In his best selling book 'Bad Medicine’ Goldacre (2008) informs us that an untenable research design in its clinical trials skewed the results for the painkiller Vioxx leading it to be withdrawn from the market in 2004 after causing some 30,000 deaths among an estimated 88,000 to 139,000 victims of heart attacks caused by the drug.
Is current USDA bad science advice killing people?
Yesterday, Best Thinking featured an article that I wrote accusing the United States Department of Agriculture (USDA) of promoting the harmful bad science fallacies that 'spinach is a good source of iron' and that 'taking vitamin C with spinach will significantly make it an even better source of iron' (Sutton 2011a).
US nutrition expert Nestle (2007) has written extensively on the how the US food industry influences the USDA's nutrition advice, which is then disseminated on its extensive and authoritative website and relied upon throughout the world.
I suspect that we will never know the extent of the damage, if any, caused by USDA perverse promotion of spinach as a good source of iron.
What we do know is that USDA nutrition advice is so influential and trusted that it can be found reproduced and cited in tens of thousands of printed and Website nutrition guides. Just Google around for ten minutes on the subject of food and nutrition and you will see what I mean.
Research on the global problem of iron deficiency (Stoltzfus 2003) reveals that, globally, iron deficiency ranks in the top 10 among 26 risk factors included in the 'Global Burden of Diseases 2000':
‘ Iron deficiency accounts for 841,000 deaths and 35,057,000 disability-adjusted life years lost. Africa and parts of Asia bear 71% of the global mortality burden and 65% of the disability-adjusted life years lost, whereas North America bears 1.4% of the global burden. There is an urgent need to develop effective and sustainable interventions to control iron-deficiency anaemia. This will likely not be achieved without substantial involvement of the private sector.’
Can Popeye save us from iron deficiency?
I have in my hand a 13.5oz can of Popeye brand spinach from the USA. It says on the can that ½ a cup (115g and 1/3 of a can) contains 10% of the daily iron values recommended for someone on a 2000 calorie a day diet. Surely then that must mean that an entire can is being promoted as containing 30% of the total iron RDA for such a person. And so that must mean that three cans would be sufficient to provide 90% of their daily iron needs. For clarity, let me add that the USA food labeling guidance is based upon a non-pregnant woman aged 18-50.
So, perhaps the private sector can indeed help out with canned spinach?
Let’s check. First of all we need to ask how what it says on my can of spinach can possibly be true, when accepted orthodox scientific evidence has it that at best only 15 percent of the iron in spinach can be absorbed by people eating it.
We need to do the math, which, incidentally, is a subject Popeye often struggled with.
Current scientific knowledge is that we can absorb no more than 1 mg of the 6.6 mg of iron that is at most likely to be found in a standard 13.5 oz can of spinach (see Sutton 2011b). This means that if no other source of iron is available, a man aged 19-50 would in fact need to eat at least eight cans of spinach every day to get his required level of iron, a woman of the same age would need to eat 18 cans, and a pregnant woman would need to consume a nauseating 27, which - at 10 oz of solid matter per can when drained - is well over a stone (14 lb) of the stuff.
Science suggests spinach does not do what it says on the spinach can!
So in realty, it’s an unrealistically gut churning 18 cans per person a day that would in fact be required - and not three cans a day - to come close to providing the daily recommended iron for a non pregnant woman aged between 18 and 50 on the recommended 2000 calorie per day diet.
Death by Spinach?
If poor nutrition directly kills, and in other cases takes years from lifespans, it seems reasonable to speculate that erroneous nutrition advice, if relied upon, might do likewise.
We can only hope that not a single one of the tens of millions of lost years of life globally - and the many hundreds sometimes thousands of deaths that happen as a direct result of iron deficiency each year in the USA - are due to bad science promoted by the USDA. And we can only hope that the hundreds of thousands of deaths occurring each year on Earth (Stoltzfus 2003) from iron deficiency are not due to private sector and global USDA bad science promotion of spinach as a good source of iron. Because, surely, that should be 'criminal'.
Goldacre, B. (2009) Bad Science. London. Fourth Estate.
Nestle, M. (2007) Food Politics: How the food industry influences nutrition and health. University of California Press.
Suton, M. (2011a) Spin@ge II: Does the United States Department of Agriculture’s Publication of Spuriofacts Have its Origins in a Perverse Scientific Paper Written in 1937? http://www.bestthinking.com/articles/science/chemistry/biochemistry/spin-ge-ii-does-the-united-states-department-of-agriculture-s-publication-of-spuriofacts-have-its-origins-in-a-perverse-scientific-paper-written-in-1937-
Sutton, M. (2011b) SPIN@GE USA Beware of the Bull: The United States Department of Agriculture is Spreading Bull about Spinach, Iron and Vitamin C on the Internet: http://www.bestthinking.com/articles/science/chemistry/biochemistry/spin-ge-usa-beware-of-the-bull-the-united-states-department-of-agriculture-is-spreading-bull-about-spinach-iron-and-vitamin-c-on-the-internet