Monday, January 24, 2011

Blinded Wheat Challenge

Self-experimentation can be an effective way to improve one's health*. One of the problems with diet self-experimentation is that it's difficult to know which changes are the direct result of eating a food, and which are the result of preconceived ideas about a food. For example, are you more likely to notice the fact that you're grumpy after drinking milk if you think milk makes people grumpy? Maybe you're grumpy every other day regardless of diet? Placebo effects and conscious/unconscious bias can lead us to erroneous conclusions.

The beauty of the scientific method is that it offers us effective tools to minimize this kind of bias. This is probably its main advantage over more subjective forms of inquiry**. One of the most effective tools in the scientific method's toolbox is a control. This is a measurement that's used to establish a baseline for comparison with the intervention, which is what you're interested in. Without a control measurement, the intervention measurement is typically meaningless. For example, if we give 100 people pills that cure belly button lint, we have to give a different group placebo (sugar) pills. Only the comparison between drug and placebo groups can tell us if the drug worked, because maybe the changing seasons, regular doctor's visits, or having your belly button examined once a week affects the likelihood of lint.

Another tool is called blinding. This is where the patient, and often the doctor and investigators, don't know which pills are placebo and which are drug. This minimizes bias on the part of the patient, and sometimes the doctor and investigators. If the patient knew he were receiving drug rather than placebo, that could influence the outcome. Likewise, investigators who aren't blinded while they're collecting data can unconsciously (or consciously) influence it.

Back to diet. I want to know if I react to wheat. I've been gluten-free for about a month. But if I eat a slice of bread, how can I be sure I'm not experiencing symptoms because I think I should? How about blinding and a non-gluten control?

Procedure for a Blinded Wheat Challenge

1. Find a friend who can help you.

2. Buy a loaf of wheat bread and a loaf of gluten-free bread.

3. Have your friend choose one of the loaves without telling you which he/she chose.

4. Have your friend take 1-3 slices, blend them with water in a blender until smooth. This is to eliminate differences in consistency that could allow you to determine what you're eating. Don't watch your friend do this-- you might recognize the loaf.

5. Pinch your nose and drink the "bread smoothie" (yum!). This is so that you can't identify the bread by taste. Rinse your mouth with water before releasing your nose. Record how you feel in the next few hours and days.

6. Wait a week. This is called a "washout period". Repeat the experiment with the second loaf, attempting to keep everything else about the experiment as similar as possible.

7. Compare how you felt each time. Have your friend "unblind" you by telling you which bread you ate on each day. If you experienced symptoms during the wheat challenge but not the control challenge, you may be sensitive to wheat.

If you want to take this to the next level of scientific rigor, repeat the procedure several times to see if the result is consistent. The larger the effect, the fewer times you need to repeat it to be confident in the result.


* Although it can also be disastrous. People who get into the most trouble are "extreme thinkers" who have a tendency to take an idea too far, e.g., avoid all animal foods, avoid all carbohydrate, avoid all fat, run two marathons a week, etc.

** More subjective forms of inquiry have their own advantages.

20 comments:

James Holcomb said...

Part of the problem with measuring how you feel on a day to day basis particular to diet is that your "potential" to feel good or bad is different each day. There are far too many psychological variables to create a fair correlatation.

Tuck said...

There's another approach. Once you have an idea of how a particular food makes you feel, be aware of that feeling, and if you have that feeling, backtrack and figure out why.

I discovered that soy sauce, for instance, contains wheat after eating some sushi and getting stomach cramps.

I backtracked through the ingredients of that meal, discovered it contained soy sauce, and learned that soy sauce contains wheat (except for tamari, a traditionally wheat-free soy sauce).

I've since had the same experience with a number of other meals. Soups often contain flour as a thickener.

Might-o'chondri-AL said...
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David said...

In Europe, "gluten-free" products are defined as products that contain less than 20 mg/kg gluten (see Commission regulation No 41/2009). So the "gluten-free" bread might contain some gluten.

Nigel Kinbrum said...

Super-sensitive coeliacs may react to 20mg/kg of gluten. Non-coeliacs (>99% of the population) won't.

Elizabeth Walling said...

This also might be a good way to come out of a gluten-free period to get a more formative idea about how wheat affects you.

Ned Kock said...

Nice suggestions Stephan. It is indeed hard to get unbiased perceptions if one knows in advanced what she or he is eating. It would be interesting to test blind reactions to foods with markedly different GIs as well. Sometimes I hear normoglycemic folks saying that they have headaches after eating a high GI food. I can’t help but think that their minds are playing tricks on them.

Charlie said...

well, what would be fun is take the bread shakes, and then lie. Tell the subject it is filled with gluten, when it isn't. And vice-versa. And then watch the fireworks!

Our mind is our best diet tool!

SkolVikings said...

I guess I'm not sure why it matters if a reaction to particular foods is biased by the placebo effect?

Sure it would be bad if the bias leads to something harmful (e.g. never eating veggies because of the false belief they "give me the runs"). However if the bias leads to something neutral or beneficial, then I'm not sure I care.

Whether gluten really makes me sick, or if I just think it does so therefore it does (i.e. placebo effect), gluten is not something anybody needs to eat in order to be healthy. So while it might be interesting from a scientific perspective to determine if a gluten sensitivity is real or imagined, if the end result of eating gluten is sickness, just don't eat it!

Glenn Ammons said...

You should also try to guess each day which smoothie you drank, as a check on your blinding.

Might-o'chondri-AL said...
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Me said...

The concept is good but the implementation seems cumbersome. You can buy wheat gluten in a grocery store. Why not simply have your friend add some wheat gluten to your normal protein shake?

Great Lakes Unity said...

Might-o'chondri-AL - regarding your comment about sugar breaking the cortisol loop - is that why sugar helps "settle my stomach"? I often find if my gut is a little unsettled after a meal, that a little sugar helps set it to rights. (I have had irritable gut problems for several years.)

Might-o'chondri-AL said...
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pomo housewife said...

Might-o-condri-AL, your comments are very interesting but after a couple of reads I'm still not quite understanding what the upshot is in terms of what I should be doing for optimal gut health.

My impression is: plenty of vegetable fiber, natural iron sources (don't supplement?), minimal alcohol, and allow a little sugar if lectin-containing foods are consumed.

Avishek said...

I should check this, generally does anyone know how long it takes to develop problems with wheat? I am young and have neevr had problems, but I do not eat what anymore anyway from what I've heard. I therefore doubt that I will feel anything at all as my digestive system is still young and strong

TanyaL said...

Avishek--it really depends on the individual. My kids are 4 and 7 and are both wheat intolerant (not celiac). I'm 35, and also wheat intolerant, though avoiding it and working on my health for a few years has dramatically reduced my sensitivity/reactions. And I have no idea when my intolerance started.

Might-o'chondri-AL said...
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David said...

They sell empty gelatin capsules with carob content to opacify them. Why not fill a few capsules with whole wheat flour, and then a whole bunch with rice starch or other placebo. For two weeks take a set of, say, three capsules every day, with the set of wheat capsules in line to be taken on a random day selected by your friend. This would further reduce the chances that you would see through the blind, and it prevent the risk of not being able to choke the "smoothie" down. It would also keep it to wheat and nothing but wheat (except for the placebo starch).

Brian said...

I think a person doing this experiment might have a bad reaction in both cases, considering grain also contains phytic acid as well as lectin.