Sunlight robbery: a critique of public health policy on vitamin D in the UK

Effects of Vitamin D Supplementation in Elite Athletes: A Systematic Review

Background

Deficiency in vitamin D has been shown to increase the risk of injury.

Purpose

To synthesize current placebo-controlled randomized trials investigating the effect of vitamin D supplementation in elite athletes on (1) aerobic capacity; (2) anaerobic measures, such as strength, speed, and anaerobic power; (3) serum biomarkers of inflammation; and (4) bone health.

Study Design

Systematic review; Level of evidence, 1.

Methods

A literature search was conducted on November 30, 2022, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Included were randomized, placebo-controlled studies of longer than 2 weeks on subjects with active participation in organized sport. Excluded were nonrandomized controlled trial study designs, vitamin D administration routes other than oral, studies that did not use vitamin D supplementation as the sole intervention, and studies with nonathletic or military populations.

Results

Out of 2331 initial studies, 14 studies (482 athletes) were included. Of the 3 studies that assessed aerobic capacity, 2 demonstrated significantly greater improvements in maximal oxygen uptake and physical working capacity-170 (P < .05) in supplemented versus nonsupplemented athletes. Measurements of anaerobic power and strength were consistently increased in supplemented groups compared with nonsupplemented groups in 5 out of the 7 studies that assessed this. Of the 6 studies that assessed sprint speed, 4 found no significant difference between supplemented and nonsupplemented groups. Aside from 1 study that found significantly lower interleukin-6 levels in supplemented athletes, measures of other inflammatory cytokines were not affected consistently by supplementation. The 4 studies that assessed markers of bone health were conflicting regarding benefits of supplementation. One study found demonstrated improvements in bone mineral density in response to supplementation (P = .02) compared with control whereas another found no significant difference between supplemented and nonsupplemented groups. However, in 3 other studies, serum biomarkers of bone turnover such as bone-specific alkaline phosphatase, parathyroid hormone, and N-terminal telopeptide appeared to be higher in subjects with lower serum vitamin D levels (P < .05).

Conclusion

Results of this systematic review indicated that the greatest benefit of vitamin D supplementation in elite athletes may be improving aerobic endurance, anaerobic power, and strength. More research is needed to determine the effect of vitamin D supplementation on bone health and injury risk in this population.

Assessment of Knowledge, Attitude, and Practice of Sunlight Exposure of Infants among Mothers Attending in Governmental Health Facilities in Farta District, South Gondar Zone, North West Ethiopia, 2018

BACKGROUND

Sunlight exposure serves an important purpose in human bodies. It promotes good health and plays a major role in the production of the very essential vitamin, vitamin D. Vitamin D is important for the growth of healthy, normal bones. Research conducted in different areas suggested that daily exposure to sunshine remains the cheapest, safest, and most effective method of preventing rickets.

OBJECTIVE

To assess knowledge, attitude, and practice of infants to sunlight exposure among lactating women in Farta district, in 2018.

METHOD

Institution based cross sectional study design was conducted among mothers attending the selected health center. Systematic sampling method was used to select individual respondents. Data were entered and analyzed by using SPSS version 20.

RESULT

Among 357 respondents identified for the study, 95% (n = 339) was responding to the interview. Of the total respondents, 49.9%, 46%, and 45.7% of them had poor knowledge, unfavorable attitude, and poor practice about sunlight exposure, respectively.

CONCLUSION AND RECOMMENDATION

The results of this study showed that almost half of the mothers had inadequate knowledge, attitude, and inadequate practice about sunlight exposure. Therefore, mothers need to be educated about the importance of sunlight exposure.

Nutrition, dental caries and periodontal disease: a narrative review

AIM

To provide a narrative review of the role of macro- and micronutrients in relation to dental caries, gingival bleeding and destructive periodontal disease.

MATERIALS & METHODS

This review is based on systematic reviews (when available) and comparative human studies.

RESULTS

Dental caries cannot develop without the presence of dietary fermentable carbohydrates, in particular sugar. The susceptibility to develop caries in the presence of carbohydrates may be influenced by genetics and micronutrients such as vitamin D. Gingival bleeding and destructive periodontal disease are sensitive markers to both abnormalities in macronutrient content (excessive carbohydrates or poly-unsaturated fat intake, deficient protein intake) and micronutrient intake (e.g. vitamin C and B12).

CONCLUSION

Dental caries and periodontal diseases are a sensitive alarm bell for an unhealthy diet, which predicts the future onset of the diseases of civilizations.

Epidemic of Vitamin D Deficiency and Its Management: Awareness among Indian Medical Undergraduates

Vitamin D deficiency is prevalent across all age groups in epidemic proportions. The purpose of this study was to acquire a baseline assessment and create awareness among medical students regarding vitamin D. A cross-sectional, voluntary survey was conducted among undergraduate medical students. Data were collected using a questionnaire which assessed the level of knowledge students had with regard to where vitamin D comes from, what it does for health, how much is recommended, factors that affect its levels, and deficiency management. Majority of students were unaware that vitamin D deficiency has attained epidemic proportions. Though bone and skeletal disorders as a complication of vitamin D deficiency were known, a large number were unaware of systemic consequences (diabetes mellitus, cardiovascular diseases, and cancers). Only one-third of respondents were aware of duration and timing of sun exposure required for adequate serum vitamin D levels. However, we observed lack of awareness among students regarding the various biochemical forms, dose, and duration of vitamin D supplementation for treatment of nutritional deficiency. Our study highlighted a lack of knowledge about the importance of vitamin D, worldwide prevalence of vitamin D deficiency, and its management among medical students. Promoting vitamin D health awareness, if replicated across populations, could lead to positive health outcomes globally.

Ultraviolet radiation and effects on humans: the paradigm of maternal vitamin D production during pregnancy

Current evidence indicates that neonates born of mothers with vitamin D deficiency during pregnancy have greater risk for developing hypocalcemia, rickets and extra-skeletal disorders. Despite the classic knowledge that ultraviolet-B (UVB) exposure is the most efficient way for a future mother to obtain optimal vitamin D concentrations, no current consensus or clinical recommendations exist regarding the duration and timing of UVB exposure for pregnant women. This article offers a narrative review of available data regarding how UVB exposure affects maternal vitamin D production during pregnancy, along with a discourse on clinical implications of this public health issue. Future studies would benefit from adopting UVB exposure estimates to recommend appropriate UVB exposure to pregnant women. Doing so could provide a more holistic and practical approach in managing maternal hypovitaminosis D during pregnancy.

An estimate of the economic burden of vitamin D deficiency in pregnant women in the United Kingdom

Pregnancy is associated with an increased risk of vitamin D deficiency beyond that of the general population. The aim of the current analysis was to synthesize the current evidence on the dose-outcome relationship of vitamin D/serum 25 hydroxyvitamin D (25-OHD) and complications during pregnancy. An additional aim was to estimate the economic burden attributable to inadequate levels of serum 25-OHD. Published literature on the effects of vitamin D supplementation/serum 25-OHD on pregnancy complications, including randomized control trials and non-interventional studies, was searched in bibliographic databases including Pubmed, Google Scholar, Scopus and EMBASE. A positive and significant treatment effect was obtained for pre-eclampsia (OR = 0.75 95% CI 0.662-0.843), but not for preterm birth (OR = 0.783, 95% CI 0.49-1.251) or small for gestational age (OR = 0.76 95% CI 0.38-1.28). Inadequate vitamin D accounted for 14.04% of risk for pre-eclampsia. It is estimated that addressing vitamin D inadequacy in pregnant women in England and Wales would reduce the number of cases of pre-eclampsia by 4126; and would result in a net saving of £18.6 million for the NHS in England and Wales. The current results suggest that based on current evidence a public health policy preventing vitamin D inadequacy in pregnant women is likely to have a positive impact on the NHS budget in England and Wales. This is contingent upon further evidence regarding the vitamin D dose-pregnancy outcome relationship becoming available.

Evidence from prospective cohort studies did not support the introduction of dietary fat guidelines in 1977 and 1983: a systematic review

OBJECTIVES

National dietary guidelines were introduced in 1977 and 1983, by the USA and UK governments to reduce coronary heart disease (CHD) mortality by reducing dietary fat intake. Our 2015 systematic review examined randomised controlled trial (RCT) evidence available to the dietary committees at the time; we found no support for the recommendations to restrict dietary fat. What epidemiological evidence was available to the dietary guideline committees in 1983?

METHODS

A systematic review of prospective cohort studies, published prior to 1983, which examined the relationship between dietary fat, serum cholesterol and the development of CHD.

RESULTS

Across 6 studies, involving 31 445 participants, there were 1521 deaths from all-causes and 360 deaths from CHD during the mean follow-up of 7.5±6.2 years. The death rates were 4.8% and 1.1% from all-causes and CHD respectively. One study included men with previous heart disease. The death rate from CHD for those with, and without previous myocardial infarction was 20.9% and 1.0% respectively. None of the six studies found a significant relationship between CHD deaths and total dietary fat intake. One of the six studies found a correlation between CHD deaths and saturated dietary fat intake across countries; none found a relationship between CHD deaths and saturated dietary fat in the same population.

CONCLUSIONS

1983 dietary recommendations for 220 million US and 56 million UK citizens lacked supporting evidence from RCT or prospective cohort studies. The extant research had been undertaken exclusively on males, so lacked generalisability for population-wide guidelines.

"Test me and treat me"--attitudes to vitamin D deficiency and supplementation: a qualitative study

OBJECTIVE

Lay interest in vitamin D and the potential benefits of supplementation is considerable, but little information exists concerning lay knowledge, beliefs and attitudes towards vitamin D to inform public health initiatives and professional guidance.

DESIGN

Qualitative focus group study.

PARTICIPANTS

58 adults capturing diversity in disease status, gender, age and ethnicity.

SETTING

A large general practice in east London.

RESULTS

Many respondents lacked knowledge about vitamin D, including dietary sources and government recommendations. Most were positive about sun exposure, but confused by ambiguous health messages about risks and benefits of sunshine. Medicalised views of vitamin D were prominent, notably from those in favour of supplementation, who talked of "doses", "side effects" and "regular testing." Fortification of food with vitamin D was controversial, with opposing utilitarian (better overall for the majority) and libertarian (freedom to choose) views.

CONCLUSIONS

Knowledge about vitamin D was limited. Clearer messages are needed about risks and benefits of sun exposure. Testing and supplementation by health professionals, while potentially useful in some high-risk groups, have contributed to a medicalised view of vitamin D. Health policy should address the public's need for clear information on sources and effects of vitamin D, including risks and benefits of sun exposure, and take account of divergent views on fortification. Professional guidance is needed on testing and supplementation to counter inappropriate medicalisation.

UVA irradiation of human skin vasodilates arterial vasculature and lowers blood pressure independently of nitric oxide synthase

The incidence of hypertension and cardiovascular disease (CVD) correlates with latitude and rises in winter. The molecular basis for this remains obscure. As nitric oxide (NO) metabolites are abundant in human skin, we hypothesized that exposure to UVA may mobilize NO bioactivity into the circulation to exert beneficial cardiovascular effects independently of vitamin D. In 24 healthy volunteers, irradiation of the skin with two standard erythemal doses of UVA lowered blood pressure (BP), with concomitant decreases in circulating nitrate and rises in nitrite concentrations. Unexpectedly, acute dietary intervention aimed at modulating systemic nitrate availability had no effect on UV-induced hemodynamic changes, indicating that cardiovascular effects were not mediated via direct utilization of circulating nitrate. UVA irradiation of the forearm caused increased blood flow independently of NO synthase (NOS) activity, suggesting involvement of pre-formed cutaneous NO stores. Confocal fluorescence microscopy studies of human skin pre-labeled with the NO-imaging probe diaminofluorescein 2 diacetate revealed that UVA-induced NO release occurs in a NOS-independent, dose-dependent manner, with the majority of the light-sensitive NO pool in the upper epidermis. Collectively, our data provide mechanistic insights into an important function of the skin in modulating systemic NO bioavailability, which may account for the latitudinal and seasonal variations of BP and CVD.

Assessment of vitamin D concentration in non-supplemented professional athletes and healthy adults during the winter months in the UK: implications for skeletal muscle function

The current study implemented a two-part design to (1) assess the vitamin D concentration of a large cohort of non-vitamin D supplemented UK-based athletes and 30 age-matched healthy non-athletes and (2) to examine the effects of 5000 IU · day(-1) vitamin D(3) supplementation for 8-weeks on musculoskeletal performance in a placebo controlled trial. Vitamin D concentration was determined as severely deficient if serum 25(OH)D < 12.5 nmol · l(-1), deficient 12.5-30 nmol · l(-1) and inadequate 30-50 nmol · l(-1). We demonstrate that 62% of the athletes (38/61) and 73% of the controls (22/30) exhibited serum total 25(OH)D < 50 nmol · l(-1). Additionally, vitamin D supplementation increased serum total 25(OH)D from baseline (mean ± SD = 29 ± 25 to 103 ± 25 nmol · l(-1), P = 0.0028), whereas the placebo showed no significant change (53 ± 29 to 74 ± 24 nmol · l(-1), P = 0.12). There was a significant increase in 10 m sprint times (P = 0.008) and vertical-jump (P = 0.008) in the vitamin D group whereas the placebo showed no change (P = 0.587 and P = 0.204 respectively). The current data supports previous findings that athletes living at Northerly latitudes (UK = 53° N) exhibit inadequate vitamin D concentrations (<50 nmol · l(-1)). Additionally the data suggests that inadequate vitamin D concentration is detrimental to musculoskeletal performance in athletes. Future studies using larger athletic groups are now warranted.

Seasonal variation in vitamin D status in professional soccer players of the English Premier League

The prevalence of seasonal variation in vitamin D status was examined in 20 FA Premier League soccer players residing at a latitude of 53°N. Serum 25-hydroxyvitamin D (25(OH)D) levels decreased (P < 0.001) between August (104.4 ± 21.1 nmol·L(-1), range 68-151) and December (51.0 ± 19.0 nmol·L(-1), range 22-86), such that levels for 65% of the sample were insufficient (<50 nmol·L(-1)) in winter. Strategies to augment vitamin D(3) availability may therefore be advantageous for UK soccer players so as to maintain muscle function.

Risk factors for variation in 25-hydroxyvitamin D₃ and D₂ concentrations and vitamin D deficiency in children

CONTEXT

Vitamin D status is believed to be best indicated by serum 25-hydroxyvitamin D [25(OH)D; consisting of 25(OH)D₃ and 25(OH)D₂] that are obtained from different sources. Suboptimal vitamin D status is common and associated with adverse health outcomes.

OBJECTIVES

The objectives were to report the prevalence and risk factors of vitamin D deficiency and determine associations of characteristics that have been shown to relate to total 25(OH)D with 25(OH)D₃ and 25(OH)D₂ concentrations.

DESIGN AND SETTING

The Avon Longitudinal Study of Parents and Children is a population-based contemporary birth cohort (children born in 1991-1992) from southwest England.

PARTICIPANTS AND OUTCOME MEASURES

Seven thousand five hundred sixty children with serum 25(OH)D₃ and 25(OH)D₂ concentrations measured at the mean age of 9.9 yr participated in the study.

RESULTS

Vitamin D deficiency [total 25(OH)D concentration <20 ng/ml] was common (29%). The main risk factors were winter season, less time spent outdoors, low socioeconomic position, nonwhite ethnicity, older age, more advanced puberty stage, and female gender. Although there were some common risk factors for lower 25(OH)D₃ and 25(OH)D₂ concentrations (age, gender, puberty stage, body mass index, physical activity, household income, maternal education), several characteristics were associated with 25(OH)D₃ only (ethnicity, vitamin D intake, time spent outdoors, and UVB protection score) and others with 25(OH)D₂ only (protein and carbohydrate intake, parent's social class, and housing tenure).

CONCLUSIONS

Vitamin D deficiency was common in this contemporary U.K. cohort. Despite some overlap, there are differences in potential confounding structures for associations of 25(OH)D₃ and 25(OH)D₂ with health outcomes. These should be accounted for in future studies.

An estimate of the global reduction in mortality rates through doubling vitamin D levels

BACKGROUND/OBJECTIVES

The goal of this work is to estimate the reduction in mortality rates for six geopolitical regions of the world under the assumption that serum 25-hydroxyvitamin D (25(OH)D) levels increase from 54 to 110 nmol/l.

SUBJECTS/METHODS

This study is based on interpretation of the journal literature relating to the effects of solar ultraviolet-B (UVB) and vitamin D in reducing the risk of disease and estimates of the serum 25(OH)D level-disease risk relations for cancer, cardiovascular disease (CVD) and respiratory infections. The vitamin D-sensitive diseases that account for more than half of global mortality rates are CVD, cancer, respiratory infections, respiratory diseases, tuberculosis and diabetes mellitus. Additional vitamin D-sensitive diseases and conditions that account for 2 to 3% of global mortality rates are Alzheimer's disease, falls, meningitis, Parkinson's disease, maternal sepsis, maternal hypertension (pre-eclampsia) and multiple sclerosis. Increasing serum 25(OH)D levels from 54 to 110 nmol/l would reduce the vitamin D-sensitive disease mortality rate by an estimated 20%.

RESULTS

The reduction in all-cause mortality rates range from 7.6% for African females to 17.3% for European females. Reductions for males average 0.6% lower than for females. The estimated increase in life expectancy is 2 years for all six regions.

CONCLUSIONS

Increasing serum 25(OH)D levels is the most cost-effective way to reduce global mortality rates, as the cost of vitamin D is very low and there are few adverse effects from oral intake and/or frequent moderate UVB irradiance with sufficient body surface area exposed.

Widespread vitamin D insufficiency: A new challenge for primary prevention, with particular reference to multiple sclerosis

In the past 10 years, our knowledge of vitamin D has been revolutionized on two main points. Firstly, this vitamin is not only crucial for bone and calcium metabolism but also exerts major hormonal actions via its active metabolite (calcitriol) and specific receptors in almost all organs. The diverse non-classical actions of vitamin D-i.e. anti-inflammatory, immunomodulatory, antiproliferative and as a neurotransmitter-could have protective and preventive effects for a wide variety of pathologies, such as autoimmune diseases, cancer, infections and cardiovascular affections. Secondly, daily vitamin D requirements have been redefined thanks to many recent metabolic and pathological studies and are about 10 times higher than the amount considered sufficient until a few years ago. The fact that sunshine is the essential natural source of vitamin D and is limited in temperate and Nordic countries, coupled with the fact that modern lifestyle increasingly removes people from exposure to the sun, could explain why a great majority of the general population in these countries are in a state of vitamin D insufficiency. A lack of vitamin D can therefore also be observed in all pathologies but it may play a pathogenic role only in some of them. The incrimination of hypovitaminosis D as a risk factor is a reasonable assumption when several different research approaches used in a given pathology have consistently concluded that vitamin D is likely involved in that pathology. In multiple sclerosis, taken here as a prime example, there is a substantial rationale for vitamin D involvement, based on the findings of different experimental, epidemiological, genetic and immunological studies. Possible curative effects of vitamin D, in addition to a preventive action, are currently being tested but have not yet been demonstrated in most pathologies. However, these two questions appear to be clearly distinct and may involve notably different mechanisms. Lastly, since vitamin D insufficiency exists in most people living in mid- or high-latitude countries, vitamin D could exert multiple major preventive actions, simple supplementation is both safe and inexpensive and, for a vitamin-hormone, supplementation seems obligatory from a general preventive medical point of view alone, it follows that vitamin D supplementation should be organized in these countries to treat all those currently in a state of insufficiency, patients and 'normal' subjects alike, without further delay.