Increasing sunlight exposure increases an individuals health and decreases cancer risk. In the last year or two I remember reading a quote from a professor of dermatology at a university in the U.S. who stated, “ There is no amount of sun that is good for the skin.” Clearly said professor skipped basic biology in secondary school or has had a lifetime of examining patients with excess PUFA (polyunsaturated fatty acids) in their diet, which is associated with increased incidence of skin cancer (there’s also a hopeful possibility that he was quoted out of context but I live in hope). Sun and skin cancer are clearly linked. Or are they? It doesn’t appear so clear cut.
I first became interested in light around 2009 and its benefits to health after reading Female Hormones in Context by Ray Peat. His suggestions that sunlight can, “cure depression, improve immunity, stimulate our metabolism, while decreasing food cravings and increase our intelligence, ” (Peat, 1997) intrigued me to gain a deeper understanding.Whilst I was aware of the harms of an excess of UV light, which can damage skin but is essential for increasing vitamin D levels. The far-reaching benefits of the spectrum of red and orange lights were unbeknownst to me.
Seasonal affective disorder or SAD is well documented and the mechanisms may be due to a number of factors such as increases in serotonin and melatonin. People generally get sicker and more depressed in winter and light therapy appears to be a useful tool in overcoming some of the symptoms associated with mood, energy and immune system related issues. If light is so harmful, why is it we often need more in these times and why has sunlight become so vilified?
Sunlight appears to get a bad rap in an ever increasingly reductionist causal relationship, in as much as sunlight causes skin cancer. Therefore wear sunscreen and avoid it. However current literature suggestions are along the lines of; “Wearing sunscreen increases sun exposure and increases incidence of melanoma and skin cancer.” Like many other approaches this A to B inference neglects to mention other pertinent mechanisms that can be attributed to increased incidence of cancerous states.
Cancer is a well known metabolic disease that can occur when specific effects to cells, namely mitochondria and the electron transport chain (ETC – often termed respiratory defects which allows problematic features of metabolism to occur, increasing damaging compounds). Cancer can be a feature of poor differentiation. Damage to tissues can often require new tissue to be formed. If an architect informs the site manager how to build the structure from just the blueprints without appreciation of the surrounding land and features, you can’t always guarantee success of completion.
Vitamin A – promotes cell differentiation (this is very important when damaged tissue is rebuilt), improves immune system function and optimal hormone function. A meta analysis in 2016 highlighted vitamin A’s protective functions and usefulness in protection against skin related disease such as melanoma through inhibiting malignant transformation and decreasing tumour size and improving survival rates (Zhang, Chu, & Liu, 2014). It’s important to note that retinol from liver sources is the effective compound in this action and not carotenoids. Other findings such as anaemia are synergistic with decreased vitamin A levels due to its critical role in the immune system and fighting infection (Semba & Bloem, 2002). Vitamin A has similar actions to organisational compounds such as progesterone and thyroid.
A question worth exploring – Does a vitamin A deficiency decrease differentiation and lead to a potential increase in cancerous type states when exposed to UV light?
Estrogen has been implicated in many cancerous states, primarily due to its role in tissue proliferation. When unchecked by levels of progesterone, it can be responsible for unwanted tissue growth and mutagenicity (Mungenast & Thalhammer, 2014) (Troisi et al., 2014). Levels can be increased due to external sources in the environment and through increased conversion of testosterone in adipose tissue to estrogen via aromatase in both men and women (Skakkebæk, 2003)(Cargouët, Bimbot, Levi, & Perdiz, 2006). The potential increases in cancerous states such as melanoma due to modulation of estrogen might be an easy target for excess levels of U.V. light to exert a negative influence in susceptible tissues. Therefore keeping estrogen low and utilising estrogen lowering strategies through food choices and avoidance of certain compounds can be useful.
Fat status of tissues.
I often found that when my diet was high in unsaturated fats my skin burnt extremely quickly. It’s been noted that people who often use sunblock often burn much quicker when in the sun without sunscreen. Increased consumption of unsaturated fatty acids appear to be linked to an increase in melanoma (Bourne, Mackie, & Curtin, 1987). Anecdotally I found that with a large decrease in PUFA my skin tolerates much longer bouts of sunshine before burning (not bad for a semi ginger pasty bloke from Kent!) , even in the intense middle-eastern heat. High fat diets, whether un/saturated also decrease mitochondrial activity and lower oxidative metabolism (Titov et al., 2016). It’s well known that vegetable oil consumption is linked to cancer (Niknamian, S., Kalamian, 2016) and heated vegetable oils that enter the body are already oxidised causing additional inflammation.
Perhaps melanoma is substantially increased when an individual has increased estrogen exposure, excessive amounts of unsaturated fatty acids in the skin and vitamin A deficiency but does that still implicate sunlight as the cause of skin cancer? The A to B scenario hopefully seems less convincing.
Modulating estrogen and decreasing PUFA in the skin is a step in the right direction. Increasing skin tolerance for longer days in the sun will be beneficial for many people. Using a homemade sun screen with minimal PUFA in can be useful for those wanting to spend extra time in the sun without damaging the skin and of course depending on the latitude, avoiding peak sun times is prudent to avoid excess UV light.
More information on resolving these issues can be found in the member’s area.
Bourne, D. J., Mackie, L. E., & Curtin, L. D. (1987). Melanoma and Dietary Lipids. Nutrition and Cancer, 9(4), 219–226. http://doi.org/10.1080/01635588709513930
Cargouët, M., Bimbot, M., Levi, Y., & Perdiz, D. (2006). Xenoestrogens modulate genotoxic (UVB)-induced cellular responses in estrogen receptors positive human breast cancer cells. Environmental Toxicology and Pharmacology, 22(1), 104–112. http://doi.org/10.1016/j.etap.2006.01.002
Mungenast, F., & Thalhammer, T. (2014). Estrogen biosynthesis and action in ovarian cancer. Frontiers in Endocrinology, 5(NOV). http://doi.org/10.3389/fendo.2014.00192
Niknamian, S., Kalamian, M. (2016). Vegetable Oils Consumption as One of the Leading Cause of Cancer and Heart disease. International Science and Investigation Journal, 5(5).
Peat, R. (1997). From PMS to Menopause: Female Hormones in context.
Semba, R. D., & Bloem, M. W. (2002). The anemia of vitamin a deficiency: Epidemiology and pathogenesis. European Journal of Clinical Nutrition. http://doi.org/10.1038/sj/ejcn/1601320
Skakkebæk, N. E. (2003). Testicular dysgenesis syndrome. In Hormone Research (Vol. 60, p. 49). http://doi.org/10.1159/000074499
Titov, D. V., Cracan, V., Goodman, R. P., Peng, J., Grabarek, Z., & Mootha, V. K. (2016). Complementation of mitochondrial electron transport chain by manipulation of the NAD+/NADH ratio. Science, 352(6282), 231–235. http://doi.org/10.1126/science.aad4017
Troisi, R., Ganmaa, D., Silva, I. D. S., Davaalkham, D., Rosenberg, P. S., Rich-Edwards, J., … Alemany, M. (2014). The role of hormones in the differences in the incidence of breast cancer between Mongolia and the United Kingdom. PLoS ONE, 9(12). http://doi.org/10.1371/journal.pone.0114455
Zhang, Y.-P., Chu, R.-X., & Liu, H. (2014). Vitamin A intake and risk of melanoma: a meta-analysis. PloS One, 9(7), e102527. http://doi.org/10.1371/journal.pone.0102527