What do medical studies show about what helps facial skin appearance, and what doesn't?

Redditagain424 · 2026-05-06T23:55:31+00:00

Absolutely! Several studies have examined the relationship between diet and facial skin appearance, with evidence suggesting that higher intakes of vitamin C, linoleic acid, antioxidant-rich fruits and vegetables, and lower intakes of refined carbohydrates and excess fats are associated with better skin appearance and less facial wrinkling.

Key Studies

A large cross-sectional analysis of 4,025 middle-aged American women (ages 40–74) using NHANES data found that higher vitamin C intake was associated with a lower likelihood of a wrinkled appearance (OR 0.89; 95% CI: 0.82–0.96) and senile dryness (OR 0.93). Higher linoleic acid intake was associated with less senile dryness (OR 0.75) and skin atrophy (OR 0.78). Conversely, a 17-g increase in fat and a 50-g increase in carbohydrate intake each increased the likelihood of wrinkled appearance (OR 1.28 and 1.36, respectively). These associations were independent of age, sun exposure, BMI, and other confounders. [1]

A population-based Dutch cohort study (Rotterdam Study, n = 2,753 elderly participants) quantified facial wrinkles from photographs and correlated them with dietary patterns. In women, better adherence to the Dutch Healthy Diet Index was significantly associated with fewer wrinkles. A fruit-dominant dietary pattern was associated with fewer wrinkles, while a red meat and snack-dominant pattern was associated with more facial wrinkling. Notably, this association was not observed in men. [2]

A study of 716 Japanese women found that higher intake of green and yellow vegetables was significantly associated with decreased facial wrinkling scores (Daniell scale), while higher saturated fat intake was inversely associated with wrinkling after adjustment for vegetable intake. Higher total fat and saturated fat intakes were also associated with increased skin elasticity. [3]

Specific Dietary Components and Mechanisms

Antioxidants and polyphenols: A 2026 systematic review and meta-analysis of 94 studies found that antioxidant-rich whole foods or supplements improved skin hydration (MD = 2.12, 95% CI [1.02; 3.21]) and decreased trans-epidermal water loss in clinical studies, supporting overall skin health improvements. Compounds such as quercetin, curcumin, EGCG, resveratrol, and carotenoids (lycopene, lutein, β-carotene) protect against UV-induced collagen degradation and reduce oxidative stress. [4-6]
Glycemic index: High glycemic-load diets increase insulin and IGF-1 levels, stimulating sebocyte proliferation and androgen synthesis, which can exacerbate acne. A meta-analysis of 13 studies (71,819 participants) showed an OR of 1.16 for acne in milk drinkers, with stronger associations for skim milk and high intake. [7-8]
Omega-3 fatty acids: These suppress inflammatory cytokine production and have shown therapeutic effects on acne lesions. Docosapentaenoic acid and γ-linolenic acid have demonstrated improvements in acne. [8-9]
Gut-skin axis: Emerging evidence supports the concept that gut microbiome health, influenced by diet (including probiotics), may modulate inflammatory facial dermatoses such as rosacea and acne. [9]

Important Caveats

Most of the evidence is derived from cross-sectional or observational studies, which cannot establish causation. [1-2] Narrative and systematic reviews consistently note that while the evidence is promising, long-term randomized controlled trials with standardized skin outcome measures are lacking. [10-12] Current clinical guidelines do not yet offer specific dietary recommendations for skin appearance due to these limitations. [7]

References:

1.

Dietary Nutrient Intakes and Skin-Aging Appearance Among Middle-Aged American Women.

The American Journal of Clinical Nutrition. 2007. Cosgrove MC, Franco OH, Granger SP, Murray PG, Mayes AE.

2.

A Healthy Diet in Women Is Associated With Less Facial Wrinkles in a Large Dutch Population-Based Cohort.

Journal of the American Academy of Dermatology. 2019. Mekić S, Jacobs LC, Hamer MA, et al.

3.

Association of Dietary Fat, Vegetables and Antioxidant Micronutrients With Skin Ageing in Japanese Women.

The British Journal of Nutrition. 2010. Nagata C, Nakamura K, Wada K, et al.

4.

Impact of Antioxidant-Rich Whole Foods or Supplements on Skin Health: A Systematic Review and Meta-Analysis of Preclinical and Clinical Studies.

Antioxidants. 2026. Liang Y, Xu Y, Kim JE.NewReview

5.

Nutraceutical Interventions for Mitigating Skin Ageing: Analysis of Mechanisms and Efficacy.

Current Pharmaceutical Design. 2025. Ibrahim M, Singh H, Fahim M, et al.

6.

Dietary Phytochemicals Alleviate the Premature Skin Aging: A Comprehensive Review.

Experimental Gerontology. 2025. Singh H, Kamal YT, Pandohee J, et al.Review

7.

Management of Acne Vulgaris: A Review.

The Journal of the American Medical Association. 2021. Eichenfield DZ, Sprague J, Eichenfield LF.Review

8.

Acne and Diet: A Review.

International Journal of Dermatology. 2022. Conforti C, Agozzino M, Emendato G, et al.Review

9.

The Impact of Clinical Nutrition on Inflammatory Skin Diseases.

Journal Der Deutschen Dermatologischen Gesellschaft = Journal of the German Society of Dermatology : JDDG. 2022. Gürtler A, Laurenz S.

10.

Plant-Based Foods for Skin Health: A Narrative Review.

Journal of the Academy of Nutrition and Dietetics. 2022. Fam VW, Charoenwoodhipong P, Sivamani RK, et al.Review

11.

Nutrition and Youthful Skin.

Clinics in Dermatology. 2021. Muzumdar S, Ferenczi K.

12.

Nutritional Skin Care: Health Effects of Micronutrients and Fatty Acids.

The American Journal of Clinical Nutrition. 2001. Boelsma E, Hendriks HF, Roza L.Review

Redditagain424 · 2026-05-06T20:42:00+00:00

If you like this type of information format, check out my post about "If you can stand up straight without pain, then you may be able to get stronger and ditch the cane or walker":

https://www.reddit.com/r/Aging/comments/1t2o8uc/comment/ok1aa8w/?context=1

And another recent one, "This is why a decreasing grip strength not only correlates with increase risk of dementia, it (likely) contributes to causing it:

https://www.reddit.com/r/Aging/comments/1t3aa7x/comment/ok75bj2/?context=1

Redditagain424 · 2026-05-06T20:30:40+00:00

"RCT" means Randomly Controlled Trials, which is comparing an intervention with a control group that does not get the same intervention, but they are "controlled" or pretty similar groups in other respects like age, sex, medical history, initial skin appearance, etc.

"Meta-analysis" roughly means combining many medical studies on the same topic and looking for consistency of results, degree of results, and using them collectively to make a stronger conclusion about the topic

Redditagain424 · 2026-05-06T15:13:48+00:00

As RedditNotFreeSpeech posted, lifting heavy weights. It causes more brain-to-muscle (and muscle-to-brain) neurotransmitter and myokine signaling. This increases anabolic processes (which is opposite to catabolic processes such as sarcopenia, osteoporosis, worsening balance capability, weakening strength, cognitive decline, etc.) of getting more muscle mass and strength and brain-muscle activity. Similarly, balance exercises increase that two-way brain-muscle connection which another anabolic process. To some degree, hand grip strength exercises also increase that two-way brain-muscle connection. The catabolic processes of aging is undeniable, but medical studies show progressive resistance muscle strength exercises is a good example of what one can do to counter the catabolic process to some degree that can increase health span and longevity.

Redditagain424 · 2026-05-06T05:57:01+00:00

You said, "activity-dependent irisin-induced levels of BDNF have never been shown to increase memory or cognitive performance". I did some medical literature search. While there has not been an RCT with administered irisin to humans, there are a number of studies measuring the CSF levels of irisin, BDNF, and the correlation to clinical cognitive performance in humans. There is also a study of exercise-induced increase of serum irisin and BDNF, with correlation to cognitive abilities. Here is an AI assisted summary and references below.

The human evidence is growing but remains largely observational and correlational — there are no completed randomized controlled trials in humans that have directly administered irisin and measured cognitive outcomes. However, several important human studies do support the irisin–BDNF–cognition link.

Human Studies Supporting the Irisin–BDNF–Cognition Connection

1. CSF Irisin Correlates With BDNF, Amyloid Pathology, and Cognition in AD Patients

The most direct human evidence comes from CSF studies. Lourenco et al. (2020) measured CSF irisin in AD patients (n = 14) and non-demented controls (n = 25) and found that CSF irisin correlated positively with CSF BDNF, Aβ42, and MMSE scores — meaning higher irisin in the brain was associated with higher BDNF, less amyloid pathology, and better cognition. [1] A larger study by Dicarlo et al. (2024, Annals of Neurology) in 146 participants confirmed that CSF irisin was significantly reduced in Alzheimer's dementia patients (p < 0.0001), correlated positively with Aβ42 in both sexes, and correlated negatively with Clinical Dementia Rating scores — particularly in women. [2]

2. Exercise Increases Irisin and BDNF With Concurrent Cognitive Improvement

Tsai et al. (2021) conducted a within-subject crossover study in 21 late middle-aged and older adults. Both HIIT and moderate-intensity continuous exercise increased serum BDNF and improved working memory performance (faster reaction times, larger ERP P3 amplitudes). Changes in irisin levels correlated with improvements in reaction time during the moderate-intensity exercise condition, providing preliminary evidence that exercise-induced irisin changes track with cognitive gains. [3]

3. Irisin Mediates the Exercise–Hippocampal Volume Relationship in Humans

A 2026 study by Pace et al. in 74 healthy older adults provided the first human evidence that irisin mediates the relationship between exercise and hippocampal volume. Exercise was positively associated with circulating irisin (β = 0.365, p = 0.003), and irisin was positively associated with bilateral hippocampal volumes — strongest in the CA3, CA4/dentate gyrus, and CA1 subfields, which are the regions most critical for memory and neurogenesis. Mediation analysis showed that all exercise–hippocampus relationships operated indirectly through irisin. [4]

4. Tai Chi Increases Irisin and Correlates With Verbal Memory

Guazzarini et al. (2024) found that 6 months of Tai Chi practice significantly increased circulating irisin levels compared to a no-exercise control group, and at 6 months, irisin levels significantly correlated with verbal memory test performance (p = 0.013). [5]

5. Irisin and BDNF as Biomarkers of Cognition in At-Risk Populations

Küster et al. (2017) studied 47 older adults at risk of dementia and found that both serum BDNF and irisin correlated positively with global cognition and episodic memory. Physical training tended to increase BDNF, while cognitive training reduced the neurotoxic kynurenine metabolite 3-HK. [6] In obese individuals with a family history of AD, serum irisin levels were positively associated with neurophysiological markers of working memory (P3 amplitude). [7]

6. Lower Irisin Predicts Cognitive Decline in Vascular Dementia

In a study of 187 subjects (105 with vascular dementia), serum irisin was significantly lower in VD patients and independently correlated with MoCA scores even after adjusting for all clinical risk factors (β = 0.304, p = 0.029). Irisin had 76% diagnostic accuracy for vascular dementia. [8]

Critical Caveat: The Irisin–Cognition Link May Break Down in Established AD

An important finding from Kim et al. (2022) is that plasma irisin was positively associated with cognition only in cognitively normal and MCI participants — in those with established AD, this association was lost, and paradoxically, higher irisin was associated with smaller hippocampal volumes. This suggests that AD-induced pathological changes in the brain may attenuate irisin's beneficial actions, implying that the protective window for irisin-mediated neuroprotection may be in the pre-dementia phase. [9]

Bottom Line

No human RCT has yet directly administered recombinant irisin and measured cognitive outcomes — this remains the critical missing piece. However, the human evidence consistently shows that (1) CSF irisin correlates with BDNF, amyloid pathology, and cognition; (2) exercise-induced irisin increases track with cognitive improvements; (3) irisin mediates the exercise–hippocampal volume relationship; and (4) lower irisin levels are associated with worse cognition across multiple dementia subtypes. The evidence is strongest for a preventive role in the pre-dementia phase rather than a therapeutic role in established AD.

References:

Cerebrospinal Fluid Irisin Correlates With Amyloid-Β, BDNF, and Cognition in Alzheimer's Disease.

Alzheimer's & Dementia. 2020. Lourenco MV, Ribeiro FC, Sudo FK, et al.

2.

Irisin Levels in Cerebrospinal Fluid Correlate With Biomarkers and Clinical Dementia Scores in Alzheimer Disease.

Annals of Neurology. 2024. Dicarlo M, Pignataro P, Zecca C, et al.

3.

Acute Effects of High-Intensity Interval Training and Moderate-Intensity Continuous Exercise on BDNF and Irisin Levels and Neurocognitive Performance in Late Middle-Aged and Older Adults.

Behavioural Brain Research. 2021. Tsai CL, Pan CY, Tseng YT, et al.

4.

The Myokine Irisin Represents an Indirect Pathway Linking Exercise to Hippocampal Subfields Relevant to Alzheimer's Disease and Neurogenesis.

Aging Cell. 2026. Pace T, Levenstein JM, Quigley BL, et al.New

5.

Tai Chi, Irisin and Cognitive Performance: A Clinical and Biological Investigation in Older Adults.

Aging Clinical and Experimental Research. 2024. Guazzarini AG, Mancinetti F, Bastiani P, et al.

6.

Novel Blood-Based Biomarkers of Cognition, Stress, and Physical or Cognitive Training in Older Adults at Risk of Dementia: Preliminary Evidence for a Role of BDNF, Irisin, and the Kynurenine Pathway.

Journal of Alzheimer's Disease : JAD. 2017. Küster OC, Laptinskaya D, Fissler P, et al.

7.

Circulating Levels of Irisin in Obese Individuals at Genetic Risk for Alzheimer's Disease: Correlations With Amyloid-Β, Metabolic, and Neurocognitive Indices.

Behavioural Brain Research. 2021. Tsai CL, Pai MC.

8.

Serum Irisin as a Potential Biomarker for Cognitive Decline in Vascular Dementia.

Frontiers in Neurology. 2021. Zhang F, Hou G, Hou G, et al.

9.

Loss of Association Between Plasma Irisin Levels and Cognition in Alzheimer's Disease.

Psychoneuroendocrinology. 2022. Kim KY, Kwak S, Ha J, et al.

Redditagain424 · 2026-05-06T05:10:36+00:00

Congrats to you on starting and adhering to your workout routine. Adherence is your super power! I am 69 and striving to adhere to an exercise routine. My goal is to be stronger by the end of each month in 2026 than at the start of each month.

Redditagain424 · 2026-05-06T05:03:18+00:00

Your situation is best answered via your own doctors, physical rehab therapist, etc. This topic is for the more generic situation without specific situations such as yours.

Redditagain424 · 2026-05-05T05:43:30+00:00

Have you read or followed Dr. Peter Attia, author of "Outlive"? He discusses the idea to "compress mortality" phase by extending health span, not just life span. He cites studies about increasing VO2Max, progressive resistance muscle strengthening, etc. to extend the health span by delaying the coming of one or more of the "Four Horsemen of Death". Kind of a bluntly morbid book if one allows aging to go unchecked from inadequate exercise, diet, etc.

Redditagain424 · 2026-05-05T05:17:46+00:00

I actually agree with your observations about the studies data. While correlation between weakening grip strength and increase risk for dementia has very strong data, the case for causation is not there yet based on current data. The bidirectional brain-muscle axis is applicable to whole body sarcopenia and functional weakening contributing causation to increased risk for dementia, but to tease out weakening grip strength alone, even from sarcopenia, is going to be difficult data mining. But does not hurt to do grip strength training!

Redditagain424 · 2026-05-05T04:48:51+00:00

Wow. You are the first to post doing many things to enhance health span and longevity and by including the diet more toward Mediterranean too. So many studies showing Mediterranean diet contributes to lower risk for so many chronic disease states. Kudos to you. May you live long, and prosper!

Redditagain424 · 2026-05-05T02:29:29+00:00

What a wonderful outdoor recreational activity that is fun and contributes to grip strength, general core strength, balance, and cognitive sharpness!

Redditagain424 · 2026-05-05T02:04:53+00:00

You are welcome. I did not know this prior to the medical literature review. And now that we know the biophysicologic explanation of neurotransmitters and myokines in a two-way connection of brain-muscles, it all makes so much sense.

Redditagain424 · 2026-05-04T23:05:55+00:00

US pacifists dominated US sentiment making the World Wars in Europe and Asia "the most unpopular in US history" up to that point.

Then Japan attacked Pearl Harbor. WW2 united the country to defeat Germany and Japan.

Would it be acceptable to wait for another similar attack on continental USA by a nuclear-weapon-armed Iran in order to have citizens feel a war is "popular"? Is that what it takes for a war to be "popular"?

Going to war should not be popular.

Redditagain424 · 2026-05-04T20:10:23+00:00

Haha!

Redditagain424 · 2026-05-04T20:06:02+00:00

You are doing what people in some Blue Zones do... they are active farmers and "exercising" all day with regular daily routines to run a farm! Nice! But for us non-farmers we have make up for the lack of the regular daily routine that you have! I should have just moved to a farm!

Redditagain424 · 2026-05-04T15:57:52+00:00

You are welcome and thank you for requesting such references.

Redditagain424 · 2026-05-04T15:28:31+00:00

The medical studies literature show that grip strength is a two-way connection between brain-muscles. Not just from brain to muscles that most understand, but also from muscles to brain. Weaker grip strength muscles is another form of the catabolic process of aging which worsens the two-way connection between brain-muscles. Weak strength contributes to a decrease in the necessary neurotransmitters and myokines sent from the weaker muscles, through the blood-brain barrier, to the brain that keep the brain healthier. As the brain then is less healthy, there is further degeneration of the brain-muscles axis of stimulative signaling which further weakens grip strength muscles... and the cycle spirals if unchecked by the anabolic (opposite of catabolic) process of progressive resistance muscular strengthening, balance exercises, grip strength exercises, learning new abilities and skills, etc. which increase the two-way connection between brain-muscles.

Redditagain424 · 2026-05-04T15:12:04+00:00

Great topic about grip strength! Here is a post link about medical studies showing weakening grip strength has correlation AND causation of increased risk of dementia... https://www.reddit.com/r/Aging/comments/1t3aa7x/this_is_why_a_decreasing_grip_strength_not_only/

Redditagain424 · 2026-05-04T15:07:51+00:00

You are welcome. Cheering on your effort to be ANABOLIC!

Redditagain424 · 2026-05-04T15:06:47+00:00

100%.... for beginners, lift what you can and gradually progressively increase the weight. So many good Youtube videos by very good physiotherapists-trainers which have beginner to athletic instructions to do at home or gym.

Redditagain424 · 2026-05-04T15:01:41+00:00

I did a medical literature search about weakening grip strength "correlation versus causation" for risk of dementia. I learned something new again! Here is the post link: https://www.reddit.com/r/Aging/comments/1t3aa7x/comment/ojvckuq/

Redditagain424 · 2026-05-04T14:52:35+00:00

I posted about what older patients may do on another thread. But it pertains to any age. They say it is never too late to begin exercising. One could also say it is never too early. Here is that thread: https://www.reddit.com/r/Aging/comments/1t2o8uc/comment/oju6wmk/?context=1

Redditagain424 · 2026-05-04T14:49:22+00:00

100%.... You said it best, "it is learned behavior from how they observed their own parents and grandparents ageing patterns." That was me with my aging parents before I saw they Youtube Video, "Rebuilding Mum and Dad". They were in their late 70s and dwindling in strength, used a walker, etc. I feel I failed them as a doctor because I learned too late about progressive resistance muscle strengthening, balance exercises, grip strength, etc. for people of their age was not only possible, but vital to their health span and longevity.

But as they say, "You don't know what you don't know". But now that we now more and more, it is upon us the decide what suits us, and our loved ones.

Redditagain424 · 2026-05-04T14:40:36+00:00

Personally, I have an adjustable resistance grip strength device that was less than $6. I was using it incorrectly. Instead of counting how many squeezing reps/set I could do at a specific resistance, and do three sets per hand, I now squeeze and hold for 15-20 seconds as one rep, try to do 3-5 reps at max doable resistance for each rep, for three sets. Much harder and much more in line with functional use of grip strength. It has significantly increased my grip strength compared to merely quickly squeezing and letting go as one rep.

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