When I first started my studies to be a massage therapist, we were expected to cover the basics in nutrition. Vitamin D was glossed over – as the body can store it in the liver, we were told, then it was unlikely that we would see signs of deficiency – especially when you didn’t even have to eat ‘healthy food’ to get a supply of it. Simply by being in the sun would ensure you topped your stores of it up. The only people at risk of deficiency were thought to be those who had a ‘goth’ lifestyle – slept by day and came out at night. Presumably vampires are at risk too!
But more recently the media have been highlighting a growing concern that we are more and more likely to be deficient in this important vitamin. One study (but be cautious, they sell vitamin supplements!) claims their survey discovered 9 out of 10 people have symptoms of Vitamin D deficiency.
So What Does Vitamin D do?
Vitamin D aids the body’s absorption of calcium so it is essential to the growth and strength of bones. In extreme circumstances a deficiency in this vitamin causes rickets in children or osteomalacia in adults.
Vitamin D is important to the body in many other ways as well. Muscles need it to move, nerves need it to carry messages between the brain and every body part and the immune system needs vitamin D to fight off invading bacteria and viruses. Vitamin D is found in cells throughout the body. Together with calcium, vitamin D also helps protect older adults from osteoporosis, so this is a really important topic for post menopausal women. A prospective cohort study of 72,000 post-menopausal women in the U.S. reported that the women who took in at least 600 IU/day of vitamin D3 (through diet and supplements) had a 37% decreased risk of osteoporotic hip fracture than the women who consumed less than 140 IU/day.
Symptoms of Vitamin D deficiency include:
- Weak immune system, including frequent coughs and colds
- Fatigue, bone ache, joint and muscle pain
- SAD or depression
- Headaches and migraines
So how much Vitamin D do we need and where do we get it from?
Although this nutrient is found in foods, the greatest source for obtaining vitamin D is through the skin. When bare skin is exposed to ultraviolet light, it synthesizes vitamin D3 that is then stored in the liver. You only need 10-15 minutes of sun exposure during peak sun hours (between 10 a.m. and 2 p.m. in most locations) during the summer months to produce up to 10,000 IUs of the nutrient. After that short exposure you can continue with safe sun habits and slather on a broad-spectrum sunscreen. It’s thought that if you live above 42 degrees North latitude then the sun’s rays do not provide sufficient Vitamin D from November through February. I think that puts most of us in the United Kingdom at a bit of a disadvantage! Remember too, that UVB rays do not penetrate glass or sunscreen with a sun protection factor (SPF) of 8 or more.
But in researching this topic I have found the NHS advice confusing on NHS Choices . In the article it tells us we need 10 or 5 mg a day and then tells us to take no more than 0.025mg, but mg refers to both micrograms and milligrams. Advice also varies as to how much time should be spent in the sun and how much of our skin should be exposed to absorb sufficient quantities of Vitamin D.
There is an increased risk of deficiency in people who have one or more of these risk factors:
- Dark skinned
- Live in Northern latitudes
- Over the age of 50
- A diet low in foods containing vitamin D
- Fat malabsorption syndromes
- Inflammatory bowel disease
Some drugs reduce the absorption of Vitamin D: the weight loss drug, Orlistat (brand names include Xenical and Alli), antacids, some cholesterol lowering drugs, some anti-seizure medications, and steroids (like Prednisone) interfere with the absorption of Vitamin D, so discuss your vitamin D intake with your doctor or pharmacist if you take any of these drugs.
There are two forms of the vitamin, D2 and D3 (cholecalciferol), with D3 the form best metabolized by the body. Vitamin D is found in foods such as fish, eggs, fortified milk and that old remedy, cod liver oil.
What to do next:
Try to eat Vitamin D rich foods every day. Get some sunshine on your skin, but make sure you follow healthy guide lines to avoid the risk of skin cancer. If you are concerned you have some signs of deficiency and particularly if you are in one or more of the high risk groups, talk to you doctor about getting tested for deficiency.
And finally a note of caution. Excessive consumption of Vitamin D is toxic particularly as the body can store it in the liver. Balance in everything is the key to good health.