Health, Men's Health, Supplements & Vitamins, Women's Health
Vitamin D is currently attracting an avalanche of research funding thanks to the recognition that it does more than regulate calcium absorption to maintain strong bones. As a hormone, it has effects all over the body, including the heart, circulation, joints and brain. It even appears to regulate ageing and may protect against a number of age-related diseases. If you want to live longer, it seems that maintaining optimum intakes of vitamin D3 is key. Here is just a brief flavour of recent research findings to get you reaching for your supplements.
A large analysis of data from 14 studies, involving over 25,000 women, found that those with the highest vitamin D levels were less likely to develop breast cancer. Overall, every 10 ng/mL increment in vitamin D concentration was associated with a significant 3.2% reduction in breast cancer risk.
Data from 21 studies, involving over 76,000 people, showed that those with the highest vitamin D levels were 62% less likely to develop type 2 diabetes than those with the lowest levels. In this case, each 10 nmol/L increment in vitamin D levels was associated with a 4% lower risk of type 2 diabetes. The most likely explanation is that vitamin D improves insulin sensitivity to better regulate glucose control.
A total of 14 studies, involving almost 31,500 people, found that those with the lowest vitamin D levels were up to twice as likely to develop depression as those with highest levels.
Eleven studies involving almost 4,000 people, found that blood vitamin D levels were a third lower in people who had Alzheimer’s or Parkinson’s disease when compared with healthy controls. This strongly suggests a protective effect for vitamin D, although differences in diet and sun exposure will also play a role.
Having a low level of vitamin D appears to increase the risk of ischemic stroke due to poor blood flow to parts of the brain. Data from 10 studies, involving over 58,000 people confirmed a stepwise increase in the risk of stroke with a stepwise decrease in vitamin D blood levels. Those with the highest levels were up to 82% less likely to have a haemorrhagic stroke than those with low levels.
Studies carried out in eight countries from Europe and the US, involving over 26,000 men and women aged 50 plus found that those with the highest vitamin D levels were 57% less likely to die from any medical cause during the study durations than those with the lowest levels. Despite vitamin D3 levels varying with country, sex, and season, the association between those with the lowest and those with the highest vitamin D level within each country was remarkably consistent.
You can make vitamin D3 in your skin on exposure to sunlight when the UV index is greater than 3. In the UK, that’s only achieved during spring and summer. Used properly, a sunscreen with a sun protection factor of SPF15 reduces vitamin D production by 99%. Usual advice is therefore to obtain 10 to 15 minutes sun exposure to face, arms, hands and/or back, without sunscreen, two or three times a week. Longer exposures than this don’t provide additional benefit as vitamin D is rapidly broken down by excess UV radiation and, at the same time, your risk of skin cancer will increase.
Over the age of 50, however, your synthesise of vitamin D reduces so that skin concentration of vitamin D fall by at least half between the ages of 20 to 80 years – often more. In one study, researchers found that people aged 62 to 80 years synthesised four times less natural vitamin D than those aged 20 to 30 years.
With this in mind, Healthspan’s NEW Vitamin D3 50 Plus* has been specifically formulated with a cold pressed extra virgin olive oil capsule following recent studies from Tufts University, Boston, which found that monounsaturated fats – especially olive oil – have been associated with better absorption.
Healthspan’s advanced formula provides the optimum 50ug level of natural source vitamin D3 – as recommended by medical professionals for those over the age of 50. Healthspan’s head of Nutrition, Rob Hobson, adds: “Diet should always come first but you simply can’t get the right amount of vitamin D your body needs from food alone, and in the winter with no UVB rays to make vitamin D, it is worth considering topping up your levels with a supplement.”
Food sources of vitamin D include oily fish, fish liver oils, animal liver, eggs, butter, and fortified milk, margarine and cereals. After the age of 50, however, reduced secretion of stomach acid and enzymes, intestinal juices, bile and pancreatic secretions mean that absorption of many nutrients; including Vitamin D3 tend to reduce with increasing age.
The EU recommended daily amount (RDA) is 5 mcg (200 iu), but this is based on the old understanding that vitamin D3 was just about calcium absorption and bones. Many experts now suggest that, in the absences of exposure to sunlight, an intake of 25mcg (1000 iu) is more appropriate for optimum heart, brain and immune health – at least in those under the age of 50. A higher intake of at least 50mcg vitamin D3 may be more appropriate for older people – both to offset lower production in the skin and because of reduced dietary absorption. In the United States, for examples, studies show that an intake of 100 mcg (4000 IU) is needed to maintain vitamin D levels in all older women. This intake is equivalent to the currently suggested EU Upper Safe Level.
If taking supplements, select one containing the form known as vitamin D3 (cholecalciferol) as this is significantly more effective in maintaining blood vitamin D levels than vitamin D2 (ergocalciferol) form.
Although higher intakes of vitamin D3 are recommended by some experts, these are best taken under medical supervision. Excess can lead to side effects associated with high calcium levels, such as demineralisation of bone, kidney stones, headache and weakness.
Dr Sarah Brewer is a medical nutritionist and author of over 60 popular health books.
Follow her Nutritional Medicine blog Dr Sarah Brewer and her nutrition and recipe twitter feed @DrSarahB and her health, weight and fitness feed @DrSarahBHealthy
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