Vitamin D is important for bone growth and strength. Deficiencies in this vitamin in adults can result in osteoporosis and in children it causes a disease called rickets. Did you know that a deficiency in vitamin D has also been linked to higher incidences of cancer, heart disease, metabolic syndrome, and dysfunction of your immune system?
What is Vitamin D? Vitamin D is a vitamin that helps your body absorb calcium from the foods you eat. It also regulates the amounts of calcium and phosphorus that is in your bloodstream. Along with vitamins A, E, and K, vitamin D is stored within the fat cells in your body.
Where does Vitamin D Come From?
· Ultraviolet B Rays: One of our most potent sources of Vitamin D is the sun, and more specifically, ultraviolet B (UV-B) rays. Exposure to these UV-B rays triggers vitamin D to be made inside of your skin. Studies show that about 10-15 minutes a day of sun exposure is all you need to produce your daily requirement of vitamin D.
· Foods: Common sources include fish (i.e. salmon, mackerel, and tuna), eggs, margarine, fortified milk, cereal, and cod liver oil. Cod liver oil and fish contain the some of the highest amounts of vitamin D of any food.
· Supplements: Many calcium supplements contain vitamin D, but you can get vitamin D by itself as well.
What are some risk factors for Vitamin D deficiency?
· Elderly: The older you are, the more at risk you are for developing vitamin D deficiency. Those over the age of 50 require twice the amount of vitamin D compared to those under 50, and those over 70 require three times the amount of vitamin D. As you age, your skin becomes less efficient in synthesizing vitamin D from the sun.
· Breastfed infants: Although breast milk has many nutrients and antibodies that are important for your baby’s development, it does not have enough vitamin D. Your doctor may advise you to add vitamin D supplements to you child’s regular diet.
· Limited Sun Exposure: Unfortunately, it is difficult to obtain enough vitamin D from food sources alone. If you live further north, you are exposed to less sun and thus are at an increased risk of vitamin D deficiency.
· People with darker skin: The darkness of your skin depends on the amount of melanin within your skin. Melanin has been shown to diminish the amount of vitamin D your skin is able to produce. Thus, the darker your skin, the more at risk you are for developing vitamin D deficiency.
· Obesity: Vitamin D is a fat-soluble vitamin, which means the vitamin is stored within our body’s fat deposits. Unfortunately, this stored vitamin D is inactive and therefore cannot be utilized by your body. An excess amount of fat will result in more of this vitamin being stored, and therefore less being used by your body.
· Fat Malabsorption Syndromes: Again, this has to do with the vitamin being a fat soluble vitamin. When vitamin D is present in the gut, the only way it can be absorbed is if it is dissolved in fat. If your body can’t absorb fat correctly, then you will become deficient in vitamin D.
Now, you may be asking yourself, “Wait, I thought the sun was bad for me, now you are telling me I need it??” The answer is, yes and yes. Let me explain. Too much sun exposure can lead to many things, including early signs of aging (such as wrinkles and discolorations), precancerous, and even cancerous lesions. You do not need to sit out in the sun for hours at a time. I mentioned above that all you require is 10-15 minutes of sun exposure in order to produce enough vitamin D for the day. If you are eating foods rich in vitamin D and/or you are taking supplements, then you need much less sun to meet your requirements! So the bottom line is: everything in moderation!
There is compelling evidence to support the idea that vitamin D deficiency is unhealthy. Although vitamin D may be used in the treatment of osteoporosis and rickets, there is not sufficient data to show that increasing the amount of vitamin D you eat/make will improve or reverse the other health concerns linked with Vitamin D. However, there are several trials underway right now looking into this, and an answer appears to be just around the corner.
Here are some great sources for more information concerning vitamin D:
· Here is a Wall Street Journal article that discusses the impact of Vitamin D on your health.
· This is an extensive, but excellent article on vitamin D provided by the Office of Dietary Supplements.
· You can never go wrong with looking at what the Mayo Clinic has to offer on the topic.
· Here is another Mayo Clinic article on Skin Cancer.
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Poynter’s Pointers
1. Vitamin D deficiency is a real concern and has been linked to a variety of health issues, such as osteoporosis, rickets, heart disease, immune dysfunction, and even cancer.
2. You may be more at risk for deficiency if you are a breast-fed infant, over the age of 50, have darker skin, are obese, or have a fat malabsorption syndrome.
3. There are three main sources of vitamin D: food, sunlight and supplements. Sunlight is the most potent source of vitamin D.
4. The Bottom Line: Eat healthy foods rich in vitamin D, enjoy the sunshine (but not too long!) and talk to your doctor about supplementation if you think you are in one of the high risk categories.
Elisha Poynter, MD
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