40 migrane sufferers participated in a random trial comparing 2 treatments : 1.dietary restriction(low fat vegan diet for 4 weeks followed by elimination & reintroduction of trigger foods for 8 weeks), &

2. a placebo supplement for 16 weeks. Participants completed both treatments in a random order, so that 50% took supplement for 16 weeks first & then followed dietary restrictions for the next 16 weeks. The other half of participants completed treatments in opposite order.

a)Were subjects blind? justify

b) Participants were told that the placebo supplement contain omega-3 oil's and vitamin E that are known to be anti-inflammatory. However, the participants didn't know that concentrations were too low to have any clinical impact. Was this a good choice of placebo or not? Why or why not?

c) headache was significantly lower for subjects during the dietary restriction.. Can researchers conclude that low fat vegan diet causes a reduction in pain?