In a recent analysis of data from men and women in the United States, who participated in two large, long term observational studies, researchers examined the association between Vitamin A intake and the risk of cutaneous squamous cell carcinoma (SCC), the second most common type of skin cancer among people with fair skin. The analysis highlighted a reduced risk of skin cancer with increased Vitamin A intake (mostly obtained from food sources and not supplements).
Vitamin A, a fat-soluble vitamin, is an essential nutrient which supports normal vision, healthy skin, growth and development of cells, improved immune function, reproduction and fetal development. Being an essential nutrient, Vitamin A is not produced by the human body and is obtained from our healthy diet. It is commonly found in animal sources such as milk, eggs, cheese, butter, liver and fish-liver oil in the form of retinol, the active form of Vitamin A, and in plant sources such as carrot, broccoli, sweet potato, red bell peppers, spinach, papaya, mango and pumpkin in the form of carotenoids, which are converted to retinol by the human body during digestion. This blog elaborates a study which analyzed the association between Vitamin A intake and risk of skin cancer.
Vitamin A and Skin Cancer
Though Vitamin A intake benefits our health in many ways, different studies previously showed that high intake of retinol and carotenoids may increase the risk of cancers such as lung cancer in smokers and prostate cancer in men. However, due to limited and inconsistent data, the association of Vitamin A intake and the risk of skin cancer was not clearly established.
Association between Vitamin A and Risk of Cutaneous Squamous Cell Carcinoma- A Type of Skin Cancer
Researchers from the Warren Alpert Medical School of Brown University in Providence, Rhode Island; Harvard Medical School in Boston, Massachusetts; and Inje University in Seoul, South Korea; examined the data related to Vitamin A intake and the risk of cutaneous squamous cell carcinoma (SCC), a type of skin cancer, from participants in two large, long-term observational studies named the Nurses’ Health Study (NHS) and the Health Professionals Follow-Up Study (HPFS)(Kim J et al, JAMA Dermatol., 2019). Cutaneous squamous cell carcinoma (SCC) is the second most common type of skin cancer with an estimated incidence rate reported as 7% to 11% in US. This study included data from 75,170 US women who participated in the NHS study, with a mean age of 50.4 years, & 48,400 US men who participated in the HPFS study, with a mean age of 54.3 years. Data showed a total of 3978 people with squamous cell skin cancer during 26 years and 28 years of follow-up periods in the NHS and HPFS studies respectively.The participants were divided into 5 different groups based on the levels of Vitamin A intake (Kim J et al, JAMA Dermatol., 2019).
Key findings of the study are listed below:
a. There is an inverse association between intake of vitamin A and risk of cutaneous squamous cell carcinoma (a type of skin cancer).
b. The participants grouped under the category of highest average daily vitamin A consumption had a 17% reduced risk of cutaneous squamous cell carcinoma compared to the group which consumed the least vitamin A.
c. Vitamin A was mostly obtained from food sources and not from dietary supplements in these cases with reduced risk of cutaneous squamous cell carcinoma/cancer.
d. Higher intake of total vitamin A, retinol, and carotenoids such as beta cryptoxanthin, lycopene, lutein and zeaxanthin, which are generally obtained from various fruits and vegetables such as papaya, mango, peaches, oranges, tangerines, bell peppers, corn, watermelon, tomato and green leafy vegetables, was associated with lower risk of squamous cell carcinoma/cancer.
e. These results were more prominent in people with moles and those who had a blistering sunburn reaction as children or adolescents.
In short, the above study suggests that an increased consumption of Vitamin A (obtained mostly from food sources and not from supplements) can reduce the risk of a type of skin cancer called cutaneous squamous cell carcinoma. Having a balanced, healthy diet with the right amount of retinol or carotenoids is hence considered to be beneficial. While these results look promising for cutaneous SCC, the study didn’t evaluate the effect of vitamin A intake on other forms of skin cancers, namely, basal cell carcinoma and melanoma. More studies are also needed for evaluating whether vitamin A supplementation has a role in the chemoprevention of SCC.
Cancer patients often have to deal with different chemotherapy side effects which affect their quality of life and look out for alternative therapies for cancer.Taking the right nutrition and supplements based on scientific considerations (avoiding guesswork and random selection) is the best natural remedy for cancer and treatment related side-effects.