Because most plant-based foods are under “plants” instead of “food” in PubMed, articles on chocolate may not be retrieved in a search for Food.

By Eric Rumsey, Janna Lawrence and Xiaomei Gu

As we’ve written, searching for plant-based foods (PBFs) in PubMed is difficult because of the way the MeSH system is organized. This is especially the case because because in most cases PBFs are treated as plants rather than food.

One result of treating plant-based foods as plants is that the MeSH term is usually the botanical plant name; in the case of chocolate it’s Cacao. This is usually not a serious problem when searching for specific substances because the common food name maps to the botanical MeSH term.

A more serious consequence of treating plant-based foods as plants instead of foods is that they are usually not in any food-related explosion, but only in the Plants explosion. So the only occurrence of chocolate (Cacao) is here:

Plants
   Angiosperms
      Sterculiaceae
         Cacao

The reason this is a problem is because articles on chocolate/Cacao will not be retrieved in a search for Food. So, for example, if you do a general search for food-related causes of migraine, you will not retrieve this article:

Chocolate is a migraine-provoking agent
Journal: Cephalalgia
http://www.ncbi.nlm.nih.gov/pubmed/1860135

This is not retrieved by searching for food because Cacao is not in the Food explosion. More broadly, however, it’s also not retrieved by the Diet, Food, and Nutrition explosion.

Here are several other articles on health and medical aspects of chocolate that are not retrieved by the broad Diet, Food, and Nutrition explosion:

• Chocolate consumption modulates cytokine production in healthy individuals.
  Journal: Cytokine.
  http://www.ncbi.nlm.nih.gov/pubmed/23465690
• Protective effects of flavanol-rich dark chocolate on endothelial function and wave reflection during acute hyperglycemia.
  Journal: Hypertension.
  http://www.ncbi.nlm.nih.gov/pubmed/22851734
• Chocolate and coronary heart disease: a systematic review.
  Journal: Curr Atheroscler Rep.
  http://www.ncbi.nlm.nih.gov/pubmed/21894553
• Supraventricular tachycardia induced by chocolate: is chocolate too sweet for the heart?
  Journal: Am J Emerg Med.
  http://www.ncbi.nlm.nih.gov/pubmed/21871761
• Chocolate consumption in pregnancy and reduced likelihood of preeclampsia.
  Journal: Epidemiology.
  http://www.ncbi.nlm.nih.gov/pubmed/18379424

If chocolate were the only case of a plant-based food that is not retrieved in a broad PubMed search for food-related topics, it would be a trivial matter. But that’s far from being the case. There are many plant-based foods that have the same problem in PubMed. We have written about a few of these.

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