Douglas Lobay, BSc, ND

It was a beautiful warm June day at the Vancouver Trade and Convention Centre. The sun glistened through the large clear glass walls of the foyer. The stunning backdrop of the north shore mountains was set against the canopy of big leaf maple, Douglas fir, and western red cedar trees that adorned Stanley Park. It was another otherwise redundant naturopathic convention, until Dr. T took the podium.

Dr. T was a tall, distinguished professor-like gentleman with a plain light suit and navy shirt.  His greying white hair resembled a groomed Einstein’s hair on a good day. He was an older semi-retired dermatologist with a wealth of practical knowledge and experience. He spoke about skin cancer and the use of natural products that could prevent its development and progression. It was an amazing talk full of great visuals, up-to-date scientific research, and the clinical utility of natural antioxidants like vitamin A, C, E and niacinamide. He provided great practical information and a generous colorful booklet that summarized the information.

I was so enamored by Dr. T’s talk that I had to thank him personally as he was leaving the auditorium. I walked up to him, introduced myself, shook his hand, and lauded some compliments. He then proceeded to walk away in the company of a beautiful, young lady who I inadvertently assumed was his daughter. She had nice skin.

Dr. T began his talk by saying there is an epidemic of skin cancer.  Fifty percent of all diagnosed cancer is skin cancer. Since about 1930 the rate of skin cancer has been doubling every ten years.  That means the rate of skin cancer is increasing between 6 to 8% per year since then.  According to the statistics, eighty percent of all skin cancer is diagnosed as basal cell carcinoma, 20% is squamous cell carcinoma, and less than 1% is melanoma.¹

He further explained the risk factors for the development of skin cancer include increased exposure to sunlight, increased age, decreased latitude from the equator, increased altitude, family history, and people with fair skin who burn easily.  If you have one parent who has had skin cancer your risk of getting skin cancer increases by about four times.  If both parents have had skin cancer, your risk increases by 18 times.¹

Basal cell carcinoma is the most common type of skin cancer. It typically occurs as a shiny papule on the skin.  Most basal cell cancer occurs on the most sun-exposed areas.  Seventy percent of basal cell cancer occurs on the face and 20% on the nose.  Whereas squamous cell cancer is generally a product of cumulative sun exposure, basal cell cancer is mainly a hereditable disease.  Typical warning signs of basal cell cancer include an open sore or wound that doesn’t heal, an irritated reddish patch, a shiny bump, a pink growth or a scar-like area.¹

Squamous cell carcinoma is the second most common type of skin cancer. It typically occurs on sun-exposed areas and usually presents as an ulcer that won’t heal.¹

Melanoma is the most serious type of skin cancer and has a propensity to spread and metastasize.  If it occurs in young adults, it is typically aggressive and usually occurs on the back and back of legs.  In older people it tends to be less aggressive and typically occurs on the face and scalp.¹   

The ABC’s of skin cancer include an asymmetric lesion where one part does not look like the other part, an irregular, poorly defined border, a varied color or tone of the lesion, a diameter greater than 6 millimeters or the size of a pencil eraser or greater and an evolving or changing lesion in size, shape and color.¹ 

The electromagnetic spectrum includes a broad range of electromagnetic energy or radiation that occurs over widely different frequencies and wavelengths.  Photons are packets of energy emitted by the sun with widely different wavelength and frequencies.  The visible spectrum includes a wavelength range of 380 to 700 nanometers.  It is what the human perceives as distinct colors and typically occurs as red, orange, yellow, green, blue, indigo and violet.¹ 

Visible light accounts for about 43% of electromotive radiation or emf radiation reaching the skin.  Infrared radiation accounts for upwards of 50% of the emf energy reaching the skin. Ultraviolet light accounts for approximately 7% of emf radiation that reaches the skin. Other more recent studies implicate visible and infrared light as causing upwards of 93% of skin damage.¹

When photons of energy hit the skin surface a variety of effects can occur.  They can cause DNA damage by breaking chemical bounds between atoms and molecules. They can damage collagen fibers in skin cells leading to wrinkles.¹

There are three ranges of ultraviolet radiation, namely UVA, UVB, and UVC. They differ by their electromagnetic wavelength. The higher the number, the longer the wavelength. And generally the longer wavelengths tend to penetrate deeper into the dermis. UVA is further divided into UVA1 and UVA2. UVA1 has a wavelength between 340 and 400 nm and UVA2 has a wavelength between 320 and 340 nm. UVA is the least blocked ultraviolet radiation in the earth’s atmosphere, and it tends to penetrate deeper in the dermis.  It causes skin damage by oxidative damage to skin cells and DNA. UVB has a wavelength between 290 and 320 nm.  UVB causes sunburn and DNA damage. The ozone in the atmosphere absorbs roughly 90% of UVB radiation.  UVC has a wavelength between 100 to 280 nm. UVC is almost 100% absorbed by the ozone in the atmosphere.^2,3

SPF (Sun protective factor) is a scale of how well a sunscreen chemical will protect the skin from ultraviolet B radiation. A SPF of 15 will allow 1/15 the amount of UVB to penetrate the skin.  A SPF of 30 will allow 1/30 the amount of UVB to penetrate the skin. And a SPF of 50 will allow 1/50 the amount of UVB to penetrate the skin and so forth.  Another way of presenting this is to say than a SPF of 15 will allow a person to stay in the sun 15 times longer for a specific time interval to get the same UVB exposure.

As an example, if you wanted to stay in the sun for 10 minutes an application of SPF of 15 would increase the time to 150 minutes to get the same solar exposure of UVB. And yet another way to explain this is that a SPF of 15 filters out about 93% of UVB radiation, a SPF of 30 filters out about 97% of exposed UVB and a SPF of 50 filters out 98% of UVB.⁴ 

The Tambour (sic) study was an Australian study in which about half the participants used sunscreen and half the participants didn’t for three years duration. They were then followed for an additional seven years, and the outcomes of skin cancer rates were measured and compared. The regular application of sunscreen showed some specific value.  The regular use of sunscreen reduced the incidence of squamous cell cancer by 50%.  Sunscreen use did not prevent or reduce the risk of basal cell cancer and the prevention of melanoma was not clearly defined.¹

In the USA there are currently 16 approved sunscreen chemicals used that include 14 organic carbon-based filters and 2 non-organic sunblocks that include titanium dioxide and zinc oxide. The organic sunscreen are typically petrochemical derived and shared a common carbon ring structure with a carbon side chain with a double bonded oxygen known as a carbonyl group. The mechanism of action of organic sunscreen is that ultraviolet radiation energizes the carbonyl electrons to a higher state of excitation.  The energy is later dispersed as heat as the electrons go back to their original lesser excitable state. Non-organic sunblocks reflect, disperse, and absorb the ultraviolet radiation.^2,3

The specificity of the chemicals used as sunscreen varies.  Some block just UVB and have little or no UVA blocking ability while others block UVA and have minimal UVB blocking ability. Examples of UVA-blocking chemicals include benzophenones, anthranilates, avobenzones, and ecamsule. Benzophenones are the most common UVA blocker, and they do exhibit good UVB blockage. Examples of UVB blockade include aminobenzoates, cinnamates, salicylates, octocrylene, ensulizole, and camphor. Aminobenzoates are the most common UVB absorber but do not absorb UVA. Their use declined because they are closely associated with PABA and are involved in skin sensitivity reactions.^2,3

A review of the available current evidence suggests that regular use of sunscreen can prevent the occurrence of squamous cell cancer and melanoma.  Most reputable dermatology associations recommend the use of sunscreen rated SPF 30 or higher for regular use during periods of high intensity sun exposure. Sunscreen is not recommended for children under the age of 6 months.⁴

The recommended adequate use of sunscreen is about 30 ml or 2 tablespoons or 1 ounce per sun-exposed body parts at a concentration of 2 milligrams per square centimeter for optimal sun protection. Sunscreen should be reapplied every two hours after sweating or swimming. A SPF of 15 or higher is recommended for almost all applications.²

Several specific synthetic sunscreen chemicals are believed to damage the environment and enter the human food chain.  Oxybenzone also known as benzophenone-3 was found to accumulate and contribute to bleaching in coral reefs around the world.  Oxybenzone and octinoxinate are also believed to mimic estrogen and can possibly interfere with female hormones, adrenal hormones and testosterone to some degree. Octinoxate, octocrylene, oxybenzone, and methylbenzilidene were found to accumulate in various species of fish. Subsequently, because of their slow degradation and accumulation in marine animals, the chemicals were found to enter the food cycle chain.⁵

Oxybenzone and octinoxate have been specifically identified as two sunscreen chemicals that can damage coral reefs and accumulate in fish.⁴

There is evidence that there are varying degrees of systemic absorption of sunscreen chemicals—albeit not high concentrations, but some concerning levels nonetheless.  The long-term side effects of this absorption on human health is not known at this time.  Oxybenzone, avobenzone, octocrylene and ecamsule have been specifically identified as four sunscreen agents that can be systemically absorbed and can accumulate in the human body.  Some earlier studies suggest that these chemicals can be hormone disrupters and interact with human hormones. There effects on reproductive physiology are also being investigated.⁴

Topical antioxidants have been added to conventional sunscreens to prevent oxidative damage to the skin and replenish antioxidant stores that have been already depleted.⁵ There is wide variability and efficacy of different antioxidant additives to conventional formulations.  There is currently no standardization of formulations and widely different values of photoprotective effects.  This is in part due to differing concentrations of antioxidants added to different formulations.  The stability of the antioxidants is also variable; their interaction with the delivery base and other topical components is unknown, and their interaction with each other is also variable and unknown at present.⁶

Vitamin A appears to be concentrated in skin cells.  Vitamin A has a multiplicity of effects in the skin that include upregulation of protein synthesis, transcription, cellular apoptosis and the prevention of dimer DNA damage. Vitamin A itself can absorb UVB radiation.⁷

Vitamin A and other retinoids are intimately involved in skin cell growth and regulation and help the immune system function better.  Retinoic acid and other synthetic retinoids also provide benefit like natural retinoids.⁸

Vitamin A or retinyl palmitate is intimately involved in skin cell metabolism at many different levels.  It is easily absorbed, has a long half-life and targets the cell nucleus.  A 1-2% concentration has a skin SPF of about 20.¹ 

The addition of antioxidants like vitamin C and vitamin E to more traditional organic-based sunscreen provides additional benefit in preventing oxidative damage to skin cells and inhibiting DNA damage. The antioxidants do not prevent burning and skin pigmentation damage.⁹

Both vitamin C and vitamin E have demonstrated UVB blockage, while ascorbic acid appears to be better at blocking UVA than vitamin E.  The addition of these antioxidants to organic sunscreens appears to provide more benefit than the original sunscreen alone.¹⁰

Vitamin C, besides being a strong water-soluble antioxidant, has demonstrated many skin protective factors.  It is involved in collagen synthesis and maintaining a strong, health skin barrier in the dermis. It is involved in different cell signalling pathways.¹¹

Vitamin C is easily absorbed, is involved in aqueous phase reaction, and has a SPF of 2.  Ascorbic acid is a strong water-soluble antioxidant. Vitamin C also stimulates collagen production.  A 5-20% concentration has strong cell antioxidant activity.¹ 

Vitamin E is a major lipid-soluble antioxidant that prevent cell membranes from oxidative damage. Vitamin E can ameliorate some of the damaging effects of ultraviolet radiation to skin cells.¹²

Vitamin E primarily as d-alpha tocopherol is the premiere fat or lipid soluble antioxidant. It has an average absorption, medium persistence and typically affects lipid soluble skin cell membranes.  A 2.5-5% concentration has a SPF of about 2.¹

Vitamin B3 in the form of niacinamide has demonstrated skin protective effects both in vivo and in vitro studies.  It prevents UV damage to DNA, enhances DNA repair, improves collagen synthesis and modulates inflammatory responses.  It has shown to decrease actinic keratosis and non-melanoma skin cancers. It is virtually non-toxic and has few side effects.¹³

Niacinamide has been shown to prevent photo-aging and non-melanoma skin cancer development. It prevents DNA damage from ultraviolet radiation, promotes cellular repair, prevents immune suppression, improves mitochondrial function, and prevents transdermal water loss.¹⁴

Niacinamide has further demonstrated to regulate tumor suppressor genes such as p53 and sirtuins and restore intracellular NAD levels, a coenzyme in mitochondrial energy production.¹⁵

A systematic review and meta-analysis of 29 trials involving 3039 patients with niacinamide showed up to 50% reduction in basal cell and squamous cell skin cancer rates. Evidence was deemed moderately accurate and only some digestive adverse events were note.¹⁶

In a phase 3 double-blind randomized controlled trial with 386 patients, the rate of non-melanoma skin cancer was 23% lower with niacinamide than with placebo. The addition of 500 milligrams of niacinamide twice per day for 1 year in high-risk Australian individuals significantly reduced the rate of actinic keratosis, basal cell, and squamous cell cancers.  The authors concluded the niacinamide was both safe and effective in reducing non-melanoma skin cancers in high-risk individuals.¹⁷

Niacinamide is important in promoting DNA repair from sun damage, preventing emf-induced immune suppression and promoting collagen synthesis. A recent study showed that oral niacinamide at 500 milligrams twice per day causes a 25% reduction in basal cell and squamous cell carcinoma. It is water soluble, fairly easily absorbed, and affects intracellular reactions.  In topical preparations, it is typically produced at 2.5 to 5% concentration.¹

Silymarin is the name given to the group of flavonoids found in the plant milk thistle and collectively include silibinin, silidianin, and silycristin. At a concentration of 10% silymarin demonstrated an average SPF rating 9 and as high as 14. Silymarin was added to more convention sunscreen and sunblock chemicals for an added effect.⁵  Silymarin derived from milk thistle has demonstrated good effects for preventing UVB damage.

Green tea polyphenols have demonstrated good effects better than vitamin C and vitamin E.³

Lignins are a group of natural polymers based on a repetitive carbon ring phenolic compounds linked together with oxygen-rich side chains that are ubiquitous in plants.  Lignins are deposited in cell walls and are responsible in part with cellulose for the form and structure of plants. Lignins are good antioxidants and exhibit strong photoprotective effects from ultraviolet radiation.  A 5% concentration of lignins has demonstrated a SPF rating around 3, while a 10% lignin extract demonstrated a SPF rating around 8, and another 10% lignin extract demonstrated a higher SPF rating.⁵

Many other plant species, both aquatic and terrestrial, have demonstrated low to moderate levels of sun protective factor.  These species include various algal extracts, arctic moss, various mushrooms, calendula, saffron, turmeric, hawthorn, elderberry, grapes, green tea, and soy extracts.⁵

Calaguala (Polypodium leucotomos) is a south American fern that has been used in folk medicine to treat a wide variety of skin ailments, including eczema, psoriasis and vilitigo. Oral consumption of Polypodium in varying concentrations has been tested in animals and orally administered at a daily dose of 7.5 mg per kg or about 480 milligrams in a 65-kilogram human model. In almost all cases there has been a significant degree of sun protection. 

Potential active ingredients include chlorogenic acid, coumaric acid, vanillic acid, caffeic acid, and ferulic acid, with the latter two being the strongest antioxidants. The mechanism of action is multifactorial, including providing photoprotection and reducing UV-induced cell damage, reducing oxidative stress and DNA damage, blocking UV radiation-induced immune suppression, and inhibiting the release of UV-induced levels of cyclooxygenase-2 and inflammatory cytokines.  The possibility of taking an oral compound that prevents ultraviolet skin damage and potentially skin cancer is very exciting.⁶

Polyphenols found in a wide variety of foods and herbs have demonstrated widespread sun protection in differing degrees.  Green tea, grape seeds, blueberries, almonds, pomegranates, and other antioxidant-rich foods have demonstrated varying degrees of sun protection.⁶

Dr. T. concluded his talk by saying that naturopathic physicians and other holistically inclined medical practitioners are uniquely positioned to give practical advice and scientific information on the use of natural products that can help to prevent the development and occurrence of skin cancer. The incorporation of dietary antioxidants like vitamin A, C, E and niacinamide both orally and topically in sunscreen can provide benefit. The use of other naturally occurring sunscreens like green tea, milk thistle, Polypodium leucotomos, and other polyphenol-containing botanicals can also be beneficial.  The incorporation of dietary antioxidants and natural polyphenolic compounds has sparked an exciting era in the development of better photoprotection and more effective sunscreen. 

References

1. Telford G FRCPC (Derm). Let’s Talk Skin Cancer. Self published booklet. Victoria, BC. 2016.
2. Gabros S et al. Sunscreens And Photoprotection. StatsPearls. Internet. Last Update: March 7, 2023.
3. Rai R et al. Update on Photoprotection. Indian Journal of Dermatology. 2012 vol :57 issue:5 pages 335-342.
4. Sander M et al. The efficacy and safety of sunscreen use for the prevention of skin cancer. CMAJ. 2020 Dec 14; 192(50): E1802–E1808.
5. He hailan et al. Review Natural Components in sunscreens: Topical formulations with sun protective factor (SPF). Biomedicine & Pharmacotherapy. Volume 134, February 2021.
6. Guan LL et al. Sunscreens and Photoaging: A Review of Current Literature. Am J Clin Dermatol. 2021; 22(6): 819–828.
7. Saurat JH. Skin, sun, and vitamin A: from aging to cancer. J Dermatol. 2001 Nov;28(11):595-8.
8. Szymanki L et al. Retinoic Acid and Its Derivatives in Skin. Cells. 2020 Dec 11;9(12):2660.
9. Wu Y et al. Antioxidants add protection to a broad spectrum sunscreen. Clinical and Experimental Dermatology. Volume 36, Issue 2, 1 March 2011, Pages 178-187.
10. Darr D et al. Effectiveness of antioxidants (vitamin C and E) with and without sunscreens as topical photoprotectants. Acta Derm Venereol. 1996 Jul;76(4):264-8.
11. Wang K et al. Role of Vitamin C in Skin Diseases. Front Physiol. 2018 Jul 4;9:819.
12. Nachbar F and Korting HC. The role of vitamin E in normal and damaged skin. J Mol Med (Berl). 1995 Jan;73(1):7-17.
13. Damian DL. Nicotinamide for skin cancer chemoprevention.  Australas J Dermatol. 2017 Aug;58(3):174-180.
14. Snaidr VA et al. Nicotinamide for photoprotection and chemoprevention: A review of efficacy and safety. Exp Dermatol. 2019 Feb;28 Suppl 1:15-22.
15. Giacalone S et al. Oral nicotinamide: The role of skin cancer chemoprevention. Dermatol Ther. 2021 May;34(3):e14892.
16. Mainville L et al. Effect of Nicotinamide in Skin Cancer and Actinic Keratoses Chemoprophylaxis, and Adverse Effects Related to Nicotinamide: A Systematic Review and Meta-Analysis. J Cutan Med Surg. 2022 May-Jun;26(3):297-308.
17. Chen AC et al. A Phase 3 Randomized Trial of Nicotinamide for Skin-Cancer Chemoprevention. N Engl J Med. 2015 Oct 22;373(17):1618-26.

Published July 15, 2023

About the Author

Douglas G. Lobay, ND, is a practicing naturopathic physician in Kelowna, British Columbia. Dr. Lobay graduated with a Bachelor of Science degree from the University of British Columbia in 1987. He then attended Bastyr College of Health Sciences in Seattle, Washington, and graduated with a Doctor of Naturopathic Medicine in 1991. While attending Bastyr College, he began to research the scientific basis of natural medicine. He was surprised to find that many of the current medical journals abounded with scientific information on the use of diet, nutrition, vitamins, and botanical medicines. Besides practicing naturopathic medicine Dr. Lobay enjoys research, writing and teaching others about the virtues of good health and nutrition. He has authored several books, numerous articles, and papers and has taught many courses at seminars and colleges throughout his career. He is married to Natalie and has two daughters, Rachel and Jessica. He also enjoys hiking, hockey, skiing, tennis, travelling and playing his guitar.