The vitamin D lowdown
It’s well established that vitamin D is essential for bone health. We need vitamin D to help the body absorb calcium and phosphate minerals from our diet which, in turn, is important for ensuring healthy bones, teeth and muscles.
But, it has also been suggested that vitamin D may help prevent serious diseases such as cancer, various forms of arthritis and autoimmune diseases. During the COVID pandemic, scientists even tried to establish if there was a connection between low vitamin D levels and COVID-19 patients. In general, medical research is ongoing to fully understand the link between vitamin D and disease prevention but it seems that a lack of this essential vitamin causes health issues.
So, in today’s LifeJournal we explain some of the main facts surrounding vitamin D and how you can ensure you get enough, particularly during the long, dark winter months we currently find ourselves in.
Getting ME some vitamin D
There are two natural sources: diet and sunlight.
Sunlight with sufficient amounts of UVB light helps the body to produce or ‘synthesise’ vitamin D in the skin.
Some foods contain vitamin D but nothing quite like the dosage from a hit of sun.
In the Northern hemisphere, sunlight doesn’t contain enough UVB radiation between October to early March for our skin to be able to make vitamin D. And so, during these months, we need to ‘intake’ vitamin D to avoid a deficiency. A shortfall of vitamin D can cause muscle weakness, pain, fatigue and depression. In fairness, these are symptoms that could relate to any number of other things but a vitamin D fix might be worth trying.
Can I eat my way to a vitamin D nirvana?
The dosages found naturally in foods are quite small.
Also, vitamin D isn’t that common in many foods. It’s most prevalent in oily fish (salmon, herring, mackerel) and fortified foods like margarines, eggs, mushrooms and meat.
In the UK, an organisation called the Scientific Advisory Council on Nutrition advises the British government on matters like recommended daily amounts. Relatively recently, they re-assessed the guidance on the recommended daily dose for people over the age of four. The Council believes there’s just about enough evidence to suggest we’re better off having a base level of vitamin D flowing around our blood stream and to achieve this, we need to intake 10 micrograms per day to achieve that base level. As an example, that’s five eggs per day. Or one salmon fillet per day. Every day.
Bear in mind that in the summer, incidental exposure to sunlight probably gets you to the 10 micrograms without the need for food or supplements so this is a winter consideration. To the extant you’re not eating five eggs a day during Autumn-Winter (!), supplementation is a good option.
Many supplement brands express micrograms in UI (“international units”). 10μg is equivalent to 400 IU.
Something to consider when it comes to sunlight..
The synthesis of vitamin D in the skin when exposed to sunlight depends on multiple factors like your personal skin type, where you are, the time of day, the weather conditions and so on.
The general rule of thumb from medics and researchers is 10-15 minutes per day of sunlight (between March and September) is more than adequate to give you the recommended dose of vitamin D.
Not wishing to put a dampener on things but…..sunlight can cause cancer. In fact, 90% of melanomas are caused by too much sun. And, specifically, UVB light – which helps the body to produce vitamin D in the skin – also causes sunburn. Five sunburns in a lifetime doubles your risk of melanoma.
For some skin types, 10-15 minutes of sunlight is long enough to cause damage and so SPF should be used.
Until recently, there were concerns within the health community that sunscreen may be contributing to vitamin D deficiency. The logic being that sunscreen blocks UVB light so vitamin D synthesis in the skin could not take place.
This long-held hypothesis appears to have been quashed. Three separate studies by experts from London and Australia were published in the British Journal of Dermatology in May 2019.
The leader of one of the studies was Professor Antony Young from Kings College London. In response to the study, he confirmed that ‘Sunlight is the main source of vitamin D.
‘Sunscreens can prevent sunburn and skin cancer, but there has been a lot of uncertainty about the effects of sunscreens on Vitamin D.
‘Our study, during a week of perfect weather in Tenerife, showed that sunscreens, even when used optimally to prevent sunburn, allowed excellent vitamin D synthesis.’
In a nutshell, the Professor and his team measured vitamin D levels in people’s blood both before and after sun exposure in Tenerife. They had a control group who had very limited sun exposure (in Poland). Different sunscreen products were applied, in different quantities, to the Tenerife group. Despite the application of sunscreen, there was a ‘highly significant’ improvement in vitamin D levels after sun exposure in this group.
Holly Barber from the British Association of Dermatologists said that ‘The risk of vitamin D deficiency from sunscreen has been found to be low, and therefore is unlikely to outweigh the benefits of sunscreen for skin cancer prevention.’
Take life outside (but protect yourself)
Vitamin D deficiency is often the stick that’s used to beat those who endorse SPF as an everyday necessity. But research confirms that sunscreen doesn’t prevent vitamin D synthesis so now you can have the best of both worlds: protected skin, long-term skin health and all the vitamin D you could ever need.
And in winter, take a good vitamin D3 supplement to keep you topped up.