Nutritional Science and the Problem of Proof
Competency # 20 Lifestyles of the Long-Lived
Reference: Reference: Robert Heaney, 2008 Atwater Lecture, J Nutrition 138:1591 Sept 08
Randomized Controlled Trials or RCTs! “That’s all we accept!” We claim to be “evidence based” in our science and we wait for RCT’s to guide what we do. There’s a problem with that in nutritional science. They don’t work! If we are waiting for the rigorous standards of RCTs to guide us in where we need to go, we are waiting for Godot. It will never happen. Here’s the nugget why.
1.RCTs are designed for NEW drugs introduced to your system. Nutritional parts of your life are not new, they are key to your living. They’ve been around since Adam and Eve…You don’t introduce them as much as see whether different levels affect outcomes. You can’t give protein versus placebo.
2.Short latency versus long latency. New drugs work in a day or two, if not faster. That’s easy to measure. Nutritional components are very long latency in their effect. If you are short of protein, your body can borrow from your muscles. If you are short of calcium, you borrow from your bones. It can takes years to recognize and develop problems.
3.Single effect versus multi-factorial. An introduced drug can be targeted to work on ONE system. By definition, nutritional components relate to EVERY cell in your body. They are so multi-factorial that teasing out what’s ideal and what isn’t is hard. Vitamin D works on every cell in your body.
4.Then we have the dilemma of making a comparison. It’s not ethical to intentionally expose people to a suboptimal amount, if you really believe it to be suboptimal. That means you are left working with a little versus a lot. What’s the ideal? It’s hard to tease out.
5.Drugs are designed for SICK people. Nutrients are for WELL people. It’s a different audience. AND: as soon as you see differences between the groups, the positive effect of the treatment has not been accepted as a reason to terminate research, in the same way that negative effects terminate research with drugs. Dr Heaney stopped his Vit D research when he found a 76% reduction in cancer in the D and calcium group, and was critiqued for it.
There is also confusion about what endpoints we are looking for. Our labeling of food makes us focus on what we shouldn’t have, like food is your enemy. Don’t eat too much of this or that, while ignoring what you should eat. It’s a negative message. On top of that, our nutritional community puts out literature on what is the very minimum you need to prevent short latency disease. It’s an odd approach based on the era of vitamin research. It’s not focused on finding the optimal level that reduces long-term disease.
WWW: What will work for me? I’m trying to think about how we add this complexity with nutritional science to our review of what’s new. I’m looking for what’s optimal, long-term and comparing populations, with a multi-factorial balance. I think our research will come to that. Dr. Heaney is a genius! It was his randomized controlled trial (RCT) of Calcium and Vitamin D that found such a huge effect on cancer.