Just "D" Facts about Vitamin D

Benefits of Moderate UV Sunshine Exposure

Archive for May, 2008

Make every day a D-day by stocking up on all the sunshine vitamin your body needs

Posted by D3forU on May 24, 2008

In this changeable weather it’s good to get outside and catch a few rays when the sun does shine.

It’s the best way for our bodies to produce the Vitamin D we need.

Here we explain how to make sure you are getting enough.

It is a fat-soluble vitamin, which means you do not need it every day as it can be stored by the body. It is present in certain foods and added to others, but is most commonly made by the body when ultraviolet rays from the sun hit your skin. Without sufficient Vitamin D, your body cannot absorb calcium.

It plays a vital role in keeping bones and teeth healthy. It assists with the transmission of nerves, and with blood clotting, and helps regulate the heart beat. Studies have also suggested it may play a role in reducing the risk of certain cancers, including breast, colon and prostate.

Soaking up the rays: Sunlight is the best way to get your Vitamin D

Where does it come from?

There are two ways the body gets Vitamin D. The best is from sunlight as the body automatically regulates how much it makes when the sun’s ultraviolet rays trigger Vitamin D synthesis.

The amount produced by the skin in a set time depends on age and skin type – pale, younger skin produces Vitamin D fastest. Dietary Vitamin D – sources include cod liver oil, oily fish, liver, eggs and fortified foods such as cereals, margarine and powdered milk – or supplements are also an option.
But Catherine Collins, chief dietician at St George’s Hospital, London, warns: ‘It’s almost impossible to get sufficient Vitamin D from the diet. A person would have to drink ten tall glasses of Vitamin D-fortified milk each day just to get the minimum levels. Sunlight exposure really is the best way.’

For those aged under 70 with fair skins, five to ten minutes of casual exposure – just face and arms –between 11am and 3pm when the sun is strongest produces about 250mcg of Vitamin D. The same amount is produced by darker skins in about 20 minutes.

What is Vitamin D?

‘Just sitting by a window isn’t enough,’ says Collins.

‘You have to be exposed to the kind of strong sunlight we get between May and September that would make your skin tingle if you stayed in it for more that 15 minutes.

‘We tell parents they need to get their kids out into the sun at least twice a week.’

How much do I need?

10mcg is the minimum recommended daily amount. Most of us will get enough from normal exposure to the sun and diet.

If I soak up the sun and get my Vitamin D quota, how long will my body store it?

Any excess is stored indefinitely in the fatty tissue and used by the body as needed.

Some studies have found it will take about two months for the body to become deficient.

Will sunscreen block out Vitamin D?

Sunscreens with a protection factor of eight or more block the UV rays that create Vitamin D and reduce production by up to 95 per cent.

‘Of course, you should always use a sunblock if you’re going to be out in the sun for more than 15 minutes,’ says Collins.

What happens if I don’t get enough?

Deficiency usually arises when inadequate sunlight exposure is coupled with liver or kidney disorders that limit metabolism of the vitamin.

It leads to the bone softening diseases – rickets in children and osteomalacia in adults – and possibly contributes to osteoporosis.

Muscle and bone weakness, and pain, can occur. In rare cases, supplements can be taken, but only under medical supervision as too much can lead to kidney failure.

‘No one should be deficient, unless they have specific medical problems,’ says Collins.

‘There’s nothing easier, and more pleasant, than getting out into the sun during the summer months to get your daily dose.’

Cod liver oil, oily fish such as mackerel and salmon, liver, eggs and fortified foods such as cereals, margarine and powdered milk.



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Sunny D needed for healthy babies

Posted by D3forU on May 19, 2008

The vast majority of pregnant women in Ireland have low vitamin D levels, according to new research.

Scientists at University College Cork said this deficiency has implications for healthy growth and development in the child’s early life.

Many of us in this country are low in vitamin D because of the climate and long winter.

Severe vitamin D deficiency causes poor development of the bones in children and softening of the bones in adults.

Without vitamin D, calcium cannot be absorbed in the body, slowing bone growth and development.

Pregnant women need more calcium because the baby relies on its mother for its vitamin D stores. Good sources include fatty fish, fortified milks, cereals, baked beans, eggs, low-fat yogurt and supplements.

But the scientists stress that sunlight remains a critical source.

Vitamin D is made by the action of the sun on our skin therefore sunlight, seasons and skin colour are key factors that determine our vitamin D levels.

If you are pregnant or breastfeeding make use of the sunnier weather and try to get out for at least 20 minutes a day — but be mindful of skin cancer and ensure you use a sunscreen if exposed for long periods.

UCC scientists Mairead Kiely and her team are now looking at the potential of vitamin D as an ingredient in functional beverages for breast-feeding mothers.

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Tanning is associated with optimal vitamin D status

Posted by D3forU on May 3, 2008

Tanning is associated with optimal vitamin D status (serum 25-hydroxyvitamin D concentration) and higher bone mineral density1,2,3

Vin Tangpricha, Adrian Turner, Catherine Spina, Sheila Decastro, Tai C Chen and Michael F Holick

1 From the Vitamin D, Skin and Bone Research Laboratory (AT, CS, SD, TCC, and MFH) and the Section of Endocrinology, Diabetes and Nutrition (AT, KS, SD, TCC, and MFH), Department of Medicine, Boston University School of Medicine, Boston, and the Section of Endocrinology, Metabolism and Lipids and the Department of Medicine, Emory University School of Medicine, Atlanta (VT)

Background: Vitamin D is made in the skin on exposure to solar radiation, and it is necessary to optimal skeletal health. Subjects who use a tanning bed that emits ultraviolet B radiation (290–315 nm) are likely to have higher 25-hydroxyvitamin D [25(OH)D] concentrations than do subjects who do not regularly use a tanning bed.

Objective: The first objective of this study was to ascertain whether subjects who regularly use a tanning bed have higher 25(OH)D concentrations than do subjects who do not use a tanning bed. The second objective was to ascertain whether higher 25(OH)D concentrations correlated positively with bone mineral density.

Design: This cross-sectional analysis examined 50 subjects who used a tanning bed at least once a week and 106 control subjects. Each subject gave a blood specimen for measurement of serum 25(OH)D and parathyroid hormone concentrations. Each subject underwent bone mineral density testing of the hip and spine.

Results: Subjects who used a tanning bed had serum 25(OH)D concentrations 90% higher than those of control subjects (115.5 ± 8.0 and 60.3 ± 3.0 nmol/L, respectively; P < 0.001). Subjects who used a tanning bed had parathyroid hormone concentrations 18% lower than those of control subjects (21.4 ± 1.0 and 25.3 ± 0.8 pg/mL, respectively; P = 0.01). Tanners had significantly higher BMD and z scores at the total hip than did nontanners.

Conclusion: The regular use of a tanning bed that emits vitamin D–producing ultraviolet radiation is associated with higher 25(OH)D concentrations and thus may have a benefit for the skeleton.

Key Words: Vitamin D deficiency • secondary hyperparathyroidism • vitamin D • bone mineral density • bone mineral content • tanning

American Journal of Clinical Nutrition Article HERE

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