Between Saturdays
This week: how nutrients build the skin from within, what probiotics reveal about the gut–skin axis, how omega-3s and antioxidants defend against aging, and why diet still outperforms skincare.
Our skin is the body’s interface with the world, and it reflects more than surface beauty. It mirrors internal health — from inflammation to nutrition to microbiome balance. This week, I’m diving into four studies that illuminate how diet, microbes, supplements, and genetics shape skin health.
Caught My Eye…
Dietary Supplements and Skin Photoaging
A 2025 meta-analysis published in Frontiers in Medicine pooled data from 40 randomized controlled trials, involving over 2,100 healthy adults. Researchers evaluated the effects of various oral supplements — including collagen peptides, flavanols, carotenoids, hyaluronic acid, and plant polyphenols — on visible signs of photoaging.
The results were nuanced: supplements containing collagen peptides, flavanols, and certain polyphenols showed modest but measurable improvements in skin elasticity, hydration, and wrinkle depth compared to placebo. However, compounds like lycopene, carotenoids, and hyaluronic acid did not consistently outperform control groups. The average duration of supplementation across studies was 12 to 24 weeks, with no major safety issues reported.
The findings suggest that while some supplements can improve skin parameters in the short term, their long-term effects and optimal dosages remain unclear. It’s a reminder that nutrition-based skincare works best as a complement, not a replacement, to diet and lifestyle.
Gut Microbiome and Skin Health
The gut-skin connection continues to gain traction. A 2025 scoping review published in Proceedings of the Nutrition Society compiled evidence from dozens of studies investigating the effects of oral probiotics, prebiotics, and synbiotics on skin health across age groups.
Most of the robust data comes from studies on atopic dermatitis and acne, where certain strains — particularly Lactobacillus rhamnosus GG and Bifidobacterium breve — have shown to reduce inflammation and improve barrier function. In healthy adults, early evidence suggests probiotics may enhance skin hydration, smoothness, and elasticity, but results are mixed due to differences in strains, dosage, and study design.
The authors emphasized the need for more human trials in healthy populations, noting that the gut-skin axis likely works through immune modulation, inflammation control, and nutrient absorption pathways. In other words, nourishing your gut may quietly support your skin’s resilience — though the exact formula is still being refined.
Omega-3 Fatty Acids and Antioxidants: A Synergistic Defense
A recent review published on Preprints.org (June 2025) analyzed how omega-3 polyunsaturated fatty acids (EPA and DHA) and dietary antioxidants jointly protect the skin. The review synthesized data from animal models, human studies, and molecular research, revealing several consistent mechanisms:
Omega-3s regulate inflammatory cytokines that drive redness, irritation, and UV-induced damage.
Antioxidants such as vitamins C and E, flavonoids, and carotenoids neutralize reactive oxygen species (ROS) that break down collagen.
Combined intake of omega-3s and antioxidants improves skin barrier function, hydration, and elasticity.
This dual strategy — anti-inflammatory fats plus antioxidant compounds — appears to offer a stronger defense against oxidative stress than either nutrient alone. The message is simple: combining colorful plants (rich in antioxidants) with omega-rich foods (like salmon, chia seeds, or flaxseed) builds long-term resilience against environmental and UV stress.
Nutritional Dermatology: The Bigger Picture
A broad 2025 review in Nutrients outlined a framework for what the authors call “nutritional dermatology.” This emerging field bridges nutrition science and dermatology, focusing on how specific nutrients influence skin structure, repair, and protection.
The paper highlighted several key nutrients with consistent evidence:
Vitamin A for cell turnover and acne control.
Vitamin C and copper for collagen synthesis.
Zinc and selenium for wound healing and antioxidant protection.
Omega-3 and omega-6 fatty acids for barrier integrity.
Polyphenols (from green tea, berries, and cocoa) for anti-inflammatory action.
The authors proposed a “skin-health dietary pattern” emphasizing fruits, vegetables, nuts, seeds, lean proteins, and healthy fats — a pattern mirroring the Mediterranean diet. Their conclusion was striking:
Skincare begins in the gut and on the plate, long before it reaches the surface.
Skin health is often treated as a cosmetic concern, but it’s far more complex. The studies this week converge on a single theme: your skin is a biological reflection of inner processes — diet, microbiome, and metabolism.
The products we apply externally can help, but the nutrients, fats, and microbes that build the skin’s architecture come from within. The next time you think of skincare, imagine feeding your skin — not just treating it.
Next week, I’ll shift focus to the body’s connective tissues — the hidden framework that supports movement, posture, and strength — and what nutrition can do to keep them resilient.
Detailed Readings
Nutritional Dermatology: Optimizing Dietary Choices for Skin Health
Enhancing Skin Health Through Omega-3 Fatty Acids and Antioxidant-Rich Diets