There are a barrage of research being published constantly and much of it has various problems from simply being early research that needs broader validation to having some strong conflict of interest. Today we will go over one of those papers that shows some promise but that we would normally skip. This way we hope while covering some interesting aspect of health and veganism we can also cultivate a critical eye that can be used everywhere else. This new research is comparing biomarkers of people on various diets, including vegans. While the results seem clear and simple when we dig deeper there are a lot of issues to discuss.
Overall the research paper found that vegans had higher plasma total carotenoid concentrations, linoleic acid, proportion of total omega-3 fatty acids, excretion of urinary isoflavones and enterolactone as well as lower relative abundance of saturated fatty acids including myristic, pentadecanoic, palmitic, and stearic acids then lacto-vegetarians, ovo-vegetarians or omnivores.
This all sounds promising but there are a few caveats that would have normally caused us not to discuss this paper yet. In all fairness, these issues are fairly common to many early research and are a normal part of building scientific consensus and knowledge. Nevertheless, as logic dictates since we need countless research papers to build scientific consensus we simply could not cover all of them so we usually overlook those early stage research papers, those with possible conflict of interest, or those with generally weaker scientific footing.
With regards to this research we had some issues with sample size. While the study has a large sample size the vegan sample size is small and generate sampling error of about 10%. Furthermore, the parent cohort study is comprised of only Seventh Day Adventist member which cannot be said to be a good random sample of the entire North American or vegan population. In addition, the field of biomarkers while not new has only been booming recently. For a broader discussion of biomarker please see "Dietary and health biomarkers-time for an update" (Dragsted, et al., 2017)
The boom in the usage of biomarker in recent nutritional research is partly due to technological improvement and cost reductions. However, the correlated studies that should be looking at what all this means, for example in terms of mortality rate and quality of life, are still lacking. It’s not always the case that more is better and higher level of various biomarker may not translate into statistically significant change in mortality rate. Nevertheless, it is a reasonable hypothesis that an increase level of certain biomarkers would result in some decrease in mortality rate.
It is important to look behind the headlines and investigate the research, more often than not the reality is not as clear as the headlines would have us believe. Nevertheless, early stage research like this is crucial in paving the way for others and to advance our scientific knowledge.