Vitamin D Shortage
About 1 out of 5 people are short of vitamin D. In northern areas in winter, half of the population may be short. And as we age, our body gets less effective at making vitamin D, making a shortage more likely.
Types of Vitamin D
Vitamin D is not really a vitamin, as your body can create its own. It’s more of a pre-hormone. There are 2 forms of vitamin D: D2 and D3. Our skin makes D3, and most food D is D3, which is more potent than D2. (D1 turned out to be the same as D2.)
Skin Factory
Our skin produces a not quite finished D3, which your body converts to full vitamin D over 2-3 days. The pigment that darkens our skin and tans is called melanin. It interferes with D3 production — the more melanin, the slower vitamin D production in the skin.
Factory Production
The production of vitamin D from the skin depends on skin colour, age, time of day, season, and distance from the equator. A white teen in a bikini at noon on a sunny summer day in the tropics can max out their vitamin D production in minutes. An older, dark-skinned person in a shirt on a cloudy winter morning in Canada can’t make a day’s vitamin D. Also, windows block the kind of light that creates vitamin D, so you can’t get it inside. Aim for 5-30 minutes of sun 2 times per week, but avoid tanning beds to get vitamin D.
Food - Milk
A few foods contain natural vitamin D. Some fish, liver, and eggs contain vitamin D. Most vitamin D in food is added. Milk has had added vitamin D since the 1930s in the US and the 1960s in Canada, which virtually eliminated rickets. Canadian milk has 85-110 IU of added vitamin D per cup, and US milk has 100 IU per cup. Milk is the best food for vitamin D. Vitamin D taken by mouth requires about 12 hours to digest and process before it’s available, and it’s gone 3 days later.
Rickets
Rickets is a condition caused by low vitamin D that makes bones soft. In 1946, half of Canadian schoolchildren had signs of past rickets. Cod liver oil was an old and effective treatment. Today, rickets is rare in Western countries but is still common in the Middle East. Even though the sun is intense, cultural practice limits sun exposure, especially for women. Three-quarters of adolescent girls in Arabia have insufficient vitamin D.
Bone Builder
One of the critical functions of vitamin D is the body can’t absorb calcium without it. To keep bones strong, you need vitamin D. It helps prevent fractures. It also plays a part in many diseases.
MS & Diabetes
Higher blood levels of vitamin D seem to be associated with a lower risk of developing MS, and vitamin D may slow the progression of the disease. MS is more common in northern areas. Vitamin D deficiencies also seem to be linked to the development of diabetes.
Cancer Link
Vitamin D seems to have a small protective effect against cancer, especially colon cancer. Overall, better vitamin D levels are linked to a longer life. High levels of vitamin D are also linked to kidney stones — too much may cause problems.
Not Getting Enough
As you gain weight, you need even more vitamin D and are more likely to have a deficiency. A simple blood test can tell you your vitamin D levels. As we age, our body has a harder time absorbing vitamin D, and our skin doesn’t produce as much, so we need more sun and more vitamin D than a young person. Also, some cholesterol medications interfere with vitamin D absorption.
Let the Sun Shine In
The best way to get it is to expose some skin to the sun every other day. It only takes about 15 minutes to get a full day’s production of vitamin D, longer if your skin is darker or it’s winter. And for those 15 minutes, don’t use sunscreen, as sunscreen blocks the rays that create vitamin D.
Play D by Taking D
Take vitamin D pills, especially in winter. Taking 2,000IU every day with food should keep your vitamin D level in the target range, but the only way to know for sure is through a blood test. Don’t take more than 6,000IU a day. That could cause a toxic level of vitamin D.
