In winter the lack of sunlight causes our vitamin D levels to significantly drop [ALAMY] In these dark days are you feeling drained of energy? Some experts might suggest you’ve hit your D-day, the time of year when your reserves of vitamin D are so depleted by a lack of sunshine it is affecting your health. But others could say the growing interest in the so-called sunshine vitamin is misplaced.A recent meta-analysis, a super study which pools data from previously published research, reported that despite a clear association between low levels of vitamin D and an increased incidence of heart disease, diabetes and other conditions there is no evidence that taking vitamin D supplements protect against these problems. Case closed you might think, except that closer scrutiny of the Lancet study shows it actually found “slight gains in survival” when older people take top-up vitamin D and experts argue the debate is far from over.Professor Simon Pearce, a vitamin D expert based at Newcastle University, says: “This meta-analysis doesn’t tell you that much because they are taking data collected for one reason and using it for another.”
US-based academic and internationally renowned vitamin D expert Dr Michael Holick is even more sceptical, arguing that the meta-analysis was based on poor studies.“The scientific term for it is ‘silly’,” he says. “Basically all they have done is rehash old studies but most of those studies are meaningless because they used sub-optimal doses of vitamin D.”Dr Holick believes that adults need a daily top-up of at least 75mcg and that’s the dose he takes every day. However the 290 trials collated for the meta-analysis used much less with daily doses ranging from 20 to 50mcg.WHY WE’RE DEFICIENT IN VITAMIN DUnlike any other nutrient we can’t get enough vitamin D from food alone no matter how well we eat. Instead we make it from sunshine which means the further away from the Equator we live and the more time we spend indoors the higher the risk of deficiency.The reality is that if you live north of Birmingham it is impossible to make vitamin D from October to March and even in the most southerly parts of Britain there is not enough sunlight to synthesise it for around three months during the winter.
Working in an office also undermines our ability to build up the reserves needed to get through the winter because even at the height of summer there are only four hours a day from 11am to 3pm when it is bright enough to make vitamin D. Professor Pearce says: “We think of the UK as being parallel to New York City but we’re more in line with Alaska. We are a lot further north than we realise.”HOW A LACK OF SUN MAKES US SICKLike Dr Holick, Professor Pearce also takes a vitamin D supplement and says there is no doubt we need the nutrient for healthy bones.“There is absolutely 100 per cent cast iron evidence that lack of vitamin D has adverse effects on musculoskeletal health. He says: “There is also pretty good evidence linking low vitamin D to certain cancers in particular bowel cancer and Type one diabetes, as well as some autoimmune diseases.”Dr Holick believes there is also strong evidence of a link between low vitamin D and heart disease, asthma and other allergies, depression, dementia, pregnancy complications and even schizophrenia.“
Population studies have suggested that adequate vitamin D is also critical for the prevention of various solid tumours including prostate, breast, ovarian and colon cancers.”Further evidence of the link between sunshine and health can be seen in the way geography can influence the risk of multiple sclerosis, an autoimmune condition which damages nerves in the spinal cord and brain.Around 127,000 people in the UK have MS but the further north you live the greater the risk. In England and Wales around one in 1,000 people has MS but in Scotland it is twice that number while the Orkney Islands, one of the most northerly parts of the UK, has the highest incidence in the world with around four in 1,000 people affected.Similar patterns have been mapped for some cancers. A European Prospective Investigation into Cancer and Nutrition (EPIC) study which tracks the health of more than 520,000 people across Europe reported a “strong” association between low vitamin D – levels in the blood of less than 25 nmol/l – and bowel cancer which kills around 15,000 people a year in the UK.
A Canadian study of 1,200 women found that those who regularly took a vitamin D supplement cut their cancer risk by 60 per cent.Professor Kefah Mokbel, a surgeon at the London Breast Institute, a private centre based at The Princess Grace Hospital, argues: “This is a low-cost, cheap intervention and there is no toxicity from taking it.”Vitamin D is a steroid vitamin from a group of fat-soluble pro hormones. Vitamin D and pregnancy are important together. Expecting mothers need to make sure they get the recommended amounts of vitamin D during pregnancy for both their own well being and the healthy development of their baby. The most significant compounds for human development are D2 and D3. It is unlikely your prenatal vitamin provides enough vitamin D. A recent study found women taking 4,000 IU of vitamin D daily had the greatest benefits in preventing preterm labor/births and infections. The study confirmed vitamin D at this level is not only safe for you, but for your baby, and the researchers from this study now recommend this daily dosage of vitamin D for all pregnant women.
The average prenatal vitamin only contains 400 IU of vitamin D, so additional supplementation should be taken daily. Vitamin D is beneficial for your own personal health. Vitamin D now has extensive research supporting its role in immune function, healthy cell division and bone health. Vitamin D is necessary for the absorption and metabolism of calcium and phosphorus. Many studies are finding a connection between low serum vitamin D levels and an increased risk of certain types of cancers, autoimmune disease, neurological disease, insulin resistance, and cardiovascular disease. Vitamin D invests in the well-being of your baby by supporting healthy bone development. Deficiency with vitamin D is also related to preeclampsia. At this time, 40-60% of the entire U.S. population is vitamin D deficient, including pregnant women. The reasons for this widespread deficiency are many, and to begin to unfold this issue you can start with understanding there is a very short list of foods that contain vitamin D.
These foods are egg yolk, salmon and cod liver oil, however, most vitamin D is consumed through fortified foods like milk. For the 75% of the population that is lactose intolerant, fortified milk products are not a reliable source of vitamin D consumption. Additionally, many factors influence the body’s ability to make and absorb vitamin D. These factors include: where you live, the season, how much time you spend outdoors without sunscreen, skin pigmentation, age, obesity, pollution, and having healthy intestines with optimal absorption capacity. These factors come in to play because Vitamin D is actually a hormone and needs sunlight, in order for the body to manufacture it properly. At this time, a large part of the U.S. population falls into one, or more, of these categories: You can begin by making an effort to eat more vitamin D containing foods. Next, research suggests sensible sun exposure (usually 5-10 min of exposure of the arms and legs or the hands, arms, and face, 2 or 3 times per week) can help as well.
However, the best way to really ensure adequate vitamin D is through simple supplementation. When supplementing, your choices will be between two forms of vitamin D. Ergocalciferol is the vegetarian form of vitamin D and cholecalciferol is the animal-sourced form, usually derived from fish liver oil or lanolin from sheep. The cholecalciferol form is the most absorbable and utilized form for the body, but if you are vegan you should choose ergocalciferol. We recommend Nordic Naturals Vitamin D3 (1000 IU per soft gel) in the natural form cholecalciferol form. The carrier oil is organic, extra virgin olive oil and they come in small, soft gels that are very easy to swallow. We also recommend Nordic Naturals Prenatal DHA with added vitamin D3 (400 IU per 2 soft gels). This product provides two of the most important nutrients for pregnant women backed by a long standing, reliable company that guarantees optimum purity, quality and freshness. Vitamin D Supplementation during Pregnancy Part 2 NICHD/CTSA Randomized Clinical Trial (RCT): Outcomes.