For example, the matching of food with nutrient for B12. The abstract says…
…but if we go to bottom of page 5, we find…The associations of vitamin B12, vitamin D and ω-3 PUFA with PiB retention were independent of gender, APOE and family history. The identified nutrient combination was associated with higher intake of vegetables, fruit, whole grains, fish and legumes, and lower intake of high-fat dairies, meat and sweets.
So I would think that their data suggest that meat, eggs and butter were good because they are good for B12, but no. Later on on page 6 in the Discussion, the authors make a general statement anchored by references, but do not reference the data… then follow it with a 'consistent with' statement that does reference their own data and a call to get more data...Correlations between nutrients associated with PiB and food groups showed that vitamin B12 was mainly from meat, eggs and butter with correlation coefficients of 0.35, 0.31 and 0.36, respectively, (p<0.04). Vitamin D was mostly from low-fat dairies and fish (0.64 and 0.55, p<0.001), and ω-3 PUFA EPA from fish and other vegeta- bles (0.36 and 0.31, p<0.01).
So isn't there an inconsistency in their own data and conclusions? Do I miss something? On this aspect, although I think they gathered good data, it's one of those cases where actually digging deeper into the data would be required. Specifically, the details of how they mapped foods to nutrients may be key.Despite differences in the analytic approaches, high adherence to dietary patterns charac- terised by higher intakes of fruits, vegetables, fish, nuts and legumes, and lower intake of meat, high-fat dairies and sweets, is consistently associated with reduced risk for AD.3 4 21 55–59 The food sources associated with the nutrients identified as being AD protective using brain PET in this study are consistent with prior epidemio- logical findings. Other studies are needed to test for spe- cific associations between PET biomarkers, specific food groups and risk for AD.
On another aspect, I, too, was at first confused by whether increased or decreased brain glucose metabolism was good or bad. The authors do make it clear that they (and the literature) think that increased glucose metabolism is desirable. Seems like it might be important to understand what exactly this FDG-PET Scan is actually measuring. Off to do a little googling...