Hi all,
I am writing my MSc thesis on vitamin B deficiency and obesity and I've got my data from a study that looked at weight loss and satiety products.
They used a 3 day weighted diet diaries and I believe this isn't the best way of measuring micronutrient intake, considering that e.g. folate serum concentrations highly fluctuate when diet changes.
What would, in your opinion, be the golden standard for measuring vitamin intake? I am having a hard time finding papers looking at it, I found one that showed that 7 day diet diaries are better than FFQ, which I already knew.
Thank you for your help!
All methods for evaluating dietary intake have their own problems. As weighed food diaries give the most precise data short-term, they don't work very well for nutrients and food groups that have big variation in intake and in those cases FFQ usually gives better data. As you say, 7-day food diary is a precise methos and much better than 3-day diary, but it means a lot of work for the study participants, and reporting bias increases. On the other hand, vitamin B compounds are found in many different foods, and in thus 3-day food diary might give relatively good estimate of intake.
Maybe this systematic review could be helpful? https://pdfs.semanticscholar.org/7cc1/b80e52eb152f6aaa4d1a5e58979718f2ee12.pdf