Dear Dr. Cannell:
I suspect that a great proportion of those taking a supplement only take the officially recommended level of 400 IU up to 1000 IU, so having little effect on blood levels and their health. It is the recommendation that baffles me! “Food-based strategies, including fortified foods, need to be explored.” Hasn’t this approach really failed in the US?
How can you get the required levels up by adding a bit to milk? Or even bread? How can that be controlled given the diets of the average American or Irishman or New Zealander? The “add a bit to food” is fine if you want to prevent rickets but we now know that adequate levels of around 50-70 ng/ml are required/normal for full protection against many modern diseases.
Surely two things must be at the basis of an extensive public health promotion: In the summer get more sunshine and in the winter, take a supplement of 5000 IU per day.
Sally, New Zealand
Adequate food fortification will not solve the problem but has the potential to do enormous good. Remember, most studies show raising your level from 5 ng/ml to 20 ng/ml is where most (not all) of the good is done.
In the USA, food fortification has failed because of dose and the food we fortify the most, milk. Many of the people with very low levels, such as Blacks, seldom drink milk due to fear of lactose intolerance. These days, mothers usually wean toddlers on juice and not milk. However, both Blacks and toddlers eat cheese, cereal, yogurt, juice, bread, cookies, eggs, butter, and meat at the same frequency as white adults.
In tackling this public health problem, as many approaches as possible are needed. Supplementation and sun exposure by people like you and other health conscious persons is very important. Those taking a 400 IU supplement will eventually increase their dose as more research comes out. However, we cannot ignore the 50% of people who will not take a supplement or sunbathe.
For those people, food fortification of multiple foods will do tremendous good, although in my opinion, few will obtain natural vitamin D levels from food fortification. Say there was a 200 IU/serving in cheese, yogurt, juice, cereal, bread, meat, cookies, eggs, butter, and even beer (as was done in the USA in the 1930s). Many people would get a 1,000 IU/day or even more from food and that would be a very good thing.
In the next ten years, the best we could hope for with food fortification is to get 97% of people above 20 ng/ml. While inadequate, it is so much better than 5 or 10 ng/ml that it is not a failure just because it is not perfect. Why the recent Food and Nutrition Board did not recommend food fortification to get Blacks and toddlers above their lower limit of 20 ng/ml, is any one’s guess. While perfect is better than good, remember what Voltaire said: “Perfect is the enemy of good.”