Redhead – Red hair - vitamin D

Red hair "might" allow more production of vitamin D from the same amount of sunlight

The portion of the UK with the least amount of sunlight, Ireland and Scotland, is also the portion of the UK which has the least amount of sunlight. Wikipedia

One person in 2010 made the observation that there are a higher percentage of diabetics with red hair than the general population.

This is understandable since diabetes is associated with low levels of vitamin D and people with red hair tend to stay away from the sun, and thus have low levels of vitamin D

Probably taking vitamin D will permit a redhead to not burn in the sun

Google Search ("red-hair" OR redhead) "vitamin d" ("burn less" OR "not burn") 15,000 hits Jan 2015

There has been several anecdotes about this. Seems as though if a red head cannot make melanin to protect the skin from burning that adding vitamin D should not help reducing burning. Wonder if the vitamin D in the skin, rather than the melanin prevents burning.

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Do redheads have lower levels of vitamin D - Claudia AI March 2026

Redheads carry a built-in physiological advantage for vitamin D synthesis—but most evidence suggests they don't fully use it. Their MC1R gene variants produce pheomelanin-dominant skin that lets far more UVB radiation through to the vitamin-D-producing layers of the epidermis. Yet population studies consistently show that the fairest-skinned individuals, including many redheads, tend to have lower circulating vitamin D than slightly darker Caucasians. The culprit is behavior: sun avoidance driven by extreme burn susceptibility and elevated skin cancer risk. One small but provocative Czech study challenges this narrative, finding redheads actually had higher vitamin D through an apparent physiological mechanism independent of sun exposure. The contradiction remains unresolved, but the practical consensus is clear—redheads should supplement rather than sunbathe.

How MC1R rewires the skin's UV response

The MC1R gene encodes a receptor on melanocytes that, when activated by α-MSH, switches pigment production from the default reddish-yellow pheomelanin to the brown-black eumelanin. In redheads, loss-of-function MC1R variants (most commonly R151C, R160W, and D294H) cripple this switch. The result is not simply less melanin—it is a fundamentally different type of melanin dominating the skin and hair.

This distinction matters enormously for vitamin D. Eumelanin is an extraordinarily efficient UV absorber, dissipating over 99.9% of absorbed UV radiation as heat within picoseconds. It acts as a natural sunscreen with an estimated SPF of ~13.4 in dark skin versus ~3.3 in light skin. Pheomelanin, by contrast, absorbs UVB far less effectively and can paradoxically amplify UV damage by generating reactive oxygen species. Black skin blocks approximately 92.6% of incoming UVB, while white skin blocks about 76%—meaning substantially more UVB reaches the 7-dehydrocholesterol molecules in the upper epidermis of fair-skinned individuals, where vitamin D3 photosynthesis occurs.

For redheads specifically, three factors compound this permeability advantage: predominant pheomelanin (poor UV filtration), lower total melanin content, and smaller melanosomes that cluster together rather than dispersing individually across keratinocytes. The net result is that redhead skin should, molecule for molecule, produce vitamin D more efficiently than any other skin type for a given dose of sunlight.

What the clinical evidence actually shows

The most directly relevant study is Flegr et al. (2020), which measured serum 25(OH)D3 in 73 redheads and 130 non-redheads in Prague. Redheads had higher vitamin D concentrations, and levels correlated positively with the intensity of hair redness. The striking finding was that in non-redheads, vitamin D tracked predictably with sun exposure and tan intensity—but in redheads, no such correlation existed. The authors concluded the difference was physiological, not behavioral, and proposed that redheadedness may represent an evolutionary adaptation for vitamin D synthesis in low-UVB environments.

This finding stands in tension with larger population studies. Glass et al. (2009) measured vitamin D in 1,414 UK Caucasian women and found that Fitzpatrick skin types I and II had lower mean 25(OH)D (71 nmol/L) compared to types III and IV (82 nmol/L). Over 60% of skin type I subjects had suboptimal vitamin D in winter, and 10% were clinically deficient—double the rate of skin type IV. The Newton-Bishop group (2011) in Leeds confirmed this pattern among ~1,200 participants: fair-skinned individuals had significantly lower vitamin D and could not reach optimal levels (≥60 nmol/L) without supplementation. Flegr's own earlier work (2019, n=4,117) found that pale-skinned Czechs had less vitamin D than their darker-skinned counterparts.

The genetic association data adds another layer. The LURIC study (n≈3,000 German Caucasians) tested 244 SNPs across 15 pigmentation genes for association with serum vitamin D. While several pigmentation-related variants showed nominal associations, MC1R variants specifically did not survive statistical correction, and the combined explanatory power of all pigmentation gene variants accounted for just 1.6% of total vitamin D variance. Whatever advantage MC1R confers, it appears modest at the population-genetic level.

The paradox at the heart of the question

Two competing forces shape redhead vitamin D status, and the balance between them determines whether an individual redhead ends up deficient or sufficient.

The efficiency advantage is real and rooted in physics. Fair skin needs roughly 10–15 minutes of midday summer sun on arms and legs to produce adequate daily vitamin D, compared to 25 minutes for moderately pigmented skin and potentially hours for deeply pigmented skin. Redheads sit at the extreme efficient end of this spectrum. The Flegr 2020 data hints that MC1R variants may confer an additional physiological boost beyond simple melanin reduction—perhaps through altered cutaneous vitamin D metabolism—though no mechanism has been identified.

The behavioral penalty is equally real and well-documented. Fitzpatrick type I skin can burn in under 10 minutes at high UV index, with minimal erythemal doses roughly half those of type III skin. Studies using the Sun Exposure and Protection Index show that UV-sensitive individuals adopt significantly safer sun habits, use more sunscreen, take fewer sun vacations, and spend less time outdoors. Public health campaigns in the UK, Australia, and Ireland explicitly target fair-skinned populations with sun-avoidance messaging—medically appropriate given their cancer risk, but with vitamin D consequences.

The sunscreen question adds nuance. Laboratory studies confirm that properly applied sunscreen substantially blocks vitamin D synthesis. But systematic reviews of real-world use, including a 2019 analysis of 76 studies, consistently find minimal or no reduction in vitamin D levels among sunscreen users. The explanation is mundane: people apply only 25–33% of the recommended amount, reapply inconsistently, and sunscreen users tend to spend more time outdoors. Even SPF 50 lets 2% of UVB through. A field study in Tenerife found "excellent vitamin D synthesis" even with optimal sunscreen application during a week of perfect weather.

Pheomelanin's dark side changes the calculus

The vitamin D discussion cannot be separated from melanoma risk, and here the science has shifted dramatically. A landmark 2012 study in Nature by Mitra et al. demonstrated that mice with inactivating Mc1r mutations developed invasive melanomas with zero UV exposure—and that eliminating pheomelanin (by introducing an albino mutation) abolished this risk. Pheomelanin itself generates oxidative DNA damage through reactive oxygen species. Human data confirms this: Wendt et al. (2016) found that carriers of two MC1R variants had a 2.63-fold increased melanoma risk even after adjusting for UV exposure history.

This UV-independent cancer pathway fundamentally reshapes the vitamin D question for redheads. Complete sun avoidance does not eliminate their melanoma risk—it only addresses the UV-dependent component. This makes the case for vitamin D supplementation even stronger: supplementation provides the nutrient without adding any UV-related risk to an already elevated baseline cancer risk.

What redheads should actually do about vitamin D

No clinical trial has specifically studied vitamin D supplementation in redheads, and no medical body has issued redhead-specific dosing guidelines. The evidence converges on a practical recommendation nonetheless.

Newton-Bishop's group stated directly that "fair-skinned individuals who burn easily are not able to make enough vitamin D from sunlight and so should take vitamin D supplements." The American Academy of Dermatology recommends obtaining vitamin D from diet and supplements rather than UV exposure for all skin types. Standard dosing is 600 IU/day for adults under 70 and 800 IU/day for those over 70, with an upper tolerable limit of 4,000 IU/day. International expert panels recommend vitamin D screening for individuals with photosensitivity who require rigorous photoprotection—a category that inherently includes most redheads.

The Flegr finding that redheads may have a physiological vitamin D advantage is intriguing but rests on a single small study (n=203) that has not been replicated, did not include MC1R genotyping, and came from a single center. It has not been translated into differential dosing recommendations. The much larger body of evidence—Glass (n=1,414), Newton-Bishop (n≈1,200), and Flegr's own earlier work (n=4,117)—consistently shows fair-skinned populations running vitamin D deficits in practice.

Conclusion

The redhead vitamin D story is a case study in how biology and behavior can pull in opposite directions. MC1R loss-of-function variants create skin that is, photochemically, a superior vitamin D factory—pheomelanin-dominant, low in total melanin, maximally permeable to the UVB wavelengths that drive cholecalciferol synthesis. But this same skin burns in minutes, faces elevated cancer risk from pheomelanin's intrinsic oxidative damage, and belongs to people who have rationally learned to avoid the sun. The single study suggesting redheads may overcome this behavioral deficit through an unknown physiological mechanism is fascinating but unreplicated. The weight of clinical evidence points toward a net vitamin D disadvantage in practice. The most important gap in the literature is the absence of a large, genotyped cohort study measuring both MC1R status and longitudinal vitamin D levels—until that exists, the prudent recommendation remains straightforward: redheads should supplement, get their 25(OH)D levels tested, and not rely on their efficient skin to compensate for the sun exposure they wisely avoid.

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Red Hair and Vitamin D: Claude AI March 2026

Current evidence is mixed on whether natural red-haired individuals have lower serum vitamin D than others. Some large European studies have found slightly lower 25(OH)D in redheads, while other recent data suggest higher levels in redheads. Red hair is caused by MC1R gene variants that reduce eumelanin (dark pigment) and increase pheomelanin (red pigment) in skin and hair【29†L194-L202】【67†L250-L258】. Pheomelanin offers very little UV protection【29†L194-L202】, so redheads have very fair skin that burns easily. In theory, less melanin could allow more UV‑B penetration per sun exposure (boosting vitamin D synthesis), but redheads often use more sun protection and avoid sunlight (reducing actual UV exposure)【57†L788-L797】【45†L49-L57】. Two key studies illustrate this conflict: a UK population found lower vitamin D in red-haired controls (≈50.5 vs 56.1 nmol/L in blondes)【52†L137-L144】 (chart below), whereas a Czech case-control found higher 25(OH)D in redheads【71†L30-L35】【57†L788-L797】. In large Finnish cohorts (“ATBC”), no difference by hair color was seen【61†L663-L669】. Overall, the data are inconsistent and often limited by design. Known confounders (sun exposure, latitude, skin type, sunscreen use, diet, supplement use, age, sex, socioeconomic status) strongly affect vitamin D levels and must be controlled. Biologically, red hair (via MC1R loss-of-function) indeed yields a skin phenotype (pale, burns easily) that maximizes vitamin D synthesis at low UV, but real-world behavior complicates this. Clinically, no specific vitamin D guideline exists for redheads; prudent advice is that fair-skinned redheads should follow standard vitamin D intake and sun-protection guidelines (as for other pale individuals). Key takeaway: Evidence does not clearly show red-haired people have chronically lower vitamin D than others; behavior and environment matter more. Redheads synthesize vitamin D efficiently but often avoid sun, so clinicians should ensure adequate vitamin D through normal routes (sun, diet, supplements) as for any fair-skinned patient.

Definitions: Red Hair, MC1R, and Pigments

“Natural red hair” refers to a rare phenotype (∼1–2% of Europeans, up to 10% in Ireland/Scotland) caused by MC1R gene variants【67†L250-L258】. MC1R is a receptor on melanocytes that normally signals production of brown-black eumelanin. Loss-of-function MC1R variants (the common “red hair color” [RHC] alleles R151C, R160W, D294H, etc.) shift melanin synthesis toward red/yellow pheomelanin【67†L250-L258】【29†L194-L202】. These alleles (often denoted R variants) are highly penetrant: individuals with two copies typically have full red hair【67†L250-L258】. The r alleles (e.g. V60L, V92M, R163Q) have weaker effects【67†L250-L259】. MC1R loss also yields fair (Fitzpatrick I–II) skin and often light eyes; such skin burns rapidly under UV.

Physiology: Melanin, UV and Vitamin D Synthesis

Vitamin D₃ is produced in skin when UVB photons convert 7-dehydrocholesterol to previtamin D₃, which is later hydroxylated to circulating 25(OH)D (calcidiol)【69†L197-L204】. Melanin absorbs UV; high eumelanin (dark skin/hair) strongly shields and lowers vitamin D synthesis, whereas low melanin (very fair skin) allows more UV penetration【69†L197-L204】【57†L788-L797】. Pheomelanin (red) provides little UV protection【29†L194-L202】; it even generates reactive oxygen species under UV【29†L194-L202】. Thus, red-haired fair skin admits more UV per unit exposure. In effect, physiologically redheads are primed to produce vitamin D efficiently: mathematical models and animal data suggest that lighter pigmentation at high latitudes was an adaptation for adequate vitamin D under low UV【57†L788-L797】【69†L197-L204】.

However, fair skin has higher sunburn risk, so behavioral factors intervene. Redheads typically report greater sun-sensitivity and often use more sunscreen and protective clothing【57†L788-L797】【45†L49-L57】. Their paler “natural” complexion (even without sun tan) further limits need for sun. In a Czech survey, redheads reported significantly more frequent use of suncream and shade【45†L49-L57】. In that study, redheads did avoid sun significantly – yet still had higher vitamin D (suggesting physiology outweighed behavior)【57†L788-L797】【71†L30-L35】. This apparent paradox (good vitamin D with low sun) is interpreted as an evolutionary trait: even minimal UV yields adequate vitamin D for redheads【57†L788-L797】.

Mermaid causal pathway:

flowchart LR
  MC1R(Genetics: MC1R & pigment genes) --> PIGMENT[Melanin type: ↓eumelanin, ↑pheomelanin] 
  PIGMENT --> FAIR[Fair, UV-sensitive skin]
  FAIR --> BURN[High sunburn risk]
  BURN --> PROTECT[Sun avoidance & sun protection]
  PROTECT --> UVE[Reduced effective UV exposure]
  PIGMENT --> SHIELD[UV absorption]
  SHIELD --> UVE
  UVE --> VITD[Skin vitamin D synthesis]
  DIET[Diet/supplements] --> VITD
  VITD --> 25OH[Serum 25(OH)D levels]
  LATITUDE[Latitude/Season/UVB availability] --> UVE
  AGE[Age], SEX[Sex], SES[Socioeconomic factors] -.- 25OH
  SKIN[Other skin factors] -.- 25OH

Epidemiology: Population Studies

Only a few studies have directly compared vitamin D status by hair color. In a large UK melanoma case-control analysis (Randerson-Moor et al. 2009), controls with red hair had lower mean serum 25(OH)D than blonds【52†L137-L144】. Specifically, mean 25(OH)D was about 50.5 nmol/L in red-haired controls versus 56.1 nmol/L in blond controls【52†L137-L144】. Blonds overall had higher levels than brunettes in that study, and red-haired subjects were lowest【5†L978-L982】. (A bar chart below illustrates the red vs blond contrast from this UK data【52†L137-L144】.)

【52†L137-L144】【52†L137-L144】

【2†embed_image】 Chart: Mean serum 25(OH)D in red-haired vs blond individuals in a UK study【52†L137-L144】.

By contrast, Flegr et al. (2020, Czech Republic) reported higher vitamin D in redheads. In 203 Czech volunteers (73 red-haired vs 130 others), 25(OH)D₃ levels were significantly higher in redheads【71†L30-L35】. The authors used spectrophotometric hair color measures and controlled for sun exposure; even with lower tan and sun habits, redheads had higher calcidiol【71†L30-L35】【57†L788-L797】. Another report from Finland (Albanes et al. in the ATBC cohort) found no difference by hair color; in thousands of Finnish men, 25(OH)D did not vary with hair color【61†L663-L669】, though they note that red-haired men had about half the prostate cancer risk (mechanism unclear).

These findings are inconsistent: (a) UK data suggested red hair lower vitamin D【52†L137-L144】, (b) Finnish data showed no difference【61†L663-L669】, and (c) Czech data found redheads higher【71†L30-L35】【57†L788-L797】. Importantly, the UK and Finnish studies were large cohorts/controls (though originally collected for other purposes), while the Czech study was modest and self-selected. Methodologies vary (assays, timing of blood draw, season, etc.).

Table: Key studies comparing vitamin D by hair color (red vs others).

Study (year)	N (red / total)	Population	Hair-Color Definition	25(OH)D Measure	Main Finding	Limitations
Randerson-Moor et al. 2009【52†L137-L144】	Controls: ~50 / ~350	UK adults (controls in melanoma case-control)	Red vs Blond vs Brunette (self-report)	Serum 25(OH)D by immunoassay	Red-haired: lower 25(OH)D (50.5 nmol/L) vs blond (56.1)【52†L137-L144】	Hair self-reported; sun exposure not fully controlled; seasonal variation.
Albanes et al. (ATBC) 2013【61†L663-L669】	~??? / ~3400 (boys baseline)	Finnish male smokers (~50–69 y)	Red vs other (questionnaire)	Serum 25(OH)D by RIA	No difference by hair color; noting one study found lower D in redheads【61†L663-L669】	Cohort homogenous (smokers, all male); vitamin D seasonal and supplement use not detailed.
Flegr et al. 2020【71†L30-L35】【57†L788-L797】	73 / 203	Czech adults (volunteers)	Red vs non-red (observer- & instrument-assessed intensity)	Serum 25(OH)D₃ by HPLC	Red-haired: higher 25(OH)D₃ (statistically significant)【71†L30-L35】	Small sample; self-selection; single latitude (Prague, ~50°N); supplements use varied.

Sources: Randerson-Moor (2009, UK controls)【52†L137-L144】; Albanes (2013, Finland)【61†L663-L669】; Flegr (2020, Czech)【71†L30-L35】【57†L788-L797】.

Confounding Factors

Many variables can confound or mediate the hair-color–vitamin-D relationship:

• Sun exposure & behavior: Time spent outdoors, clothing, sunscreen use vary widely. Redheads often report less sunbathing and more sunscreen than others【57†L788-L797】【45†L49-L57】. In Flegr’s Czech sample, sun exposure frequency was similar by hair color, but redheads had lighter tan and used more protection【45†L49-L57】. Seasonal and latitudinal UVB availability also strongly affect vitamin D; people at high latitudes get little UVB in winter regardless of hair【69†L197-L204】.

• Skin phototype: Red hair almost always comes with very fair skin (Fitzpatrick I–II). Fair skin is a known factor in vitamin D synthesis – typically fair-skinned people make vitamin D more easily than dark-skinned ones【69†L197-L204】. Thus comparing red vs brown hair inherently compares differing skin phototypes, which itself drives 25(OH)D levels【69†L197-L204】.

• Diet and supplements: Intake of vitamin D from diet or pills can override sun effects. Flegr noted redheads in his sample used supplements less often (though the effect was modest)【45†L49-L57】. Socioeconomic factors correlate with supplement use and outdoor activity.

• Age and sex: Older age reduces skin D production; many red hair genetic studies show red-haired women predominate (sex ratio ~2:1 in Flegr’s cohort). In Flegr, women had slightly higher 25(OH)D than men【15†L61-L65】. These differences could skew results if not stratified.

• Genetic variants beyond MC1R: Other pigmentation genes (e.g. variants in TYR, TYRP1, etc.) and non-pigment genes (e.g. exocyst complex) have been linked to 25(OH)D levels【35†L343-L352】. Thus MC1R effects may interact with overall pigmentation genotype.

• Health status: Chronic illnesses, BMI, and medication use affect vitamin D metabolism. The UK study (in melanoma patients) noted potential selection biases: healthier blond controls vs possibly sun-dodging red cases, etc.

Most studies adjust for at least season, age, BMI, and lifestyle. However, disentangling hair color from skin color is hard; a more rigorous test would compare red-haired vs non-red with similar skin fairness.

Effect Sizes and Significance

Reported effect sizes are modest. Randerson-Moor (UK) found a difference ~5.6 nmol/L between red and blond mean vitamin D【52†L137-L144】. Flegr’s Czech study reported a statistically significant increase (p<0.05 after multiple test correction) in redheads【71†L30-L35】【57†L788-L797】, but did not quote absolute differences in the abstract. In Flegr’s partial correlations, hair redness had the strongest effect on 25(OH)D among all pigmentation variables【15†L79-L82】. In contrast, Albanes (ATBC) found no significant hair color effect【61†L663-L669】. No meta-analysis is available, and confidence intervals are often wide. Given conflicting directions, any true effect is likely small.

Biological Plausibility

There is a plausible mechanism: Lower eumelanin → more UV penetration per exposure. Red-haired fair skin lets more UVB reach 7-dehydrocholesterol, boosting vitamin D production. In fact, 11 of 29 pigmentation genes influence vitamin D status【48†L119-L126】. Evolutionarily, MC1R loss (red hair/fair skin) likely arose to improve D synthesis at high latitudes【57†L788-L797】. Pheomelanin does not block UVB (unlike eumelanin)【29†L194-L202】, so redheads need less sun to reach a given vitamin D level.

However, behavior counters this: if redheads avoid sun, their actual UV exposure (and thus D synthesis) can be lower. The Czech study suggests the physiological gain can outweigh behavioral loss, but results may vary.

There is no known direct biochemical effect of MC1R variants on vitamin D metabolism beyond UV absorption. MC1R’s role in melanocytes appears limited to pigmentation pathways【67†L245-L254】. Thus any link is indirect (via skin pigment, not via vitamin D binding or metabolism genes).

Clinical Implications and Recommendations

At present, no special clinical guidelines target red-haired individuals for vitamin D screening. Instead, redheads should follow general dermatology and nutrition advice for fair-skinned people:

• Sun exposure: Red-haired patients should avoid sunburn but get some safe sun for vitamin D (e.g. arms exposed short times, especially in summer). Because they burn easily, sunscreen use is recommended; just remember it reduces D synthesis. On balance, moderate sun exposure (5–15 minutes on arms/day in summer) without burning is usually adequate.

• Dietary/supplemental D: If UV exposure is limited (e.g. winter, high latitude, or heavy sun avoidance), encourage dietary sources (fatty fish, fortified foods) or vitamin D supplements as per standard guidelines (e.g. Endocrine Society 600–800 IU/day for adults)【69†L197-L204】. Red-haired patients need not necessarily take more than other fair-skinned individuals, but monitor those at risk (elderly, obese, institutionalized).

• Testing: Consider measuring 25(OH)D in red-haired patients who have other risk factors for deficiency (e.g. osteoporosis, malabsorption, chronic kidney disease). There is no evidence that red-hairedness alone mandates a test.

• Sun avoidance & cancer risk: Redheads have higher melanoma risk, so aggressive sun protection is a priority. Physicians should balance this with maintaining adequate vitamin D. Annual screening for vitamin D deficiency may be more important in redheads with strict sun avoidance.

Key practical point: Red hair per se does not automatically predict vitamin D deficiency. Redheads typically have enough capacity for D production but may underutilize it due to sun-avoidant behavior. Clinicians should treat vitamin D needs based on overall risk (skin type, sun exposure, diet) rather than hair color alone.

Gaps and Research Needs

Evidence is limited and somewhat contradictory. Major gaps include:

• Population surveys: Large-scale cohort or biobank studies that record hair color (and ideally MC1R genotype) alongside serum 25(OH)D and adjust for confounders. For instance, UK Biobank or NHANES might contain hair color, but analyses are not yet published.

• Mechanistic studies: Research on how exactly pheomelanin vs eumelanin affects UV penetration and D synthesis (animal or in vitro skin models) could clarify biology.

• Behavior quantification: More data on actual sun exposure habits of redheads vs others (wearable UV dosimeters, questionnaires) to separate behavior vs physiology.

• Dose-response: Studies to quantify how much less sun (if any) redheads need to reach D sufficiency, to inform guidelines.

• Global diversity: All studies so far are European (red hair is mostly European in origin). Data on similar pigmentation variants in other ancestries could be insightful.

In summary, further research should aim to isolate hair color effects from skin color and lifestyle, perhaps through controlled trials (e.g. giving equal UV doses to red vs non-red volunteers).

Conclusion

The question of whether natural red hair implies lower vitamin D has no simple answer. Existing studies conflict: some show lower 25(OH)D in redheads【52†L137-L144】, others higher【71†L30-L35】 or no difference【61†L663-L669】. Given their fair skin, redheads are physiologically poised to make vitamin D efficiently, but they may avoid sun more than others. Clinicians should be aware that red-haired patients carry both high sunburn risk and the capacity for robust D synthesis. The practical advice is to follow standard care for pale-skinned individuals: protect from burns, yet ensure enough D through diet or supplements, especially in low-sun conditions.

Bottom line for lay readers: Redheads do not automatically need extra vitamin D, but like all fair-skinned people they should ensure they get enough sun (without burning) or take supplements, following usual health advice.

Bottom line for clinicians: Hair color alone is not a proven risk factor for hypovitaminosis D. Monitor vitamin D status based on overall sun exposure, skin type, and lifestyle. If a red-haired patient avoids sun entirely, counsel on diet/supplements as you would for any patient with limited UV exposure.

Sources: The above conclusions are based on epidemiological studies【52†L137-L144】【71†L30-L35】【61†L663-L669】, genetic/pigmentation research【29†L194-L202】【67†L250-L258】, and authoritative reviews of vitamin D physiology【69†L197-L204】.

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Freckles

What Causes Freckles? At EzineArticles

Clips

“The underlying freckles cause is a cluster of concentrated melanin”

Melanin helps to protect against damage caused by overexposure to the sun”

“Others are referred to as senile freckles, age spots, liver spots, sun spots or lentigines. They do not fade in the winter. But, the underlying freckles cause is still the production of melanin clumps.”

Many diseases appear to be associated with redhair – examples

MS

Google search ("red-hair" OR redhead) "vitamin d" "Multiple Sclerosis" got 104,000 hits Dec 2016

1 example    Another example

Autism

Google search ("red-hair" OR redhead) "vitamin d" autism got 503,000 hits Dec 2016

1 example

Cancer

Google search ("red-hair" OR redhead) "vitamin d" cancer got 333,000 results Dec 2016

Lupus

Google search ("red-hair" OR redhead) "vitamin d" lupus got 137,000 results Dec 2016

Rickets

Google Search ("red-hair" OR redhead) "vitamin d" rickets got 192,000 results Dec 2016

Tuberculosis

Google Search ("red-hair" OR redhead) "vitamin d" tuberculosis got 459,000 results Dec 2016

RA

Google Search ("red-hair" OR redhead) "vitamin d" (RA or Arthritis) 103,000 results Dec 2016

Allergy

Google Search ("red-hair" OR redhead) "vitamin d" allergy 125,000 results Dec 2016

Example

See also VitaminDWiki

• Search of VitaminDWiki for (redhead OR "red hair") 114 items as of July 2019

• Skin fairness, red hair both associated with poor health (perhaps low vitamin D) – Dec 2019

• Sunburning reduced by 200,000 IU of Vitamin D – RCT April 2017

• People more likely to freckle are more likely to get prostate cancer (low vitamin D) – April 2013

• Overview Rare Allergic reaction to vitamin D

• Photosensitivity (sun allergy) and vitamin D

• Less than 18 percent of Irish take vitamin D, and 76 percent have less than 30 ng – April 2013

• Allergic to the sun (Polymorphic light eruption) – you may need UVB or vitamin D

• Skin fairness, red hair both associated with poor health (perhaps low vitamin D)

• Overview Deficiency of vitamin D

  • which has the following image: note in upper left - Fear of Sun