Randomized double-blind clinical trials for nutrition interventions are prohibitively expensive and lack commercial incentive due to non-patentable substances.

“Well, one problem is randomized double-blind clinical trials are hugely expensive. To get something through FDA, you have to spend a billion dollars. And nobody can afford that for nutrition. Nobody makes money out of nutrition. So it means that you might have a small clinical trial in some micronutrient, but you can't patent magnesium. You can't patent vitamin D.”