Are the New Recommendations on Vitamin D a Missed Opportunity?

The new report released today by the Institute of Medicine on recommended vitamin D intake is a bit like getting that shirt you wanted for your birthday, but it turned out to be the wrong color and the wrong size (report).  It’s sort of what you wanted but not really.

While the new report kicks up recommended intake of vitamin D to 600 IU daily for adults up to age 70 and 800 IU daily for those over 70, these amounts fall short of the levels shown in research studies that could have benefit for conditions such as heart disease and cancer1, 2, 4.  Looking at colon cancer alone, studies have found that high levels of vitamin D could cut the risk of the disease in half compared to low levels4 (previous post).

And it's estimated that over half of all women, and over 40 percent of all men, in the United States have less than optimal blood levels of vitamin D, often suggested to be 75 nmol/dL of a type of circulating vitamin D called 25(OH)D 5, 6 .  Those prone to very low sun exposure or low vitamin D levels are even worse off:  the elderly, the very overweight, people with dark skin, and those who largely live in northern areas (where vitamin D-producing UV-B sunlight can be low for much of the year).

To reach beneficial blood levels of vitamin D, most people would need to take about 1000 IU per day, with those prone to lower levels taking perhaps 1500 IU per day.  This is well above the new guidelines of 600 per day for most adults.

The IOM report takes a typically conservative approach to assessing studies of potential benefits and potential risks related to vitamin D intake, as well as to the blood levels of vitamin D that qualify as “sufficient.” Such an approach often minimizes potential benefits while highlighting potential risks.  This can help safeguard the nation’s health from the zeitgeist of diet crazes, but when it comes to vitamin D it seems more like a missed opportunity. 

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References Cited
  1. Heaney RP. Vitamin D in health and disease. Clin J Am Soc Nephrol 2008;3:1535-41.
  2. Melamed ML, Michos ED, Post W, Astor B. 25-hydroxyvitamin D levels and the risk of mortality in the general population. Arch Intern Med 2008;168:1629-37.
  3. Institute of Medicine. Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. In; 1997.
  4. Bischoff-Ferrari H. Health effects of vitamin D. Dermatol Ther 2010;23:23-30.
  5. Zadshir A, Tareen N, Pan D, Norris K, Martins D. The prevalence of hypovitaminosis D among US adults: data from the NHANES III. Ethn Dis 2005;15:S5-97-101.
  6. Dietary Supplement Fact Sheet: Vitamin D. 2008. (Accessed 2008, at http://ods.od.nih.gov/factsheets/vitamind.asp.)


Passive smoke exposure kills


New data on the global burden of disease caused by exposure to second hand smoke (see report) adds to the urgency for action to prevent cancer heart disease asthma and other conditions caused by this exposure (Oberg M, Jaakkola MS et al. 2010). As noted in media coverage of the new findings, worldwide exposure to second had smoke is substantial – approximately 40 percent of children are exposed. Together, this exposure in children and adults caused 379,000 deaths from heart disease, 165,000 from lower respiratory infections, 36,900 from asthma and 21,400 from lung cancer.

Exceptionally strong evidence shows that reducing exposure to second hand smoke reduces the risk of acute myocardial infarction (Lightwood and Glantz 2009; Meyers, Neuberger et al. 2009; Mackay, Irfan et al. 2010). Strong data from Scotland shows a marked decline in hospitalizations due to asthma among children following the passage of smoke free legislation in 2006, which banned smoking in public places (Mackay, Haw et al. 2010).

It is time we followed the evidence and implemented policies that support public health throughout the world. Implementing the US tobacco control strategy  would be a useful first step locally. International efforts must also address the large and preventable cause of premature morbidity and mortality.

Literature cited



The Long Haul: New Study Suggests Specific Protein & Carbs Combo May Help Keep Weight Off

As anyone who's ever been on a diet knows: taking the pounds off can be hard, but keeping the pounds off can be even harder.  The main reason for this simply seems to be that it's just easier to keep up with a new exercise and diet program over the short term than it is over the long-term.  While we may be willing to sustain ourselves on some wild, restrictive diet for a few months, especially if the pounds start to melt away, over time it gets harder and harder to keep it up, and eventually our old habits, our old ways of doing things, slowly bubble back to the surface, and we find ourselves putting the weight back on.

This is why most experts suggest making a small number of small changes when it comes to weight loss.  Taking baby steps gives us time to get our footing with a new behavior, with a new approach to eating, and helps it to actually become part of our lifestyle rather than a strange restriction that needs to be endured and then eventually discarded after three months because its so unpleasant.

In this vein of small changes breeding long term success is a Danish study in the latest issue of the New England Journal of Medicine that shows that small differences in the make-up of what eat can help maintain real weight loss over time.

In this study, about 800 overweight participants who had recently lost weight were randomly assigned to one of five diet groups - each group had a varied combination of protein level and glycemic load, a measure of how quickly the carbohydrates in the diet are converted to glucose in the blood (study).  Diets with high glycemic loads (such as those with a lot of white bread, potatoes, and white rice) have been shown in some studies to increase the risk of weight gain as well as heart disease and diabetes.  Diets with a low glycemic load (such as those with a lot of whole grains or low amount of carbohydrates) may help keep calorie intake in check and promote feelings of fullness.

The researchers found that the group who ate a high protein, low glycemic load diet had the most success keeping weight off over time.  Those who ate a low protein, high glycemic load diet did the worst.  Worth noting: those who ate the high protein, low glycemic load diet not only had the most weight loss success but also had the highest rate of adherence of any group, meaning more people in this group were more likely to keep up with that way of eating than in any other group.

While the weight benefits were pretty modest, with participants in the high protein, low glycemic group weighing an average of about 4.5 pounds less over six months than those in the low protein, high glycemic group, it is a real difference that if sustained over time could have a big impact on health, both for the person, and on a broader scale, the nation.

Although this is just a single study, what's most heartening from these results is that maintaining the new weight after weight loss, and even continuing to lose weight, seems possible over the long term with a diet that isn't that radical and that's enjoyable enough to continue over the long term.

A healthy high protein diet with a low glycemic load would include foods like skinless chicken, fish, beans, low fat dairy as well as whole grains and brown/wild rice.  Healthy fats, like canola oil and olive oil, also help keep glycemic load down because they slow down digestion.  Red meat, high-fat dairy, and refined grains should always be kept to a minimum.

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