total vitamins. A contribution.
Those in the highest category reported consuming an average amount of vitamin A equivalent to a sweet potato baked or two large carrots a day. People in the lowest category reported consuming an average daily amount of vitamin A equivalent to one-third of a cup of sweet potato fries or a small carrot, which is still above the recommended dietary allowance. vitamin A from the United States.
The team also found that the majority of vitamin A came from the participants' diets, especially fruits and vegetables, rather than animal-based foods or vitamin supplements. Vegetable sources of vitamin A include not only sweet potatoes and carrots, but also green leafy vegetables and fruits such as apricots and cantaloupe. Milk, certain types of fish and liver are rich sources of vitamin A of animal origin.
Cho warned that too much vitamin A, especially from supplements and animal sources, could lead to nausea, liver toxicity, increased risk of osteoporosis and hip fracture, and even conbad anomalies. The side effects of high levels of herbal vitamin A are minimal, she added.
The researchers also found that high consumption of herbal pigments similar to vitamin A, such as lycopene, which is commonly found in tomatoes and watermelon, was badociated with a decreased risk of cancer skin.
As the badysis was based on studies interviewing a large number of people about the foods they ate and observing whether or not they had skin cancer, rather than a randomized clinical trial, this does not help to establish the cause and the effect. The differences may be due to another factor, such as the fact that people who consume more vitamin A also tend to consume less alcohol.
In a next step, Cho would like to conduct a clinical trial to see if vitamin A supplements can prevent squamous cell carcinoma. However, she added, conducting a food trial is quite difficult from a technical point of view, as is ensuring that participants adhere to the diet.
"If a clinical trial can not be done, a large-scale prospective study like this is the best alternative for studying diet," said Cho.
Reference: Kim et al. 2019. Association of vitamin A consumption with the risk of cutaneous squamous cell carcinoma in the United States. Dermatology JAMA. doi: 10.1001 / jamadermatol.2019.1937.
This article has been republished from the following materials. Note: Content may have changed for length and content. For more information, please contact the cited source.
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