Two recent studies are getting a lot of popular attention online. Both studies showed that vegetarians had lower mortality than nonvegetarians. The studies join a large number of similar studies. Although vegetarians as a group do have a lower mortality than nonvegetarians, it probably is not because they exclude all animal products, which is the usual implication. It is most likely because vegetarians have a higher potassium to sodium ratio in the foods they eat.
These two articles are excellent examples of how individual articles need a framework so they can be understood in context. The first article (1) was out of England. The study included a larger number of vegetarians than most studies. Over 15,000 of the over 44,000 participants were vegetarians. Consequently, this meant that the authors were able to compare vegetarians and nonvegetarians with similar other characteristics, such as exercise, smoking, and alcohol consumption. And they showed that the vegetarians were less likely to be hospitalized or die from ischemic heart disease.
The second article (2) was a Seventh Day Adventist study of 73,308 subjects. And it studied various degrees of vegetarianism. The authors compared nonvegetarian, semi-vegetarian, pesco-vegetarian, lacto-ovo-vegetarian and vegan. The conclusion was that vegetarian diets are associated with lower mortality. Accordingly, the implication is that avoidance of meat is desirable. However, the lowest mortality was found in the pesco-vegetarians. If animal products are the source of worse mortality, this group should not have the lowest mortality. Vegans should have lower mortality than those with any animal products.
How You Divide Data Makes A Difference
A pair of reports (3) we discussed previously had similar findings. One report showed that vegetarians had a lower mortality than nonvegetarians. However, the second report showed that pesco-vegetarians and lacto-ovo-vegetarians had a lower mortality than pure vegans. What was interesting in these reports is that both reports were on the same group of people. In this case, the researchers simply divided the data differently in the two reports.
Processed Meat Clue
Another recent study (4) gives a clue about what goes on with these large population studies. This particular study included more than 448,000 people. In brief, they found a mortality correlation with processed meat. And the higher the processed meat consumption, the worse the mortality.
For the most part, red meat eaters tended to also eat processed meat, and thus did worse. But eliminating the processed meat effect for the red meat eaters eliminated their higher mortality. Additionally, poultry consumption did not lead to higher mortality.
Specifically, processed meat has a very high ratio of sodium to potassium. Other factors in meat processing may also contribute to the problem, such as nitrosamines, aromatic hydrocarbons, and amines. But neglected in the majority of studies is the ratio of sodium to potassium in the diet. Processed meat consistently has a horribly poor ratio of sodium to potassium. See the sausage and processed meat table here.
Emerging Areas Of Knowledge
There is increasing knowledge concerning phytochemicals, antioxidants, AGEs and other substances in our food. The relationship of genetics to nutrition (nutrigenomics) is slowly emerging. Eventually this knowledge can be put into a framework to show the relative importance of each of these factors. But, at present their relative importance is unclear.
Potassium To Sodium Ratio Has Clear Effects
However, there is a very clear framework for the relation of sodium to potassium in our food, and how it affects our body. Until they can be placed in a framework, the studies of these other components remain isolated bits of information. But the evidence for the role of food's potassium to sodium ratio in hypertension, cardiovascular disease, osteoporosis and kidney stones is strong. And it presents a clear, consistent story.
Next post we will present an overview of the framework for the potassium to sodium ratio that has been assembled by researchers throughout the world. Putting the research done on how potassium and sodium affect the cell, the organs, and hormones together with large epidemiological and historical studies gives a very clear framework into which many otherwise unclear studies can be placed.
1. Risk of hospitalization or death from ischemic heart disease among British vegetarians and nonvegetarians: results from the EPIC-Oxford cohort study. Crowe FL, Appleby PN, Travis RC, Key TJ. Am J Clin Nutr. 2013 Mar;97(3):597-603. doi: 10.3945/ajcn.112.044073. Epub 2013 Jan 30.
2. Vegetarian Dietary Patterns and Mortality in Adventist Health Study 2. Michael J. Orlich, MD; Pramil N Singh, DrPH; Joan Sabaté, MD, DrPH; Karen Jaceldo-Siegl, DrPH; Jing Fan, MS; Synnove Knutsen, MD, PhD; W. Lawrence Beeson, DrPH; Gary E. Fraser, MBchB, PhD. JAMA Intern Med. 2013;():1-8. doi:10.1001/jamainternmed.2013.6473. Published online June 3, 2013
4. Meat consumption and mortality–results from the European Prospective Investigation into Cancer and Nutrition. Rohrmann S, Overvad K, Bueno-de-Mesquita HB, Jakobsen MU, Egeberg R, Tjønneland A, Nailler L, Boutron-Ruault MC, et al. BMC Med. 2013 Mar 7;11:63. doi: 10.1186/1741-7015-11-63.