Why is vitamin D important?
A large percentage of people worldwide are not meeting their vitamin D requirements. Doctors and dietitians have known for decades that this nutrient is important for bone health, but the list of reasons why we need optimal levels is growing. Researchers note an extensive list which includes warding off cancer, heart disease, depression, dementia, certain skin diseases, and high blood pressure. As vitamin D receptors are everywhere in the body, any part of the body will be affected by a deficiency.
Why we aren’t getting enough to reach our goals?
It’s dubbed the “sunshine” vitamin because we can both make it from sun exposure and get it from food. Given the right circumstances, our bodies are very adept at making this vitamin. Ultraviolet light from the sun shines on a cholesterol compound on our skin, then that compound is transformed into a vitamin D precursor which gets absorbed into the blood. Over the next day, the liver and kidneys finish converting this compound to the active form of vitamin D.
The factors that interfere with making this vitamin are directly related to factors that block our exposure to the sun. Think sunscreen use, air pollution, city living, geography, and dreary winters. Even our skin pigment is a factor as darker-skinned people synthesize less vitamin D than lighter-skinned people.
So if we cannot make it efficiently, how we can we get it from food? In terms of food sources, it’s interesting to compare sunshine vs. food. According to an old but very interesting 2009 AARP article (unknown author), you would need to eat the following amounts of food just to get the amount the amount of vitamin D your body makes in 10 minutes:
- 6.5 pounds of mushrooms
- 150 egg yolk
- 3.75 pounds of salmon
- 30 servings of fortified cereal
- 2 pounds of sardines
- 30 cups of fortified orange juice
While this is an interesting comparison, it is not a realistic diet strategy. The current adult recommendations for vitamin D intake are 600 IUs for those aged 19-70 and 800 IUs for those over 70 years old. Unfortunately, foods with vitamin D are limited. Some common foods with vitamin D content include:
- 566 IU from 3 oz. swordfish
- 440 IU from 1 tsp. cod liver oil
- 400 IU from 3 oz. salmon
- 228 IU from 3 oz tuna
- 137 IU from 1 cup fortified orange juice
- 120 IU from 1 cup fortified milk
- 100 IU from 3/4 cup enriched cereals
- 40 IU from 1 egg
As you can see, with limited sun exposure and limited foods with vitamin D, it can be challenging to have adequate vitamin levels. This is why supplementation is such a hot topic and why many people end up taking a supplement. The question is, “how much to take?” A simple blood test determines if you need a supplement and how much to take.
What is your experience with vitamin D levels on your health and how did you determine you needed to supplement your diet?