8 replies to this topic

[osris]

Article by ChatCPT:

 

Limitations of Laboratory Studies on Skin Cancer and UVA Radiation

 

Introduction:

 

The correlation between sun exposure and skin cancer is a well-established scientific concept, supported by a variety of research methodologies, including laboratory studies, clinical trials, and epidemiological investigations. While these studies have significantly contributed to our understanding of the biological mechanisms underlying the link between UV radiation and skin cancer, it's crucial to acknowledge the inherent limitations of laboratory-based research.

 

Biological Mechanisms and Limitations:

 

Laboratory studies have extensively explored the biological mechanisms through which UV radiation, particularly UVB and UVA rays, can damage the DNA in skin cells, potentially leading to mutations associated with skin cancer. However, the controlled conditions of these experiments, utilizing specialized equipment to simulate UV light exposure, present limitations. Direct sunlight, with its broad spectrum of wavelengths, dynamic intensity, and diverse environmental factors, was not employed in these studies. Consequently, the extent to which laboratory-generated UV light accurately reflects the real-world impact of sunlight on skin remains a subject of scrutiny.

 

Animal and Cell Culture Studies:

 

Animal studies and in vitro experiments using human skin cells have played a crucial role in unraveling the causal relationship between sun exposure and skin cancer. These studies provide valuable insights into the effects of UV radiation on the development of skin cancers. Nonetheless, the use of artificial UV sources in these experiments, while allowing for precise control, introduces a potential gap in the translation of findings to natural sunlight exposure scenarios.

 

Clinical Trials and Real-World Application:

 

Clinical trials evaluating sun protection measures, such as sunscreen use, have contributed practical insights into skin cancer prevention. However, the controlled environment of clinical trials may not fully capture the complexity of real-world sun exposure conditions. The effectiveness of interventions in a controlled setting might not perfectly mirror their impact under diverse and uncontrolled environmental circumstances.

 

Geographical and Population Studies:

 

Observational studies exploring the correlation between sun exposure, latitude, and skin cancer rates across different populations contribute to the broader understanding of this relationship. However, the laboratory-based evidence, while informative, may not encapsulate the nuances and variations observed in real-world scenarios.

 

Photoprotection Studies and Artificial UV Sources:

 

Research on the effectiveness of sun protection measures, including sunscreen and protective clothing, underscores the importance of reducing UV exposure. Yet, the use of artificial UV sources in these studies raises questions about the applicability of findings to the diverse and dynamic conditions of natural sunlight.

 

Conclusion:

 

In conclusion, while laboratory studies provide valuable insights into the biological mechanisms linking UV radiation to skin cancer, their limitations must be recognized. The absence of direct sunlight in these experiments raises concerns about the generalizability of findings to real-world scenarios. A holistic understanding of the sun-skin cancer relationship necessitates a multifaceted approach that incorporates diverse research methodologies, emphasizing the importance of combining laboratory insights with real-world observations to advance our understanding of this complex and multifactorial phenomenon.

 

[Mind]

Another good article on the benefits of some UV sunlight. The "Midwestern Doctor" has a great substack highlighting the fraudulent aspects of modern medicine and detailing some of the things that were previously known to promote health but were stamped out by the US Government and big pharma.

[gamesguru]

The key to sun exposure is moderation.
 
The body's natural defenses can adequately compensate for and repair the damages associated with mild sun exposure. And it does this so well that (at 15-30 minutes per day) sun exposure is likely a net positive.
 
However, when you start talking about 1-2 hours of continuous, noon-day sun exposure on unprotected fair skin, it becomes increasingly likely that the severe sunburn will overwhelm our antioxidant and repair mechanisms and become a net negative.
 


It is well-known that long UVA has the most ability to penetrate deeper layers of the dermis and cause Basal cell or Melanoma (which are "deeper" skin cancers than Squamous cell). (Image is from source [1]). UVB seems to be a higher risk, but more so to the upper and middle layers of skin.

Theoretically, just as picrotoxin imbues an otherwise healthy plant with lethal properties, sunlight can be decomposed into fundamental constituents, of which we may argue that, in excess, the positive effects are insufficient to balance out the bad.

Although sun exposure may not cause Melanoma in everyone, age and level of exposure likely affect the risk. And in many cases, over time, this UV exposure can add up.



"DNA damage is caused by UV-B radiation. While most living cells have adapted and can repair simple damage, increased exposure to UV radiation can cause cells to mutate beyond repair, or to die." [3]
 
Age of exposure may also play a risk[2]. The question is: at what point does sun exposure cease to be beneficial and become problematic and damaging? That's a difficult question to answer. I would rather exercise caution and get under 30 minutes. Tanning booths are a no-go for me.

References
 
[1]
Comprehensive Review of Ultraviolet Radiation and the Current Status on Sunscreens - PMC
https://www.ncbi.nlm...les/PMC3460660/
 
[2]
Patterns of Ultraviolet Radiation Exposure and Skin Cancer Risk: the E3N-SunExp Study - PMC
https://www.ncbi.nlm...les/PMC5742376/
 
[3]
Solar Radiation & Photosynthetically Active Radiation - Environmental Measurement Systems
https://www.fondries...tive-radiation/

[pamojja]

However, when you start talking about 1-2 hours of continuous, noon-day sun exposure on unprotected fair skin, it becomes increasingly likely that the severe sunburn will overwhelm our antioxidant and repair mechanisms and become a net negative.

 

I'm probably the living lab rat with UV-exposure and mega-dosing antioxidants here on Longecity. I found with comprehensive supplementation and lifestyle-changes against severe chronic diseases - all in remission since some time - it has become impossible for me to get sun-burned. The last time was 2012 on my left arm, since I was sitting the whole day in an Indian train without glass windows, that arm mostly towards the sun. But up to 4hrs, even tropical close to midday sun, without sun cream doesn't burn me. I will report if it would ever change again.
 

Edited by pamojja, 11 July 2024 - 06:45 PM.

[gamesguru]

I'm probably the living lab rat with UV-exposure and mega-dosing antioxidants here on Longecity. I found with comprehensive supplementation and lifestyle-changes against severe chronic diseases - all in remission since some time - it has become impossible for me to get sun-burned. The last time was 2012 on my left arm, since I was sitting the whole day in an Indian train without glass windows, that arm mostly towards the sun. But up to 4hrs, even tropical close to midday sun, without sun cream doesn't burn me. I will report if it would ever change again.

 
Are you fair-skinned? Building up sun tolerance is a thing. However, what you described (4 hours of tropical summer sun) may not be the healthiest for everyone every day.
 
And yes, it's possible with advanced age that sun tolerance decreases (back to lower thresholds for some of us).

[pamojja]

 Are you fair-skinned? Building up sun tolerance is a thing. However, what you described (4 hours of tropical summer sun) may not be the healthiest for everyone every day.

 

4 hrs is usually just the max tried, in tropical heat that long is of course a rarer feat. Only possible at the ocean, Daily maybe 2 hrs, with 1 hrs swimming in between in the ocean. Therefore, in total 3 hrs/d. Blue-eyed, blond haired and before arriving always in the deepest winter at the tropical beach, fair-skinned too. But for a week or two only, before a strong tan sets in. Tan pics there in the linked treat scrolled far down, along with some statistics of yearly sun-exposures and some lab-markers.
 

But no building up of tolerance, just a surprise experience - with having started to supplement comprehensively - that my ability to sun-burn was gone at once. So definitely don't try to replicate if sunshine is still burning your skin even a little bid.

 

 

with advanced age that sun tolerance decreases

 

Well, endogenous antioxidants decrease with age.

Edited by pamojja, 11 July 2024 - 09:35 PM.

[gamesguru]

But no building up of tolerance, just a surprise experience - with having started to supplement comprehensively - that my ability to sun-burn was gone at once. So definitely don't try to replicate if sunshine is still burning your skin even a little bid.

 

Which antioxidant supplements helped with your sun tolerance the most? For some reason, my mind came to astaxanthin. But it's probably not relevant, lol.

 

Some things (St. Johns Wort, 9-Me-BC, C60) tend to sensitize one to UV and have the opposite effect of what you're describing.

[pamojja]

Which antioxidant supplements helped with your sun tolerance the most? For some reason, my mind came to astaxanthin.

 

Xanthophylls were my first guess too. But then many more users would report being immune to sun-burn. Then I came across one paper, which talked about the UV-protecting properties of ascorbic acid, and since I'm probably the only one here, who also took 24 g/d of ascorbic acid in average for the last 15 years, that probably is the addition which makes it so effective in my case.

 

For a fast check asked perplexity.ai, and added my average daily dose in blue:

 

 

There are several nutrients and supplements that can help increase your tolerance to UV rays from the sun:

## Vitamins and Antioxidants

- **Vitamin C** - Helps reverse sun damage, increases collagen production, and has antioxidant properties[10] - 24 g
- **Vitamin E** - May absorb and offset some of the sun's UV rays, reducing free radicals and cell damage[10] - 810 ,g (tocoperols and tocotrienols)
- **Beta-carotene** - Directly absorbs UV rays, diverting them away from skin cells[10]  - 1.2 mg
- **Vitamin B6** - May increase tolerance to UV rays[12] - 170 mg

## Polyphenols

- Found in berries, fruits, wine, nuts, seeds, coffee, olives, beans, and dark chocolate[10] - 2,2 g Bioflavonoids, 1.8 g other Polyphenols
- Help protect plants against UV rays and may do the same for humans by reducing skin sensitivity[10]

## Carotenoids

- Lycopene from tomatoes and watermelon can significantly increase skin's protection from UV rays[11] - 15 mg
- Anthocyanins like ellagic acid in red berries, pomegranates, and acai can reduce skin's inflammatory response to UV[11] - 50 mg Elagic acid (isn't an Anthocyanin, but a breakdown product for example Punicaalgin: 220 mg), 40 mg Anthocyanins

## Minerals

- **Selenium** - Helps repair cellular damage caused by the sun[10] - 300 mcg
- **Zinc** - Works as an antioxidant for cellular regeneration and DNA repair, supporting recovery from sun exposure[10] - 53 mg

The key is to build up your tolerance over time by consistently consuming these nutrients, rather than relying on them for immediate sun protection. Supplements like powdered fruit concentrates can provide benefits with less sugar[11]. However, topical sunscreen is still essential for adequate sun protection.

Citations:
[1] https://growvitamin....=45084443509038
[2] https://sunsaferx.co...=40520713076802
[3] https://solaray.com/...=39844870815804
[4] https://pharmarcie.c...=41539341516972
[5] https://seresag.com/...=40507763490873
[6] https://www.amazon.c...=A2A5589R3DTAUE
[7] https://www.caretobe...age-30-capsules
[8] https://www.walmart....mlspartner=wlpa
[9] https://www.ncbi.nlm...les/PMC6994571/
[10] https://bodybio.com/...-sun-protection
[11] https://themodelheal...onal-sunscreen/
[12] https://health.usnew...sun-sensitivity
[13] https://www.healthli...skin-protection

[pamojja]

Follow up with perplexity, brought those additionally:

 

 

## Key Nutrients and Supplements

3. **Omega-3 Fatty Acids**:- 3.9 g EPA/DHA
   - Present in fatty fish and flaxseeds, omega-3s can help reduce inflammation and improve skin health, potentially enhancing UV tolerance[2][4].

4. **Astaxanthin**:- 8.5 mg
   - A carotenoid found in algae that has been shown to act as an "internal sunscreen," reducing UV-induced skin damage[2][4].

6. **Vitamin D**:- 200 mcg
   - While primarily known for its role in bone health, adequate levels of vitamin D may also enhance skin's ability to tolerate UV exposure[2][5].

## Dietary Strategies

In addition to supplementation, a diet rich in antioxidants, healthy fats, and carotenoids can further support your skin's defenses against UV rays. Foods such as tomatoes, watermelon, and leafy greens are particularly beneficial due to their high content of protective compounds[1][4].

Citations:
[1] https://bodybio.com/...-sun-protection
[2] https://www.backtoth...e-sun-tolerance
[3] https://health.usnew...sun-sensitivity
[4] https://blog.nourish...-uv-resistance/
[5] https://www.katietho...-with-real-food

 

Guess difficult not to find a nutrient without UV-protection:

 

 

Yes, preformed vitamin A (retinol and retinyl esters) has UV-protecting properties: - 4.2 mg-

Absorption of UV Radiation

• Retinyl esters, a storage form of vitamin A, concentrate in the epidermis and absorb ultraviolet radiation with a maximum at 325 nm

• Due to its physical properties, vitamin A (retinyl esters and retinol) strongly absorbs ultraviolet radiation between 300 and 350 nm

Photoprotective Effects

• In vitro, retinyl palmitate was shown to be as efficient as the commercial filter octylmethoxycinnamate in preventing ultraviolet-induced fluorescence or photobleaching of fluorescent markers

• Topical application of retinyl palmitate significantly inhibited the formation of thymine dimers in mouse epidermis exposed to UVB radiation
• In human subjects, topical retinyl palmitate was as efficient as an SPF 20 sunscreen in preventing sunburn erythema and the formation of thymine dimers after UVB exposure
• Emulsions containing vitamin A exhibited higher UV protection than other emulsions, with a W/O emulsion containing 2% wt vitamin A presenting the highest sun protection factor (SPF)

These studies demonstrate that preformed vitamin A has biologically relevant UV-filtering activity and can provide photoprotection against UVB-induced skin damage. However, some concerns have been raised about the potential for retinyl palmitate to accelerate the development of skin tumors when exposed to sunlight.