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Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths.
Grant, WB, Lahore, H, McDonnell, SL, Baggerly, CA, French, CB, Aliano, JL, Bhattoa, HP
Nutrients. 2020;12(4)
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This narrative review article looks at the role of Vitamin D in reducing the risk of respiratory tract infections, in relation to the incidence and prevalence of influenza and COVID-19. It also discusses how Vitamin D testing and optimisation with supplementation might be a simple measure to reduce risk. The authors site evidence supporting the possible role of Vitamin D: the fact that the outbreak occurred in winter when Vitamin D concentrations are lowest; vitamin D deficiency has been shown to contribute to acute respiratory distress; and case fatality rates increasing with age and incidence of underlying conditions, both of which are associated with lower Vitamin D concentrations. The authors goal is to raise Vitamin D concentrations to 100-150 nmol/l. Nutrition Practitioners wanting to support overall health and resilience to seasonal viral infections may want to consider testing and supplementing Vitamin D.
Abstract
The world is in the grip of the COVID-19 pandemic. Public health measures that can reduce the risk of infection and death in addition to quarantines are desperately needed. This article reviews the roles of vitamin D in reducing the risk of respiratory tract infections, knowledge about the epidemiology of influenza and COVID-19, and how vitamin D supplementation might be a useful measure to reduce risk. Through several mechanisms, vitamin D can reduce risk of infections. Those mechanisms include inducing cathelicidins and defensins that can lower viral replication rates and reducing concentrations of pro-inflammatory cytokines that produce the inflammation that injures the lining of the lungs, leading to pneumonia, as well as increasing concentrations of anti-inflammatory cytokines. Several observational studies and clinical trials reported that vitamin D supplementation reduced the risk of influenza, whereas others did not. Evidence supporting the role of vitamin D in reducing risk of COVID-19 includes that the outbreak occurred in winter, a time when 25-hydroxyvitamin D (25(OH)D) concentrations are lowest; that the number of cases in the Southern Hemisphere near the end of summer are low; that vitamin D deficiency has been found to contribute to acute respiratory distress syndrome; and that case-fatality rates increase with age and with chronic disease comorbidity, both of which are associated with lower 25(OH)D concentration. To reduce the risk of infection, it is recommended that people at risk of influenza and/or COVID-19 consider taking 10,000 IU/d of vitamin D3 for a few weeks to rapidly raise 25(OH)D concentrations, followed by 5000 IU/d. The goal should be to raise 25(OH)D concentrations above 40-60 ng/mL (100-150 nmol/L). For treatment of people who become infected with COVID-19, higher vitamin D3 doses might be useful. Randomized controlled trials and large population studies should be conducted to evaluate these recommendations.
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Breast cancer risk markedly lower with serum 25-hydroxyvitamin D concentrations ≥60 vs <20 ng/ml (150 vs 50 nmol/L): Pooled analysis of two randomized trials and a prospective cohort.
McDonnell, SL, Baggerly, CA, French, CB, Baggerly, LL, Garland, CF, Gorham, ED, Hollis, BW, Trump, DL, Lappe, JM
PloS one. 2018;13(6):e0199265
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Numerous studies have shown an association between Vitamin D status and risk of breast cancer. However to date, there are few studies that look at concentrations of Vitamin D in excess of 100 nmol/l and breast cancer risk. This study pooled the results of 2 randomised controlled trials and one prospective cohort study to investigate the relationship between Vitamin D levels and breast cancer incidence. The pooled results included 5,038 women. The analysis revealed that women with Vitamin D status of >150 nmol/l had an 80% lower risk of breast cancer than women with Vitamin D concentrations of <50 nmol/l, adjusting for age, BMI, smoking status and calcium supplementation. The findings also show that the risk of breast cancer is dose responsive, with the lowest risk of breast cancer at Vitamin D levels of >150 nmol/l. Testing for Vitamin D status and optimising levels to >150 nmol/l could be considered as part of a strategy for breast cancer prevention.
Abstract
BACKGROUND While numerous epidemiologic studies have found an association between higher serum 25-hydroxyvitamin D [25(OH)D] concentrations and lower breast cancer risk, few have assessed this association for concentrations >40 ng/ml. OBJECTIVE To investigate the relationship between 25(OH)D concentration and breast cancer risk across a broad range of 25(OH)D concentrations among women aged 55 years and older. METHODS Analyses used pooled data from two randomized clinical trials (N = 1129, N = 2196) and a prospective cohort (N = 1713) to examine a broad range of 25(OH)D concentrations. The outcome was diagnosis of breast cancer during the observation periods (median: 4.0 years). Three analyses were conducted: 1) Incidence rates were compared according to 25(OH)D concentration from <20 to ≥60 ng/ml (<50 to ≥150 nmol/L), 2) Kaplan-Meier plots were developed and 3) multivariate Cox regression was used to examine the association between 25(OH)D and breast cancer risk using multiple 25(OH)D measurements. RESULTS Within the pooled cohort (N = 5038), 77 women were diagnosed with breast cancer (age-adjusted incidence: 512 cases per 100,000 person-years). Results were similar for the three analyses. First, comparing incidence rates, there was an 82% lower incidence rate of breast cancer for women with 25(OH)D concentrations ≥60 vs <20 ng/ml (Rate Ratio = 0.18, P = 0.006). Second, Kaplan-Meier curves for concentrations of <20, 20-39, 40-59 and ≥60 ng/ml were significantly different (P = 0.02), with the highest proportion breast cancer-free in the ≥60 ng/ml group (99.3%) and the lowest proportion breast cancer-free in the <20 ng/ml group (96.8%). The proportion with breast cancer was 78% lower for ≥60 vs <20 ng/ml (P = 0.02). Third, multivariate Cox regression revealed that women with 25(OH)D concentrations ≥60 ng/ml had an 80% lower risk of breast cancer than women with concentrations <20 ng/ml (HR = 0.20, P = 0.03), adjusting for age, BMI, smoking status, calcium supplement intake, and study of origin. CONCLUSIONS Higher 25(OH)D concentrations were associated with a dose-response decrease in breast cancer risk with concentrations ≥60 ng/ml being most protective.