We’re taking more vitamin D

If you’ve added vitamin D to your supplement list, join the crowd.  According to a new survey, more Americans say they’re taking vitamin D, up 16% in the past 2 years.  Still, just 27% of supplement users say they’re taking extra D.  Anyone taking a general purpose multiple vitamin is likely getting vitamin D from that, but most of those doses are limited to the standard recommended intake of 400 i.u./day.  Most vitamin D experts think that’s a woefully inadequate amount.

If you are one of that 27%, what are your reasons?  Research news has plenty of possible reasons, mostly based on relationships between intake or blood level of vitamin D and incidence of a disease.  Cognitive decline with age has been linked to low blood levels of D in a study reported this summer.  More than 800 elderly subjects were followed for 6 years, and various changes in mental acuity was measured.  Those subjects with the lowest vitamin D were more likely to experience “substantial” decline.  The researchers point out that, if vitamin D was actually a factor in this process, more research is needed to clarify whether supplements could prevent decline.

Another important link is to cancer.  Research suggests that incidence of breast cancer may be lower for women with higher blood levels.  Other data indicates recurrence may be less likely when blood levels are higher.   The strongest cancer relationship may be to colon cancer.  Studies of both intake and blood levels indicate that poor vitamin D status is linked to higher risk for developing cancer and worse outcomes once cancer was diagnosed.

The only problem with vitamin D supplements is taking more than you need.  Taking a supplement just because you heard about it on the evening news is a bad idea.  The only way to know if you’re deficient is to have a blood test.  If you’re deficient, or low, you then take supplements to raise the level.  But how much and for how long?  Recommendations are all over the map, with the US government recommending only 400 i.u./day and experts recommending far more, some saying 2000 i.u./day is the ideal.  If you take vitamin D to improve your level, you should be re-tested after a couple of months, to be sure the dose was correct.  Once your levels are normal, you can cut back, but you probably can’t stop them entirely.  Tip: don’t take supplements on an empty stomach, or just with your morning coffee.  Take them with a meal to enhance absorption.  No use taking supplements that are poorly absorbed.


  1. […] This post was mentioned on Twitter by Alicia Zimm, Donna Feldman MS RD. Donna Feldman MS RD said: Winter's coming, are you taking #vitaminD? More Americans are. https://radionutrition.com/?p=980. […]

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