New research published late last year may come as a kick in the pants for coffee drinkers. It found that when caffeine is consumed excessively, vitamin D absorption may plummet.

The study, published in the International Journal for Vitamin and Nutrition Research, looked at data from a 2005-2006 National Health Examination Survey on vitamin D levels and caffeine intake from more than 13,000 adults between ages 30 and 47.

Their findings showed that higher caffeine intake was associated with poor vitamin D absorption and, therefore, lower blood levels of the vital vitamin. It is important to note that more work is required to determine if caffeine actually causes vitamin D deficiency.

What is high caffeine intake? Likely more than about 4-5 eight-ounce cups of coffee or two energy drinks (about 400 mg of caffeine per day).

In any event, vitamin D can be challenging to come by this time of year. The “sunshine vitamin” is best absorbed through skin exposure to the sun. Depending on your skin complexion, roughly 10-30 minutes of sun exposure a couple of times per week is good.

Winter, of course, can make that difficult. Supplementation, therefore, is a good idea.

Adequate vitamin D is linked to several potential health benefits. It may contribute to healthier, stronger bones, better nutrient absorption, stronger immunity, improved heart health, better mental health, and more.

The sun and supplements are the best sources of vitamin D, but it is available in a small selection of foods, many of which are fortified. Here are some options:

  • Eggs: One of the few nutritional sources of natural vitamin D, two egg yolks have about 82 international units (IU’s) (ultimately, you’d like about 800 IU’s per day).
  • Sardines: If you like sardines, you’re in luck: a tin has about 178 IU. You can also get some vitamin D if you like wild-caught salmon.
  • Mushrooms: A half-cup of raw mushrooms has about 366 IU.
  • Milk: A cup of milk has 117 IU of vitamin D.


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