The Power of Vitamin D

Posted February 15, 2018 by Lynn M. Hamrich, M.D., FAAFP

You may have heard of the health benefits of vitamin D in the fight against the common cold.

A British investigation published in February 2017 concluded that taking vitamin D supplements can help protect against respiratory infections like colds, bronchitis and pneumonia. The researchers looked at data from 25 clinical trials involving some 11,000 patients from 14 countries and found a significant but modest benefit. These results occurred mostly among those who had very low levels of vitamin D to begin with. No benefit was seen in people who received one big dose of the vitamin instead of regular (daily or weekly) supplementation.

Vitamin D is thought to protect against illness by boosting levels of natural, antibiotic-like peptides in the lungs. This may be one of many reasons why colds and flus are most common in the winter, when sunlight exposure, and therefore the body’s natural vitamin D production, is at the lowest, some researchers say. It may also explain why vitamin D appears to be protective against asthma attacks, which can be triggered by respiratory viruses.

Interestingly, vitamin D supplementation in community dwelling elderly people also has unique health benefits. It has been shown to reduce the risk of broken bones by improving muscle function and reducing the risk of falls.

Best Sources of Vitamin D

So, where do you get vitamin D? Sometimes referred to as the “sunshine” vitamin, your body makes vitamin D when skin is directly exposed to the sun, and most people meet at least some of their vitamin D needs this way. Skin exposed to sunshine indoors through a window will not produce vitamin D.

Very few foods naturally have vitamin D. That’s why fortified foods play an important role in your diet to help you get a sufficient amount of vitamin D. The best food sources include:

• Fatty fish such as salmon, tuna, and mackerel
• Milk
• Beef liver, cheese and egg yolks provide small amounts
• Mushrooms (some mushrooms that are newly available in stores have vitamin D content boosted by exposing these mushrooms to ultraviolet light)
• Breakfast cereals and some brands of orange juice, yogurt, margarine and soy beverages

Having an insufficient level of vitamin D can cause rickets, where the bones become soft and bend. It’s a rare disease but still occurs, especially among African-American infants and children. In adults, vitamin D deficiency can cause bone pain and muscle weakness.

Risk Factors

You might be at a higher risk of vitamin D deficiency if you:

• Have dark skin
• Are elderly
• Live indoors too much or are far from the equator where the sun is not abundant
• Don’t drink milk
• Don’t eat fish
• Are obese
• Have celiac disease or inflammatory bowel disease
• Have osteoporosis

Most healthy adults, including pregnant women, do not need screening for vitamin D deficiency unless they have one or more of these risks factors. Talk with your doctor about your vitamin D levels and if testing is necessary. And be sure to pay attention to your daily diet to ensure you are getting the vitamin D your body needs. For more information, or to make an appointment, call 800.237.8662.