Vitamin D 4,000 IU Tablets, Maximum Strength Vitamin D3 Supplement, 365 Easy to Swallow Tablets - Full Year Supply

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Sunlight is the most common source of Vitamin D but due to Britain's climate, it is very difficult to maintain its levels throughout the year. Our D3 High Strength supplement is the same form of D vitamin that is naturally produced in your body when exposed to the sun.

Vitamin D2 has been reported to be less potent than vitamin D3, (Heaney, 2008), with its potency cited as being one third of that of vitamin D3 (Armas et al., 2004). Other sources report vitamin D2 as half the potency of vitamin D3 in raising and maintaining serum 25(OH)D levels (Heaney et al., 2011). National Institute for Health and Care Excellence (NICE). (2021). COVID-19 rapid guideline: vitamin D NICE guideline [NG187] Recommendations | COVID-19 rapid guideline: vitamin D | Guidance | NICE (Accessed 02 July 2021)Mean and 97.5th percentile estimates are based on 48 vitamin D containing supplements. Estimated total vitamin D exposure from food sources (excluding supplements) Burt, L.A., Billington, E.O., Rose, M.S., Raymond, D.A., Hanley, D.A. and Boyd, S.K. (2019). Effect of high-dose vitamin D supplementation on volumetric bone density and bone strength: a randomized clinical trial. Jama, 322(8), pp.736-745. However, a number of studies have reported uniquely high levels of 1,25(OH)2D during pregnancy; the conversion of 25(OH)D to 1,25(OH)2D during the first trimester (12 weeks of pregnancy) results in a doubling of 1,25(OH)2D levels, and that levels continue to rise 2 to 3-fold from a non-pregnant adult baseline to over 700 pmol/L (0.7 nmol/L) (1 pmol/L = 0.001 nmol/L), until delivery without the onset of hypercalciuria or hypercalcemia (Hollis et al., 2017; Heaney et al., 2008; Kovacs, 2008). The increase in 1,25(OH)2D observed during pregnancy is not continued throughout lactation (Hollis and Wagner, 2017). Hollis et al. (2011) demonstrated that circulating levels of approximately 40 ng/ml (100 nmol/L) (1 ng/mL = 2.5 nmol/L) of 25(OH)D are required to optimize the production of 1,25(OH)2D during human pregnancy via renal and/or placental production. Pregnant women with normal placental function but non-functional renal enzyme 1-α-hydroxylase fail to increase circulating 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) during pregnancy (Greer et al., 1984).

Vitamin D is a fat-soluble vitamin, so it's best to have your supplement with food for optimum absorption. Vitamin D is sometimes referred to as the 'sunshine vitamin' as your body makes it when exposed to the sun. OH)D is transported via the placenta to the fetus and also converted there to 1,25(OH)2D or 24,25-dihydroxyvitamin D (24,25(OH)2D) (discussed EFSA, 2018).Breastfed babies should also have between 8.5-10mcg a day. Babies on formula milk don't need an additional supplement as it already contains vitamin D. You can find out more in our guide to vitamin D supplements for babies and children. Some supplements contain both vitamins D and K together. This is because both are needed for calcium metabolism: vitamin D promotes calcium absorption and vitamin K promotes the calcification of bones and reduces the calcification of soft tissues such as blood vessels (which is a risk with very high vitamin D and calcium intake). Dietary vitamin D supplements contain either vitamin D2 or D3, which are synthesised commercially by UVB irradiation of 7-DHC (from sheep wool) and ergosterol (from fungi), respectively (Bikle, 2009). Vitamin D supplements can also be administered by intramuscular injection.

There has been huge, renewed interest in vitamin D recently, with new global research showing that the health benefits of this nutrient stretch beyond bone health. There is increasing evidence for the beneficial effects from dietary vitamin D which has shown benefits for its contribution to: Increased requirement at certain life stages e.g. the elderly population, whose skin may not be able to synthesise vitamin D as effectively. Don't overdo it as vitamin D can build up in the body - 100mcg (4000IU) is the maximum safe daily dose for adults. Table 4. shows comparisons of vitamin D exposure from different sources: food sources (excluding supplements, supplements only, and food sources (including supplements)). These figures indicate that supplements are likely to be the greatest contributor to vitamin D exposure. Eat well, live better, stay healthy: sign up to our free monthly Food & Health newsletter for the latest insights delivered straight to your inbox

Kiely, M.E., Wagner, C.L. and Roth, D.E. (2020). Vitamin D in pregnancy: Where we are and where we should go. The Journal of steroid biochemistry and molecular biology, p.105669. Exposure estimates of vitamin D2 in wild mushrooms were calculated using consumption data from online sources (listed in Annex B), and the minimum and maximum estimated vitamin D2 levels for wild mushrooms which are 130 and 300 µg/kg (5,200 and 12,000 IU/kg) respectively (SACN, 2016); these are provided in Table A2 of Annex A. As for cultivated mushrooms and UV treated mushrooms vitamin D2 levels of 2.1 µg/kg (84 IU/kg) (Mattila et al., 1994) and 50 µg/kg (2,000 IU/kg) were used to calculate exposure estimates presented in Table A3 and A4 of Annex A respectively. It is important to note that UV-treated mushrooms tend to have a slightly higher retail price, though consumption estimates are assumed to be similar to those for cultivated mushrooms. Exposure estimates from foods with naturally occurring vitamin D3 Egg yolk Minimum and maximum estimated vitamin D levels for margarine and fat spreads were 50 and 75 µg/kg (2,000-3,000 IU) (Sainsbury’s, Tesco, 2020) respectively. For breakfast cereals minimum and maximum estimated vitamin D levels were 25 and 84 µg/kg (1,000 and 3,360 IU) (Sainsbury’s 2020). For dried milk minimum and maximum estimated vitamin D levels were 1.5 and 46 µg/kg (60 and 1,840 IU) respectively, and for evaporated milk estimated vitamin D levels were 26 and 29 µg/kg. Plant-based drinks had minimum and maximum estimated vitamin D levels of 7.5 and 18 µg/kg (300-720 IU), respectively. More specifically soya, coconut and almond milk alternatives had vitamin D levels of 7.5 µg/kg (300 IU) and oat milk alternatives had minimum and maximum estimated vitamin D levels of 7.5 and 18 µg/kg (300-720 IU), respectively (Sainsbury’s, Tesco, 2020).