Good post endless, i just like to add that the problem with saturated fats is usually that people eat way to much saturated and not enough poly saturated and unsaturated, the optimal ratio is 1/1/1...

Often people point out articles that suggest that sunscreen may be bad for you. Or other people get all histerical and say we should be slathering ourselves in sunscreen - often with the argument that skin cancer has gone up so much since 19xx and that we need more sunscreen. I love how all of these arguments are things are getting worse, so lets try to do more of the same stuff that hasn't been working (or as I'd argue, makes things worse). Quick disclamer: I'm only talking about mechanisms here and trying to extrapolate to the effects on humans. I'm making no representation about our evolutionary adaptations to handle things. I'm just talking about the underlying chemistry.

Light that we see comes in many different "colors", we call them "red", "blue", "green", etc. Ultraviolet light also comes in may different "colors", the terms physicists use are "UVA", "UVB", "XUV", "VUV" (the atmosphere absorbs all of the XUV and VUV, so we don't encounter that in the real world). Not all sunscreen absorbs all colors of UV. They generally absorb the colors of UV that cause tanning and burning (because that's the observable that people care about), but they don't generally block the higher energy UV colors that actually cause the cancer. Because the effect of that isn't marketable, no one would know it's happening.

Without sunscreen, your skin "sees" some UV colors and starts to "tan". The tanning is your body's natural protection against the higher energy UV colors that cause the cancer. So as long as you're not out long enough to get burnt (actual skin damage), the tan protects you against the bad stuff.

Strike 1 against sunscreen: it stops the good stuff that promotes tanning and lets through the bad stuff that causes cancer (that our tan would protected us against if it was allowed to form).

Strike 2 against sunscreen: The UV that causes us to tan is the same color of UV that is used in the formation of Vit D which also protects against cancer.

Now, lets say that there was a magical sunscreen that blocked 100% of all colors of UV, would I feel comfortable using it? No. Here's why:

Sunscreen works by "absorbing" UV rays. How does it work. Well it's generally a long polycyclic aromatic with lots of conjugated double bonds. The UV light is resonate with the electronic transitions of the conjugated states. When the UV light hits the sunscreen molecule, it promotes an electron into a higher state which actually breaks one of the double bonds. Most of the time the sunscreen molecule will then shed that extra energy it just absorbed as heat and reconnect that double bond. But sometimes it won't and you'll be left with a free radical (you're probably aware that PUFAs are susceptible to oxidative damage - just image a sunscreen molecule as a more reactive PUFA). So when you started, you put a reasonably harmless chemical on your skin (or else the FDA wouldn't allow it to be sold), but it's interaction with light turns it into a potential carcinogen just like PUFAs and PAHs.

Strike 3 against sunscreen: The act of doing it's job (absorbing UV) turns it into a potential carcinogen which is now slathered over your largest organ.

Polyunsaturated acids consist of various sub classes and very rarely there is problem with not enough PUFA (polyunsaturated fatty acids). PUFA/saturated fats ratio is probably heavily on the PUFA side with most people.

One of theories today is that excess Omega 6 (mass consumption of vegetable oils)or a bad Omega 6 and Omega 3 ratio is responsible for the health decline. I think this all started with William Lands' study of the Eskimos (who had no heart attacks, hypothesis being that Omega3 fatty acids act protectively)

6 - There is a condition called gluten sensitivity and it's more prevalent than celiac disease
https://www.ncbi.nlm.nih...ding=f1000,f1000m,isrctn
https://www.ncbi.nlm.nih.gov/pubmed/21224837
https://www.ncbi.nlm.nih...pmc/articles/PMC1954879/

7 - Benefits of "Omega 3" fatty acids come mostly from EPA and DHA (fish) and not from ALA (hemp, seeds, etc)

Omega 3 content of seeds is just a sales tactic since ALA to DHA/EPA conversion is very low.

8 - Sunscreen is probably bad for you

How is the chemistry behind the argument, especially "strike two" part ? Benz, InMo, other chemically inclined peepz ?



About saturated fat. Some subclases can increase cholesterol values but the link between that and hard disease isn't really that strong.

Certain populations (Masaai, Kitavans) with great saturated fat intake live(d) free of heart attacks.

Meta analysis that end was talking about - https://www.ncbi.nlm.nih.gov/pubmed/20071648

I think point number three is a misguided one. Plants don't want to be eaten. They want to live and they will defend. That's nature.

Secondary metabolite (shoutout to burnt !)
Plant defense against herbivory

Solanine is pretty much concentrated in the skin of the potato so peel them good !

6 - There is a condition called gluten sensitivity and it's more prevalent than celiac disease
https://www.ncbi.nlm.nih...ding=f1000,f1000m,isrctn
https://www.ncbi.nlm.nih.gov/pubmed/21224837
https://www.ncbi.nlm.nih...pmc/articles/PMC1954879/