The macular pigments zeaxanthin and lutein, due to their photophysical and antioxidant properties, are believed to protect the retina from photoinduced oxidative stress, and to prevent age-related macular degeneration (AMD) [21–24]. The AREDS study demonstrated that supplementation with carotenoids, zinc, vitamin C, and vitamin E reduced the 5-year risk of advanced AMD by 25% [25,26]. Higher intake of bioavailable lutein/zeaxanthin was found to be associated with a long-term reduced risk of advanced AMD [27]. In several model systems it was also demonstrated that antioxidant protection increased synergistically when combination of carotenoids and vitamin E was used [28–30]. Importantly, carotenoids are among the most efficient quenchers of singlet oxygen, while vitamin E is an efficient scavenger of peroxyl radicals [31–34]. Synergistic protection by zeaxanthin and vitamin E against photic stress in ARPE-19 cells, mediated by photosensitizing dyes [35], lipofuscin granules [13], or melanosomes [36], was shown in our previous studies
Although RPE cells were pooled from the same number of younger and older donors, about 17–20% more MLF granules was obtained in the group of older donors, compared to younger donors. Differences in pigmentation of MLF granules between both age groups were observed visually, and confirmed by EPR spectroscopy as discussed below. Here, we analyzed photoreactivity of MLF granules isolated from RPE of younger (MLF_18-29) and older (MLF_50-59) human donors, and examined the effects of zeaxanthin and vitamin E. First, the ability of the pigment granules to induce oxygen photoconsumption was compared. Although oxygen consumption accompanying a photoreaction provides limited information about the photoreaction mechanism, it is a convenient indicator of oxygen-dependent reactivity [52].
Thus, preincubation of MLF with antioxidants lowered the observed rates of the DMPO-OOH accumulation by factor of 1.4 for MLF_18-29 + ZEA/TOC and by factor of 1.2 for MLF_50-59 + ZEA/TOC, when compared to the nonsupplemented granules. Although the rate of oxygen photoconsumption previously determined for purified lipofuscin granules was about six-fold higher than that of melanosomes, an inverse relation was observed for the corresponding accumulation of hydrogen peroxide [18]. It was concluded that in lipofuscin mediated photoprocesses, unlike in photoreactions involving melanosomes, only a small fraction of the photoconsumed dioxygen was
The results demonstrate that melanolipofuscin granules after phagocytosis by ARPE-19 cells were able to photoinduce oxidation of cellular proteins. The pro-oxidizing effect of MLF increases with age of human donors. It is worth noticing that supplementation of MLF granules with zeaxanthin and α-tocopherol reduced almost in half the extent of protein oxidation mediated by MLF from both age groups (Figure 5d). The inhibitory effect of supplementation of MLF with antioxidants on photooxidation of cellular proteins and the efficient quenching of singlet oxygen (vide supra) by the antioxidants, suggest Type II photochemistry of melanolipofuscin, with a major involvement of singlet oxygen. The apparent disparity between the efficiency of quenching of singlet oxygen by antioxidants and their inhibitory effect on photooxidation of cellular proteins, could result from different content of the antioxidants in MLF granules expected in model systems and in cells after phagocytosis of the granules.
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tho all of this is for A2E which is a photopigment and more for the eyes than the brain
Sources of Zeaxanthin: Gogi berry powder and Kale…
1mg Xeaxanthin per gram gogi berry powder
(1 tsp gogi berrry powder = 2 gram gogi powder)
Lutein / Xeaxanthin: 18g total of lutein and xeaxanthin in 100g kale, 6 g daily is best, 66g kale in one cup
Lutein (fat soluble)
Rda 10mg day
Source (I forgot, from notes, directly quoted below)
Zeaxanthin in dried goji berries [2] 1860 mcg/g of saponified zeaxanthin (186.0 mg/100 g) 1588 mcg/g of unsaponified zeaxanthin (158.8 mg/100 g) Total: 3448 mcg zeaxanthin per single gram
The same study also found other carotenoids in dried goji berries [2] 57.0 mcg/g of lutein in dried goji berries (5.7 mg/100 g) 61.0 mcg/g of beta-cryptoxanthin (6.1 mg/100 g) 10.0 mcg/g of beta-carotene (1.0 mg/100 g)
These are the same supplements found in typical vision-care supplements like this one:
PRESERVISION AREDS 2 EYE VITAMINS: This formula uses Lutein & Zeaxanthin, zinc, copper, Vitamin C & Vitamin E to exactly match the nutrient formula recommended by the AMD experts at the National Eye Institute based on the Age Related Eye Disease Study 2.
Yea, they are very easily confused with each other…
here’s a bold claim to cross-check:
Astaxanthin is one of the only known dietary antioxidants that spans the entire cell membrane (and thus, provides end-to-end protection) like this - i.e., protecting both surfaces and the vulnerable fatty-acid core.
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Which has better longevity data: zeaxanthin vs astaxanthin?
Zeaxanthin (usually reported combined with lutein) has better human “longevity-adjacent” evidence because it shows up in big cohort datasets measuring serum carotenoids vs all-cause / CVD / cancer mortality. Example: a long Japanese cohort with repeated blood measurements found higher “zeaxanthin and lutein” levels associated with lower all-cause, cancer, and CVD mortality risk. JAMA Network
Caveat, because humans: that’s still observational, so “healthy diet / lifestyle marker” confounding is always lurking.
Astaxanthin, by contrast, is mostly supplement RCTs on biomarkers, not lifespan. Even meta-analyses in humans tend to be about things like LDL-C, blood pressure, oxidative stress markers, etc., and the authors explicitly note the evidence base is small and more robust trials are needed. PMC
So: more mechanistic + biomarker data, less real-world longevity/outcomes data.
How do their lengths compare to the mitochondrial membrane?
You’re basically asking: can these molecules physically span a bilayer like a little antioxidant “rivet”? Yes, and the numbers are annoyingly neat.
Mitochondrial inner membrane thickness (ballpark)
In model mitochondrial-like membranes (with cardiolipin etc.), reported thicknesses are roughly:
Hydrophobic core (hC): ~28–29 Å (≈ 2.8–2.9 nm)
Phosphate-to-phosphate (headgroup-to-headgroup): ~40 Å (≈ 4.0 nm) PMC
Zeaxanthin length
A classic way to define “length” for zeaxanthin is distance between the two terminal hydroxyls (polar ends). That’s reported as ~32 Å (≈ 3.2 nm). Cyanotech
That’s very close to the mitochondrial hydrophobic core thickness (2.8–2.9 nm), which is why zeaxanthin is often described as spanning the membrane with polar ends anchored near the headgroups. Cyanotech+1
Astaxanthin length
In the same membrane-biophysics context, astaxanthin is also cited at ~32 Å molecular length (≈ 3.2 nm). Cyanotech
A separate review frames its hydrocarbon backbone as ~30 Å and notes that’s in the range of lipid bilayer thickness (~25–32 Å), supporting a perpendicular, membrane-spanning orientation. MDPI
So what’s the punchline?
Both zeaxanthin and astaxanthin are “bilayer-core-sized”: ~3.0–3.2 nm vs a mito-like hydrophobic core ~2.8–2.9 nm. Cyanotech+2PMC+2
They don’t need to match the full ~4.0 nm head-to-head thickness because their polar end groups sit in/near the headgroup regions, not out in empty space like a confused tourist.
In other words: yes, their geometry is plausibly compatible with “spanning the membrane” antioxidant behavior, especially in membranes with the right thickness/composition. Humans still manage to turn that into marketing, but the physics part is real.